Urban Nutrient

Management
Handbook
 Urban Nutrient
Management
Handbook
Content Coordinators:
Michael Goatley Jr., Professor,
Crop and Soil Environmental Sciences, Virginia Tech
Kevin Hensler, Research Specialist Senior, Crop and
Soil Environmental Sciences, Virginia Tech
Published by:
Virginia Cooperative Extension
Project funded by:
Virginia Department of Conservation and Recreation
Produced by:
Communications and Marketing,
College of Agriculture and Life Sciences,
Virginia Polytechnic Institute and State University
Director:
Thea Glidden
Copy Editor:
Bobbi A. Hoffman
Assistant Editor:
Liz Guinn
Layout:
Christopher Cox

This material is based upon work supported by the Virginia Department of Conservation
and Recreation, under Agreement 50301-2009-01-SF. Any opinions, findings, conclusions
or recommendations expressed in this publication are those of the author(s) and do not
necessarily reflect the view of the Virginia Department of Conservation and Recreation.

May 2011
 Table of Contents

Chapter 1. The Objectives of Turf and Landscape Nutrient Management

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
What Is Nutrient Management? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Improving Water Quality Through Turf and Landscape Nutrient Management. . . . . . . . . . . . . . . . . . . . . 1-4
Literature Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

Chapter 2. General Soil Science Principles

Soil Formation and Soil Horizons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Soil Physical Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Soil Organic Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Soil-Water Relationships. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Essential Elements for Plant Growth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
Soil Survey. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
Literature Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13

Chapter 3. Managing Urban Soils

What Is an Urban Soil?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Urban Soil Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Types of Urban Soil Materials and Their Variability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Common Soil Limitations in the Urban Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Managing Urban Soils and Their Limitations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Acid Sulfate Soil Conditions and Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Soil Conditions in Highway Rights-of-Way. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
Manufactured Soils. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
Modified Soils and Mulches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
Literature Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12

Chapter 4. Basic Soil Fertility

Plant Nutrition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Soil pH, Nutrient Availability, and Liming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Nitrogen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
Phosphorus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
Potassium. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
Secondary Plant Nutrients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
Micronutrients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
Acknowledgement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14

Urban Nutrient Management Handbook I

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Chapter 5. Soil Sampling and Nutrient Testing

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Soil Test Interpretation and Recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Soil Sampling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Understanding Soil Test Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
Plant Analysis as a Diagnostic Tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Nutrient Monitoring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Sampling Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8
Interpreting a Plant Analysis Result. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8
Literature Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8

Chapter 6. Mid-Atlantic Turfgrasses and Their Management

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Primary Cool-Season Grasses of Importance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Primary Warm-Season Grasses of Importance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Native Turfgrasses and Specialty Use Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Turfgrass Establishment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
Maintenance Fertility Programs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14
Mowing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18
Literature Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19

Chapter 7. The Ornamental Landscape

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
Site Assessment and Environmental Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
Correct Plant Selection and Planting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Determining the Need to Fertilize. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Soil Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3
Factors Affecting Nutrient Uptake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3
Fertilizers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3
Specific Fertility Needs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6
Fertilizer Calculations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7
Fertilizer Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7
Organic and Other Soil Amendments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-10
Nutrient Deficiencies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-10
Literature Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-11
Appendix 7-A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-13
Appendix 7-B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-15

II Urban Nutrient Management Handbook

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Chapter 8. Fertilizer and Lime Sources for Turf and Landscapes

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
Defining Fertilizers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
Nitrogen Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2
Phosphorus Fertilizer Sources and Fertility Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7
Potassium Fertilizer Sources and Fertility Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8
Calcium, Magnesium, and Sulfur Fertilizer Sources and Fertility Guidelines. . . . . . . . . . . . . . . . . . . . . . 8-9
Micronutrient Fertility Sources and Fertility Guidelines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10
Liming Materials and Chemical Composition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10
Best Management Practices for Water Quality Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12
Literature Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-13

Chapter 9. Organic and Inorganic Soil Amendments

Introduction to Organic Amendments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1
Sources of Organic Amendments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1
Processes for Generating Organic Amendments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1
Composition of Organic Amendments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2
Factors That Affect Nutrient Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6
Uses of Organic Amendments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7
Organic Byproduct Summary With Regard to Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-13
Inorganic Materials for Amending Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-13
Inorganic Amendment Use Strategies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-14
Topdressing With Inorganic Amendments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-15
Literature Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-16

Chapter 10. Equipment Calibration and Fertilizer Application Methods

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1
Dry Fertilizer and Application Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1
Broadcast (Rotary) Spreader Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4
Liquid Fertilizers and Sprayer Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-7
Literature Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-10

Chapter 11. Soil-Water Budgets and Irrigation Sources and Timing

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1
The Hydrologic Cycle and Soil-Water Budgets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1
Watering Basics for Turf and Landscape Plantings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3
Water Reuse: Using Reclaimed Water for Irrigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-4
Literature Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-7

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Chapter 12. Principles of Stormwater Management for Reducing

Nutrients From Urban Landscaped Areas
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1
Introduction to Stormwater Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1
Managing Urban Stormwater. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-8
Managing Stormwater on a Residential Lot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-9
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-13
Literature Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-13
Appendix 12-A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-15
Appendix 12-B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-19

Chapter 13. Turf and Landscape Nutrient Management Planning

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1
Assessment of Planned Areas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1
Initial Client Visit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-3
Components of a Nutrient Management Plan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-5
Sample Nutrient Management Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-9
Plan Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-24
Plan Revision. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-25
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-25
Literature Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-25

IV Urban Nutrient Management Handbook

 Chapter 1. The Objectives of Turf and Landscape Nutrient Management

Chapter 1. The Objectives of Turf

and Landscape Nutrient Management
Steven Hodges, Professor, Crop and Soil Environmental Sciences, Virginia Tech
Michael Goatley Jr., Professor and Extension Specialist, Crop and Soil Environmental Sciences, Virginia Tech
Rory Maguire, Associate Professor, Crop and Soil Environmental Sciences, Virginia Tech

1. The overall climate (rainfall patterns) of a particu-

Introduction lar location and the variability in topography, such
The locations of many towns and cities in the mid-Atlan- as aspect, slope, elevation, etc.
tic region are closely linked to a clean, readily available,
and abundant water resource. The water source must be 2. An understanding of the plant material’s periods of
sufficient in size and quality to meet the daily life needs active growth and its inherent growth rate.
of the general population at home (e.g., drinking, cook- 3. The physical and chemical characteristics of the
ing, cleaning, leisure, etc.) and its industrial base (e.g., soil as determined by soil testing (an absolute
transportation/shipping, cooling/heating, manufactur- requirement for an NMP) and/or review of soil
ing applications as a solvent/diluent, etc.). maps (where appropriate).
By nature, urban areas are frequently undergoing either 4. The intended use of the plant material.
expansion and/or renovation in both commercial and/
or residential development. Expansive development in 5. The selection and application of the nutrient
rolling topography requires significant soil disturbance. source.
Soils that took millions of years to form are quickly 6. Consideration of the surrounding environment
altered and/or removed during construction, eliminating and how it can either impact or be impacted by
sod cover and forested areas that are naturally occurring fertilization.
water filtration and soil stabilization systems. Expan-
sions in roof area and paved surfaces increase the need An NMP considers each of these factors and presents a
for comprehensive stormwater management planning. recommendation for the selection and timing of nutri-
ent applications that meets the needs of the plant and
By law, soil disturbance, therefore, must be accompa-
minimizes the loss of nutrients to the environment.
nied by appropriate stormwater management strategies
(e.g., silt fences, compost berms, natural and synthetic
erosion-control mats, etc.) that are designed to protect What Is Nutrient Management?
water quality and minimize soil erosion and sediment Nutrient management plans serve two primary pur-
loss. poses: (1) ensuring that plants have optimum soil nutri-
In the final stages of both commercial and residential ent availability for good productivity and quality, and
development, an urban ecosystem intermingles grasses, (2) ensuring minimum movement of nitrogen and phos-
groundcovers, shrubs, ornamental plants, and trees with phorus from the specified area of application to surface
the structural and hardscape (e.g., sidewalks, parking and groundwaters where they can potentially have a
lots, driveways, streets, etc.) components. This myriad detrimental effect on water quality. Although NMPs
of urban landscape components results in many recom- cover more than nitrogen and phosphorus, only these
mendations regarding appropriate plant material selec- two nutrients are considered a risk for impairing water
tion and management protocol. Due to the complexity quality. Other nutrients are essential for plant growth
of plant materials, the abundance of hardscapes, and but do not cause water quality problems in the mid-
the proximity of water sources, urban ecosystems have Atlantic region.
great potential to negatively impact water quality if Most soils in the mid-Atlantic are highly weathered and
managed inappropriately. All plant materials have nutri- low in plant-available nutrients, particularly nitrogen,
ent requirements, but the levels and timing of applica- phosphorus, and potassium. Some form of fertiliza-
tions of nutrients are highly variable and plant-specific. tion is required for even the lowest quality turfgrass,
The following factors are a few of the most important if only to maintain a functioning turfgrass population
to consider in the development and implementation of a that will protect the soil from erosion. Turf stands sub-
nutrient management program (NMP): jected to high traffic and intensive use require regular

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 Chapter 1. The Objectives of Turf and Landscape Nutrient Management

fertilization to maintain functionally adequate levels of Knowledge of the physical and chemical characteris-
leaf density, vigor, recuperative potential, stress toler- tics of nutrient sources can prove invaluable in calcu-
ance, and color. Similarly, ornamental landscape plants lating application rates, reducing fertilizer costs, and
require appropriate fertilization and cultural manage- managing applications to minimize potential for losses
ment strategies in order to optimize their aesthetic and through volatilization, runoff, and leaching. Most soil
functional uses. The challenge of nutrient management test reports will provide specific recommendations
is to consider the characteristics of the turfgrass and regarding appropriate fertilizer and/or liming materials
landscape plants being grown on each specific site and to address soil limitations. However, a greater under-
then make appropriate decisions regarding the timing, standing of fertilizer sources, their characteristics, and
material, and application method of required nutrients. their appropriate use (information presented in chapters
8 and 9) is invaluable in optimizing nutrient manage-
Nutrient management plans also have economic con-
ment strategies. For instance, knowing that prilled urea
siderations, because there are both savings and costs
can volatilize under existing conditions may lead you
involved in the process. One cost may be hiring a certi-
to choose another nitrogen source, a different applica-
fied nutrient management planner to write a plan. Some
tion method, or a best management practice (e.g., irri-
lawn care companies and other consultants may offer
gating immediately after application) to reduce volatile
free nutrient management planning as part of their ser-
nitrogen losses. In other situations, a slow-release
vice. Making extra trips to apply nitrogen, purchasing
nitrogen source might be most appropriate because of
different fertilizer materials to meet specific recommen-
an anticipated rainy season or the inability to deliver
dations, setting aside buffer areas along water bodies,
suitable levels of readily available nitrogen sources on
etc., could all potentially increase a client’s budget. By
a frequent basis.
implementing an NMP, savings accrue from avoiding
the purchase and application of unnecessary fertilizer There is a great deal of interest in expanding the use of
and lime. There may also be savings from greater plant organic compounds (both fertilizers and soil amend-
survival because nutrient deficiency will be avoided. ments), and information in this handbook will detail
Nutrient management planning is also expected to how to properly utilize these materials in responsible
have a societal economic benefit by maintaining high- plant management programs. Organic sources are per-
quality water for drinking, ecological, and recreational ceived by most to be “environmentally friendly,” and
purposes. generally speaking, this is true. Organic fertilizers and
amendments are often an effective way of recycling
A brief overview of the basic components of nutrient
waste products and they also can improve the physical,
management planning and implementation follows.
chemical, and biological aspects of soils. However,
consider that organic sources almost always contain
Selection of Nutrient Sources phosphorus, and if a soil test shows that no phospho-
There are substantial differences in nutrient require- rus is needed, then an organic fertilizer does not fit
ments between plants and also in the time nutrients are the requirements of an NMP. Instead, an inorganic
required. For example, legumes can produce their own fertilizer containing no phosphorus would be a bet-
nitrogen and therefore do not require nitrogen fertiliza- ter fertilizer selection. Knowledge of nutrient sources
tion, making them a popular component of highway will greatly improve your management options and
rights-of-way vegetation where there is no desire to sup- capabilities.
ply additional nitrogen after establishment. However,
cool- and warm-season grasses (discussed in chapter 6) Nutrient Application Rates
require nitrogen, but their periods of maximum growth
Nutrient needs for turfgrasses and landscape materials
differ, resulting in different timing of optimal nitrogen
are based on Virginia Cooperative Extension and land-
applications.
grant university research. Nutrient application rates for
The age of plants is also important because mature plan development are determined differently for nitro-
plants with well-developed root systems require fewer gen compared to phosphorus and potash. Nitrogen rates
nutrients than young plants. This is often realized for are determined on an annual basis and are specific to
phosphorus recommendations when they are typi- the plant species, the use of the plant material, and the
cally greater for plant establishment than they are for management area. For turf, nitrogen rates are often spe-
maintenance. cific to the plant species; for instance, whether it is a

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 Chapter 1. The Objectives of Turf and Landscape Nutrient Management

heavy or light nitrogen feeder. In cool-season grasses, Sound fertility programs are obviously not based on
Kentucky bluegrass has a higher seasonal nitrogen nitrogen alone, because any excess or deficiency of
requirement than does fine-leaf fescue. In warm-season other nutrients can negatively affect plant health and
grasses, bermudagrass responds to aggressive nitrogen survival. The annual requirements of most other macro-
programs whereas zoysiagrass requires much smaller nutrients (those required in large quantities) such as
amounts annually. The use of the turf is also an impor- phosphorus, potassium, calcium (Ca), and magnesium
tant factor in seasonal application rates, with lawns (Mg) are applied based on current soil test results. In
often utilizing a simple nitrogen program involving rel- conjunction with an appropriate pH, soil levels of these
atively low annual nitrogen rates and a limited number nutrients are maintained within a range that assures
of applications per growing season. an adequate supply of these nutrients to provide good
turf growth and quality. Similar to nitrogen, excessive
On the other hand, athletic fields and golf courses will applications can be damaging to the plant, resulting in
have higher annual nitrogen application rates with nutrient imbalances and, particularly for phosphorus,
more frequent applications. Higher rates are often the potential to negatively impact water quality.
required due to the foot and vehicular traffic associ-
ated with areas of concentrated play at these facilities. Nutrient Application Timing
Intensive management of these areas enables the turf
to recover from constant, and, in some cases, dam- Ideally, nutrient applications should be timed to maxi-
mize use efficiency by the targeted plants (VDCR
aging use and often includes the practice of “spoon
2005). To minimize losses, it is important to closely
feeding” (very low, but frequent applications) nitro-
match growth cycles and nutrient demands. Proper tim-
gen over the course of the growing season as a key
ing is especially important to prevent losses on soils
component in maintaining acceptable turf. Experi-
with high leaching or runoff potential. From the view-
enced turf professionals are constantly evaluating
point of the plant, appropriate timing of the first and last
their nitrogen programs as the turf they manage reacts
applications in the growing season is crucial to plant
and responds to daily use and seasonal changes. The health, survivability, disease, stress tolerance, and so
relationship between nutrient application and overall forth.
turf and landscape plant quality (and often density for
grasses) is used to make the appropriate adjustments
in their fertility programs. Nutrient Placement and Application
Methods
Is it possible for turf to negatively impact the environ-
For turfgrass, a variety of application methods may be
ment if it is inadequately fertilized? Certainly. Inade-
used, depending on the situation. For turf establish-
quately fertilized turfgrass can be too weak to recover
ment, broadcast application followed by incorporation
from environmental stress or pest attack. Turf that is
is commonly used for lime and fertilizer amendments.
thin, weak, and spindly due to lack of adequate nitrogen
Surface applications of granular fertilizers on new
levels is considered to be “hungry” and can experience
plantings and established turf may be made using truck-
soil loss due to inadequate soil cover. Experienced turf
mounted, push-type rotary, or drop spreaders, depend-
managers identify a “hungry turf” not just by its color, ing on the size of the area to be covered. In addition,
but also by its growth rate and its ability to recover from liquid fertilizers and foliar nutrients may be sprayed.
pest or environmental stress. New equipment can even vary the rate of application
However, the part of turfgrass management that gets the in conjunction with global positioning systems (GPS)
most attention when it comes to environmental impact and preprogrammed application maps. Each method
is excessive fertilization. Excessive nitrogen applica- has advantages, such as increased labor efficiency,
tions increase plant succulence, making the turf more improved application precision, and reduced potential
susceptible to environmental stress (e.g., heat, cold, for nutrient losses.
and moisture extremes) and pest attack, and overall, A nutrient management plan should also include the
less wear-tolerant. Overfertilization of nitrogen leads to detailing of site characteristics that require changes in
excessive shoot and stem growth at the expense of root management from place to place. Considerations should
growth. And of course, excessive applications of nitro- include environmentally sensitive areas such as buffers
gen increase the potential that it enters a water source and water bodies and significant differences in soils,
and becomes a pollution hazard. vegetative cover, management intensity, and potential

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 Chapter 1. The Objectives of Turf and Landscape Nutrient Management

nutrient loss pathways. Finally, best management prac- This handbook provides a series of chapters devoted to
tices to prevent or reduce losses of soil, nutrients, and the challenges associated with water quality protection
plant protection chemicals should be identified for each in an urban environment. It presents extensive informa-
of these areas and the site as a whole. tion on the basic principles in soil and plant sciences,
fertility and fertilizers, plant management, soil amend-
ments, equipment calibration for fertilizer delivery,
Improving Water Quality irrigation sources and quality, and stormwater manage-
Through Turf and Landscape ment. A standard NMP format is provided in the chap-
ter 13. A certified nutrient management planner will
Nutrient Management combine the information from a soil test with extensive
A primary goal of turf and landscape nutrient manage- agronomic knowledge of plants, soils, fertilizers, nutri-
ment is water quality protection. Appropriate product tion, and the climate in developing the NMP. Incor-
selection, delivery rate and timing, and method of appli- porating this information into the design, installation,
cation are by far the most important variables in water and management of urban soils and plant materials will
quality protection in urban landscape management. The greatly improve water quality.
development and implementation of a nutrient man-
agement plan also provides potentially significant eco-
nomic savings as applications are made based on soil Literature Cited
test recommendations. Similarly, since soil test data are Virginia Department of Conservation and Recreation
used in developing the plan, plant health and perfor- (VDCR), Division of Soil and Water Conservation.
mance will also be enhanced on the basis of scientific 2005. Virginia Nutrient Management Standards
data. Nutrient management plans allow for informed and Criteria, 96-107.
decisions to be made regarding fertilization such that
plant health and function are optimized in an environ-
mentally responsible manner.

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 Chapter 2. General Soil Science Principles

Chapter 2. General Soil Science Principles

W. Lee Daniels, Professor, Crop and Soil Environmental Sciences, Virginia Tech
Kathryn C. Haering, Research Associate, Crop and Soil Environmental Sciences, Virginia Tech

discussed below) can form in several months to years.

Soil Formation and Soil Horizons More detail on parent material and soil relationships in
our area can be found at www.mawaterquality.org/pub-
Introduction and Soil Composition lications/pubs/manhcomplete.pdf.
Soil covers the vast majority of the exposed portion of
the earth in a thin layer. It supplies air, water, nutrients, The rate and extent of parent material and soil weather-
ing depends on:
and mechanical support for the roots of growing plants.
The productivity of a given soil is largely dependent 1. T
 he chemical composition of the minerals that make
on its ability to supply a balance of these factors to the up the rock or sediment.
plant community.
2. T
 he type, strength, and durability of the material that
A desirable surface soil in good condition for plant holds the mineral grains together.
growth contains approximately 50 percent solid mate-
3. The extent of rock flaws or fractures.
rial and 50 percent pore space (figure 2.1). The solid
material is composed of mineral material and organic 4. The rate of leaching through the material.
matter. Mineral material comprises 45 to 48 percent of
the total volume of a typical mid-Atlantic soil. About 2 5. The extent and type of vegetation at the surface.
to 5 percent of the volume is made up of organic matter, Physical weathering is a mechanical process that occurs
which may contain both plant and animal residues in during the early stages of soil formation as freeze-thaw
varying stages of decay or decomposition. Under ideal processes and differential heating and cooling break up
moisture conditions for growing plants, the remaining rock parent material. After rocks or coarse gravels and
50 percent soil pore space would contain approximately sediments are reduced to a size that can retain adequate
equal amounts of air (25 percent) and water (25 per- water and support plant life, the rate of soil formation
cent) on a volume basis. increases rapidly. As organic materials decompose in
the surface soil, the evolved carbon dioxide dissolves
in water to form carbonic acid — a weak acid solu-
tion that constantly bathes weatherable minerals below.
The carbonic acid reacts with and alters many of the
primary minerals in the soil matrix to chemically alter
and etch the sand and silt fractions and to produce sec-
ondary clay minerals. The decomposing organic matter
also releases other organic acids (e.g., oxalic, citric, and
tartaric) that further accelerate weathering (Brady and
Weil 2008).
As soil-forming processes continue, some of the fine
Figure 2.1. Volume composition of a desirable surface soil. clay soil particles (smaller than 0.002 mm) are carried,
or leached, by percolating water from the upper por-
Soil Formation tions of the soil (topsoil) down into the lower or subsoil
layers. As a result of this leaching action, the surface
The mineral material of a soil is the product of the
soil texture becomes coarser and the subsoil texture
weathering of underlying rock in place or the weathering
becomes finer as the soil weathers.
of transported sediments or rock fragments. The mate-
rial from which a soil has formed is called its “parent
material.” The weathering of residual parent materials Soil Horizons
to form soils is a slow process that has been occurring Soils are layered because of the combined effects of
for millions of years in most of the mid-Atlantic region. organic matter additions to the surface soil and long-
However, certain soil features (such as “A horizons,” term leaching. These layers are called “horizons.” The

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 Chapter 2. General Soil Science Principles

vertical sequence of soil horizons found at a given loca- The subsoil (B horizon) is typically finer in texture,
tion is collectively called the “soil profile” (figure 2.2). denser, and firmer than the surface soil. Organic mat-
ter content of the subsoil tends to be much lower than
The principal master soil horizons found in managed
that of the surface layer, and subsoil colors are often
soil systems are:
stronger and brighter, with shades of red, brown, and
• A
 horizon or mineral surface soil. (If the soil has yellow predominating due to the accumulation of iron-
been plowed, this is called the “Ap horizon.”) coated clays. Subsoil layers with high clay accumula-
tion relative to their overlying A horizon are described
• B horizon or subsoil. as Bt horizons. If the B is still observed based on color
• C
 horizon or partially weathered parent material, or structural development but not enriched in clay, it is
which is also part of the subsoil. labeled “Bw” by default.

• R
 ock (R layer) or unconsolidated parent materials The C horizon is partially decomposed and weathered
similar to that from which the soil developed. parent material that retains some characteristics of the
parent material. It is more like the parent material from
Unmanaged and relatively undisturbed forest soils also which it has weathered than the subsoil above it. By
commonly contain an organic O horizon (litter layer) definition, C horizons are “diggable” with a spade or
on the surface and a light-colored, acid-leached zone (E soil auger, while R layers cannot be excavated with
horizon) just below the A horizon. hand tools. Images with horizon designations for soils
In addition to the master soil horizons that are noted by typical of our region (Ultisols), along with distribution
capital letters (e.g., A and B), soil scientists also assign maps and information links can be found at http://soils.
lowercase letters called “subscripts” (e.g., cals.uidaho.edu/soilorders/ultisols.htm.
Ap) to describe the nature of the master
horizon (U.S. Department of Agriculture
(USDA) 1993). There are several dozen
commonly used subscripts, but the most
common ones in urbanized areas of the
mid-Atlantic are Ap (plowed topsoil), “Bt”
(clayey subsoil), and “Cd” (very dense,
compacted subsoil). Another important
combination to recognize is “Btg,” which
indicates a clayey subsoil with color fea-
tures (gleying or gray coloration) indicative
of poor internal drainage, as discussed later
in this chapter.The surface soil horizon(s)
or “topsoil” (the Ap or A plus E horizons)
is often coarser than the subsoil layer and
contains more organic matter than the other
soil layers. The organic matter imparts a
tan, dark-brownish, or black color to the
topsoil. Soils that are high in organic mat-
ter (more than 3 percent) usually have very
dark surface colors. The A or Ap horizon
tends to be more fertile and have a greater
concentration of plant roots than any other
soil horizon. In unplowed soils, the “elu-
viated” (E) horizon below the A horizon
is often light-colored or gray, coarser-tex-
tured, and more acidic than either the A
horizon or the horizons below it because of
acid leaching over time.
Figure 2.2. Soil profile horizons. Graphic by Kathryn Haering.

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 Chapter 2. General Soil Science Principles

As discussed in greater detail in chapter 3, soils in the Silt particles range in size from 0.05 mm to 0.002 mm.
urban landscape are frequently highly disturbed and When moistened, silt feels smooth but is not slick or
often contain distinct layering due to cut/fill and grad- sticky. When dry, it is smooth and floury and if pressed
ing practices that are quite dissimilar from the natural between the thumb and finger, it will retain the imprint.
soil horizons discussed above. It is also quite common Silt particles are so fine they cannot usually be seen
for the native topsoil (A horizon) layers to be absent by the unaided eye and are best seen with the aid of a
and for deeper subsoil materials (Bt) to appear at the strong hand lens or microscope.
surface. Graded and layered urban soils also com-
monly contain highly compacted subsoil layers (Cd Clay is the finest soil particle size class. Individual
horizons). particles are finer than 0.002 mm. Clay particles can
be seen only with the aid of an electron microscope.
They feel extremely smooth or powdery when dry and
Soil Physical Properties become plastic and sticky when wet. Clay will hold the
The physical properties of a soil are the result of soil form into which it is molded when moist and will form
parent materials being acted on by climatic factors a long ribbon when extruded between the fingers.
(such as rainfall and temperature), and being affected
There are 12 primary classes of soil texture defined
by relief (slope and direction or aspect) and by vegeta-
tion over time. A change in any one of these soil-form- by the USDA (1993). The textural classes are defined
ing factors usually results in a difference in the physical by their relative proportions of sand, silt, and clay as
properties of the resulting soil. The important physical shown in the USDA’s “textural triangle” (figure 2.3).
properties of a soil are texture, aggregation/structure, Each textural class name indicates the size of the min-
porosity, and bulk density. eral particles that are dominant in the soil. Regardless
of textural class, all soils in the mid-Atlantic region
contain sand-, silt-, and clay-sized particles, although
Texture the amount of a particular particle size may be small.
The relative amounts of the
different soil-sized particles
(smaller than 2 mm), or the
fineness or coarseness of the
mineral particles in the soil,
is referred to as soil “tex-
ture.” Mineral grains that are
larger than 2 mm in diame-
ter are called rock fragments
and are measured separately.
Soil texture is determined by
the relative amounts of sand,
silt, and clay in the fine-
earth fraction (smaller than
2 mm).
Sand particles vary in size
from very fine (0.05 mm)
to very coarse (2.0 mm) in
average diameter. Most sand
particles can be seen without
a magnifying glass. Sands
feel coarse and gritty when
rubbed between the thumb
and fingers, except for mica
flakes, which tend to smear
when rubbed.
Figure 2.3. The USDA textural triangle (USDA 1993).

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 Chapter 2. General Soil Science Principles

Texture can be estimated in the field after a moderate Effects of Texture on Soil Properties
amount of training by manipulating and feeling the soil
between the thumb and fingers. However, for precise The clay fraction in soils is charged and relatively minor
measurement and/or prescriptive use, texture should be amounts (10 to 15 percent) of clay can significantly
quantified by laboratory particle-size analysis. increase net charge that directly influences both water-
holding and nutrient retention in soils. Water infiltrates
To use the textural triangle: more quickly and moves more freely in coarse-textured
1. F
 irst, you will need to know the percentages of sand, or sandy soils, which increases the potential for leach-
silt, and clay in your soil, as determined by labora- ing of mobile nutrients. Sandy soils also hold less total
tory particle-size analysis. water and fewer nutrients for plants than finer-textured
soils like clays or clay loams. In addition, the relatively
2. L
 ocate the percentage of clay on the left side of the low water-holding capacity and the larger amount of air
triangle and move inward horizontally, parallel to present in sandy soils allow them to warm faster than
the base of the triangle. fine-textured soils. Sandy and loamy soils are also more
3. F
 ollow the same procedure for sand, moving along easily tilled than clayey soils, which tend to be denser.
the base of the triangle to locate your percentage of In general, fine-textured soils hold more water and plant
sand. nutrients and therefore require less frequent applica-
4. T
 hen, move up and to the left until you intersect the tions of water, lime, and fertilizer. Soils with high clay
line corresponding to your clay percentage value. content (more than 40 percent clay), however, actually
hold less plant-available water than loamy soils. Fine-
5. A
 t this point, read the “textural class” written within textured soils have a narrower range of moisture con-
the bold boundary on the triangle. For example, a ditions under which they can be worked satisfactorily
soil with 40 percent sand, 30 percent silt, and 30 than sandy soils. Soils high in silt and clay may puddle
percent clay will be a clay loam. With a moderate or form surface crusts after rains, impeding seedling
amount of practice, soil textural class can also be emergence. High-clay soils often break up into large
reliably determined in the field. clods when worked while either too dry or too wet.
When soil textures fall very close to the boundary
between two adjacent classes, it is appropriate to name Aggregation and Soil Structure
both (e.g., sandy clay loam to sandy clay). Also, within Soil “aggregation” is the cementing of several soil par-
a given textural class, soils with high clay contents are ticles into a secondary unit or aggregate. Soil particles
often referred to as “heavy” versus those low in clay are arranged or grouped together during the aggregation
content that are called “light.” Thus, a “heavy clay process to form structural units (known to soil scientists
loam” indicates a soil texture in the upper portion of as “peds”). These units vary in size, shape, and distinct-
that textural class, close to being clay. This latter con- ness (also known as strength or grade). In topsoils, soil
vention is not defined or formally accepted by the organic matter is the primary material that cements par-
USDA but is commonly used by field practitioners. ticles together into water-stable aggregates. In subsoil,
If a soil contains 15 percent or more rock fragments aluminum and iron oxides play a major role in cement-
(larger than 2 mm), a rock fragment content modifier is ing aggregates, as do finer clay particles which — due
added to the soil’s texture class. For example, the tex- to their charge (discussed later in this chapter) — can
ture class designated as “gravelly silt loam” would con- also bind and stabilize much larger sand and silt par-
tain 15 to 35 percent gravels within a silt loam (smaller ticles together. The types of soil structure found in most
than 2 mm), fine-soil matrix. A sample with more than mid-Atlantic soils are described in table 2.1 and illus-
35 percent gravel would be described as “very gravelly trated in figure 2.4.
silt loam,” etc. More detailed information on USDA
particle-size classes and other basic soil morphological Effects of Soil Structure on Soil Properties
descriptors can be found at http://soils.usda.gov/techni-
The structure of the soil affects pore space size and dis-
cal/handbook/download.html or in the USDA Soil Sur-
tribution, and therefore, rates of air and water move-
vey Manual (USDA 1993).
ment and overall root proliferation. Well-developed
structure allows favorable movement of air and water,

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 Chapter 2. General Soil Science Principles

Table 2.1. Types of soil structure.

Structure type Description
Granular Soil particles are arranged in small,
rounded units. Granular structure
is very common in surface soils
(A horizons) and is usually most
distinct in soils with relatively high
organic matter content.
Blocky Soil particles are arranged to form
block-like units, which are about
as wide as they are high or long.
Some blocky peds are rounded
on the edges and corners; others Figure 2.4. Types of soil structures. Graphic by Kathryn Haering.
are angular. Blocky structure is
commonly found in the subsoil, while poor structure retards movement of air and water.
although some eroded fine-textured Because plant roots move through the same channels in
soils have blocky structure in the the soil as air and water, well-developed structure also
surface horizons. encourages extensive root development. With respect
Platy Soil particles are arranged in plate- to rooting, the size of the pores and their degree of
like sheets. These plate-like pieces interconnection are also critically important. In general,
are approximately horizontal in the the penetration of air, water, and roots through soils is
soil and may occur in either the favored by “macropores” (larger than or equal to 0.05
surface or subsoil, although they are mm, or sand-sized) that are physically interconnected,
most common in the subsoil. Platy particularly vertically. In general, soil productivity is
structure strongly limits downward favored when water, air, and roots can move readily
movement of water, air, and roots.
through the soil. It is also important that soil metabolic
It may occur just beneath the plow
gasses (e.g., carbon dioxide) be able to diffuse back
layer, resulting from compaction
by heavy equipment, or on the soil into the atmosphere.
surface when it is too wet to work Water can enter a surface soil that has well-developed
satisfactorily.
(strong) granular structure (particularly fine-textured
Prismatic Soil particles are arranged into soils) more rapidly than one that has relatively weak
large peds with a long vertical axis. structure. Surface soil structure is usually granular, but
Tops of prisms may be somewhat such granules may be indistinct or completely absent if
indistinct and normally angular. the soil is continuously tilled, the soil is very coarse, or
Prismatic structure occurs mainly
if organic matter content is low.
in subsoils, and the prisms are
typically much larger than other The size, shape, and strength of subsoil structural peds
typical subsoil structure types such are particularly important to soil productivity. Sandy
as blocks. soils generally have poorly developed structure relative
Structureless Massive, with no definite structure to finer-textured soils because of their lower clay con-
or shape, as in some C horizons or tent. When the subsoil has well-developed blocky struc-
compacted material. ture, there will usually be good air and water movement
- or - in the soil. If platy structure has formed in the subsoil,
Single grain, which is typically downward water, air movement, and root development
individual sand grains in A or C in the soil will be slowed. Distinct prismatic structure is
horizons not held together by often associated with subsoils, but those larger prisms
organic matter or clay. will usually break down into primary blocky peds. Very
large and distinct subsoil prisms are also commonly
associated with “fragipans” (Bx horizons), which are
massive and dense subsoil layers.

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 Chapter 2. General Soil Science Principles

Porosity and Bulk Density development and microbial activity. The loosening and
granulation of fine-textured soils promote aeration (gas
Soil “porosity,” or pore space, is the volume percentage exchange) by increasing the number of macropores.
of the total soil that is not occupied by solid particles.
Pore space is commonly expressed as a percentage:
Soil Organic Matter
% pore space = 100 − ( bulk density
particle density)x 100 Soil organic materials consist of plant and animal resi-
dues in various stages of decay. Primary sources of
“Bulk density” is the dry mass of soil solids per unit vol- organic material inputs are dead roots, root exudates,
ume of soils, and “particle density” is the density of soil litter and leaf drop, and the bodies of soil animals such
solids, which is assumed to be constant at 2.65 grams as insects and worms. Earthworms, insects, bacteria,
per cubic centimeter (g/cm3). Bulk densities of mineral fungi, and other soil organisms use organic materials
soils are usually in the range of 1.1 to 1.7 g/cm3. A soil as their primary energy and nutrient source. Nutrients
with a bulk density of about 1.32 g/cm3 will generally released from the residues through decomposition are
possess the ideal soil condition of 50 percent solids and then available for use by growing plants.
50 percent pore space. Bulk density varies depending
on factors such as texture, aggregation, organic matter, Soil “humus” is fully decomposed and stable organic
compaction/consolidation, soil management practices, matter that is primarily derived from the bodies of soil
and soil horizon. In general, root penetration through microbes and fungi. Humus is the most reactive and
soils will be limited in sandy soils when the bulk den- important component of soil organic matter and is the
sity approaches 1.75 g/cm3 and in clayey soils at 1.40 form of soil organic material that is typically reported
g/cm3 (Brady and Weil 2008). However, water, air, and as “organic matter” on soil testing reports. Soil organic
roots can penetrate high bulk-density soils that have matter in Virginia soils typically ranges between 0.5 and
well-developed structure with interconnected macropo- 2.5 percent in A horizons and can approach 5 percent in
res, as discussed above. heavily enriched garden soils or soils with poor drain-
age. Higher levels are typically found only in wetlands.
Macropores (larger than 0.05 mm) allow the ready Soil organic matter is so reactive (charged) that when
movement of air, roots, and percolating water. In con- it exceeds 12 to 20 percent by weight, it dominates soil
trast, micropores (smaller than 0.05 mm) in moist soils properties and we refer to it as “organic soil material.”
are typically higher in water content and poorly inter-
connected, and this does not permit much air move-
Factors That Affect Soil Organic Matter
ment into or out of the soil. Internal water movement
is also very slow in micropores. Thus, the movement Content
of air and water through a coarse-textured sandy soil The organic matter content of a particular soil will
can be surprisingly rapid despite its low total porosity depend on:
because of the dominance of macropores.
Type of vegetation: Soils that have been in grass for
Under field conditions, the total soil pore space is filled long periods usually have a relatively higher percent-
with a variable mix of water and air. If soil particles are age of organic matter in their surface. Soils that develop
packed closely together, as in well-graded surface soils under trees usually have a low organic matter percentage
or compact subsoils, total porosity is low and bulk den- in the surface mineral soil but do contain a surface lit-
sity is high. If soil particles are arranged in porous aggre- ter layer (O horizon). Organic matter levels are typically
gates, as is often the case in medium-textured soils high higher in a topsoil that supports perennial hay, pasture, or
in organic matter, the pore space per unit volume will be forest than in a topsoil used for cultivated crops.
high and the bulk density will be correspondingly low.
Tillage: Soils that are tilled frequently are usually
Fine-textured clay soils, especially those without a lower in organic matter. Plowing and otherwise till-
stable blocky (Bt) or granular (Ap) structure, may ing the soil increases the amount of oxygen in the soil,
have reduced movement of air and water even though which increases the rate of organic matter decomposi-
they have a large volume of total pore space. In these tion. This detrimental effect of tillage on organic matter
fine-textured soils, micropores are dominant. Because is particularly pronounced in very sandy, well-aerated
these small pores often stay full of water, aeration — soils because of the tendency of frequent tillage to pro-
especially in the subsoil — can be inadequate for root mote organic matter oxidation to carbon dioxide.

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 Chapter 2. General Soil Science Principles

Drainage: Soil organic matter is usually higher in poorly Field Capacity and Permanent Wilting
drained soils because of limited oxidation, which slows
down the overall biological decomposition process. Percentage
The term “field capacity” defines the amount of water
Soil texture: Soil organic matter is usually higher in remaining in a soil after downward gravitational drain-
fine-textured soils because soil humus forms stable age has stopped. This value represents the maximum
complexes with clay particles and fine-textured soils amount of water that a soil can hold against gravity fol-
limit the penetration of atmospheric oxygen in and car- lowing saturation by rain or irrigation. Field capacity is
bon dioxide out of surface soils. usually expressed as percentage by weight (for exam-
ple, a soil holding 25 percent water at field capacity
Effect of Organic Matter on Soil contains 25 percent of its dry weight as retained water).
Properties On a volumetric basis, values for field capacity range
from 8 percent in a sand to 35 percent in a clay (Brady
Adequate soil organic matter levels benefit soils in
and Weil 2008).
several ways. The addition of organic matter improves
soil physical conditions, particularly aggregation and The amount of water a soil contains after plants are
macropore space. This improvement leads to increased wilted beyond recovery is called the “permanent wilt-
water infiltration, improved soil tilth, and decreased ing percentage.” Considerable water may still be pres-
soil erosion. Organic matter additions also improve soil ent at this point, particularly in clays, but it is held so
fertility because plant nutrients are released to plant- tightly that plants are unable to extract it. The amount
available mineral forms as organic residues are decom- of water held by the soil between field capacity and the
posed (or “mineralized”), and soil humus is highly permanent wilting point is the “plant-available water”
charged and retains nutrients against leaching, as dis- and is maximized in loamy-textured soils. The volumet-
cussed later. ric plant-available water for sand is typically less than 5
percent but may approach 25 percent volumetric water
A mixture of organic materials in various states of
for a well-aggregated, loamy soil (see figure 2.1).
decomposition helps maintain a good balance of air and
water components in the soil. In coarse-textured soils,
organic material bridges some of the space between Tillage and Moisture Content
sand grains, which increases water-holding capac- Soils with a high clay content are sticky when wet and
ity. In fine-textured soil, organic material helps main- form hard clods when dry. Therefore, tilling clayey
tain porosity by keeping very fine clay particles from soils at the proper moisture content is extremely impor-
packing too closely to one another, thereby enhancing tant. Although sandy soils are inherently droughty,
macroporosity. they are easier to till at varying moisture contents
because they do not form dense clods or other high-
strength aggregates. Sandy soils are also far less likely
Soil-Water Relationships than clays to be compacted if cultivated when moist
or wet. However, soils containing high proportions of
Water-Holding Capacity very fine sand or coarse silts may be compacted by
Soil water-holding capacity is determined largely by tillage when moist.
the interaction of soil texture, bulk density/pore space,
and aggregation. Sands hold little water because they
have little net charge and their large intergranular
Soil Drainage
pore spaces allow water to drain freely from the soils. The overall hydrologic balance of soils — including
Clays adsorb a relatively large amount of water, and infiltration and internal permeability — is discussed
their small pore spaces retain it against gravitational in greater detail in chapter 11. However, soil scientists
forces. However, clayey soils hold water much more commonly use the term “soil drainage” to describe the
tightly than sandy soils so that much of the water rate and extent of vertical or horizontal water move-
retained (more than 40 percent) is unavailable to grow- ment and internal soil saturation during the growing
ing plants. As a result, moisture stress can become a season.
problem in fine-textured soils despite their high total
water-holding capacity.

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 Chapter 2. General Soil Science Principles

Important factors affecting soil drainage class are: support hydrophytic vegetation typical of wetlands,
and exhibit redoximorphic features are designated as
• Slope (or lack of slope).
“hydric soils.” Further information on mid-Atlantic
• Depth to the seasonal water table. hydric soils and redox features can be found online at
www.epa.gov/reg3esd1/wetlands/hydric.htm.
• T
 exture of surface and subsoil layers and of underly-
ing materials. Interpretation of soil redox features can be highly com-
plicated in an urban environment due to the effects of
• Type and strength of soil structure.
soil layer mixing via the cut/fill and grading processes
• P
 roblems caused by improper tillage or grading, and changes in internal soil drainage due to ditching
such as compacted subsoils or lack of surface soil and pavement interception of normal infiltration.
structure.
Another definition of drainage refers to the removal Drainage Classes
of excess water from the soil to facilitate agriculture, The “drainage class” of a soil defines the frequency of
forestry, or other higher land uses. This is usually soil wetness as it limits agricultural practices and is usu-
accomplished through a series of surface ditches or the ally determined by the depth in soil to significant gray
installation of subsoil drains. redox depletions. The soil drainage classes in table 2.2
are defined by the USDA Natural Resources Conser-
Soil Drainage and Soil Color vation Service (USDA 1993). They refer to the natural
The nature of internal soil drainage in relatively undis- drainage condition of the soil without artificial drainage.
turbed soils is usually indicated by soil color patterns
and color variations with depth. Clear, bright red, and/or Table 2.2. Soil drainage classes.
yellow subsoil colors indicate well-drained conditions Soil
where iron and other compounds are present in their Drainage class characteristics Effect on cropping
oxidized forms. A soil is said to be well-drained when Excessively Water is removed Will probably
the “solum” (A plus E plus B horizons) exhibits strong drained rapidly from soil. require
red/yellow colors without any gray coloration (mottles supplemental
Somewhat
or redox depletions). The term “mottle” is used generi- excessively
irrigation.
cally to describe any differences in coloration within drained
a given soil horizon. When those differences in color-
Well-drained Water is removed No drainage
ation are due to wetness, however, the correct term is
readily, but not required.
“redoximorphic features.” rapidly.
When soils become saturated for significant periods of Moderately Water is removed May require
time during the growing season, these oxidized (red/ well-drained somewhat slowly supplemental
yellow) forms of iron are biochemically reduced to at some periods drainage if crops
soluble forms and can be moved with drainage waters. of the year. that require good
This creates a matrix of drab, dominantly gray colors drainage are
that are described as “redox depletions.” The iron that grown.
is mobilized is typically reprecipitated locally into Somewhat Water is removed Will probably
contrasting red/yellow features that are called “redox poorly drained so slowly that require
concentrations.” Subsoil zones with mixtures of bright soil is wet at supplemental
red/yellow and gray colors are indicative of seasonally shallow depths drainage for
fluctuating water tables, where the subsoil is wet during Poorly drained periodically satisfactory use
during the in production of
the winter/early spring and unsaturated in the summer/ growing season. most crops.
early fall. Poorly drained soils also tend to accumulate
large amounts of organic matter in their surface hori-
Very poorly Free water is
zons because of limited oxidation and may have very
drained present at or near
thick and dark A horizons. the surface during
Soils that are wet in their upper 12 inches for consid- the growing
erable amounts of time during the growing season, season.

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 Chapter 2. General Soil Science Principles

Soil Chemical Properties minerals and organic matter that typically possess neg-
ative electrical surface charges. These negative charges
The plant root obtains essential nutrients almost entirely are present in excess of any positive charges that may
by uptake from the soil solution. The chemistry and exist, which gives soil a net negative charge.
nutrient content of the soil solution is, in turn, controlled
by the solid material portion of the soil. Soil chemical Negative surface charges attract positively charged
properties, therefore, reflect the influence of soil miner- cations and prevent their leaching. These ions are held
als and organic materials on the soil solution. against leaching by electrostatic positive charges but
are not permanently bound to the surface of soil par-
ticles. Positively charged ions are held in a “diffuse
Soil pH cloud” within the water films that are also strongly
Soil pH defines the relative acidity or alkalinity of the attracted to the charged soil surfaces. Cations that are
soil solution. It is important to note that pH can only be retained by soils can thus be replaced, or “exchanged,”
measured in soil solution that has equilibrated with soil by other cations in the soil solution. For example, Ca2+
solids; you cannot measure the pH of a solid. The pH can be exchanged for Al3+ and/or K+ and vice versa. The
scale in natural systems ranges from 0 to 14. A pH value higher a soil’s CEC, the more cations it can retain.
of 7.0 is neutral. Values below 7.0 are acidic and those
above 7.0 are alkaline, or basic. Many agricultural soils There is a direct and positive relationship between the
in the mid-Atlantic region have a soil pH between 5.5 relative abundance of a given cation in solution and
and 6.5. Any soil pH value less than 4.0 is indicative of the amount of this cation that is retained by the soil
acid-sulfate influenced soils (see chapter 3). CEC. For example, if the predominant cation in the
soil solution is Al 3+, Al3+ will also be the predominant
Soil pH is a measurement of hydrogen ion (H+) activity exchangeable cation. Similarly, when large amounts of
in soil solution or effective concentration in a soil and Ca2+ are added to soil solution by lime dissolving over
water solution. Soil pH is expressed in logarithmic terms, time, Ca2+ will displace Al3+ from the exchange com-
which means that each unit change in soil pH amounts to plex and allow it to be neutralized in solution by the
a tenfold change in acidity or alkalinity. For example, a alkalinity added with the lime.
soil with a pH of 6.0 has 10 times as much active H+ (or
is 10 times more acidic) as one with a pH of 7.0. The CEC of a soil is expressed in terms of moles of
charge per mass of soil. The units used are “cmol+/kg”
Soils become acidic when basic cations (positively (centimoles of positive charge per kilogram) or “meq/100
charged ions such as calcium, or Ca2+) held by soil g” (milliequivalents per 100 grams; 1.0 cmol+/kg = 1.0
colloids are leached from the soil and replaced by alu- meq/100 g). Soil scientists have used the former unit in
minum ions (Al3+), which then hydrolyze to form alu- publications since the early 1980s, while meq/100 g is
minum hydroxide (Al(OH)3) solids, which then liberate commonly used in other disciplines. Numerically, they
H+ ions to solution as water hydrolyzes (splits into H+ are the same. Soil CEC is calculated by adding the charge
and OH- ions). This long-term acidification process is equivalents of K+, NH4+, Ca2+, Mg2+, Al3+, Na+, and H+
accelerated by the decomposition of organic matter that that are extracted from a soil’s exchangeable fraction.
also releases acids to soil solution. Most soils in the
mid-Atlantic region were formed under high rainfall
with abundant vegetation and are considerably more
Sources of Negative Charge in Soils
acidic than soils of the midwestern and western United The mineralogy of the clay fraction and the soil’s
States. In fact, very few soils in Virginia were above pH humus content greatly influence the quantity of nega-
6.0 when settlers first arrived in the 17th century. tive charges present. One source of negative charge is
“isomorphous substitution,” which is the replacement
of a Si4+ or Al3+ cation in the clay mineral structures
Cation Exchange Capacity: Our with a cation that has a lower surface charge. For exam-
Measure of Soil Charge and Reactivity ple, Si4+ might be replaced with Al3+, or Al3+ might be
The net ability of a soil to hold, retain, and exchange replaced with either Mg2+ or Fe2+. Clay minerals with
cations such as calcium (Ca2+), magnesium (Mg2+), a repeating layer structure of two silica sheets sand-
potassium (K+), sodium (Na+), ammonium (NH4+), wiched around an aluminum sheet (two-to-one clays,
aluminum (Al3+), and hydrogen (H+) is called “cation such as vermiculite or smectite), typically have a higher
exchange capacity,” or CEC. All soils contain clay total negative charge than clay minerals with one silica

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 Chapter 2. General Soil Science Principles

sheet and one aluminum sheet (one-to-one clays, such If cations are present in equal amounts, the general
as kaolinite). Soil humus is also highly charged due to a strength of adsorption that holds cations in the soil is in
large number of chemically reactive sites called “func- the following order:
tional groups.”
Al3+ >> Ca2+ > Mg2+ > K+ = NH4+ > Na+
Soil pH also has a direct relationship to the quantity of
negative charges contributed by organic matter and, to a Effect of CEC on Soil Properties
lesser extent, from mineral surfaces such as iron oxides.
As soil pH increases, the quantity of negative charges A soil with a low CEC value (1-10 meq/100 g) may
have some, or all, of the following characteristics:
increases due to the reactions of exposed organic matter
functional groups and similar reactions that occur on • High sand and low clay content.
the surfaces of iron and aluminum oxides and the edges
of clays. This pH-dependent charge is particularly • Low organic matter content.
important in highly weathered topsoils where organic • Low water-holding capacity.
matter dominates overall soil charge.
• Low soil pH.
It is important to point out that while we use CEC as
our measure of net charge or reactivity in soils, all • N
 ot easily resistant to changes in pH or other chemi-
soils contain a certain amount of positive charges as cal changes.
well. These positive charges are important in retaining • E
 nhanced leaching potential of plant nutrients such
anions (negatively charged ions) like NO3-, Cl-, or SO42- as Ca2+, NH4+, K+..
against leaching in certain soils as well. In particular,
highly weathered soils that are high in aluminum and • Low productivity.
iron (very red) and low in pH (less than 5.5) may actu- A soil with a higher CEC value (11-40 meq/100 g)
ally have more positive charges on their surfaces than may have some or all of the following characteristics:
negative charges. These soils also have a very strong
affinity to bind (or fix) phosphorus in very tight com- • Lower sand and higher silt plus clay content.
plexes that will be discussed in chapter 4. • Moderate-to-high organic matter content.
• High water-holding capacity.
Cation Retention and Leaching in Soils
The negatively charged surfaces of clay particles and • A
 bility to resist changes in pH or other chemical
organic matter strongly attract cations. However, the properties.
retention and release of these cations, which affects • Less nutrient losses to leaching than low CEC soils.
their mobility in soil, is dependent on several factors.
Two of these factors are the relative retention strength
of each cation and the relative amount or mass of each Base Saturation
cation present. Of the common soil-bound cations, Ca2+, Mg2+, K+, and
Na+ are considered to be basic cations. The base satura-
For a given cation, the relative retention strength by
tion of the soil is defined as the percentage of the soil’s
soil is determined by the charge of the ion and its size
CEC (on a charge-equivalent basis) that is occupied
(or diameter). In general, the greater the positive charge
by these cations. A high base saturation (more than 50
and the smaller the ionic diameter of a cation, the more
percent) enhances calcium, magnesium, and potassium
tightly the ion is held (i.e., higher retention strength)
availability and prevents soil pH decline. Low base sat-
and the more difficult it is to remove that cation and uration (less than 25 percent) is indicative of a strongly
leach it down through the soil profile. For example, Al3+ acidic soil that may maintain Al3+ activity high enough
has a positive charge of three and a very small ionic to cause phytotoxicity.
diameter and thus moves through the soil profile very
slowly. Potassium (K+), on the other hand, has a charge
of one and a much larger ionic radius, so it leaches Buffering Capacity
much more readily. This difference in cation retention The resistance of soils to changes in the pH of the soil
has important soil fertility implications that will be dis- solution is called “buffering.” In practical terms, buffer-
cussed in chapter 4. ing capacity for pH increases with the amount of clay and

2-10 Urban Nutrient Management Handbook

 Chapter 2. General Soil Science Principles

organic matter. Thus, soils with high clay and organic hold and supply sufficient plant-available water, be
matter content (high buffer capacity) will require more able to moderate extreme air temperatures, and allow
lime to increase pH than sandy soils with low amounts of for adequate exchange of gasses between the root zone
organic matter (low or weak buffer capacity). and the atmosphere. Chemically, the soil must main-
tain an adequate pH and soluble-salt environment for
One laboratory measure of the acid buffering capacity
locally adapted plants and supply all of the soil nutri-
(or lime demand) of a given soil is called “buffer pH”
ents detailed above in adequate amounts to meet the
and will be discussed in more detail in chapters 4 and 5.
plant’s demand. The overall productivity of the plant
It is very important to realize, however, that buffer pH
community will be controlled by the soil factor that is
is quite different from conventional soil-to-water pH,
present in the lowest relative amount, regardless of the
as discussed above.
adequacy/availability of the rest of the important soil
physical and chemical factors. This concept is known
Essential Elements for Plant Growth as the “the law of the minimum.” For example, over-
Higher plants and the microbial biomass in soils need all plant growth in urban soils is commonly directly
a wide array of essential elements to sustain them and limited by compaction and associated lack of rooting
build biomass. The soil biota take carbon, hydrogen, volume, regardless of the adequacy of soil pH and
and oxygen from soil, air, and water, so these are not nutrient levels. Once you loosen these soils to provide
considered soil-supplied nutrients. Six essential ele- adequate rooting depth, plant growth will increase until
ments (nitrogen, phosphorus, potassium, sulfur, cal- it becomes limited by the next limiting factor (e.g., low
cium, and magnesium) are taken up by plants from the soil pH or phosphorus). Therefore, the overall guiding
soil in relatively large amounts; these are referred to as principle underpinning appropriate soil management is
“macronutrients.” All of the essential elements are taken that we must manage all important plant growth factors
up primarily as dissolved ions from solution; table 2.3 together to maintain adequate plant growth over time.
lists their common forms and sources. The ionic form
(i.e., cation versus anion) of each nutrient and its spe- Soil Survey
cific charge characteristics directly control its relative The soils of all counties have been mapped by the
sorption and availability from the soil. Higher plants USDA-NRCS soil survey (1993), and these maps are
also require a wide range of other elements (boron, available in soil survey reports, although some county
chlorine, cobalt, copper, iron, molybdenum, manga- reports are quite old and in need of modern recorrela-
nese, nickel, and zinc) in much smaller amounts and tion. A soil survey report reveals the kinds of soils that
these are referred to as “micronutrients.” More detail exist in the county (or other area) covered by the report
on the specific forms and supply of plant nutrients can at a level of detail that is usually sufficient for agricul-
be found in chapters 4, 5, 7, 8, and 9. tural interpretations. The soils are described in terms
of their location on the landscape, their profile charac-
Limiting Factors to Plant Growth
teristics, their relationships to one another, their suit-
Higher plants rely on the soil for a wide range of ser- ability for various uses, and their needs for particular
vices in support of their growth. Physically, the soil types of management. Each soil survey report contains
must be deep and strong enough to support the plant, information about soil morphology, soil genesis, soil

Table 2.3. Soil-supplied macronutrients, sources, and ionic forms for plant uptake.
Nutrient Primary sources Dominant form in soil solution
Nitrogen (N) Organic matter, manures, fertilizers (N-P-K), legumes NH4+: low pH or wet
NO3-: moderate pH and oxidized
Phosphorus (P) Organic matter, fertilizers H2PO4-: between pH 5 and 7
Potassium (K) Plant litter, fertilizers, soil minerals (micas and feldspars) K+
Calcium (Ca) Limes, plant litter, soil minerals (feldspars and carbonates) Ca2+
Magnesium (Mg) Dolomitic limes, soil minerals Mg2+
Sulfur (S) Atmospheric and gypsum additions, soil sulfides SO42-

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 Chapter 2. General Soil Science Principles

conservation, and soil productivity. Soil survey reports Map units are the actual units that are delineated on
are available from county and state USDA-NRCS the soil map and are usually named for the dominant
cooperative Extension offices and online at http://soils. soil series and slope phase. Map units generally contain
usda.gov/survey/online_surveys/. more than one soil series. Units are given the name of
the dominant soil series if 85 percent or more of the
Parts of a Soil Survey area is correlated as a single soil series (or similar soils
in terms of use and management). Soil complexes are
There are two major sections in a soil survey report.
used to name the map unit if the dissimilar inclusions
One section contains the soil maps. In most reports,
exceed 15 percent. Each map unit is given a symbol
the soil map is printed over an aerial photographic base
(numbers or letters) on the soil map that designates the
image. In the past, soil mapping was done at scales
name of the soil series or complex being mapped and
ranging from 1-to-10,000 to 1-to-50,000, with 1-to-
the slope of the soil. More details on how soil map-
15,840 being the most common scale used before the
ping units are developed and named can be found in the
1980s. Current USDA-NRCS mapping is published
Soil Survey Manual at http://soils.usda.gov/technical/
at 1-to-24,000 to match U.S. Geologic Survey topo-
manual/.
graphic quadrangle maps.
Each soil area is delineated by an enclosing line on Using a Soil Survey
the map. Soil delineation boundaries are drawn wher-
ever there is a significant change in the type of soil. A user interested in an overall picture of a county’s soils
The boundaries often follow natural contours, but they should probably turn first to the soil association section
may also cross and incorporate multiple portions of of the soil survey report. The general soil pattern of the
the landscape if the soils are similar across local topo- county is discussed in this section. A user interested in
graphic variations. the soils of a particular farm must first locate that farm
on the soil map and determine what soils are present.
The other section of a soil survey report is the narra- Index sheets located with the soil maps help the user
tive portion. Without it, the soil maps would have little find the correct section of the map. The map legend
meaning. Symbols on each map are keyed to a list of gives the soil map the unit names for each symbol and
soil mapping units. The nature, properties, and clas- assists with the location of descriptive and interpretive
sification and use potentials of all mapping units are material in the report.
described in detail.
Detailed soil descriptions that provide information to
those who are primarily interested in the nature and
Terminology Used in Soil Surveys properties of the soils mapped are located in the nar-
Soil series is a basic unit of soil classification, consist- rative portion of the soil survey report. The section
ing of soils that are essentially alike in all main pro- concerned with the use and management of the soils
file characteristics. Most soil mapping units in modern (soil interpretations) is helpful to farmers and others
cooperative soil surveys are named for their dominant who use the soil or give advice and assistance in its
component soil series. use (e.g., soil conservationists, cooperative Extension
Soil phase is a subdivision of a soil series or other unit agents). Management needs and estimated yields are
of classification having characteristics that affect the included in this section. Newer reports have engineer-
use and management of the soil but do not vary enough ing properties of soils listed in tables that are useful to
to merit a separate series. These include variations in highway engineers, sanitary engineers, and others who
slope, erosion, gravel content, and other properties. design water storage or drainage projects.

Soil complexes and soil associations are naturally It is important for the urban user of soil surveys to
occurring groupings of two or more soil series with understand that very few soil surveys recognize and
different use and management requirements that occur appropriately interpret the drastically disturbed nature
in a regular pattern across the landscape but cannot of their landscape. Where the soil survey shows map-
be separated at the scale of mapping that is used. Soil ping units named for soil series, they represent the
complexes are used to map two or more series that are dominant undisturbed soils in that landscape that
commonly intermixed on similar landforms in detailed existed predevelopment. Some older soil surveys sim-
county soil maps. Soil associations are utilized in more ply mapped previously developed areas as “made land”
general and less detailed regional soil maps. or “urban lands.” Virginia soil surveys produced after

2-12 Urban Nutrient Management Handbook

 Chapter 2. General Soil Science Principles

1980 often map disturbed soils as “Udorthents,” which

simply indicates that they are dominantly young soils
due to their native profiles being largely destroyed.

Literature Cited
Brady, N. C., and R. R. Weil. 2008. The Nature and
Properties of Soils. 14th ed. Upper Saddle River,
N.J.: Pearson Prentice Hall.
U.S. Department of Agriculture (USDA). Natural
Resources Conservation Service. Soil Service
Division Staff. 1993. Soil Survey Manual. Hand-
book No. 18. Washington: U.S. Government
Printing Office. http://soils.usda.gov/technical/
manual/.

Urban Nutrient Management Handbook 2-13

 Chapter 2. General Soil Science Principles

2-14 Urban Nutrient Management Handbook

 Chapter 3. Managing Urban Soils

Chapter 3. Managing Urban Soils

W. Lee Daniels, Professor, Crop and Soil Environmental Sciences, Virginia Tech

• P
 resence of anthropic materials (e.g., wood, rags,
What Is an Urban Soil? cement) and other contaminants (e.g., oil, metals).
More often than not, the soils we manage for plant
growth in urban and suburban areas have been signifi- • H
 igher temperature variability due to lack of natural
cantly altered from their natural state by excavation (cut litter layer or vegetation.
and fill), grading, topsoil return, or other operations that Figure 3.1 depicts a number of these plant-growth lim-
fundamentally alter their morphological, physical, and iting soil factors that we commonly encounter around
chemical properties (Brown et al. 2000; Scheyer and building sites, particularly (1) high variability, (2) lay-
Hipple 2005). In rural areas, similar disturbances asso- ering, (3) presence of acidic and infertile clayey mate-
ciated with road construction, mining, and utility cor- rials at the surface, and (4) issues related to excessive
ridors generate similar soil conditions that frequently compaction (high bulk density). Recognizing and deal-
limit plant growth (Booze-Daniels et al. 2000). Simply ing with these limitations will therefore be the primary
put, urban soils do not contain the natural sequence of focus of this chapter, but other issues and their remedies
intact soil horizons that was described in chapter 2. will be addressed as well.
Therefore, many of our underlying assumptions about
soil testing results, plant growth response and overall
soil-plant relations may not apply to these materials,
and they must be modified to overcome their inherent
limitations for plant growth.

Urban Soil Properties

When we compare these urban soils materials with
nearby natural soil profiles (see chapter 2), a number of
differences are usually readily apparent (adapted from Figure 3.1. Diagram of urban soils and important plant growth limiting
Craul 1992): features. Note that the soil limitations in one portion of a home lot
may be quite different from those encountered in another location of
the same lot. Diagram by Kathryn Haering.
• Highly variable in all directions.
• A
 brupt differences in soil texture and density (layer-
ing) with depth. Types of Urban Soil Materials and
• P
 resence of high-clay materials at the surface/lack of
Their Variability
topsoil. The entire process of site development for housing,
construction, or landscape development results in large
• S
 oil structure that has been degraded, leading to loss of amounts of soil disturbance, movement, and mixing. The
large pores (macropores) and their vertical continuity. degree of impact ranges from limited surface soil com-
• H
 igh bulk density due to mechanical compaction and paction to complete removal of the native soil profile and
lack of structure/macropores. its replacement with mixed and dissimilar fill materials
(figures 3.1 and 3.2). Thus, while predevelopment native
• C
 ommon occurrence of surface crusts on finer-tex- soil properties will be fairly uniform and predictable on a
tured materials. given site due to the long-term effect of the soil-forming
• Soil pH may be higher or lower than normal. factors (see chapter 2) the postdevelopment site will be
much more variable and extreme short-range differences
• Restricted aeration and water drainage. in important plant-growth related properties such as com-
paction, texture, and pH will be common. While there
• I nterrupted nutrient cycles and associated microbial
is an almost endless variety of mechanisms and expres-
populations.
sions of soil disturbance, the most common types are (1)
• V
 ery low organic matter and nutrient levels compared exposed subsoil materials, (2) exposed cut materials, and
to natural topsoils. (3) filled materials that are compacted and layered.

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 Chapter 3. Managing Urban Soils

1. Exposed Subsoil Materials 3. Fills

The simplest urban soil scenario to recognize and deal Overall site development and final land shaping and
with is where the topsoil (A plus E horizons) has been grading generate extensive areas of filled materials
removed. Subsoil materials (B and C horizons) are fre- at most sites (figure 3.1). These fills may range from
quently encountered at the surface of the ground as a relatively shallow lifts of returned topsoil over intact
result of erosion of the native topsoil or severe soil dis- subsoils to very thick, multi-layered fills of strongly
turbance associated with earthmoving and construction contrasting materials. Fills can often be recognized due
activities. In most instances, these materials will be red to their long linear and uniform slopes or “unnatural”
or yellow in color, but they may range from white to slope shapes and configurations. However, competent
gray in certain instances. Unlike topsoil, this material is grading and landscaping can make fills virtually indis-
often quite clayey and dense, devoid of organic matter, tinguishable from natural landforms. Fills are typically
and generally resists plant growth. Subsoils in the mid- much more difficult to manage than either exposed sub-
Atlantic region are usually highly leached, acidic, and soils or cuts for a variety of reasons that are discussed
infertile and may also be gravelly or rocky. in more detail below. Fill materials tend to be highly
variable and layered and compacted, all of which limit
plant growth and water movement.

Common Soil Limitations in the

Urban Environment
Compaction
Simple soil compaction (high bulk density) is the most
common plant growth and water movement limitation
in urban soils (see figure 3.3). Dense layers in soils are
commonly called “pans” and may result from a variety
Figure 3.2. Typical soil disturbance in subdivision during construction. of natural long-term soil processes (e.g., dense Bt hori-
Each lot is graded out (cut and filled) to approximately level the area zons), but are most commonly formed by site develop-
immediately surrounding the house. Note large amounts of sand and
other construction debris that will more than likely be graded out and ment and grading machinery. These compacted zones
incorporated into fills. may occur at the surface or deep in the subsoil but are
often denser than natural pans or subsoil layers. Arti-
2. Cut Slopes and Banks ficially induced pans are particularly common where
several layers of soil have been disturbed, such as
Cut materials are commonly encountered on sites where
when topsoil is returned to a regraded lawn after house
the natural topography is rolling or sloping and must be
construction, or where cut-and-fill operations have
reshaped to accommodate yards, driveways, landscap-
reshaped an area for landscaping. Natural soil structure
ing, and/or drainage features. Cuts are usually a rela-
is usually destroyed by these activities; not only are
tively minor component of subdivision developments
soils made abnormally dense, but there are no longer
but are a dominant feature on highway rights-of-way,
any natural channels or planes of weakness for roots,
as discussed in more detail later. In general, cut mate-
water, and air to penetrate. It is also important to point
rials expose subsoil and/or deeper geologic strata and
out that normal foot traffic, game playing, or infrequent
may therefore be very clayey and/or quite coarse and
tire traffic can also cause compaction of the immedi-
rock-like. One limitation of these materials is that dur-
ate surface soil, particularly when the soil is moist and
ing grading, cut clays will smear and seal and thereby
readily compressible.
limit water and root penetration. The lower sections
of cut materials may also be subject to the limitations The ability of a growing root tip to penetrate soil is
described above for exposed subsoils such as clayey directly dependent on soil strength. Soil strength —
textures and acidic pH. However, due to the fact that which essentially is its resistance to deformation or
they are much less variable, less compacted, and tend to shearing — is controlled primarily by a soil’s bulk den-
retain their native soil structure, cut slopes are usually sity and moisture content. Workable, loose soils have
superior to fill materials as described next. bulk densities of 1.0 to 1.4 grams per cubic centimeter

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 Chapter 3. Managing Urban Soils

(g/cm3). In a clayey soil, root penetration is greatly

retarded during dry conditions when bulk density
exceeds 1.5 g/cm3. The same soil when moist, how-
ever, may not impede rooting because soil strength is
then decreased. Sandy soils resist compaction due to
their larger packing voids between particles and can
support adequate rooting at bulk densities approaching
1.8 g/cm3, but will still be limiting at higher levels of
compaction.
Soils that are compacted also resist water movement
and gas exchange, which can seriously hinder plant
growth. Compacted soils also lack macropore space, Figure 3.4. Turf growth limited by compaction. The bare soil on the
which lessens water-holding capacity and rooting depth. left was pH 6.5 and fertile but heavily compacted and therefore, not
capable of supporting viable turf after seed germination. The turf in
Due to their lack of large pore spaces, water passes very the rest of this photo is also growing in moderately compacted soil as
slowly; therefore, dense soils often alternate between evidenced by its “clumpy” appearance.
being very wet in the winter and very dry in the summer.
Compacted soils also perch wet spots in unexpected Soil Layering and Associated Problems
locations and enhance runoff over infiltration. Finally,
a compacted soil can severely limit plant growth, even When downward percolating water encounters a com-
if other physical and chemical characteristics such as pacted zone or a zone of strongly contrasting soil tex-
texture and pH are optimal (see figure 3.4). Thus, soil ture (such as sand over clay or vice versa), water will
compaction cannot be recognized by conventional soil back up or “perch” just above the contact and saturate
testing and is often a “hidden limitation.” the zone above it. The nature and quantity of poros-
ity, particularly the amount of large, continuous pores
and channels in the soil, is the primary factor control-
ling the rate of water movement. Temporarily perched
water tables may persist close to the soil surface from
several days to months, depending on local soil and cli-
matic conditions. A similar perching occurs when water
passes through a coarse-textured soil layer with many
large pores and then encounters a finer-textured soil
layer (even if noncompacted) with much smaller pores.
Perching also occurs — but for an altogether different
reason — when water passing through a fine-textured
layer encounters a coarser sand or gravel stratum. In
this case, the finer-textured clay soil actually holds on
to its water so tightly (due to capillary forces or suction)
that it significantly slows its movement into the coarser
material below. Saturated conditions within the root-
ing zone cause a number of problems for plant growth,
including lack of oxygen, loss of available nitrogen,
and potential heavy-metal toxicities.

Adverse Soil Texture or Rock Content

As discussed in detail in chapter 2, loamy textures are
optimum for plant growth, and most native A horizons
Figure 3.3. High bulk density (2.0 g/cm3) traffic pan on a mining site
under loose spoil materials. Similar traffic pans are routinely found
(topsoil) are within this texture class. However, sub-
in home construction and highway environments. Roots cannot pen- soil layers (B horizons) are commonly quite clayey, and
etrate or loosen zones that are packed to a bulk density greater than deeper C horizons may be very sandy or rocky. Because
approximately 1.5 g/cm3 for a clay or 1.9 g/cm3 for a sandy-textured
soil. of the very fine texture and small pore size of clayey
soils, water is so tightly held that uptake by plant roots

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 Chapter 3. Managing Urban Soils

is limited. Clayey soils also limit plant growth due to Low Organic Matter and Microbial
higher soil strength, their tendency to dry and crack,
their tendency to form crusts after rain events, and other Activity
adverse chemical properties as discussed below. On the Unless topsoil layers are properly salvaged, stored, and
other hand, very coarse-textured (sandy) or rocky soils returned, newly constructed urban soils are much lower
are also prone to drought and do not retain added fertil- in their organic matter content and microbial biomass
izer and lime elements. than nearby natural soil profiles. This particularly affects
surface soil aggregation, infiltration, and water-holding
capacity. The lack of microbial activity may also limit
Adverse pH and Nutrient Status
the soils’ nitrogen, phosphorus, and sulfur cycles, which
Most subsoils (B and C horizons) in our region are are highly dependent on the active microbial biomass
low in pH (4.0 to 6.0) due to long-term acid-leach- for important mineralization transformations. Reveg-
ing processes and are very low in available nutrients etated urban soils will accumulate stable organic matter
because they formed well below the zone of active levels and microbial communities over time, but their
nutrient cycling and/or fertilization and liming. This development may also be strongly limited by the com-
acidic condition greatly increases the solubility of nat- bined adverse soil properties discussed above.
urally occurring phytotoxic metals like aluminum and
manganese. In certain instances (e.g., Piedmont sap-
rolites), however, deep subsoil materials may actually Inclusion of Mixed and Foreign Materials
be quite moderate in pH and nutrient cations (calcium, One of the unique diagnostic features of most urban
magnesium, potassium), but they will still be very low soils is their inclusion of a wide array of dissimilar nat-
in plant-available nitrogen and phosphorus. The red ural and man-made (anthropogenic) materials. This is
and yellow colors commonly seen in subsoil materi- particularly true of soils on residential lots where con-
als are due to coatings of iron-oxides, which tend to tractors are unlikely to remove excess sand, gravel or
be ubiquitous in regional subsoils. These amorphous other materials due to the cost of loading and hauling.
iron coatings along with associated aluminum oxides By definition, these materials usually are found in the
(which are not readily visible) have the ability to fill portions of urban soils, but they may also occur in
adsorb large amounts of applied phosphorus fertiliz- scattered pockets or thin veneers over exposed subsoils
ers via a process called phosphorus-fixation (see chap- or cut areas. Following is a summary of a few of the
ter 4), particularly when the soil pH is less than 6.0 more problematic materials:
(Brady and Weil 2008).
Gravel and sand are commonly found in layers or
In certain instances — particularly where high pH pockets related to mortar mix areas, temporary roads,
mortar mix or quick lime (see discussion later) have or storage areas. These are usually capped with finer-
been added to the soil in excessive amounts — the textured fill or topsoil layers, generating a very strong
soil pH may be abnormally high (more than 8.2). This textural discontinuity that limits water drainage.
can lead to a variety of plant nutrient deficiencies and
Cement and mortar mix are usually found in localized
toxicities and soil physical problems (Brady and Weil
areas but may be mixed throughout a given fill layer
2008). If the soil is alkaline (pH more than 8.2) but
when materials are bulldozed or moved during final
weakly buffered, the pH can be readily reduced via
site grading. Mortar mix will impart very high soil pH
addition of aluminum sulfate (Al2(SO4)3) or by add-
(9.0 or more) to localized areas for long periods of time
ing acid-forming organic matter like pine needles and
until it fully reacts with natural soil acidity. Poorly cured
leaves and allowing natural decomposition to reacid-
waste concrete can also cause locally high soil pH.
ify the soil. However, if the soil alkalinity is highly
buffered (i.e., more than 5 to 10 tons of calcium car- Waste wood, drywall, nails, rags, etc. tend to be dis-
bonate equivalence; CCE) it will be necessary to add carded or to fall into the open excavation next to home
elemental sulfur (flowers of sulfur) to quickly form foundations and block walls and are commonly mixed
sulfuric acid in soil solution to neutralize the excess into the soils that constitute the backfill. As waste wood
alkalinity. This must be done very carefully because, or rags decompose, they generate locally anaerobic
as discussed later, reduced sulfur is highly reactive in zones that are adverse to the roots of many native and
the soil and even a minor over-application can drive ornamental plants. Drywall, on the other hand, is pri-
the soil pH below 4.0. marily gypsum and paper and is actually used as an
approved soil amendment (after grinding) in several

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 Chapter 3. Managing Urban Soils

southeastern states. Nails, wire, metal flashing, and Managing Dense Soils
glass are also commonly encountered in this zone and
pose more of a safety hazard to the home gardener than Field determination of bulk density is difficult for an
a plant growth limitation. untrained person, but a general identification of com-
pacted or dense soils can be estimated via the “calibrated
shovel” technique discussed above. Tillage (e.g., roto-
Managing Urban Soils and Their tilling) or deep ripping (via a ripper or chisel plow) is
Limitations the only practical way to improve soil porosity but may
be too expensive or impractical for many home lawns or
Soil Sampling, Testing, and Fertilizer confined urban situations. Hollow-tine aerification can
also be effective for surface compaction in home lawns.
Plus Lime Prescriptions However, care must be taken to avoid excessive tillage,
Appropriate soil sampling and testing is critical to manag- which can lead to destruction of large aggregates. Too
ing urban soils. First of all, you need to take some time to much tillage also decreases organic matter content by
try to understand the nature of your local urban soil land- speeding its oxidation and decomposition. Addition of
scape. Start by looking for areas of obvious cut slopes compost and/or other organic amendments into surface
and fills. Using a shovel or a tiling spade, try to discern if soil layers will promote aggregation and macroporosity
you have topsoil return over cut subsoils or exposed cut and thereby decrease bulk density over time.
and fill materials. With a little investigation and thought
about how your landscape’s soil materials were moved Gypsum and other soil amendments and conditioners
around, you should be able to discern a pattern. As you are commonly advertised as being able to “cure com-
do this, pay attention to whether or not the soil is readily paction.” While these products may improve soil aggre-
“diggable” or dense and resists penetration. Remember gation they will have virtually no effect on soil bulk
that soils are much stronger and resistant to digging and density unless they are actively tilled and mixed into the
penetration when they are dry, so try to do this evaluation loosened soil zone. Similarly, certain plants (e.g., switch-
when the soil is moist (but not too wet). grass and alfalfa) are widely touted as being able to root
deeply into compacted soils and “loosen” them. This is
Next, follow the soil sampling instructions outlined not a viable solution for highly compacted soils that lack
in chapter 5, but try to separate areas of cut, fill, and structure and vertical continuous macropores, because
exposed subsoil where possible into different soil the growing root tip of these plants is actually quite pli-
sampling zones. Once a competent lab analyzes the able and must find an open soil pore to exploit before it
samples, follow the fertilizer and lime prescriptions. If can subsequently enlarge and open it further as it pene-
areas of strongly contrasting vegetation patterns occur trates downward and subsequently expands in diameter.
(see figure 3.4), sample them separately. When pos-
sible, resample and retest problematic areas in future
years to confirm that soil conditions are improving. Managing Clayey Subsoils
First, problems of acidity and infertility must be solved
It is important to note that the soil testing procedures through appropriate soil liming and fertilization strat-
and fertilizer/lime recommendation systems used by egies as discussed above. Usually, another factor to
the majority of university and private-sector laborato- correct immediately is the low organic matter con-
ries were developed and correlated for use on natural tent. Appropriate amounts of compost or other organic
weathered surface soils and therefore may not accu- materials (see chapter 9) should be repeatedly mixed
rately predict amendment needs for newly disturbed in deeply (6 inches or more, if possible). Over time,
urban soils. This is not to say that soil testing is not the organic matter decomposes and stabilizes the new
appropriate for urban soils, but the results of a given surface soil, aiding in essential soil particle aggrega-
test need to be specifically interpreted for their applica- tion and building nutrient supplies. Remember that
tion to these types of materials. This is particularly true
the establishment and maintenance of organic matter
when unweathered sediments or soft rocks are being
in the soil does much to aid long-term fertility as well
revegetated or the road cut exposes unusually reactive
as physical properties like aggregation, infiltration, and
materials (e.g., sulfidic soils) as discussed later. Once
water-holding capacity.
these urban soils have been managed and equilibrated
to support vegetation for several years, however, inter- Most subsoils are dense and/or clayey, so particular
pretation of soil testing results is more straightforward. attention must be paid to the problems of poor drainage

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 Chapter 3. Managing Urban Soils

and water saturation as discussed next. Even the addi-

tion of trucked-in topsoil usually will not solve poor
drainage problems caused by clayey or compacted
subsoils. Before new topsoil is added or created by the
addition of organic matter, poorly drained exposed sub-
soils should be deeply ripped or tilled. In many situa-
tions the use of raised beds greatly eases the required
modification of surface soil properties.

Preserving and Maintaining Native

Shrubs and Trees
Most of our native woody trees and shrubs in the mid-
Atlantic region are adapted to acidic soil conditions but
also rely on the maintenance of a litter layer (O horizon) Figure 3.5. Inappropriate addition of topsoil over native trees: The
topsoil material was added too thickly (12 inches) and then com-
and its provision of essential nutrients as it decomposes pacted (as seen at left) to a point that gas exchange by the living tree
over time. Thus, a large majority of the tree’s fine feeder roots was limited. Most of these white oaks died within two years of
roots exist in the upper 6 inches or so of soil and are this application.

generally adapted to a loose and well-aerated surface.

Unfortunately, the urban soil development process fre- A Common Combination of Problems
quently removes the litter layer and compacts the soil. and a Prescription
Furthermore, typical home lawn liming targets (i.e., pH
6.5 to 7.0) can drive the soil pH to levels where the Dense, clayey, acidic soils are commonly found
trees become deficient in critical micronutrients, par- throughout the urban and roadside environment and
ticularly iron and manganese. To protect these valuable these materials are usually quite low in plant-available
trees during the construction process, it is important phosphorus when they are freshly graded or exposed in
to keep all heavy traffic and fill placement off the soil cuts. Because of this, it is always important to sample
immediately around and under the tree’s canopy. This and soil test these materials. Based on soil tests, it is not
will usually require placing a temporary fence around uncommon to see recommendations calling for appli-
the tree (to the extent of the canopy drip line) and con- cations of lime at 2 to 4 tons per acre, coupled with
tinued vigilance by the homeowner or an informed con- enhanced phosphorus fertilization (150 pounds or more
struction supervisor. per acre as phosphorus oxide (P2O5)) to address fertility
issues. The addition of high-quality compost (1 inch)
After construction is completed, it is best to leave and tillage of all amendments to 6 inches will rapidly
natural litterfall on these areas where possible and to remediate these problems for turf establishment and
avoid the addition of excess lime or fertilizers to the growth. This treatment will not correct deeper com-
soil. Unfortunately, many homeowners and landscap- paction problems, however, so other soil modification
ers desire to establish turfgrass on these areas, which procedures may be necessary for deeper-rooted land-
are often undulating due to shallow roots and other scape plantings or to solve problems with water perco-
manifestations of the formerly forest soil profile. One lation, as discussed below. It is also important to point
particularly damaging practice is the placement of thick out that older established home lawns may actually be
(more than 4 inches) lifts of topsoil over the roots in quite high in plant-available phosphorus due to long-
an effort to smooth the surface soil out and establish term fertilization, so phosphorus fertilizer rates should
viable turf. This frequently leads to soil compaction, always be based on an appropriate soil test.
inadequate gas exchange, and a soil chemical environ-
ment that is not suitable for the long-term survival of Managing Wet Soils
the native trees or shrubs (see figure 3.5).
Compacted and/or clayey soils cause numerous water-
ing problems. The most obvious is surface ponding
caused by slow water penetration into the ground. When
dense or high-clay layers limit downward water move-
ment, the soil becomes saturated and oxygen — which

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 Chapter 3. Managing Urban Soils

moves very slowly through water — cannot reach plant here. Sulfidic soil and geologic materials occur through-
roots. If the saturated condition persists, roots will die out the mid-Atlantic region, but are particularly com-
from oxygen starvation. Highly compacted soils, even mon in the Middle and Upper Coastal Plain region
when dry, cause the same problem. Extended periods between Richmond and Stafford County, Va. (Orndorff
of water saturation also lead to increased availability and Daniels 2004).
of heavy metals such as iron and manganese, which in
Acid sulfate soils are earthen materials that have been
some soils may actually be phytotoxic. Saturated con-
degraded by oxidation of sulfides (like pyrite, FeS2) to
ditions can also accelerate soil nitrogen losses due to
produce unusually low soil pH conditions (less than
denitrification (see chapter 4).
3.9) when they are excavated from nonoxygenated
There are a number of ways to manage saturation prob- zones below the surface and exposed to atmospheric
lems in soil. One is to increase internal water move- conditions. As they oxidize, a wide array of acidity and
ment by improving aggregation and pore space. There soluble-salt-related plant growth and material damage
are several ways to do this: increasing and maintaining problems are common. Essentially, these materials con-
organic material levels, changing or keeping pH in the tain sulfidic minerals that react with water and oxygen
range between 5.5 and 6.5, adding a soil conditioner to form sulfuric acid. This active set of processes is
such as very coarse sand, cultivation only when mois- called “sulfuricization.” The vast majority of acid sul-
ture levels are ideal, and remediating compaction. How- fate soils is the result of land-disturbing activities that
ever, the addition of organic material and associated bring previously unoxidized (reduced) materials up to
mixing and tillage is probably the single most-effective the surface and allow them to react.
action you can take, assuming the underlying soil zone The normal maximum range of pH for soils in the mid-
is well-drained and can accept percolating water. Atlantic region is between 4.0 and 7.5. In the absence
Another way to increase internal water movement in of liming, the great majority of these soils are naturally
wet soils is to shatter subsoil pans. If just a few deep acidic with a pH between 4.5 and 5.5. In almost all
cracks for water percolation are made down through instances, any soil with a pH less than 3.9 in Virginia is
the subsoil, large amounts of saturated water will flow indicative of active or historic acid sulfate soil condi-
through them (assuming the underlying layers will tions and is quite toxic to plant growth and local receiv-
accept the water). Alternatively, subsurface drainage ing streams. In worst-case instances, soil pH values as
can be installed beneath the soil to carry away excess low as 1.8 have been measured at locations such as the
water. This is usually expensive, but may be the only Stafford Airport in Virginia (Fanning et al. 2004).
alternative in many situations. Still another approach is
to limit the amount of water entering the soil by divert- Where Do Sulfidic Materials Come
ing surface water away from the poorly drained area From and What Do They Look Like?
or by digging interceptor trenches just uphill from it.
Sulfides precipitate naturally in tidal marshes, accumu-
Plastic mulch can also be used to decrease total water
late in sediments, and are enriched in certain metamor-
penetration.
phic and igneous rocks. Thus, they occur naturally in
many of the sediments underlying our Coastal Plain and
Acid Sulfate Soil Conditions and in other rock types throughout the mid-Atlantic region.
For example, most of the soils in the Fredericksburg/
Management Stafford County, Va., area formed out of parent materi-
Over the past decade, many highway, commercial, als that originally contained sulfides, but they oxidized
and home residential construction activities in the and weathered out of the surface soil horizons (layers)
mid-Atlantic region have exposed what are known as tens of thousands of years ago. These subsoil horizons
“sulfidic materials” that quickly react to produce “acid are usually bright yellow to red in color and are usu-
sulfate soil conditions” (Wagner et al. 1982). Without ally quite acidic (pH 4.0 to 5.5). However, many deeper
question, these materials and their associated effects on cuts (more than 10 to 20 feet) can reveal unoxidized
plant growth, water quality, and construction materi- sulfidic materials that are typically gray, steel blue, or
als pose the greatest risk of any materials managed in sometimes black in color but still have a high pH (more
the urban soil environment (Fanning et al. 2007). Even than 6.5) in situ. Once exposed at the surface, however,
though they are not routinely encountered, their affects the pH of these materials can drop below 4.0 within
are so catastrophic that they deserve detailed coverage several months.

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 Chapter 3. Managing Urban Soils

How Do I Recognize Acid Sulfate 1,000 tons of material, which handily also happens to
be the average weight of 1 acre of soil, 6 inches deep.
Materials? Reduced sulfur is very reactive and every 1.0 percent of
Because fresh, unreacted, sulfidic materials have a sulfidic sulfur, if fully reacted, generates enough acidity
near-neutral pH, the only way to identify them before to require approximately 32 tons of agricultural lime-
disturbance is appropriate testing and lab analyses as stone (finely ground calcium carbonate (CaCO3)) per
described later. Once they react to become “active acid 1,000 tons of soil to fully neutralize! Thus, even 0.3
sulfate” soils, distinctive indicators include (1) dead percent sulfidic sulfur in these materials can generate a
vegetation, (2) red iron staining on concrete and block lime demand of 10 tons per acre (6 inches deep), which
walls, (3) concrete etching and dissolution, (4) rapid is much higher than we ever apply to “normal” soils.
corrosion of iron and galvanized metal, and (5) strong Occasionally, Coastal Plain sediments do contain suf-
sulfurous odor from rubbed hand samples. ficient lime (as fine shell fragments, etc.) to completely
or partially offset their acid-forming potential, but this
What Is the Potential Risk and Damage is a rare occurrence.
From Acid Sulfate Soil Processes? At Virginia Tech, we use a similar technique to ABA for
Acid sulfate soil conditions and associated sulfuriciza- potential acidity called the peroxide potential acidity
tion reactions generate a number of extreme soil and (PPA) technique. In this method, we use strong hydro-
water quality challenges. First of all, plants are killed gen peroxide (H2O2) to force the complete reaction of
by the direct effects of low pH, high heavy-metal sol- the sulfides and their internal neutralization by carbon-
ubility, and soluble sulfate salt stress. The extremely ates. In our experience, it correlates very well with ABA
acidic (pH 1.8 to 3.8) soil solutions and percolates for a wide range of Virginia materials. For example,
directly degrade concrete, iron, and galvanized metal our long-term research results indicate that acid sulfate
via a number of mechanisms. Finally, acid runoff and materials in the Fredericksburg/Stafford County region
seepage from these materials can seriously degrade average between 10 and 20 tons of lime demand per
local receiving streams. Thus, it is critically important acre (or per 1,000 tons of soil) in their fresh/unoxidized
that these materials be isolated or treated to remediate state. On occasion, we have tested small pockets of
their acid-producing potential and limit damage. materials that exceeded 50 tons of lime per 1,000 tons
of soil or per acre net acid demand! Once these materi-
als have fully reacted and oxidized, however, they typi-
How Do I Confirm Whether or Not I cally require only 4 to 6 tons of lime per acre to bring
Have Acid Sulfate Materials in My Soil? their low pH (less than 4.0) up to 7.0.
In addition to the visual symptoms described above,
active acid sulfate materials will usually exhibit a com- What Can I Do to Remediate Acid
bination of low pH (less than 3.9) and high levels of
potential acidity (total lime demand) relative to native
Sulfate Soil Conditions?
soils. Fresh, unoxidized, sulfidic materials may have a First of all, the only way to prevent these reactions
normal pH but will have high levels of potential acidity from occurring in disturbed cut/fill materials is to keep
(see below). them out of contact with the oxidizing atmosphere and
water. However, once they are placed and graded on
a home site, the only practical way to remediate them
What Is Potential Acidity and How Is It is to bulk blend sufficient agricultural limestone (or
Expressed? other approved liming materials) with them to offset
Potential acidity is estimated by several lab techniques the full amount of acidity that will be produced over
that have been used and refined by the mining industry extended periods of time (i.e., their potential acidity).
since the 1970s to prevent the formation of “acid mine We also recommend applying 25 percent more lime to
drainage” from coal and metal mines. The most widely ensure long-term alkaline buffering in the system. For
used technique is called “acid-base accounting” (ABA), example, let’s assume the soil in your backyard has a
which assumes that all sulfides in the material will fully net potential acidity of 10 tons per acre of lime demand.
react to form sulfuric acid and then balances that against With the 25 percent buffer factor added to it, you need
the material’s inherent lime or neutralizing capacity. to add the equivalent of 12.5 tons of lime per acre, 6
The results are expressed in tons of lime demand per inches deep. Usually, your yard will be much less than

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 Chapter 3. Managing Urban Soils

an acre in size, so we need to convert this to a more color, and any gray, blue-gray, or black strata should
practical liming rate per 1,000 square feet. As a matter be tested for total sulfur. If total sulfur is more than
of convenience, one 50-pound bag of agricultural lime 0.25 percent, those same strata should be tested for
per 1,000 square feet is approximately equivalent to 1 acid-base-accounting or peroxide potential acidity. Any
ton per acre. So, the basic liming requirement for your materials with a net lime demand of more than 5 tons of
back yard would be 12.5 x 50 pounds = 625 pounds of lime per 1,000 tons of material (or soil) should be iso-
agricultural lime per 1,000 square feet. These materi- lated from the surface and either heavily compacted in
als would need to be well-mixed (with a rototiller or place to limit permeability or bulk limed before place-
air knife) to a depth of 6 inches to ensure full reaction ment to offset acidity production over time.
and remediation of the surface rooting zone. Once this
material is allowed to react following several rainfall
or irrigation events, you should be able to use normal
Where Can I Get More Information?
plant/lawn establishment procedures, but we recom- We maintain current information and reports on this
mend adding compost to the surface soil mix whenever subject posted to our research website at Virginia Tech
possible. It is important to note that the deeper soil lay- (www.cses.vt.edu/revegetation/remediation.html). Addi-
ers will not be affected by this treatment, so planting tionally, the most sophisticated program in the world
holes for deep-rooted vegetation (e.g., trees) require for recognition and remediation of acid sulfate materi-
deeper treatment. als is carried out in Queensland, Australia, due to its
preponderance of acid-forming parent materials. Their
We also recommend a similar remedial treatment for all website (www.nrw.qld.gov.au/land/ass/index.html) is
soils in direct contact with uncoated concrete or foun- quite comprehensive and informative, with numerous
dations, block walls, or metal conduits and pipes. The links to their reports, methods, and regulations.
exception would be where those materials (concrete,
metal, etc.) are under the water table or buried deeply
enough in the soil that they are beyond the depth of Soil Conditions in Highway
oxygen diffusion. Rights-of-Way
In a typical highway construction corridor, materials
What Kind of Lime Should I Use? lying above the grade of the proposed road are removed
The “lime” that we refer to above is “agricultural (cut) by a variety of earthmoving techniques and hauled
lime” (CaCO3 or Ca/MgCaCO3) and not hydrated lime to adjacent lower areas for disposal. Whenever possi-
(Ca(OH)2) or burnt lime (CaO). These two latter mate- ble, the cut materials are utilized as subgrade materials
rials are commercially available and occasionally used for the roadbed or as fill to span depressions and valleys
by the geotechnical engineering community for soil beneath the corridor. Excess fill materials are usually
cementation or waste treatment. They do have advan- disposed of in compacted fills as near to the road cor-
tages of being more concentrated and quicker to react. ridor as possible to minimize hauling costs. The com-
However, they are more expensive, can burn your eyes, bination of cut and fill activity generates fundamentally
and can rapidly drive soil pH to very high values that different surfaces for revegetation as the road-building
are also toxic to plants. Therefore, we only recommend project progresses across the landscape. Cut slopes will
the use of certified agricultural lime for this purpose. frequently expose a surficial weathered soil profile and
The use of pelletized lime products is acceptable and then extend well down into the underlying rock or sedi-
may make application of the very high rates easier with ments. These materials will therefore vary consider-
minimal dusting issues. ably in fundamental chemical and physical properties
with depth, particularly in regions like the mid-Atlantic
Ideally, How Can We Avoid These United States, where the geochemical weathering pro-
Problems in the First Place? files are deep and soil horizonation is strong. These gra-
dations with depth are predictable, however, and will
Based on our work with the Virginia Department tend to recur in a prescribed sequence as the cuts pro-
of Transportation and others (see website below for
ceed through the landscape.
details), we have developed a statewide map layer that
indentifies all geologic strata that have documented sul- Fill materials, on the other hand, tend to be quite dif-
fide risk. Predisturbance geologic drill cores by devel- ferent from road cuts due to the mixing effects of
oper’s consultants in these units should be evaluated for the earthmoving operations and the fact that they are

Urban Nutrient Management Handbook 3-9

 Chapter 3. Managing Urban Soils

typically heavily compacted in place to meet stability imperative to minimize water flow and sediment losses
and strength specifications. Fill materials may be more from the initial stages of grading operations. Uncon-
or less variable than adjacent cut areas, depending on trolled erosion also can severely degrade the site qual-
how they are handled and placed, but they are typically ity of the eroded area, particularly if applied topsoil,
quite compact and lack the well-developed aggrega- lime, and fertilizers are lost or a less-hospitable sub-
tion or structure that undisturbed soils usually possess. strate is exposed.
Therefore, soils in highway fill materials as a rule will
be less permeable to air, water, and roots than their nat-
ural precursors. Fills and fill slopes also are plagued
Manufactured Soils
by inclusions of aggregate, rock, concrete, and other In certain high-value situations like landscape planting
construction debris that seriously limit their water- beds and constructed athletic fields, the use of manufac-
retention characteristics. In contrast, soils on cut slopes tured topsoil materials is a viable alternative to having
generally retain the physical and chemical properties to manage the pre-existing urban soils (Puhalla et al.
of the original soil/geologic profile, but their surfaces 2010). This is particularly true when we consider what
are often compacted to some extent by the earthmoving is typically available and marketed as topsoil in rap-
equipment, and the soil is often “smeared” and sealed, idly developing areas of the mid-Atlantic. The majority
particularly in fine-textured soils. of materials that are marketed and sold as topsoil are
generated by the land development and construction
Regardless of whether you are dealing with cut or fill process and may or may not be true topsoil as defined
materials, it is critically important to understand that earlier (A plus E horizons). Additionally, these natural
the vast majority of materials that will be revegetated topsoils are highly variable over time as they are hauled
are composed primarily of subsoil or deeper geologic from differing sites with different soil properties, soil-
materials that will be very low in organic matter and removal depths, and handling/storage procedures. Very
associated macronutrients, particularly nitrogen and few of these materials are offered with any guarantee
phosphorus. When highly weathered subsoils are of pH, texture, or nutrient-supplying ability relative to
exposed, we are often left with a very clayey and highly established soil testing standards.
acidic substrate that will require significant inputs of
lime and phosphorus fertilizers before its basic chemi- The “ideal” soil for most turf establishment and land-
cal properties begin to resemble native topsoils. Deeper scaping applications is loamy in texture to ensure ade-
cuts that extend below the weathered soil zone will fre- quate water-holding capacity and aeration without being
quently contain large amounts of fresh, unweathered sticky and plastic when handled and graded. Beyond
rocks and sediments that can be significant sources of that, the soil should be moderate in pH (between 6.5
calcium, magnesium, potassium, and other nutrient ele- and 7.5) to ensure maximum beneficial biological
ments as they rapidly weather in their newly exposed activity and moderate to high in plant-available nutri-
geochemical environment. Acid-forming sulfidic mate- ents such as calcium (Ca), magnesium (Mg), potassium
rials (as discussed earlier) are also commonly encoun- (K), and phosphorus (P). Good topsoils also contain
tered in deeper road cuts in a variety of geologic settings small but adequate amounts of plant-essential micronu-
and can generate extremely harsh soil chemical condi- trients like iron (Fe) and copper (Cu), but should also
tions and associated runoff water quality complications be low in soluble salts and sodium (Na), which can dis-
as they oxidize. perse soil structure and harm plants. Finally, the ideal
soil would contain approximately 3 to 5 percent organic
The cut/fill and site development operations for new
matter that serves as a long-term source of plant nutri-
highways or other construction activities may cause
ents (especially nitrogen), maintains biological activity,
uncontrolled water flows and sediment loss from bare
and greatly enhances physical properties such as water-
soil areas. Many small, localized, disturbed areas with
holding capacity. Perhaps most importantly, the ideal
seemingly insignificant losses of water and soil will
soil for turf and landscaping applications would be con-
often coalesce into massive and rapid flows of water
sistent over time in all of the above properties so that
with high sediment loads, causing severe damage in
the user will not have to “fine-tune” establishment and
highway corridors as well as flooding and contamina-
management protocols for each batch of soil received.
tion of receiving streams. Even the initial slow flows of
clear water from numerous small areas of disturbance There are currently a number of manufactured topsoils
within a highway development corridor can cause available in the region. One example of a manufac-
progressively larger erosive flows of water. Thus, it is tured soil developed cooperatively by Luck Stone and

3-10 Urban Nutrient Management Handbook

 Chapter 3. Managing Urban Soils

Virginia Tech (Greene premium topsoil) is described Due to the inherent fertility of the Greene topsoil, use
below. This description is not intended as an endorse- of initial or starter fertilizers (especially phosphorus
ment of this particular product, but simply as an exam- and potassium) is probably not necessary or warranted,
ple of one of many commercially viable products. particularly in light of current concerns over minimiz-
ing losses of nutrients to surface waters. However, ini-
The Greene topsoil product is manufactured from
tially high levels of available nutrients will be depleted
native soil saprolite, compost, and mineralized igne-
over time by plant uptake, and like any soil, subsequent
ous rock dust to produce loamy topsoil that is well-bal-
fertilization will be required. The Greene topsoil prod-
anced in organic matter, available plant nutrients, and
uct is not recommended for root zone use with acid-
pH. This product was developed cooperatively with the
loving plants such as blueberries, azaleas, and native
Department of Crop and Soil Environmental Sciences
pines unless it is blended with naturally acidic (pH less
at Virginia Tech, and as seen in table 3.1, is equal to
than 6.0) soil materials.
or exceeds natural topsoils in productivity potential for
most horticultural, landscaping, and gardening applica-
tions. The Greene topsoil is high in organic matter (5 to Modified Soils and Mulches
7 percent), moderate in pH (6.0 to 7.5) and soluble salts Another approach to mitigate the adverse properties of
(up to 2.0 millimhos per centimeter (mmhos/cm)), and urban soils is via “soil modification” or “conditioning,”
low in sodium. Plant-available phosphorus is more than a process that generally involves the incorporation
70 parts per million (ppm), potassium and magnesium of inorganic or organic amendments into bulk soil to
are both more than 100 ppm, and calcium is more than fundamentally alter important soil physical properties
1,000 ppm. This topsoil also provides balanced levels
(Wallace and Terry 1998). Certain inorganic amend-
of plant-available micronutrients (e.g., boron, copper,
ments (e.g., sand or bottom ash) can be added to clayey
iron, manganese, and zinc).
soils to reduce their stickiness and plasticity, but the
The Greene topsoil is higher than natural topsoils in volumes required to generate a loamy texture (10 to 40
organic matter content and available nutrients because percent), coupled with the costs and logistics involved
it is carefully blended with fresh, unweathered primary limit this approach to high-value locales. Similarly,
mineral fines and compost to generate the characteris- waste clays from sand mining operations (e.g., slimes)
tics displayed in table 3.1. Perhaps most importantly, the can be added into extremely coarse-textured soils to
Greene topsoil product has been tested and proven to be convert them to loamy textures but similar issues of cost
quite consistent over time and has been proven effec- and logistics apply. Other inorganic amendments (e.g.,
tive in a wide range of plant growth uses in research at gypsum and lime) can be added to clayey or dispersed
Virginia Tech and on-site applications by the producer’s soils to promote aggregation, but this usually involves
client base of landscapers and developers. much lower loading rates than textural modification

Table 3.1. Important soil properties for the Greene topsoil compared to highly productive
prime farmland topsoil from Dinwiddie County, Va., and the range of typical topsoil
properties found in Virginia.
Soil property Greene topsoil Prime farmland Average Virginia topsoil
Texture Sandy loam Sandy loam Sandy loam to clay loam
pH (acidity) 6.6-7.2 6.0-6.5 4.5-7.5
Organic matter 5-7% 1-2% 0.5-3%
Available* calcium (Ca) >1,200 ppm 300-600 ppm <50-600 ppm
Available potassium (K) >250 ppm 30-60 ppm <20-80 ppm
Available phosphorus (P) 75-150 ppm 20-30 ppm <5-30 ppm
Available copper (Cu) 1.5 ppm 0.6 ppm 0.2-0.7 ppm
Data compiled from research reports by W. Lee Daniels, Virginia Tech.
*Available soil nutrients are those contained in an acid-extractable form that would be expected to contribute to plant uptake needs over
the growing season and are typically expressed in parts per million (ppm) of total soil weight. For a common-sense conversion, 100 ppm of
available Ca in a soil would equate to approximately 200 pounds of calcium in the upper 6 inches of topsoil over 1 acre.

Urban Nutrient Management Handbook 3-11

 Chapter 3. Managing Urban Soils

and really differs little from conventional liming prac- Craul, P. J. 1992. Urban Soil in Landscape Design.
tice. Certain inorganic soil conditioners (e.g., fly ash New York: John Wiley & Sons.
or waste gypsum) may also contain significant levels
Fanning, D. S., Cary Coppock, Z. W. Orndorff, W.
of soluble salts or potentially phytotoxic elements like
L. Daniels, and M. C. Rabenhorst. 2004. Upland
boron, so their use must be carefully considered and
active acid sulfate soils from construction of new
controlled.A wide array of organics (e.g., composts,
Stafford County, Virginia, USA, Airport. Austra-
biosolids, animal manures, and paper sludges) are also
lian Journal of Soil Resources 42:527-36.
routinely utilized to enhance aggregation, porosity, and
water-holding capacity in urban soils. Usually, these Orndorff, Z. W., and W. L. Daniels. 2004. Evaluation of
materials are most effective when incorporated or bulk acid-producing sulfidic materials in Virginia high-
blended with surface soil layers, which may require up way corridors. Environmental Geology 46:209-16.
to 25 percent volumetric addition rates. One potential
drawback of many organic amendments (e.g., biosolids Puhalla, J. C., J. V. Krans, and J. M. Goatley Jr. 2010.
and manures) is that addition at these rates may pose Sports Fields: Design, Construction, and Mainte-
significant nutrient runoff or leaching risks (see chap- nance. 2nd edition. Hoboken, N.J.: John Wiley &
ters 2, 9, 10, and 12). Another long-term management Sons.
factor to consider is that organic amendments will natu- Scheyer, J. M., and K. W. Hipple. 2005. Urban Soil
rally decompose with time, and their “bulking effect” Primer. USDA-NRCS, National Soil Survey Cen-
on porosity will thereby decline as well. However, the ter. Lincoln, Neb.: USDA. http://soils.usda.gov/
humus fraction they leave behind will make a very valu- use/urban/primer.html.
able and long-lived contribution to urban soil quality.
Wagner, D. P., D. S. Fanning, J. E. Foss, M. S. Pat-
Finally, surface mulches can also be utilized to buffer terson, and P. A. Snow. 1982. Morphological and
soil temperature, enhance water infiltration and reten- mineralogical features related to sulfide oxida-
tion, limit traffic-related soil compaction, and reduce tion under natural and disturbed land surfaces in
weed competition (Brady and Weil 2008). More detail Maryland. In Acid Sulfate Weathering, ed. J. A.
on use of organic mulches is found in chapter 9. Kittrick, D. S. Fanning, and L. R. Hossner, 109-25.
A more thorough discussion of the full array of soil Soil Science Society of America Special Publica-
amendments, conditioners, and mulches and their rela- tion No. 10. Madison, Wis.: Soil Science Society
tive advantages and management is beyond the scope of America.
of this book. However, greater detail on these topics Wallace, A., and R. E. Terry, eds. 1998. Handbook of
can be found in the various resources cited below. Soil Conditioners: Substances That Enhance the
Physical Properties of Soil. New York: Marcel
Literature Cited Dekker.
Booze-Daniels, J. N., J. M. Krouse, W. L. Daniels, D. L.
Wright, and R.E. Schmidt. 2000. Establishment of
low maintenance vegetation in highway corridors.
In Reclamation of Drastically Disturbed Lands, ed.
R. I. Barnhisel, W. L. Daniels, and R. G. Darmody,
887-920. Agronomy Monograph No. 41. Madison,
Wis.: American Society of Agronomy, Crop Sci-
ence Society of America, and Soil Science Society
of America.
Brady, N. C., and R. R. Weil. 2008. The Nature and
Properties of Soils. 14th ed. Upper Saddle River,
N.J.: Pearson Prentice Hall.
Brown, R. B., J. H. Huddleston, and J. L. Anderson,
eds. 2000. Managing Soils in an Urban Environ-
ment. Agronomy Monograph No. 39. Madison,
Wis.: American Society of Agronomy.

3-12 Urban Nutrient Management Handbook

 Chapter 4. Basic Soil Fertility

Chapter 4. Basic Soil Fertility

Greg Mullins, Former Professor and Extension Specialist, Crop and Soil Environmental Sciences, Virginia Tech
Kathryn C. Haering, Research Associate, Crop and Soil Environmental Sciences, Virginia Tech
David J. Hansen, Associate Professor, Plant and Soil Sciences, University of Delaware

Plant Nutrition Table 4.1. Eighteen essential elements for

plant growth and the chemical forms most
Essential Elements commonly taken up by plants.
An essential mineral element is one that is required for Form absorbed
normal plant growth and reproduction. With the excep- Element Symbol by plants
tion of carbon (C) and oxygen (O), which are supplied Carbon C CO2
from the atmosphere, the essential elements are obtained Hydrogen H H+, OH-, H2O
from the soil. The amount of each element required by Oxygen O O2
the plant varies; however, all essential elements are Nitrogen N NH4+, NO3-
equally important in terms of plant physiological pro-
Phosphorus P HPO42-, H2PO4-
cesses and plant growth.
Potassium K K+
The exact number of elements that should be considered Calcium Ca Ca2+
“essential” to plant growth is a matter of some debate. Magnesium Mg Mg2+
For example, cobalt (Co), which is required for nitrogen
Sulfur S SO42-
(N) fixation in legumes, is not considered to be an essen-
tial element by some researchers. Table 4.1 lists 18 ele- Iron Fe Fe2+, Fe3+
ments that are considered essential by many scientists. Manganese Mn Mn2+, Mn4+
Other elements that are sometimes listed as essential are Boron B H3BO3, BO3-, B4072-
sodium (Na), silicon (Si), and vanadium (V). Zinc Zn Zn2+
Copper Cu Cu2+
Categories of Essential Elements Molybdenum Mo MoO42-
Essential elements can be grouped into four catego- Chlorine Cl Cl-
ries, based on their origin or the relative amount a plant Cobalt Co Co2+
needs in order to develop properly (table 4.2). Nickel Ni Ni2+
1. N
 onmineral essential elements are derived from the
air and water.
Table 4.2. Essential elements, their relative
2. P
 rimary essential elements are most often applied in uptake, and sources where plants obtain
commercial fertilizers or in manures. them.
3. S
 econdary elements are normally applied as soil Macronutrients
amendments or are components of fertilizers that Nonmineral Primary Secondary Micronutrients
carry primary nutrients. (Mostly from (Mostly (Mostly (Mostly
air and water) from soil) from soil) from soil)
 onmineral, primary, and secondary elements are
N
Carbon Nitrogen Calcium Iron
also referred to as “macronutrients,” because they Hydrogen Phosphorus Magnesium Manganese
are required in relatively large amounts by plants. Oxygen Potassium Sulfur Boron
Zinc
4. “ Micronutrients” are required in very small, or
Copper
“trace,” amounts by plants. Although micronutrients Molybdenum
are required by plants in very small quantities, they Chlorine
are equally essential to plant growth. Cobalt
Nickel

Urban Nutrient Management Handbook 4-1

 Chapter 4. Basic Soil Fertility

Functions of Essential Elements in Plants Sulfur (S)

• R
 equired for the synthesis of the sulfur-containing
Carbon (C), Hydrogen (H), and Oxygen (O) amino acids cystine, cysteine, and methionine, which
• D
 irectly involved in photosynthesis, which accounts are essential for protein formation.
for most plant growth.
• I nvolved with development of enzymes and vita-
mins, chlorophyll formation, and formation of sev-
Nitrogen (N) eral organic compounds that give characteristic odors
• F
 ound in chlorophyll, nucleic acids, and amino to garlic, mustard, and onion.
acids.
• C
 omponent of protein and enzymes, which control
Iron (Fe)
almost all biological processes. • Serves as a catalyst in chlorophyll synthesis.
• I nvolved in many oxidation-reduction reactions dur-
Phosphorus (P) ing respiration and photosynthesis.
• E
 ssential component of adenosine triphosphate (ATP)
— which is directly responsible for energy transfer Manganese (Mn)
reactions in the plant — and of DNA and RNA. • F
 unctions primarily as a part of the enzyme systems
• E
 ssential component of phospholipids, which play in plants.
critical roles in cell membranes. • Activates several important metabolic reactions.
• I mportant for plant development — including devel- • Plays a direct role in photosynthesis.
opment of a healthy root system, normal seed devel-
opment, and photosynthesis — respiration, cell • A
 long with iron, serves as a catalyst in chlorophyll
division, and other processes. synthesis.

Potassium (K) Boron (B)

• R
 esponsible for regulation of plants’ water usage, • E
 ssential for germination of pollen grains and growth
disease resistance, and stem strength. of pollen tubes, seed, and cell wall formation.

• I nvolved in photosynthesis, drought tolerance, winter • E

 ssential for development and growth of new cells in
hardiness, and protein synthesis. meristematic tissue.
• S
 ugar/borate complexes associated with translocation
Calcium (Ca) of sugars, starches, nitrogen, and phosphorus.
• Essential for cell elongation and division. • Important in protein synthesis.
• S
 pecifically required for root and leaf development,
function of cell membranes, and formation of cell wall Zinc (Zn)
compounds. • E
 ssential for promoting certain metabolic/enzymatic
reactions.
• Involved in the activation of several plant enzymes.
• N
 ecessary for the production of chlorophyll, carbo-
Magnesium (Mg) hydrates, and growth hormones.
• P
 rimary component of chlorophyll, and therefore, • A
 ids in the synthesis of plant growth compounds and
actively involved in photosynthesis. enzyme systems.
• S
 tructural component of ribosomes, which are
required for protein synthesis. Copper (Cu)
• Necessary for chlorophyll formation.
• I nvolved in phosphate metabolism, respiration, and
the activation of several enzyme systems. • Serves as a catalyst for several enzymes.

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 Chapter 4. Basic Soil Fertility

Molybdenum (Mo) Elements can be either “mobile” or “not mobile” within

plants. This determines where symptoms of an element
• R
 equired for the synthesis and activity of the enzyme deficiency will first appear in a plant. A mobile element
system that reduces nitrate to ammonium in the is one that is able to “translocate” (move) from one part
plant. of the plant to another depending on its need. Mobile
• E
 ssential in the process of symbiotic nitrogen fixation elements generally move from older (lower) plant parts
by Rhizobia bacteria in legume root nodules. to the meristem, or growing point.

Chlorine (Cl) Soil pH, Nutrient Availability, and

• I nvolved in energy reactions in the plant, breakdown Liming
of water, regulation of stomata guard cells, mainte-
nance of turgor, and rate of water loss. Effect of pH on Nutrient Availability
• I nvolved in plant response to moisture stress and Many soil elements change form as a result of chemical
resistance to some diseases. reactions in the soil. Plants may or may not be able to use
elements in some of these forms. Because pH influences
• Activates several enzyme systems.
the soil concentration and, thus, the availability of plant
• S
 erves as a counter ion in the transport of several nutrients, it is responsible for the solubility of many nutri-
cations in the plant. ent elements. Figure 4.1 illustrates the relationship between
soil pH and the relative plant availability of nutrients.
Cobalt (Co)
• E
 ssential in the process of symbiotic nitrogen fixation
by Rhizobia bacteria in legume root nodules.
• N
 ot proven to be essential for the growth of all higher
plants.

Nickel (Ni)
• Component of the urease enzyme.
• E
 ssential for plants in which ureides are important in
nitrogen metabolism.

Nutrient Deficiency Symptoms

Visual diagnosis of plant deficiencies can be very risky.
There may be more than one deficiency symptom
expressed, which can make diagnosis difficult. Both
soil and tissue samples should be collected, analyzed,
Figure 4.1. Relationship between soil pH and nutrient availability.
and interpreted before any recommendations are made Graphic by Kathryn Haering.
concerning application of fertilizer.
Phosphorus solubility and plant availability are con-
Terminology used to describe deficiency symptoms trolled by complex soil chemical reactions, which are
(table 4.3) includes: often pH-dependent. Plant availability of P is gener-
ally greatest in the pH range of 5.5 to 6.8. When soil
Chlorosis Yellowing or lighter shade of green.
pH falls below 5.8, P reacts with Fe and Al to produce
Necrosis Browning or dying of plant tissue. insoluble iron and aluminum phosphates that are not
Interveinal Between the leaf veins. readily available for plant uptake. At high pH values,
phosphorus reacts with Ca to form calcium phosphates
Meristem Growing point of a plant.
that are relatively insoluble and have low availability
Internode Distance of the stem between the leaves. to plants.

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 Chapter 4. Basic Soil Fertility

Table 4.3. Element mobility and specific deficiency symptoms.

Element Mobility Deficiency Symptoms and Occurrence
Nitrogen Mobile within plants; lower leaves Stunted, slow-growing, chlorotic plants; reduced yield; plants more
show chlorosis first. susceptible to weather stress and disease. Some plants may mature
earlier.
Phosphorus Mobile within plants; lower leaves Overall stunted plant and a poorly developed root system. Can cause
show deficiency first. purple or reddish color associated with the accumulation of sugars.
Difficult to detect from visual symptoms.
Potassium Mobile within plants; lower leaves Scorching or firing along leaf margins, slow growth, poorly
show deficiency first. developed root systems, weak stalks, small and shriveled seeds and
fruit, and low disease-resistance.
Deficiencies most common on acidic sandy soils or soils that have
received large applications of Ca and/or Mg.
Calcium Not mobile within plants; upper Poor root growth and failure of terminal buds of shoots and apical
leaves and the growing point show tips of roots to develop, causing plant growth to cease.
deficiency symptoms first. Most often occurs on very acidic soils where Ca levels are low but
other deficiency effects such as high acidity usually limit growth
before Ca deficiency becomes apparent.
Magnesium Mobile within plants; lower leaves Yellowish, bronze, or reddish color in leaves while leaf veins remain
show deficiency first. green.
Sulfur Somewhat mobile within plants, Chlorosis of the longer leaves and possible chlorosis and stunting of
but upper leaves tend to show entire plant with severe deficiencies. Symptoms resemble those of N
deficiency first. deficiency; can lead to incorrect diagnoses.
Boron Not mobile within plants; upper Reduced leaf size and deformation of new leaves, interveinal
leaves and the growing point show chlorosis, distorted branches and stems, possible flower and/or fruit
deficiency symptoms first. abortion, stunted growth.
May occur on very acidic, sandy-textured soils or alkaline soils.
Copper Not mobile within plants; upper Reduced leaf size, uniformly pale yellow leaves, leaves may lack
leaves and the growing point show turgor and can develop a bluish-green cast, become chlorotic, and/or
deficiency symptoms first. curl. Flower production fails to take place.
Iron Not mobile within plants; upper Interveinal chlorosis that progresses over the entire leaf. With severe
leaves show deficiency symptoms deficiencies, leaves turn entirely white.
first. Factors contributing to Fe deficiency include imbalance with other
metals, excessive soil P levels, high soil pH, wet and cold soils.
Manganese Not mobile within plants; upper Interveinal chlorosis, brownish-black specks.
leaves show deficiency symptoms Occurs most often on high-organic-matter soils and soils with
first. neutral-to-alkaline pH and low native Mn content.
Zinc Not mobile within plants; upper Shortened internodes between new leaves, death of meristematic
leaves and the growing point show tissue, deformed new leaves, interveinal chlorosis.
deficiency symptoms first. Occurs most often on alkaline (high pH) soils or soils with high
available P levels.
Molybdenum Not mobile within plants; upper Interveinal chlorosis, wilting, marginal necrosis of upper leaves.
leaves show deficiency symptoms Occurs principally on very acidic soils because Mo becomes less
first. available with low pH.
Chlorine Mobile within plant, but deficiency Chlorosis in upper leaves; overall wilting of plants.
symptoms usually appear on the Deficiencies may occur in well-drained soils under high rainfall
upper leaves first. conditions.
Cobalt Used by symbiotic N-fixing Causes N deficiency, chlorotic leaves, and stunted plants.
bacteria in root nodules of legumes Occurs in areas with soils deficient in native Co.
and other plants.

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 Chapter 4. Basic Soil Fertility

Potassium, calcium, and magnesium are most present • H

 ydrogen is released into the soil by plants’ root sys-
in soils with pH levels greater than 6.0. They are gen- tems as a result of respiration and ion uptake pro-
erally not as available for plant uptake in acidic soils cesses during plant growth.
because they may have been partially leached out of
• N
 itrogen fertilization speeds up the rate at which
the soil profile.
acidity develops, primarily through the acidity gen-
At pH values less than 5.0, Al, Fe, and Mn may be sol- erated by nitrification:
uble in sufficient quantities to be toxic to the growth of
2NH4+ + 4O2 → 2H2O + 4H+ + 2NO3-.
some plants. Aluminum toxicity limits plant growth in
most strongly acidic soils. Aluminum begins to solu- Liming is a critical management practice for maintain-
bilize from silicate clays and Al hydroxides below a ing soil pH at optimal levels for plant growth. Liming
pH of approximately 5.3, which increases the activ- supplies the essential elements Ca and/or Mg, reduces
ity of exchangeable Al3+. High concentrations of the solubility and potential toxicity of Al and Mn, and
exchangeable Al are toxic and detrimental to plant root increases the availability of several essential nutrients.
development. Liming also stimulates microbial activity (e.g., nitri-
fication) in the soil, and improves symbiotic nitrogen
In general, most micronutrients are more available in
fixation by legumes. However, over-liming can induce
acidic than in alkaline soils. As pH increases, micronu-
micronutrient deficiencies by increasing pH above the
trient availability decreases, and the potential for defi-
optimum range.
ciencies increases. An exception to this trend is Mo,
which becomes less available as soil pH decreases. In Most plants grow well in the pH range 5.8 to 6.5. Legu-
addition, B becomes less available when the pH is less minous plants generally grow better in soils limed to
than 5.0 and again when the pH exceeds 7.0. pH values of 6.2 to 6.8. Some plants, such as blueber-
ries, mountain laurel, rhododendron, and others, grow
Soil organisms also grow best in near-neutral soil. In
best in strongly acidic (pH less than 5.2) soils.
general, acidic soil inhibits the growth of most organ-
isms, including many bacteria and earthworms. Thus,
acidic soil slows many important activities carried on Determining Lime Requirements
by soil microbes, including nitrogen fixation, nitrifica- Soil pH is an excellent indicator of soil acidity; how-
tion, and organic matter decay. Rhizobia bacteria, for ever, it does not indicate how much total acidity is pres-
instance, thrive at near-neutral pH and are sensitive to ent, and it cannot be used to determine a soil’s lime
solubulized Al. requirement when used alone.
The “lime requirement” for a soil is the amount of agri-
Soil Acidification and Liming cultural limestone needed to achieve a desired pH range
Acidification is a natural process that occurs continu- for the plants that are grown. Soil pH determines only
ously in soils throughout the mid-Atlantic region and is active acidity — the amount of H+ in the soil solution
caused by the following factors: at that particular time — while the lime requirement
determines the amount of exchangeable or reserve acid-
• T
 he breakdown of organic matter can cause acidifi-
ity held by soil clay and organic matter (figure 4.2).
cation of the soil as amino acids are converted into
acetic acid, hydrogen gas, dinitrogen gas, and carbon Most laboratories use soil pH in combination with
dioxide by the reaction: “buffered” solutions to extract and measure the amount
of reserve acidity, or “buffering capacity” in a soil.
2C3H7NO3 + O2 → 2HC2H3O2 + 3H2 + N2 + 2CO2.
The measured amount of exchangeable/reserve acidity
• T
 he movement of acidic water from rainfall through is then used to determine the proper amount of lime
soils slowly leaches basic essential elements such needed to bring about the desired increase in soil pH.
as Ca, Ma, and K, below the plant root zone and
The rate of limestone applied to any area should be
increases the concentration of exchangeable soil Al.
based on soil test recommendations. A soil test every
Soluble Al3+ reacts with water to form hydrogen ions,
two to three years will reveal whether or not lime is
which make the soil acidic.
needed. Sandy soils generally require less lime at any
• S
 oil erosion removes exchangeable cations adsorbed one application than silt loam or clay soils to decrease
to clay particles. soil acidity by a given amount. Sandy soils, however,

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 Chapter 4. Basic Soil Fertility

usually need to be limed more frequently because their

buffering capacity is low.
Nitrogen
The Nitrogen Cycle
Nitrogen is subject to more transformations than any
other essential element. These cumulative gains,
losses, and changes are collectively termed the “nitro-
gen cycle” (figure 4.3). The ultimate source of N is N2
gas, which comprises approximately 78 percent of the
earth’s atmosphere. Inert N2 gas, however, is unavail-
able to plants and must be transformed by biological or
industrial processes into forms that are plant-available.
As a result, the turf and landscape industry is heavily
dependent on commercial N fertilizer. Some of the
more important components of the N cycle are dis-
Figure 4.2. Relationship between residual, exchangeable, and active cussed below.
acidity in soils. Graphic by Kathryn Haering.

Figure 4.3. The nitrogen cycle (modified from the Potash & Phosphate Institute website at www.ppi-ppic.org).

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 Chapter 4. Basic Soil Fertility

Nitrogen Fixation amino sugars, and other complex nitrogen compounds.

Inorganic forms of soil nitrogen include ammonium
“Nitrogen fixation” is the process whereby inert N2 (NH4+), nitrite (NO2-), nitrate (NO3-), nitrous oxide
gas in the atmosphere is transformed into forms that (N2Ogas), nitric oxide (NOgas), and elemental nitrogen
are plant-available, including ammonium (NH4+) and (N2 gas). Ammonium, nitrite, and nitrate are the most
nitrate (NO3-). Fixation can take place by biological or important plant nutrient forms of N and usually make
by nonbiological processes. up 2 to 5 percent of total soil N.
Biological nitrogen-fixation processes include: Nitrogen “mineralization” (figure 4.4) is the conversion
of organic nitrogen to NH4+. This is an important pro-
Symbiotic Nitrogen Fixation cess in the N cycle because it results in the liberation of
This process is mediated by bacteria with the ability plant-available, inorganic nitrogen forms.
to convert atmospheric N2 to plant-available N while Nitrogen “immobilization” is the conversion of inor-
growing in association with a host plant. Symbiotic ganic, plant-available nitrogen (NH4+ or NO3-) by soil
Rhizobium bacteria fix N2 in nodules present on the microorganisms to organic N forms (amino acids and
roots of legumes. Through this relationship, the bacteria proteins). This conversion is the reverse of mineraliza-
make N2 from the atmosphere available to the legume tion, and these immobilized forms of N are not readily
as it is excreted from the nodules into the soil. available for plant uptake.

Nonsymbiotic Nitrogen Fixation

This is a N2-fixation process that is performed by free-
living bacteria and blue-green algae in the soil. The
amount of N2 fixed by these organisms is much lower
than that fixed by symbiotic N2 fixation. Figure 4.4. Mineralization and immobilization of soil nitrogen.
Graphic by Greg Mullins.
Nonbiological N-fixation processes include:
Carbon-to-Nitrogen Ratios
Atmospheric additions Mineralization and immobilization are ongoing pro-
Small amounts of N in the order of 5 to15 pounds per cesses in the soil and are generally in balance with one
acre per year can be added to the soil in the form of rain another. This balance can be disrupted by the incorpora-
or snowfall. This includes N that has been fixed by the tion of organic materials that have high carbon to nitro-
electrical discharge of lightning in the atmosphere and gen ratios (C:N). The ratio of %C to %N, or the C:N
industrial pollution. ratio, defines the relative quantities of these elements in
residues and living tissues. Whether N is mineralized
Industrial Nitrogen Fixation or immobilized depends on the C:N ratio of the organic
material being decomposed by soil microorganisms.
The industrial fixation of nitrogen is the most impor-
tant source of N as a plant nutrient. The production of • W
 ide C:N ratios of more than 30-to-1: Immobiliza-
N by industrial processes is based on the Haber-Bosch tion of soil N will be favored. Materials with wide
process where H2 and N2 gases react to form ammonia C:N ratios include bark mulch, straw, pine needles,
(NH3). Hydrogen gas for this process is obtained from dry leaves, and sawdust.
natural gas and N2 comes directly from the atmosphere.
The NH3 produced can be used directly as a fertilizer • C
 :N ratios of 20-to-1 to 30-to-1: Immobilization and
mineralization will be nearly equal.
or as the raw material for other N fertilizer products,
including ammonium phosphates, urea, and ammo- • N
 arrow C:N ratios of less than 20-to-1: Favor rapid
nium nitrate. mineralization of N. Materials with narrow C:N ratios
include manure and biosolids.
Forms of Soil Nitrogen The decomposition of an organic material with a high
Soil N occurs in both inorganic and organic forms. Most C:N ratio is illustrated in figure 4.5. Shortly after incor-
of the total N in surface soils is present as organic nitro- poration, high C:N ratio materials are attacked and used
gen. Organic soil N occurs in the form of amino acids, as an energy source by soil microorganisms. As these

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 Chapter 4. Basic Soil Fertility

Nitrate-N can be also be lost through denitrification, the

process where NO3- is reduced to gaseous nitrous oxide
(N2O) or elemental nitrogen (N2) and lost to the atmo-
sphere. During nitrification, 2 H+ ions are produced
for every NH4+ ion that is oxidized. These H+ cations
will accumulate and significantly reduce soil pH; thus,
any ammonium-containing fertilizer will ultimately
decrease soil pH due to nitrification.

Phosphorus
Figure 4.5. Nitrogen immobilization and mineralization after material
with a high C:N ratio is added to soil. Graphic by Kathryn Haering. The Phosphorus Cycle
organisms decompose the material, there is competi- Soil P originates primarily from the weathering of soil
tion for the limited supply of available N because the minerals, such as apatite, and from P additions in the
material does not provide adequate N to form proteins form of fertilizers, plant residues, manure, or biosolids
in the organisms. (figure 4.6). Orthophosphate ions (HPO4-2 and H2PO4-)
are produced when apatite breaks down, organic resi-
During this process, available soil N is decreased and the dues are decomposed, or fertilizer P sources dissolve.
carbon in the decomposing material is liberated as CO2 These forms of P are taken up by plant roots and are
gas. As decomposition proceeds, the material’s C:N ratio present in very low concentrations in the soil solution.
narrows and the energy supply is nearly exhausted. At
this point, some of the microbial populations will die and Many soils contain large amounts of P, but most of that
the mineralization of N in these decaying organisms will P is unavailable to plants. The types of P-bearing min-
result in the liberation of plant-available N. The timing erals that form in soil are highly dependent on soil pH.
of this process will depend on such factors as soil tem- Soluble P, regardless of the source, reacts very strongly
perature, soil moisture, soil chemical properties, fertility with Fe and Al to form insoluble Fe and Al phosphates
status, and the amount of organic material added. in acid soils and with Ca to form insoluble Ca phos-
phates in alkaline soils. Phosphorus in these insoluble
forms is not readily available for plant growth and is
Nitrification said to be “fixed.”
“Nitrification” is the biological oxidation of ammonium
(NH4+) to nitrate (NO3-) in the soil. Sources of NH4+
for this process include both commercial fertilizers and Phosphorus Availability and Mobility
the mineralization of organic residues. Nitrification is a As discussed earlier, plant roots take up P in the forms
two-step process where NH4+ is converted first to NO2-, of orthophosphates: HPO4-2 and H2PO4-. The predomi-
and then to NO3- by two autotrophic bacteria in the soil nant ionic form of P present in the soil solution is pH-
(Nitrosomonas and Nitrobacter). These bacteria get dependent. In soils with pH values greater than 7.2, the
their energy from the oxidation of nitrogen and their HPO4-2 form is predominant, while in soils with a pH
carbon from CO2. between 5.0 and 7.2, the H2PO4- form predominates.
Nitrification is important to N fertility because nitrate- Phosphorus has limited mobility in most soils because it
nitrogen (NO3-N) is readily available for uptake and reacts strongly with many elements and compounds and
use by plants and microbes. However, NO3- is an the surfaces of clay minerals. Unlike nitrate, P anions
“anion,” or negatively charged ion. Anions usually (HPO42-, H2PO4-) do not easily leach through the soil pro-
leach more readily than cations because they are not file because of their specific complexing reactions with
attracted to the predominantly negative charge of soil soil components. The release of soil P to plant roots and
colloids. Because of its negative charge and relatively its potential movement to surface water is controlled by
large ionic radius, nitrate is not readily retained in the several chemical and biological processes (figure 4.6).
soil and is easily leached to groundwater and surface Phosphorus is released to the soil solution as P-bearing
waters. Nitrate losses can be minimized through proper minerals dissolve, as P bound to the surface of soil min-
N management, including the proper rate and timing of erals is uncoupled or “desorbed,” and as soil organic
N fertilizer applications. matter decomposes or mineralizes (figure 4.7).

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 Chapter 4. Basic Soil Fertility

Figure 4.6. The phosphorus cycle (modified from the Potash & Phosphate Institute website at www.ppi-ppic.org).

Most of the P added as fertilizer and organic sources is

rapidly bound by soil minerals in chemical forms that
are not subject to rapid release; thus, soil solution P
concentrations are typically very low (less than 0.01
to 1.00 ppm). The supply of adequate P to a plant will
depend on the soil’s ability to replenish soil solution P
throughout the growing season (figure 4.7).
Phosphorus availability and mobility is influenced by
several factors:

Soil pH
In acidic soils, P precipitates as relatively insoluble
iron and Al phosphate minerals. In neutral and calcare-
ous soils, P precipitates as relatively insoluble Ca phos- Figure 4.7. Phosphorus content of the soil solution.
Graphic by Greg Mullins.
phate minerals. As illustrated in figures 4.1 and 4.8, soil
P is most available in the pH range of 5.5 to 6.8, where
the availability of soluble Al and Fe is low.

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 Chapter 4. Basic Soil Fertility

Movement of Soil Phosphorus to Plant Roots contribute to excessive growth of aquatic organisms,
which can have detrimental environmental impacts.
Phosphorus moves from soil solids to plant roots
through the process of “diffusion.” Diffusion is a slow Soils have a finite capacity to bind P. When a soil
and short-range process with distances as small as 0.25 becomes saturated with P, desorption of soluble phos-
inch. This limited movement has important implications phorus can be accelerated, with a consequent increase
because soil P located more than 0.25 inch from a plant in dissolved inorganic P in runoff. Thus, if the level
root will never reach the root surface. Dry soils reduce of residual soil phosphorus is allowed to build up by
the diffusion of P to roots; therefore, plants take up repeated applications of phosphorus in excess of plant
P best in moist soils. needs, a soil can become saturated with P and the poten-
tial for soluble phosphorus losses in surface runoff will
Residual Fertilizer Phosphorus Recovery increase significantly.
A plant uses only 10 to 30 percent of the P fertilizer Research conducted in the mid-Atlantic shows that the
applied during the first year following application. The potential loss of soluble P will increase with increasing
rest goes into reserve and can be used by plants in later levels of soil test P. Very high levels of soil-test P can
years. result from over-application of manure, biosolids, or
commercial phosphate fertilizer. Soils with these high
Timing and Placement of Phosphorus Fertilizer soil-test P levels will require several years without P
New plants need a highly available P source in order additions to effectively reduce these high P levels.
to establish a vigorous root system early in the season.
Once the root system begins to explore the entire soil Potassium
volume, there should be adequate amounts of residual
P to maintain plant growth. The Potassium Cycle
Potassium is the third primary plant nutrient and is
absorbed by plants in larger amounts than any other
nutrient except nitrogen. Plants take up K as the mon-
ovalent cation K+. Potassium is present in relatively
large quantities in most soils, but only a small per-
centage of the total soil K is readily available for plant
uptake.
The K cycle is illustrated in figure 4.9. In the soil,
weathering releases K from a number of common min-
erals, including feldspars and micas. The released K+
can be taken up easily by plant roots, adsorbed by the
Figure 4.8. Effect of pH on phosphorus availability to plants.
Graphic by Kathryn Haering. cation exchange complex of clay and organic matter,
or “fixed” in the internal structure of certain two-to-
one clay minerals. Potassium that is fixed by these clay
Phosphorus Transport to Surface Waters minerals is very slowly available to the plant.
Transport of soil P occurs primarily via surface flow
(runoff and erosion), although leaching and subsurface
lateral flow may also be possible in soils with high
Potassium Availability and Mobility
degrees of P saturation and artificial drainage systems. Although mineral K accounts for 90 to 98 percent of the
Water flowing across the soil surface may dissolve and total soil K, readily and slowly available K represent
transport soluble P, and erode and transport particulate only 1 to 10 percent of the total soil K. Plant-available K
P. Virtually all soluble P transported by surface run- (K that can be readily absorbed by plant roots) includes
off is biologically available, but particulate phospho- the portion of the soil K that is soluble in the soil solu-
rus that enters streams and other surface waters must tion and the exchangeable K held on the soil’s exchange
undergo solubilization before becoming available for complex. Exchangeable K is that portion of soil K that
aquatic plants. Thus, both soluble and sediment-bound is in equilibrium with K in the soil solution. Potassium
P are potential pollutants of surface waters and both can is continuously made available for plant uptake through

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 Chapter 4. Basic Soil Fertility

Figure 4.9. The potassium cycle (modified from the Potash & Phosphate Institute website at www.ppi-ppic.org).

the cation exchange process. There can be a continuous, is held by cation exchange, it is less mobile in fine-tex-
but slow, transfer of K from soil minerals to exchange- tured soils and most readily leached from sandy soils.
able and slowly available forms as K is removed from Most plant uptake of soil K occurs by diffusion.
the soil solution by plant uptake and leaching.
Potassium fertilizers are completely water-soluble and
Potassium applied as fertilizer can have various fates have a high salt index, so they can decrease seed ger-
in the soil. mination and plant survival when placed too close to
seed or transplants. The risk of fertilizer injury is most
• P
 otassium cations can be attracted to the cation- severe on sandy soils, under dry conditions, and with
exchange complex where it is held in an exchange- high rates of fertilization. A convenient and usually
able form and readily available for plant uptake. effective method of applying K fertilizers is by broad-
casting and mixing with the soil before planting. Fertil-
• Some of the K+ ions will remain in the soil solution.
izer injury is minimized by this method, but on sandy
• E
 xchangeable and soluble K may be absorbed by soils, leaching may cause the loss of some K.
plants.
• I n some soils, some K may be fixed by the clay fraction. Secondary Plant Nutrients
• A
 pplied K may leach from sandy soils during periods Introduction
of heavy rainfall.
Secondary macronutrients Ca, Mg, and S are required
Potassium moves more readily in soil than phosphorus in relatively large amounts for good crop growth.
does, but less readily than nitrogen. Because potassium These nutrients are usually applied as soil amendments

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 Chapter 4. Basic Soil Fertility

or applied along with materials that contain primary organic matter. Inorganic sulfur is usually present in the
nutrients. Secondary nutrients are as important to plant sulfate (SO42-) form, which is the form of S absorbed by
nutrition as major nutrients, because deficiencies of plant roots.
secondary nutrients can depress plant growth as much
Both soluble SO42- in the soil solution and adsorbed
as major plant nutrient deficiencies.
SO42- represent readily plant-available S. Elemental
sulfur is a good source of S, but it must first undergo
Calcium and Magnesium biological oxidation to SO42-, driven by Thiobacillus
Calcium and magnesium have similar chemical proper- thiooxidans bacteria, before plants can assimilate it.
ties and behave very similarly in the soil. Both of these This oxidation can contribute to soil acidity by produc-
elements are cations (Ca2+, Mg2+), and both cations ing sulfuric acid.
have the same amount of positive charge and a similar
Several fertilizer materials contain the SO42- form of
ionic radius. The mobility of both Ca and Mg is rela-
sulfur, including gypsum (CaSO4), potassium sulfate
tively low, especially compared to anions or to other
(K2SO4), magnesium sulfate (MgSO4), and potassium
cations such as Na and K; thus, losses of these cations
magnesium sulfate (K-Mag or Sul-Po-Mag). These fer-
via leaching are relatively low.
tilizer sources are neutral salts and will have little or no
Total Ca content of soils can range from 0.1 percent effect on soil pH.
in highly weathered tropical soils to 30 percent in cal-
In contrast, there are other SO42--containing compounds,
careous soils. Calcium is part of the structure of sev-
including ammonium sulfate ((NH4)2SO4), aluminum
eral minerals and most soil calcium comes from the
sulfate ((Al2SO4)3), and iron sulfate (FeSO4), that con-
weathering of common minerals, which include dolo-
tribute greatly to soil acidity. The SO42- in these materi-
mite, calcite, apatite, and calcium-feldspars. Calcium is
als is not the source of acidity. Ammonium sulfate has a
present in the soil solution and because it is a divalent
cation, its behavior is governed by cation exchange, as strong acidic reaction primarily because of the nitrifica-
are the other cations. Exchangeable Ca is held on the tion of NH4+, and aluminum and iron sulfates are very
negatively charged surfaces of clay and organic matter. acidic due to the hydrolysis of Al3+ and Fe3+.
Calcium is the dominant cation on the cation exchange Sulfate, a divalent anion (SO42-) is not strongly
complex in soils with moderate pH levels. Normally, adsorbed and can be readily leached from most soils.
it occupies 70 to 90 percent of cation exchange sites In highly weathered, naturally acidic soils, SO42- often
above pH 6.0. accumulates in subsurface soil horizons, where posi-
Total soil Mg content can range from 0.1 percent in tively charged colloids attract the negatively charged
coarse, humid-region soils to 4 percent in soils formed SO42- ion. Residual soil SO42- resulting from long-term
from high-magnesium minerals. Magnesium occurs applications of S-containing fertilizers can meet the S
naturally in soils from the weathering of rocks with requirements of plants for years after applications have
Mg-containing minerals such as biotite, hornblende, ceased.
dolomite, and chlorite. Magnesium is found in the soil
solution and because it is a divalent cation (Mg2+), its Micronutrients
behavior is governed by cation exchange. Magnesium
is held less tightly than calcium by cation exchange Introduction
sites, so it is more easily leached and soils usually con-
Eight of the essential elements for plant growth are
tain less Mg than calcium. In the mid-Atlantic region,
called micronutrients or trace elements: B, Cl, Cu,
Mg deficiencies occur most often on acidic and coarse-
Fe, Mn, Mo, Ni, Zn. Cobalt has not been proven to be
textured soils.
essential for higher plant growth, but nodulating bac-
teria need cobalt for fixing atmospheric nitrogen in
Sulfur legumes. Although micronutrients are not needed in
Soil sulfur is present in both inorganic and organic large quantities, they are as important to plant nutri-
forms. Most of the sulfur in soils comes from the tion and development as the primary and secondary
weathering of sulfate minerals such as gypsum; how- nutrients. A deficiency of any one of the micronutrients
ever, approximately 90 percent of the total sulfur in the in the soil can limit plant growth, even when all other
surface layers of noncalcareous soils is immobilized in essential nutrients are present in adequate amounts.

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 Chapter 4. Basic Soil Fertility

Micronutrients can exist in several different forms in Recommended rates of B fertilization depend on such
soil: within structures of primary and secondary miner- factors as soil-test levels, plant-tissue concentrations,
als, adsorbed to mineral and organic matter surfaces, plant species, weather conditions, soil organic matter,
incorporated in organic matter and microorganisms, and the method of application.
and in the soil solution. Many micronutrients combine
with organic molecules in the soil to form complex Copper
molecules called chelates, which are metal atoms sur-
In mineral soils, Cu concentrations in the soil solution
rounded by a large organic molecule. Plant roots absorb
are controlled primarily by soil pH and the amount of
soluble forms of micronutrients from the soil solution.
Cu adsorbed on clay and soil organic matter. A major-
A micronutrient deficiency, if suspected, can be identi- ity of the soluble Cu2+ in surface soils is complexed
fied through soil tests or plant analysis. Total soil con- with organic matter, and Cu is more strongly bound to
tent of a micronutrient does not indicate the amount soil organic matter than any of the other micronutri-
available for plant growth during a single growing sea- ents. Sandy soils with low organic matter content may
son, although it does indicate relative abundance and become deficient in Cu because of leaching losses.
potential supplying power. Micronutrient availability Heavy, clay-type soils are least likely to be Cu-deficient.
decreases as soil pH increases for all micronutrients The concentrations of Fe, Mn, and Al in soil affect the
except Mo and Cl. availability of Cu for plant growth, regardless of soil
type.
Specific soil-plant relationships for B, Cu, Fe, Mn, Mo,
and Zn are discussed in the next sections. Like most other micronutrients, large quantities of Cu
can be toxic to plants. Excessive amounts of Cu depress
Fe activity and may cause Fe deficiency symptoms to
Boron appear in plants. Such toxicities are not common.
Boron exists in minerals, adsorbed on the surfaces of
clay and oxides, combined in soil organic matter, and in
Iron
the soil solution. Organic matter is the most important
potentially plant-available soil source of B. Iron is the fourth-most abundant element, but the solu-
bility of Fe is very low and highly pH-dependent. Iron
Factors that affect the availability of B to plants solubility decreases with increasing soil pH. It can
include: react with organic compounds to form chelates or iron-
organic complexes.
Soil Moisture and Weather Iron deficiency may be caused by an imbalance with
Boron deficiency is often associated with dry or cold other metals, such as Mo, Cu, or Mn. Other factors that
weather, which slows organic matter decomposition. may trigger iron deficiency include excessive phospho-
Symptoms may disappear as soon as the surface soil rus in the soil; a combination of high-pH, high-lime,
receives rainfall or soil temperatures increase and root wet, cold soils and high bicarbonate levels; and low soil
growth continues, but yield potential is often reduced. organic matter levels.
Reducing soil pH in a narrow band in the root zone can
Soil pH correct iron deficiencies. Several S products will lower
Plant availability of B is maximized between pH 5.0 and soil pH and convert insoluble soil iron to a form the
7.0. Boron availability decreases with increasing soil plant can use.
pH, which means that B uptake is reduced at high pH.
Manganese
Soil Texture Availability of Mn to plants is determined by the equi-
Coarse-textured (sandy) soils, which are composed librium among solution, exchangeable, organic, and
largely of quartz, are typically low in minerals that mineral forms of soil Mn. Chemical reactions affecting
contain boron. Plants growing on such soils commonly Mn solubility include oxidation reduction and compl-
show boron deficiencies. Boron is mobile in the soil exation with soil organic matter. “Redox” or oxidation-
and is subject to leaching. Leaching is of greater con- reduction reactions depend on soil moisture, aeration,
cern on sandy soils and in areas of high rainfall. and microbial activity.

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 Chapter 4. Basic Soil Fertility

Manganese solubility decreases with increasing soil compounds to form soluble complexes. Organically
pH, so Mn deficiencies occur most often on high complexed, or chelated, Zn is important for the move-
organic-matter soils and on those soils with neutral-to- ment of Zn to plant roots. Soils can contain from a few
alkaline pH that are naturally low in Mn. Manganese to several hundred pounds of Zn per acre. Fine-textured
deficiencies may also result from an antagonism with soils usually contain more Zn than sandy soils do.
other nutrients, such as Ca, magnesium, and Fe. Soil
Total Zn content of a soil does not indicate how much
moisture also affects Mn availability. Excess moisture
Zn is available. The following factors determine its
in organic soils favors Mn availability because reduc-
availability:
ing conditions convert Mn4+ to Mn2+, which is plant-
available. • Z
 inc becomes less available as soil pH increases.
Coarse-textured soils limed above a pH of 6.0 are
Manganese deficiency is often observed on sandy
particularly prone to develop Zn deficiency. Soluble
Coastal Plain soils under dry conditions that have pre-
Zn concentrations in the soil can decrease three-fold
viously been wet.
for every pH unit increase between 5.0 and 7.0.

Molybdenum • Z
 inc deficiency may occur in some plant species on
soils with very high P availability and marginal Zn
Molybdenum is found in soil minerals as exchange-
concentrations due to Zn/P antagonisms. Soil pH fur-
able Mo on the surfaces of iron/aluminum oxides and
ther complicates Zn/P interactions.
bound soil organic matter. Adsorbed and soluble Mo is
an anion (MoO4-). • Z
 inc forms stable complexes with soil organic matter.
A significant portion of soil Zn may be fixed in the
Molybdenum becomes more available as soil pH
organic fraction of high organic-matter soils. It may
increases, so deficiencies are more likely to occur on
also be temporarily immobilized in the bodies of soil
acidic soils. Since Mo becomes more available with
microorganisms, especially when animal manures
increasing pH, liming will correct a deficiency if the
are added to the soil.
soil contains enough of the nutrient. Sandy soils are
deficient in Mo more often than finer-textured soils are, • A
 t the opposite extreme, much of a mineral soil’s
and soils high in Fe/Al oxides tend to be low in avail- available Zn is associated with organic matter. Low
able Mo because Mo is strongly adsorbed to the sur- organic-matter levels in mineral soils are frequently
faces of Fe/Al oxides. Heavy P applications increase indicative of low Zn availability.
Mo uptake by plants, while heavy S applications
Zinc availability is affected by the presence of certain
decrease Mo uptake.
soil fungi, called mycorrhizae, which form symbiotic
relationships with plant roots. Removal of surface soil
Zinc in land leveling may remove the beneficial fungi and
The various forms of soil Zn include soil minerals, limit plants’ ability to absorb Zn.
organic matter, adsorbed Zn on the surfaces of organic
matter and clay, and dissolved Zn in the soil solution.
Zinc released from soil minerals during weathering can
Acknowledgement
be adsorbed onto the Cation Exchange Complex, incor- This chapter is dedicated to the memory of Greg Mullins
porated into soil organic matter, or react with organic (1955-2009).

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 Chapter 5. Soil Sampling and Nutrient Testing

Chapter 5. Soil Sampling and Nutrient Testing

Rory Maguire, Associate Professor, Crop and Soil Environmental Sciences, Virginia Tech
Steven Hodges, Professor, Crop and Soil Environmental Sciences, Virginia Tech
Steve Heckendorn, Laboratory Manager, Crop and Soil Environmental Sciences, Virginia Tech

Very low: A plant response is most likely if the indi-

Introduction cated nutrient is applied. A large portion of the nutrient
Soil testing is a fundamental management practice for requirement must come from fertilization.
turfgrass and the ornamental landscape. A soil analy-
sis provides essential information on relative levels of Low: A plant response is likely if the indicated nutrient
organic matter, pH, lime requirement, cation exchange is applied. A portion of the nutrient requirement must
capacity (CEC), and levels of plant-available nutrients come from fertilization.
(nitrogen, phosphorus, potassium, and specific micro- Medium: A plant response may or may not occur if
nutrients) contained in the soil. the indicated nutrient is applied. A small portion of the
The goals of soil testing are to determine existing nutri- nutrient requirement must come from fertilization.
ent levels, predict additional lime and nutrient needs, High: Plant response is not expected. No additional fer-
and evaluate potential excesses or imbalances within a tilizer is needed.
given soil. A soil test report usually includes suggested
lime and fertilizer treatments for turf and landscape Very high: Plant response is not expected. The soil can
areas being maintained. Note that soil tests do not mea- supply much more than the turf requires. Additional
sure nitrogen (N), because it is a highly mobile nutrient. fertilizer should not be added to avoid nutritional prob-
Suggested nitrogen rates are general recommendations lems and adverse environmental consequences.
based on years of research on the nitrogen needs of the
turf species or ornamental plant present.
While soil testing has been around for nearly 50 years,
soil test results and recommendations may vary from lab
to lab. To understand this, you need to understand how
labs use chemical extraction procedures to predict nutri-
ent needs and the amounts required to avoid deficien-
cies. The chemical extraction must be calibrated, that is,
tested and proven under actual growing conditions using
replicated nutrient response field trials with the plant
species of interest. These trials should be conducted Figure 5.1. A typical plant response curve as influenced by varying
under a wide range of soils, water regimes, and climatic levels of soil nutrients.

conditions. The calibration process is an essential com-

ponent relating laboratory results to field performance; Soil Test Interpretation and
thus, the quality of the calibration data determines the
accuracy of the resulting recommendations. Recommendations
Soil test results must be related to the expected level
Soil testing laboratories may also vary in the chemical
of plant response and the appropriate rate of fertilizers
methods they use to assess soil nutrient levels and the
required to eliminate nutrient deficiency. Soil testing
manner in which they report data. Many mid-Atlantic
labs may disagree with the manner in which results are
states use the Mehlich-1 extractant, while other labora-
interpreted and recommendations are made.
tories use the newer Mehlich-3. Some states have not
adopted the Mehlich-3 extractant because new calibration
data are required to relate soil test levels to field perfor- Sufficiency Level Approach
mance. Some labs report their results in parts per million, Most land-grant universities base their recommenda-
some in pounds per acre, and others as a predictive index. tions on the “sufficiency level” concept. Basically, this
Regardless, most laboratories report a rating indicating extensively tested approach says “fertilize the crop, not
the relative status for each nutrient (figure 5.1). the soil” by ceasing to recommend nutrient additions

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 Chapter 5. Soil Sampling and Nutrient Testing

when test levels exceed proven responsive levels. It is The following sections will describe proper soil sam-
also the most conservative approach, and as such, it has pling and interpretation of soil test reports.
been attacked at times as being too conservative. This
philosophy is difficult for the home landscape because
no yield is taken. However, this philosophy has the
Soil Sampling
greatest potential for producing the most favorable
results and is in harmony with the concepts of nutri-
General Sampling Considerations
ent management planning. In areas of the mid-Atlantic Soil sampling should be done every one to five years,
with highly weathered, low CEC soils, this philosophy depending on the soil type and management. Com-
minimizes losses of potassium (K), magnesium (Mg), pletely modified, sand-based soils used on golf greens,
and the more mobile nutrients via leaching. tees, and athletic fields should likely be tested on an
annual basis. For naturally occurring, coarse-textured
(i.e., sandy) soils, a typical sampling frequency is
Buildup and Maintenance Approach every two to three years. On fine-textured (i.e., loamy
The “buildup and maintenance” approach recommends or clayey) soil, sampling likely does not need to be
that soil test levels be built to the “high” or nonrespon- done more than every four to five years. If clippings
sive level. Soil levels are then maintained by annual are removed, sample more frequently according to the
replacement of nutrients to be removed as clippings or soil type.
sod, regardless of soil test level. This method assumes
that all soils can hold high levels of nutrients, which is When submitting soils for analysis, it is common to
not the case for soils having relatively low CEC (less request recommendations for specific plants, i.e., turf
than 10). or ornamentals. As nutrient requirements vary by plant
type, separate soil samples should be submitted for
each recommendation that is required — even if the
Cation Saturation Ratio Approach soil looks the same and is in a similar location.
The final approach, the “cation saturation ratio” method,
focuses on the ratio of nutrients on the soil exchange For fine-turf maintenance, divide the property into logi-
cal areas. For example, it is logical to divide a single
sites. Most often, these labs suggest that 5 percent of
hole on a golf course into green, tee(s), fairway, and
the CEC be occupied by potassium, 10 to 20 percent
rough categories and to conduct a test on each of these
by magnesium, and 70 to 85 percent by calcium (Ca).
areas as a unique entity.
Again, this approach assumes that the soil has suf-
ficient exchange capacity to support these ratios and The turf of a football or baseball field should be divided
stay above sufficiency level. For low CEC soils, this into two to four areas for separate sampling. It is impor-
approach can result in nutrient additions for the sake tant to remember that the quality of the test report is
of adjusting the soil ratio that are unnecessary for high- only as good as the sample submitted; simply testing a
quality turf production and could result in inadequate single sample that was gathered from a large area does
levels of potassium for some soils. not provide sufficiently detailed information regarding
that soil.
Keep in mind that regardless of the approach to fertil-
ization, in a few cases, soil-testing may not accurately Soil samples can be taken at any time of the year but, in
predict a response or lack of response in any given situ- general, it is recommended to take samples in advance
ation. Because recommendations are based on many of planting or the time of regular fertilization. Fall sam-
years of data, they may not predict needs in a specific pling is most common, as this allows time to get results
situation because of unique climatic or soil conditions, and apply lime and nutrients in advance of spring
management practices, or pest pressure. growth. Limestone takes months to fully react with
soil, so liming should be done well in advance of spring
Regardless of the lab used, familiarize yourself with
growth, while nutrients are more reactive and should
the reporting system and be especially sure the lab has
be applied closer to the time of plant growth. Soil sam-
calibrated their recommendations for the plant material
pling should not be done for at least two months after
being grown. Unverified recommendations or recom-
fertilization or liming.
mendations based on forages or row crops may prove
inadequate for intensively managed turfgrass and other Undisturbed areas need to be sampled separately from
landscape plants. disturbed areas. Because soils vary with their location

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 Chapter 5. Soil Sampling and Nutrient Testing

in the landscape, they should at the very least be sepa-

rated into upland, side slopes, and lowland or bottom-
land positions. Disturbed soil areas should be separated
into smaller units based on amount of disturbance, soil
removal, or soil addition. These soil variations are often
visible as different soil colors or as differences in soil
texture (sand versus clay).
The upper diagram in figure 5.2 shows how landscape
position affects soil properties; the lower diagram
shows how soil color can vary. Each soil type, colored
differently in these figures, should ideally be sampled
separately. Soil samples should accurately represent the Figure 5.3. Example of a soil probe, mixing bucket, and soil box filled
area being sampled. with soil.

The best way to collect a soil sample is with a soil probe, A representative soil sample consists of a well-mixed
which is fast and easy and collects an even amount of composite of many subsamples. A soil sample from
soil down to the depth sampled. Soil probes can be pur- a single spot, instead of the representative sample
chased from many locations, such as garden centers or described here, could result in inaccurate nutrient and
online, but it is acceptable to sample using a shovel or lime recommendations. Collect at least 10 subsamples
trowel if you are not going to soil-test frequently. Soil from the uniform area you have identified and mix
sample containers and information sheets are available them together in a clean plastic bucket. It is important
from laboratories that analyze the samples. the bucket is clean because small amounts of nutrients
or lime in the bucket could contaminate your sample.
Once you select uniform areas to sample, the next step
is to collect a representative sample from the correct Push the soil probe into the soil to the desired depth and
depth. The depth of sampling depends on the land use: remove any surface plant material such as turf thatch
It should be 2 to 4 inches for established turf, 6 to 8 before placing it in the bucket. Collect the subsamples
inches for vegetable and flower beds, and 6 inches for from random spots within the sample area by following
trees and shrubs, excluding any mulch (Hunnings and a zigzag pattern as you walk across the landscape (figure
Donohue 2009). For any land that is going to be tilled, 5.4). When you have collected the necessary number of
such as vegetable gardens or during turf establishment, subsamples in your bucket, break up any aggregates or
take the sample to the depth you intend to till. clumps and mix thoroughly. It is this thoroughly mixed
composite of your subsamples that you will submit for
testing.
There are several private and public soil testing labora-
tories and each has its own system for submitting sam-
ples. Virginia Cooperative Extension also has offices

Figure 5.4. Example of soil sampling locations for a homeowner. Yel-

Figure 5.2. Upper: Changes in soils by landscape position. Lower: low dots indicate individual sampling points, and lines collecting dots
How soil type and soil color can change spatially. indicate samples that are pooled and mixed.

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 Chapter 5. Soil Sampling and Nutrient Testing

located throughout the state where you can pick up soil particular, favor thatch development. Because thatch is
testing boxes appropriate for submitting soil samples to almost all organic and very lightweight, it becomes a
the Virginia Tech Soil Testing Laboratory (www.soilt- misleading component of a normal soil sample.
est.vt.edu). These soil boxes hold about a cup or 0.5
In turfgrass areas where thatch thickness exceeds 0.5
pound or more of soil, and you should try to fill them
inch, the thatch should be removed before taking any
to ensure you submit sufficient soil. An acre contains
soil sample used to measure soil pH or other nutrients,
about 2 million pounds of topsoil, so the importance
such as phosphorus and potassium. This suggests that
of collecting a representative subsample cannot be turfgrass areas with thick thatch covers should have
overemphasized. two samples taken for analysis to more correctly reflect
The sample identification should be placed on the labo- maintenance nutrient needs. Areas with a thatch thick-
ratory container and placed on a corresponding map or ness of 0.5 inch or less can be analyzed for nutrient
identification sheet for the areas to be sampled. More needs with the thatch either mixed in as part of the sam-
information on the appropriate steps in sampling soils, ple or removed before taking the sample cores.
submitting the sample, and interpreting the soil test Remember that thatch is an indication of “imbalance”
results can be found in Soil Testing for the Lawn and in turfgrass management; low-input turfgrasses, even
Landscape, Virginia Cooperative Extension publica- those with lateral stems, do not produce appreciable
tion 430-540 (Goatley, Mullins, and Ervin 2005; http:// thatch because the soil microbial population is able to
pubs.ext.vt.edu/430/430-540/430-540.html). adequately degrade the stems. Detailed information on
thatch management is presented in chapter 6.
Dealing With Thatch
Thatch is an accumulation of dead and living plant tis- Sampling Problem Areas
sue (primarily undecomposed stems) located imme- When sampling problem areas, take a representative
diately above the soil surface. Thatch is resistant to sample from the problem area and a representative
chemical change and microbial degradation. As thick- sample from an area adjacent to the problem area. Both
ness increases, thatch may become a major area of root samples should be sent to a laboratory for analysis to
proliferation and significantly influence the supply of allow for comparison and more accurate determination
plant nutrients. Grasses that creep by rhizomes (below- of the severity of the problem. Although some con-
ground stems) and stolons (aboveground stems) are clusions can be drawn from a single sample, having
most likely to produce thatch. High nitrogen rates, in another sample result from soil or growing media near

Table 5.1. Sampling considerations for problem identification and verification.

Suspected
problem Probable cause Sampling considerations
Low pH Nitrogen fertilization. Sample as needed to a depth of 3-4 inches.
High pH or Large amounts of salts Periods of high rainfall will reduce the problem, so sample during dryer
soluble or carbonates are added periods of the season to assess the maximum severity. CEC should be
salts through long-term use of determined as part of any test for “salt” problems, especially on low CEC
irrigation water applied to soils. Sample cores should be taken to a depth of 3-4 inches.
high management areas.
Nutrient Inadequate fertilization, Sample more frequently on modified or very sandy soils (at least
deficiency especially where annually). Analysis may indicate a need for more-frequent application of
clippings are removed; nutrients or modification of other management factors to reduce nutrient
excessive irrigation; low losses. Unfortunately, few soil test correlations are available for turf
CEC leading to leaching. grown in these modified soils. Sample cores should be taken to a depth
of 3-4 inches.
Nutrient Low pH; excessive Soil pH is the most important factor in determining the availability of
toxicity fertilization; sludge, these nutrients to the turfgrasses. Most grasses are quite tolerant to trace
manures, or other metals, but careful monitoring is important to prevent buildup of toxic
biosolids application. levels. Subsample cores should be taken to a depth of 3-4 inches.

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 Chapter 5. Soil Sampling and Nutrient Testing

the problem allows evaluation of results on like mate- Iron (Fe): Interveinal chlorosis of younger leaves.
rials. See table 5.1 for probable causes of a suspected
Molybdenum (Mo): Leaves become chlorotic, devel-
problem area.
oping rolled or cupped margins; plants deficient in this
element often become nitrogen-deficient.
General Crop Nutrient Deficiency
Chlorine (Cl): Deficiency not observed under field
Symptoms conditions.
Nitrogen (N): Restricted growth of tops and roots;
growth is upright and spindly; leaves pale and yellow- Source: Brann, Holshouser, and Mullins (2000).
green in early stages, more yellow and even orange or
red in later stages; deficiency shows up first on lower Understanding Soil Test Reports
leaves.
Phosphorus (P): Restricted growth of tops and roots;
Fertilizer Recommendation
growth is upright and spindly; leaves bluish-green in Fertilizer recommendations may be used for the same
early stages with green color sometimes darker than lawn or landscape situation for two to three years. When
plants supplied with adequate phosphorus; more purple the soil tests “very high” for phosphorus or potassium,
in later stages with occasional browning of leaf margins; no fertilizer for these nutrients is recommended.
defoliation is premature, starting at the older leaves.
Lime Recommendation
Potassium (K): Browning of leaf tips; marginal scorch-
ing of leaf edges; development of brown or light-colored If needed, a lime recommendation is given to neutral-
spots in some species that are usually more numerous ize soil acidity and should last two to three years. The
near the margins; deficiency shows up first on lower measured soil test levels of calcium and magnesium
foliage. are used to determine the appropriate type of limestone
to apply. If neither dolomitic nor calcitic lime is men-
Calcium (Ca): Deficiency occurs mainly in younger tioned, or just “ag” type or “agricultural” limestone is
leaves near the growing point; younger leaves distorted stated on the report, then it does not matter what type is
with tips hooked back and margins curled backward used. When no information on the soil sample informa-
or forward; leaf margins may be irregular and display tion sheet is provided regarding the last lime applica-
brown scorching or spotting. tion, the lab assumes you have not applied lime in the
past 18 months. Do not overlime! Too much lime can
Magnesium (Mg): Interveinal chlorosis with chlorotic be as harmful as too little. For best results, apply lime,
areas separated by green tissue in earlier stages, giv- when possible, several months ahead of the crop/plant
ing a beaded, streaking effect; deficiency occurs first to be planted to allow time for a more complete soil
on lower foliage. reaction.
Sulfur (S): Younger foliage is pale yellowish-green,
similar to nitrogen deficiency; shoot growth somewhat Methods and Meanings
restricted. For more detail on the lab procedures used, go to www.
Zinc (Zn): Interveinal chlorosis followed by dieback soiltest.vt.edu and click on “Laboratory Procedures.”
of chlorotic areas. Soil pH (or soil reaction) measures the “active” acid-
Manganese (Mn): Light-green to yellow leaves with ity in the soil’s water (or hydrogen ion activity in the
distinctly green veins; in severe cases, brown spots soil solution), which affects the availability of nutrients
appear on the leaves and the leaves are shed; usually to plants. It is determined on a mixed suspension of a
begins with younger leaves. 1-1, volume-to-volume ratio of soil material to distilled
water.
Boron (B): Growing points severely affected; stems and
Virginia soils naturally become acidic, and limestone
leaves may show considerable distortion; upper leaves
periodically needs to be applied to neutralize some of
are often yellowish-red and may be scorched or curled.
this acidity. A slightly acid soil is where the major-
Copper (Cu): Younger leaves become pale-green with ity of nutrients become most-available to plants and
some marginal chlorosis. where soil organisms that decompose organic matter

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 Chapter 5. Soil Sampling and Nutrient Testing

and contribute to the general “overall health” of soils calcium and magnesium are 721 to 1,440 and 73 to 144
are the most active. When a soil is strongly acidic (< pounds per acre, respectively. Calcium and magnesium
5.0 to 5.5 pH), many herbicides lose effectiveness and are normally added to the soil through the application
plant growth is limited by aluminum toxicity. When of limestone. It is rare for very high fertility levels of
soils are overlimed and become alkaline (> 7.0 pH), phosphorus, potassium, calcium, and magnesium to
micronutrients such as manganese and zinc become cause a reduction in crop yield or plant growth. Lev-
much less-available to plants. els of micronutrients, (zinc, manganese, molybdenum,
copper, iron, and boron) are typically present in the soil
For most agronomic crops and landscaping plants, lime
at adequate levels for plants if the soil pH is in its proper
recommendations are provided to raise the soil pH to a
range. See Soil Test Note 4 for documented micronu-
slightly acid level of between 5.8 and 6.8. Blueberries
trient deficiencies that occur in Virginia (www.soiltest.
and acid-loving ornamentals generally prefer a 4.5 to
vt.edu/stnotes).
5.5 pH, and an application of liming material is sug-
gested when the soil pH drops below 5.0. Soluble salts or fertilizer salts are estimated by mea-
suring the electrical conductivity of a 1-2, volume-to-
For the majority of other plants, lime may be suggested
volume ratio of soil material to distilled water. Injury to
before the pH gets below 6.0; this is to keep the soil
plants may start at a soluble-salts level above 844 parts
pH from dropping below the ideal range because lime is
per million when grown in natural soil, especially under
slow to react and it affects only a fraction of an inch of
dry conditions and to germinating seeds and seedlings.
soil per year, when the lime is not incorporated into the
Established plants will begin to look wilted and show
soil. If the soil pH is above the plant’s target pH, then no
signs related to drought. This test is used primarily for
lime is recommended. If the pH is well above the ideal
greenhouse, nursery, and home garden soils where very
range, then sometimes an application of sulfur is recom-
high application rates of fertilizer may lead to an exces-
mended to help lower the pH faster; however, most of
sive buildup of soluble salts.
the time one can just let the soil pH drop on its own.
Soil organic matter (SOM) is the percentage by weight
The Buffer Index, which provides an indication of
of the soil that consists of decomposed plant and ani-
the soil’s total (active and reserve) acidity and ability
mal residues and is estimated by using either the weight
to resist a change in pH, is determined by a Mehlich
Loss-on-Ignition (LOI) method from 150 to 360 degrees
buffer solution. This buffer measurement is the major
Celsius (C) or a modified Walkley-Black method. Gen-
factor in determining the amount of lime to apply. The
erally, the greater the organic matter level, the better
Buffer Index starts at 6.6 and goes lower as the soil’s
the overall soil tilth or soil quality, because nutrient
total acidity increases and more lime is needed to raise
and water-holding capacities are greater, and improved
the soil pH. A sandy soil and a clayey soil can have
aeration and soil structure enhance root growth.
the same soil pH; however, the clayey soil will have
greater reserve acidity (and a lower Buffer Index) as The percentage of soil organic matter in a soil can affect
compared to the sandy soil, and the clayey soil will the application rate and performance of some pesticides,
require a greater quantity of lime be applied in order but this is not usually a problem in lawn and landscape
to raise the soil pH the same amount as the sandy soil. situations. Soil organic matter levels from 0.5 percent
A reported Buffer Index of “N/A” means that it was to 2.5 percent are ordinary for natural, well-drained
not measured because the soil (water) pH was either soils. For completely modified, sand-based soils, it is
neutral or alkaline and not acidic (soil pH ≥ 7.0) and typically recommended that SOM levels become no
therefore requires no lime. greater than 3 percent because large SOM levels can
greatly reduce water infiltration and percolation rates in
Nutrients available for plant uptake are extracted
these soils. Due to relatively large amounts of organic
from the soil with a Mehlich-1 solution using a 1-5,
materials being commonly added to gardens, the SOM
volume-to-volume, soil-to-extractant ratio and are
in garden soils can be raised into the range of 5 percent
then analyzed by Inductively Coupled Plasma-Atomic
to 10 percent.
Emission Spectrometry (commonly referred to as an
ICP-AES instrument). An extractable Mehlich-1 level The remaining values that are reported under the
of phosphorus from 12 to 35 pounds per acre is rated “Lab Test Results” section are calculated from the
as medium or optimum. A medium level of potassium previously measured values and are of little use to
is from 76 to 175 pounds per acre. Medium levels of most turf and landscape managers.

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 Chapter 5. Soil Sampling and Nutrient Testing

Estimated cation exchange capacity (Est-CEC) gives the problem. Visual symptoms can offer helpful clues
an indication of a soil’s ability to hold some nutrients but can also be easily confused and misinterpreted,
against leaching. Natural soils in the mid-Atlantic usu- especially where micronutrients or sulfur are involved.
ally range in CEC from 1 to 12 millequivalent (meq) Turf and landscape managers should confirm a sus-
per 100 grams (g). A very sandy soil will normally have pected deficiency by plant analysis before applying
a CEC of 1 to 3 meq per 100 g. The CEC value will a corrective treatment. Numerous cases can be given
increase as the amount of clay and organic matter in the where incorrect diagnosis in the field has led to turf
soil increases. This reported CEC is an estimate because problems as well as costly and ineffective corrective
it is calculated by adding the Mehlich-1 extractable cat- treatments.
ions (calcium plus magnesium plus potassium) and the
acidity estimated from the Buffer Index and converting
to units commonly used for CEC. This is also an “effec- Nutrient Monitoring
tive CEC” because it is the CEC at the current soil pH. It is important to remember that tissue-sufficiency
This value can be erroneously high when the soil pH or ranges used by most labs are based on values com-
soluble-salts level is high. mon in turfgrasses and landscape plants with accept-
The percentage of acidity is a ratio of the amount of able quality under a wide range of growing conditions
acid-generating cations (as measured by the Buffer and management levels. It is not, at this point, refined
Index) that occupy soil cation-exchange sites to the to the point that it can ensure quality for your specific
total CEC sites. The higher this percentage, the higher growing conditions, management practices, and quality
the amount of reserve acidity in the soil, the higher the demands. Some golf course superintendents currently
amount of acidity there will be in the soil solution, and submit samples bimonthly or monthly — especially
the lower the soil pH will be. A reported acidity per- for creeping bentgrass grown on completely modi-
centage of “N/A” means that a Buffer Index was not fied, sand-based putting greens. Upward or downward
determined, the acidity is probably less than 1 meq per trends can be observed and adjustments in lime and fer-
100 g and/or 5 percent, and the soil pH is alkaline (> tilizer treatments made before deficiencies or excesses
7.0). develop that would reduce quality.

The base saturation percentage is the ratio of the quan- Establishing your own routine monitoring program
tity of nonacid-generating cations (i.e., the exchange- using these recommendations as a base will allow you
able bases calcium, magnesium, and potassium) that to follow the effectiveness of your nutrient management
occupy the cation exchange sites. practices while making corrective treatments before
significant loss in quality occurs. In addition, by com-
The percentage of calcium, magnesium, or potas-
paring plant analysis results with turf quality, nutrient
sium saturation refers to the relative number of CEC
applications, and soil test levels samples over time, you
sites that are occupied by that particular nutrient and is
can refine the nutrient sufficiency ranges and nutrient
a way of evaluating for any gross nutrient imbalance.
management practices required to maintain turf quality
for your specific site, climatic conditions, and manage-
Plant Tissue Analysis ment constraints.
Tissue analysis has two main applications:
Monitoring does not need to be done for every possible
• T
 o confirm a suspected nutrient element deficiency situation. Carefully decide the areas you may need to
when visual symptoms are present. sample. Choose areas representative of the turf qual-
ity, use, composition, and soils to be managed. Take
• T
 o monitor plant nutrient element status in order to
determine whether each tested nutrient is in sufficient plant samples at regular intervals from each representa-
concentration for optimum performance. tive area prior to and during growth cycles. Record turf
quality (clipping yields, if available), weather situation,
and any known problems at the time of sampling. Track
Plant Analysis as a Diagnostic Tool nutrient additions on each monitored site and collect
Whenever turfgrasses fail to meet color and quality routine soil samples at least once a year (prior to phos-
expectations in response to nutrient applications, plant phorus and potassium fertilization) to supplement your
analysis is the tool used by many managers to diagnose records.

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 Chapter 5. Soil Sampling and Nutrient Testing

Sampling Considerations Interpreting a Plant Analysis Result

Sample the aboveground portion of the plant, clipped Plant analysis indicates only what the root and internal
just above ground level no more than two days after transport system is able to deliver to the sampled tissue.
mowing. As a general rule, monitoring samples can Tissue analysis is excellent for determining nutrient
be taken from turfgrass clippings. When whole plants deficiencies, but as previously discussed, the analysis
are sampled, cut off and discard the roots and wash the does not tell you why the limitation is occurring; that
shoots to remove soil particles. Under normal condi- is the importance of usually submitting a soil sample
tions, rainfall is frequent enough to keep leaf surfaces at the same time as a tissue sample. Levels below the
fairly free from dust and soil particles. If recently sufficiency range can result from low or excessive soil
sprayed or if iron is of primary interest, a quick wash test levels, inadequate or excessive fertilization, and
in a dilute (0.3 percent) detergent solution followed by improper pH. Even where soil fertility levels are cor-
a quick rinse in a strainer or colander will help remove rectly managed, biotic factors (e.g., nematodes, dis-
residues and soil particles that could bias the sample. ease, herbicide injury, etc.) and physical conditions
(e.g., compaction, flooding, drought, root injury, incor-
To prevent decay during transport to the lab, reduce
rect mowing) can limit nutrient uptake and distribution
excess moisture by partially air-drying plant tissue
in the plant. In other cases, visual symptoms might
samples before shipment to the laboratory. Never put
not even be nutrient-related (for example, pesticide
fresh samples in a tightly sealed or plastic bag unless
injury).
they will be kept cold during transport. Decayed sam-
ples will not be analyzed. The effects of the time of sampling, turf species, traf-
fic and use, and environmental factors such as soil
It is a good idea to have recent soil test results available
moisture, temperature, light quality, and intensity may
when interpreting the results of a plant tissue analysis.
significantly affect the relationship between nutri-
If none are available, submit a soil sample along with
ent concentration and turf quality. It is important that
the tissue sample.
the time of sampling, stage of growth, and character
For diagnostic samples, obtain samples as soon as of growth prior to sampling be known and considered
symptoms appear. Plants showing severe deficiency when interpreting a plant analysis result.
symptoms are often the most difficult to interpret cor-
rectly because a difficult-to-detect deficiency of one Table 5.2 offers general guidelines on interpretations
element may result in deficiencies or excess accumu- of plant analysis results for turfgrasses. Other land-
lation of other elements if uncorrected. Plants under scape plant materials would also likely fall within these
prolonged stress of any kind can also display unusual ranges, but there are exceptions for particular catego-
nutrient contents. This would include damage from heat, ries of plants. Ornamental landscape plant management
cold, drought, flooding, disease, insects, or mechanical is covered in chapter 7. A complete discussion of fertil-
treatments. izer sources and programs is provided in chapter 8.

Comparative sampling can improve diagnosis accuracy.

Collect both plant and soil samples from “good” and Literature Cited
“bad” areas in close proximity to each another. Both Brann, D. E., D. L. Holshouser, and G. L. Mullins.
areas should have similar soil types, species composi- 2000. Agronomy Handbook. Virginia Cooperative
tion, and management (mowing height, irrigation, etc.). Extension Publication 424-100. http://pubs.ext.
Because the recommended ranges of plant nutrient con- vt.edu/424/424-100/424-100.pdf.
tent are somewhat general, a “good” sample offers a
Goatley, M., G. Mullins, and E. Ervin. 2005. Soil Test-
measure of what should be expected for your site and
ing for the Lawn and Landscape. Virginia Coop-
management conditions. Differences in nutrient con-
erative Extension Publication 430-540. http://pubs.
centrations can then be compared with soil samples to
ext.vt.edu/430/430-540/430-540.html.
determine if the problem is related to fertility manage-
ment or is an uptake problem, such as disease, water, Hunnings, J. R., and S. J. Donohue. 2009. Soil Sam-
compaction, or root damage. For example, differences pling for the Home Gardener. Virginia Coopera-
in magnesium and manganese between plants could be tive Extension Publication 452-129. http://pubs.
related to differences in soil pH. ext.vt.edu/452/452-129/452-129.pdf.

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 Chapter 5. Soil Sampling and Nutrient Testing

Table 5.2. Typical nutrient sufficiency ranges, interpretations, and recommendations for the
analysis of turfgrass tissues.
Sufficiency
range
Element (% or ppm) Interpretation and recommendation
Nitrogen (N) 2.2-4.0% Nitrogen is the nutrient most commonly found to be low in turfgrasses, which is
generally due to inadequate fertilization, heavy leaching rains, overirrigation, or
possible root damage. N deficiency may be manifested with a light-green color,
slow growth rate, or excessive seedhead production. If a deficiency is detected,
apply N according to soil test recommendations, being sure to split applications
where leaching may be a problem.
Phosphorus (P) 0.3-0.7% Deficiency is usually due to low soil P; cool, wet growing conditions; or
excessively low soil pH. If deficiency is detected, apply P and limestone based
on soil test recommendations. High levels of P generally pose more problems
with intensively managed turf than deficiencies do. Excessive P levels in the
leaves can cause deficiencies of other nutrients, particularly iron. High P-K
ratios in leaf tissue increase winterkill in bermudagrass and St. Augustinegrass.
When high P is detected, omit P from the fertilization program until P is within
acceptable limits. In most instances, three or more years may be required.
Potassium (K) 1.5-3.0% Low K is generally due to low soil test K levels, inadequate K fertilization, or
when grass is grown on coarse-textured, sandy soil that is subject to leaching.
Low K may also be associated with low N fertilization. When soil K is adequate,
N fertilization increases the uptake of K by the grass. When low K is detected
in the tissue, apply potash and nitrogen based on soil test recommendations.
When K drops below 1.0 percent in the tissue, deficiency symptoms appear
and are characterized by spindly growth (narrow leaves, thin turf), leaf tip burn,
reduced wear, cold and disease tolerance, and reduced growth rate. Excessive
K levels may induce Mg deficiency. If high K levels are detected in the tissue,
reduce the K fertilization rate or omit K from the program until K is within the
sufficiency range.
Calcium (Ca) 0.20-1.25% Grasses are able to take up Ca under a wide range of soil conditions and
it is rarely deficient. May be drought induced. Heavy N and K fertilization
will decrease Ca levels but not cause deficiencies in well-limed soils. If low
levels are detected, check for low soil pH and apply limestone based on
recommendations. A high Ca level may indicate some other nutrient deficiency
or disorder.
Magnesium (Mg) 0.15-0.60% Low levels may occur on sandy soils, soils with low pH and low Mg, where
high rates of NH4-N and K fertilizers have been applied, and where clippings
are continuously removed. If low levels are detected, include Mg in the
fertilization program at the rate of 0.5 pounds Mg per 1,000 sq ft. If soil pH is
low and limestone is required, apply dolomitic limestone according to soil test
recommendations. Excessively high Mg in tissue is not a common occurrence.
Sulfur (S) 0.2-0.4% Low S may occur on sandy soils low in organic matter where S-free fertilizers
have been used following extensive periods of heavy rainfall, where grass has
been overirrigated, and where high application rates of N have been applied.
The ratio of N to S is as important as the S content itself and should not exceed
20-to-1. Ideally, the N-S ratio should be approximately 14-to-1 for optimum
growth and turf quality. If S is low and/or the N-S ratio exceeds 20-to-1, include
0.25-0.50 pound S per 1,000 sq ft in the fertilization program. Sulfur may be
supplied as gypsum elemental sulfur or sulfur-containing fertilizers.

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 Chapter 5. Soil Sampling and Nutrient Testing

Table 5.2. Typical nutrient sufficiency ranges, interpretations, and recommendations for the
analysis of turfgrass tissues. (cont.)
Sufficiency
range
Element (% or ppm) Interpretation and recommendation
Manganese (Mn) 20-300 ppm Deficiencies are rare but may occur occasionally on sandy soils that are low in
Mn, high in organic matter, and when the soil pH is 6.8. Mn deficiencies can be
corrected by applying a foliar application of manganese sulfate or manganese
chelate by dissolving 2 ounces of manganese sulfate or 1 ounce of manganese
chelate in 1 gallon of water and spraying at the rate of 0.5 gal per 1,000 sq ft.
Color should improve within 24 hours. Repeated applications will be required
to prevent reoccurrence of the deficiency. Excessive Mn levels can occur in
some turfgrasses when the soil pH is < 5.5 or where soils are consistently
overwatered. High Mn levels can be corrected by proper liming, proper
irrigation practices, and by improving drainage on waterlogged soils.
Iron (Fe) 50-200 ppm Iron determinations are invalid unless samples are properly washed to remove
soil contaminates. Generally if Fe and Al levels are both high, it is due to
contamination rather than inherent levels in the grass. Iron deficiency can occur
on high pH soils (≥ 7.0), during periods of cool temperatures, where grasses
are overwatered, and where soil P levels are excessively high. Iron deficiency
is best controlled by applying a foliar application of iron as iron sulfate or iron
chelate at a rate of 0.5 ounce of Fe per 1,000 sq ft. Repeated applications may
be needed indefinitely to prevent reoccurrence of the deficiency. Do not apply
foliar applications of iron to grasses in the heat of the day. Soil applications of Fe
materials are not recommended for correcting Fe deficiencies.
Boron (B) 5-60 ppm Grasses have very low B requirements. Deficiency is unlikely; however, toxicity
is possible with some sources of irrigation water, particularly along the coastal
areas. Boron content of irrigation water should be less than 0.5 ppm to guard
against the possible development of toxic soil levels.
Copper (Cu) 5-20 ppm Deficiency is not likely to occur unless high levels of organic matter are added
or pH is excessively high.
Zinc (Zn) 15-50 ppm Deficiencies are not common on turfgrasses unless grown under alkaline soil
conditions. In some cases, low Zn levels will be detected in grass grown on soils
that are excessively high in P or when grown on compacted or waterlogged
soils. Deficiency symptoms do not show up unless the Zn content is less than 10
ppm. Zinc deficiencies can be corrected with foliar applications of zinc sulfate
or zinc chelate at the rate of 0.5 ounce per gal of water per 1,000 sq ft.
Aluminum (Al) Aluminum is not an essential plant nutrient but can be a factor affecting plant
growth. High Al levels (soil-free samples) result from very low soil pH (<5.0) or
anaerobic soil conditions such as flooded or heavily compacted soils. Plants do
not readily absorb Al; its presence indicates an extreme soil condition.

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

Chapter 6. Mid-Atlantic Turfgrasses and Their Management

Michael Goatley Jr., Professor and Extension Specialist, Crop and Soil Environmental Sciences, Virginia Tech

Introduction
Much of the mid-Atlantic climate falls into what is
commonly termed the “transition zone” of the United
States. This region is noted for its hot summers, cold
winters, and varying levels of moisture. In terms of
selecting appropriate turfgrasses, it means that almost
any warm- or cool-season turfgrass can be grown in
much of the region, but not necessarily grown well,
given the possible environmental extremes of winter
and summer. Most species grown in the mid-Atlantic
offer a wide variety of cultivars from which to select.
The U.S. Department of Agriculture’s National Turf-
Figure 6.1. Kentucky bluegrass is a highly desirable lawn grass in the
grass Evaluation Program (NTEP) presents regularly cooler regions of the mid-Atlantic, but it requires intensive mainte-
updated field research data on numerous turfgrass nance to perform as desired.
variety trials from around the country (www.NTEP.
Strengths: Excellent cold tolerance; excellent den-
org). Within the mid-Atlantic, the research efforts of
sity; rapid recuperation potential due to aggres-
turfgrass scientists at Virginia Tech and the Univer-
sive lateral growth habit; summer dormancy during
sity of Maryland result in an annual Turfgrass Variety
drought.
Recommendations list that features the top-perform-
ing cultivars in the region. This report can be found at Weaknesses: Poor shade tolerance; 14 to 21 days for
http://pubs.ext.vt.edu. seed germination; aggressive lateral growth habit from
rhizomes can make it a weed in plant beds; heavy thatch
Primary Cool-Season Grasses of (an organic layer primarily composed of nondecom-
posed stems) under aggressive maintenance programs;
Importance disease and insect pressures can be high under intensive
The primary cool-season grasses used in this region are maintenance programs.
Kentucky bluegrass (Poa pratensis L.); hybrid blue-
Typical seasonal nitrogen requirements: 1 to 2 pounds
grass (Poa pratensis x P. arachnifera); tall fescue (Fes-
per 1,000 square feet for low-maintenance lawns; 3 to
tuca arundinacea Schreb.); perennial ryegrass (Lolium
4.5 pounds per 1,000 square feet for golf- and sports-
perenne L.); the fine-leaf fescues of creeping red (Fes-
turf uses.
tuca rubra L.), chewings [F. rubra L. ssp. fallax (Thu-
ill.) Nyman], and hard fescue (F. brevipila Tracey)];
creeping bentgrass (Agrostis stolonifera var. palustris Hybrid Bluegrasses
L.); and annual ryegrass (Lolium multiflorum L.). Similar descriptive and maintenance characteristics as
for Kentucky bluegrass, but these grasses potentially
Kentucky Bluegrass (figure 6.1) have genetic improvements in heat and drought toler-
ance. See more comments below in the section on tall
Description: A fine-to-medium-textured grass noted
fescue.
for its dark green color and aggressive lateral growth
habit from rhizomes (below-ground stems).
Tall Fescue (figure 6.2)
Primary uses: Lawns, athletic fields, golf course fair-
Description: “Turf-type” varieties are fine- to medium-
ways, tees, and roughs; commonly mixed with peren-
textured, older varieties are medium- to coarse-textured;
nial ryegrass for athletic fields, and with ryegrass and
managed primarily as a bunch/clump-forming grass
fine fescue for sun/shade lawns.
with little spreading potential, but newer varieties with
Primary establishment method(s): Seed readily avail- more aggressive rhizome formation are in development;
able for many improved cultivars; sod also available. deepest root system of the cool-season grasses.

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

Primary establishment method(s): Seed readily avail-

able for many improved cultivars.
Strengths: Rapid germination (four to seven days) and
establishment from seed; exceptional visual appeal due
to glossy leaf surface that results in striping by mow-
ing; excellent wear tolerance as a mature turf; tolerates
cutting heights as low as 0.5 inch.
Weaknesses: No recuperative potential; poor cold tol-
erance; poor drought tolerance; high disease pressure.
Typical seasonal nitrogen requirements: 1 to 2 pounds
per 1,000 square feet for low-maintenance lawns; 3 to
Figure 6.2. A general purpose, turf-type tall fescue turf at a business 4.5 pounds per 1,000 square feet for golf- and sports-
park in Richmond, Va.
turf uses.
Primary uses: Most important lawn and “all purpose”
turf for the mid-Atlantic; low-maintenance athletic fields, Fine-Leaf Fescues (figure 6.3)
golf course roughs; turf-type varieties are commonly Three species of fine-leaf fescues predominate in the
mixed with either Kentucky bluegrass or hybrid blue- mid-Atlantic: creeping red, chewings, and hard fescue.
grass in sod production systems. Preliminary research in
the warmer, coastal regions of the mid-Atlantic suggest Description: All species have exceptionally fine leaf
that 90 percent/10 percent (by weight) seed mixtures of blades commonly referred to as “needle-like.” Chew-
tall fescue and hybrid bluegrass provide a more disease- ings and hard fescues are bunch-type grasses, while
tolerant lawn turf than single species plantings. creeping red possesses short rhizomes; all are managed
as bunchgrasses.
Primary establishment method(s): Seed readily avail-
able for many improved cultivars; sod available also. Primary uses: Excellent low-maintenance turf with
the best shade tolerance of cool-season grasses; often
Strengths: Excellent drought avoidance characteris- mixed with Kentucky bluegrass as the “shade compo-
tics; rapid germination rates (four to seven days); early nent” of sun/shade seed mixtures.
spring greening; moderate shade tolerance; adapted to
a wide range of soils. Primary establishment method: Seed available for
limited number of varieties.
Weaknesses: High mowing requirement during active
growing periods; limited to no recuperative potential; Strengths: Good shade tolerance; excellent cold tol-
Rhizoctonia blight is a common disease problem under erance; good drought tolerance; minimal fertility and
aggressive spring fertility programs. liming requirement; reduced mowing requirement
compared to other grasses.
Typical seasonal nitrogen requirements: 0.5 to 1
pound per 1,000 square feet for low-maintenance lawns;
up to 3.5 pounds per 1,000 square feet for higher-main-
tenance lawns and golf/sports turfs.

Perennial Ryegrass
Description: A shallow-rooted, fine-textured, bunch-
type grass noted for its dark green color and exceptional
visual appeal due to “striping” when clipped.
Primary uses: Not recommended as a monostand
except at elevations above 2,000 feet, where it can be
used for lawns and golf and sports turf; also commonly
mixed with Kentucky bluegrass for lawns and athletic Figure 6.3. Fine-leaf fescues are ideal for minimal-maintenance turfs
fields; primary cool-season grassing option for over- where limited fertility and mowing are desired.
seeding bermudagrass for winter color/playability.

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

Weaknesses: Intolerant of persistently wet soils; poor Primary uses: Cost-effective temporary soil stabiliza-
traffic tolerance and recuperative potential; 10 to 14 tion, either seeded alone or as a nurse grass for perennial
day germination from seed. species; winter overseeding of lawns or sports fields.
Typical seasonal nitrogen requirements: 0.5 to 2 Primary establishment method: Exclusively by seed
pounds nitrogen per 1,000 square feet. with most cultivars available having been developed as
a temporary forage grass; the first releases of annual
Creeping Bentgrass (figure 6.4) ryegrass varieties developed for turfgrass use are now
available; there are also intermediate ryegrass hybrids
Description: a very shallow-rooted, fine-textured grass
(Lolium perenne x L. multiflorum) for which early
with an aggressive stoloniferous (aboveground stem)
releases were of similar quality to annual ryegrass, but
growth habit; many cultivars have a characteristic pale
later releases display quality characteristics more com-
blue-green color.
parable to perennial ryegrass.
Primary uses: Almost exclusively for golf turf as
Strengths: The most rapid germination from seed
bentgrass is the primary choice on putting greens; also
results in quick establishment and soil stabilization.
receives extensive use on tees and is used for fairways
at high-maintenance/well-budgeted golf facilities. Weaknesses: A very fast growth rate results in a very
high mowing requirement; poor cold tolerance; dies
Primary establishment method: Seed available for many
quickly the following summer (but note that some might
improved cultivars; sod available from regional producers.
consider this a strength when used for winter overseed-
ing and a rapid, natural transition is desired).
Typical seasonal nitrogen requirements: 1 to 2.5
pounds nitrogen per 1,000 square feet.
Figure 6.5 details the seasonal anticipated shoot and
root growth and carbohydrate (i.e., stored food) lev-
els across the seasons. Optimal temperatures for cool-
season grass growth are 65 to 75° F, resulting in the
primary period for nitrogen fertilization being late sum-
mer through midfall, followed by early to midspring.
Under the cooling temperatures and shorter days of fall,
fertilization optimizes root development and carbohy-
Figure 6.4. Owing to its ability to be maintained at cutting heights of drate storage rather than excessive shoot growth, and
0.1 to 0.5 inch, creeping bentgrass is a popular grass for golf putting the benefits of fall fertilization continue into the spring
greens, tees, and fairways. by delivering a steady and sustained spring greening
Strengths: Surface smoothness, density, and growth response.
and its tolerance to cutting heights as low
as 0.1 inch are predominate reasons for
bentgrass use; excellent cold tolerance.
Weaknesses: Very poor heat and
drought tolerance; poor traffic toler-
ance; high disease and insect pressure.
Typical seasonal nitrogen require-
ments: 2.5 to 4.5 pounds nitrogen per
1,000 square feet.

Annual Ryegrass
Description: A bunch-type, medium-
to-coarse-bladed grass typically having
Figure 6.5. The anticipated seasonal root and shoot growth patterns and carbohydrate levels of
a very light green color. cool-season turfgrasses.

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

During the secondary window for fertilizing cool-

season grasses during the spring, limited amounts of
nitrogen (0.5 to 1 pound nitrogen per 1,000 square feet
total) can support the period when the largest increase
in root development occurs. However, as indicated
in the figure, spring shoot development very quickly
responds to the increasing temperatures and can exceed
root development if promoted by heavy nitrogen fer-
tilization. Excessive shoot growth, while resulting in
a great-looking turf for the spring months, promotes
a shallow-rooted turf that will struggle in the summer
months when environmental extremes are likely. Car-
bohydrate levels begin to decline in the spring (and
Figure 6.6. Improvements in density and cold tolerance of bermuda-
continue to decline throughout the summer) as the plant grasses, coupled with its rapid recuperative potential and tolerance to
utilizes stored food to support early season root and close clipping, have made bermudagrass a popular sports turf through-
shoot growth; the decline can be exaggerated by exces- out the mid-Atlantic.

sive spring nitrogen applications. For most purposes, Strengths: Exceptional heat and drought tolerance;
summer nitrogen fertilization is discouraged because rapid establishment and recuperation rates; exceptional
temperatures exceed optimal growing conditions for density; cutting heights as low as 0.1 inch for golf green
the turfgrasses. ecotypes, 0.5 to 0.75 inch for golf and fairway uses, to
2.5 inches for lawn use; minimal pest pressure.
Primary Warm-Season Grasses of Weaknesses: Rapid lateral and foliar growth rates
result in high mowing requirement and weed poten-
Importance tial in ornamental beds, gardens, etc.; cold tolerance a
The primary warm-season grasses used in the mid- concern in extreme winter conditions; poor shade toler-
Atlantic are bermudagrass (Cynodon spp.), zoysiagrass ance; loss of color due to winter dormancy.
(Zoysia spp.), centipedegrass [Eremochloa ophiuroides
(Munro) Hack], and St. Augustinegrass [Stenotaphrum Typical seasonal nitrogen requirements: 1 to 2 pounds
secundatum (Walter) Kuntze]. Bermudagrass and zoy- per 1,000 square feet for low-maintenance lawns and 4
siagrass can be found throughout the region, while cen- to 6 pounds of nitrogen per 1,000 square feet for inten-
tipedegrass and St. Augustinegrass are primarily found sively maintained golf and sports turfs, higher rates
in the southern Piedmont and coastal plains. being used for ryegrass-overseeded turf.

Bermudagrass (figure 6.6) Zoysiagrass (figure 6.7)

Description: A highly diverse species with ecotypes Description: An extremely dense, fine-to-medium-
varying in leaf textures from very fine to coarse; textured species that spreads by both rhizomes and
aggressive lateral growth habit from both rhizomes and stolons.
stolons. Primary uses: Lawns, golf fairways and tees.
Primary uses: An important lawn grass in central
Primary establishment method(s): Improved culti-
to southern Piedmont and coastal regions, with uses
vars are mostly established by sod, sprigs, or plugs (sod
ranging from roadside turf to manicured lawns; major
is available throughout the region); a limited number of
advancements in the cold tolerance and quality of seeded
seeded cultivars now available.
(Cynodon dactylon L.) and vegetative bermudagrasses
(C. dactylon x transvaalensis) have greatly expanded Strengths: Exceptional heat tolerance and moderate
bermudagrass use throughout the mid-Atlantic, espe- drought tolerance; exceptional density; slow verti-
cially on golf and sports turfs. cal and lateral growth rates result in reduced mowing
requirement and limited invasiveness; moderate shade
Primary establishment method: Improved common
tolerance; minimal pest pressure.
varieties now available from seed; vegetative-only cul-
tivars are sterile and can only be established by sod, Weaknesses: Slow to establish from seed, sprigs, or plugs;
sprigs (i.e., stems), or plugs. sod very expensive; loss of color due to winter dormancy.

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

St. Augustinegrass
Description: Coarse-textured species with a stolonifer-
ous growth habit.
Primary uses: Lawns and general-purpose turf in the
Tidewater region.
Primary establishment method: Sod or plugs; limited
varieties available in the region.
Strengths: Best shade tolerance of warm-season
grasses; good quality, very dense turf with an aggres-
sive growth rate; good heat and drought tolerance.
Figure 6.7. Zoysiagrass provides one of the highest-quality, lowest-
maintenance lawn turfs in the mid-Atlantic, while also being used for
Weaknesses: Poor cold tolerance; requires frequent
golf fairways and tees. mowing; the most insect and disease pressures of the
warm-season grasses.
Typical seasonal nitrogen requirements: 1 to 2
pounds per 1,000 square feet. Typical seasonal nitrogen requirements: 3 to 4
pounds per 1,000 square feet.
Centipedegrass (figure 6.8) The growth rates for warm-season grasses are opti-
Description: Medium-to-coarse-textured species with mized at 85 to 95° F. Their seasonal root and shoot
a stoloniferous growth habit. growth patterns and stored carbohydrate levels are
detailed in figure 6.9. The grasses enter dormancy after
Primary uses: Lawns and other low-maintenance turfs,
frost events in the fall and do not resume active growth
primarily in the coastal regions.
until early to midspring the following season. Nitrogen
Primary establishment method(s): Both seed and sod fertilization is preferably initiated in the spring after
are available; very limited variety selection. complete greening, but — at the least — after 50 per-
cent spring greening for situations where fertilizers are
Strengths: Good-quality, low-maintenance turf that is applied in combination with pre-emergent herbicides in
well-adapted to acidic soils; moderate shade tolerance; traditional “weed and feed” products. Fertilization can
slow vertical and lateral growth rates that reduce mow- continue through the summer and into early fall during
ing requirement and its ability to become a weed. periods of active growth. As the persistently cool tem-
Weaknesses: Poor traffic tolerance; slow to establish; peratures of fall arrive, nitrogen fertilization ceases as
marginal cold tolerance. the plants prepare for winter dormancy.

Typical seasonal nitrogen requirements: 1 to 2 Warm-season grasses have inherent advantages in

pounds per 1,000 square feet. water-use efficiency over cool-season grasses, and for
this reason alone, their use is increasing. However, the
winter dormancy period that results in the complete
loss of green color (figure 6.10) continues to be a pri-
mary reason why many homeowners are reluctant to
establish and maintain warm-season lawns.

Native Turfgrasses and Specialty

Use Applications
A native plant evolved in a particular climate and where
it can be grown, there are logical advantages to uti-
lizing plant materials that evolved in a site’s specific
climate and soils. Since the climax vegetation of the
Figure 6.8. Centipedegrass is an excellent choice for low-input
turfgrass sites such as cemeteries in the southern coastal plain of the mid-Atlantic is primarily hardwood forest, there are
mid-Atlantic. no native turfgrasses of significance for turfgrass use.

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

Blue grama [Bouteloua gracilis (Willd.

ex Kunth) Lag. ex Griffiths] is a min-
imal-maintenance native that has con-
sistently performed well in Virginia
Tech’s low-input turf trials. This fast-
establishing, bunch-type, seeded warm-
season native of the Midwestern plains
is likely not suitable as a fine turf where
aesthetics and/or traffic tolerance are
important. However, it has persisted for
multiple seasons in low-input turf vari-
ety trials at Virginia Tech with minimal
invasion by weedy species. Blue grama
will require mowing only a few times
Figure 6.9. The anticipated seasonal root and shoot growth patterns and carbohydrate levels of
per year as a low-input turf.
warm-season turfgrasses.
In research that simulated a cemetery
setting at Virginia Tech, a cool-season native turfgrass
called Prairie junegrass [Koeleria macrantha (Ledeb.)
J. A. Schultes, variety “Barleria”] that was mixed at 95
percent junegrass to 5 percent “Baron” Kentucky blue-
grass (by weight) at establishment was one of the high-
est-quality, lowest-input turfgrasses in the trial. After
three years in the field, this was one of the highest-rated
cool-season grass plots that particularly withstood the
extreme drought of 2007 in this region. By the end of
the trial, no Kentucky bluegrass was visibly evident
in the plots. There are very few choices in cultivars
of prairie junegrass, but it is anticipated there will be
future development in this area.
Figure 6.10. Warm-season grasses have a winter dormancy period
ranging from four to five months in the mid-Atlantic. Other native grasses that are used for minimal-
maintenance, no-mow situations are little bluestem
However, there are native grasses that evolved in the
[Schizachyrium sco-
arid (less than 15 inches of annual rainfall) plains states
parium (Michx.)
of the Midwestern United States that have desirable
Nash], big bluestem
characteristics as potential turfgrasses for low-input
(Andropogon gerar-
management situations.
dii Vitman, figure
Buffalograss [Bouteloua dactyloides (Nutt.) J.T. 6.11), Indiangrass
Columbus] is a plains grass that has had a great deal [Sorghastrum nutans
of breeding work to improve its quality as a managed (L.) Nash], and
turf. Buffalograss has many highly desirable character- switchgrass (Pani-
istics, such as outstanding heat, cold, and drought tol- cum virgatum L.).
erance and slow lateral growth by stolons. Improved These tall-grass
varieties tolerate regular clipping as low as 1.5 inches. prairie species are
However, even with all of these desirable features of a intended for low-
low-input turf, buffalograss has struggled to persist as maintenance sites
an acceptably dense turf under the much higher rainfall that will typically
conditions of the mid-Atlantic (30 to 45 inches per year receive only an
on average). Recently released seeded and vegetatively annual “cleanup”
established cultivars and experimental lines show mowing event to Figure 6.11. Big bluestem serves as a
wildlife-friendly, visually appealing, low-
promise in this region, but they have not yet withstood control woody spe- input perennial groundcover in out-of-
the test of time. cies that develop in play areas on this golf course.

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

these minimal-maintenance conditions. They are noted

for the color of their foliage and seedheads and serve as a
refuge for animal life. They can be found in turfed areas
as divergent as highway rights of ways and secondary
roughs on golf courses. Their establishment to desirable
quality stands takes patience, because two to three years
are often required to achieve the “look” associated with
a tall-grass prairie. During this establishment period,
herbicide applications are often required to reduce weed
invasion in these relatively low-density grasses.
In summary, the best way to achieve long-term suc-
cess with low-input grasses is to select adapted spe-
cies that have demonstrated perennial success in this Figure 6.12. Stockpile topsoil prior to construction for later distribu-
tion before turf and landscape planting.
region, rather than those classified as natives because
they originate in the United States. The native grasses
Unfortunately, stockpiled topsoil is often not avail-
detailed here are outstanding performers in the arid
able in urban settings and what remains is a nutrient-
prairie states of this country. In the aforementioned
deficient, compacted, poorly drained subsoil material
simulated cemetery trial at Virginia Tech, the highest-
that is to be used for turf and landscape plant estab-
quality, lowest-input turfgrasses were hard fescue, prai-
lishment. Far too often, the unsuitable soil is masked
rie junegrass, and either seeded or sodded zoysiagrass.
by a sod installation that provides immediate cover but
Of this group, only prairie junegrass is native to the
ultimately fails as environmental extremes (heat, cold,
United States and it is still considered somewhat of an
drought, or saturated conditions) arrive.
“experimental” turfgrass with very limited availability.
The other grasses — while not native by definition — No amount of water, fertilizers, and pesticides can over-
are well adapted to the mid-Atlantic and have better come an unsuitable soil, and the potential for turfgrass
performance characteristics than most natives. management to impact water quality is exaggerated as
homeowners attempt to overcome the soil limitations
with excessive water and chemical inputs. Instead of
Turfgrass Establishment utilizing the benefits of turfgrass as a filter and soil
stabilizer to protect water quality, the end result is a
Soil Preparation declining stand of turfgrass that negatively impacts
Whether it is a new establishment or a spot renovation, water quality by the likely movement of sediment and
it is important to ensure that soil’s physical or chem- unused nutrients during heavy rainfall events.
ical properties are suitable for turfgrass establishment
and long-term success. If a turf stand has failed, is it Remove and dispose of all rocks and construction debris
possibly due to the soil? For native soils, conducting (brick, piles of gravel, lumber, spilled concrete, electri-
a soil test is an inexpensive and logical preventative cal wire, etc.) from the site — do not bury it in the soil.
maintenance step that should accompany almost any Any utility, irrigation, drainage, or sewer lines for the
establishment scenario, especially if a soil test has not site should be installed well before the installation of
been conducted for the past three years. Applying rec- turf or ornamentals. Be sure to confirm that these lines
ommended levels of lime and fertilizer will ensure the have been installed to appropriate depths so they won’t
turf has maximum opportunity to establish. be hit by tillage equipment during final soil preparation.
Ensure that the grade on the property is suitable so that
For new establishments in many urban settings, the surface drainage moves water away from buildings,
physical properties of the existing soil (often a “B” sidewalks, etc. This is also the time to consider the fea-
horizon subsoil remaining after construction) are an sibility (and/or design and installation) of rain gardens
immediate limitation to turf establishment (see chap- or other stormwater retention systems.
ter 4 for a complete discussion on the challenges of
urban soils). Whenever possible, stockpile the top 4 to Conduct soil tests for the lawn and ornamental beds in
6 inches of the topsoil before construction begins for order to address any chemical limitations (pH and nutri-
later redistribution across the site after construction is ent levels) of the growing medium (Goatley, Mullins,
complete (figure 6.12). and Ervin 2009). Prior to planting, recommended lime

Urban Nutrient Management Handbook 6-7

 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

and fertilizer materials should then be incorporated into is viable but of limited availability since it cannot easily
the top 4 to 6 inches of soil. This will also be the time be extracted from the seedhead). Sprigging (inserting
to incorporate any organic or inorganic amendments vegetative stems into a prepared seedbed) establish-
recommended to improve the soil (discussed in chapter ments should follow these same timing guidelines.
9). Thoroughly till the soil but do not attempt to turn
Sod establishments are much more flexible in terms
the lawn seedbed into a fine powder typically equated
of timing success, but the ideal establishment period
to garden soil — some clods are fine for turf establish-
follows the previous guidelines for both warm- and
ment! The soil can then be smoothed and firmed with a
cool-season grasses. However, both warm- and cool-
lightweight roller prior to planting, but avoid extensive
season sods can be successfully established as long as
surface compaction. If additional construction traffic
they are not applied to frozen soils. The key to success
occurs prior to planting, conduct another light tillage to
is to remember that these sods, while having reduced
remove surface compaction.
moisture needs, still require some water to prevent des-
Little (or no) soil preparation of thinning or degraded iccation of the newly emerging roots. Dormant sods of
turf areas most often leads to failed turfgrass establish- warm-season grasses should have minimal moisture
ment, even though it might seem logical that sowing requirements but should be checked regularly during
seed or installing sod into/on a sparse turf canopy could abnormally dry winters. Establishing cool-season sods
work. Seed applied into thin turfs usually germinate, in the summer is possible, but it requires regular moni-
but many of the newly emerging roots do not adequately toring and applications of soil moisture because evapo-
penetrate the soil such that the new plants persist. For transpiration losses are so high. No nitrogen fertilizer
spot seed renovations, it is recommended to core aerate should be applied to sods when established outside the
the soil in multiple directions, seed, and then drag the optimal establishment window.
cores back into the area after seeding to improve soil-
to-seed contact. For sod installations, success is usually Nutrient Management and Fertility
achieved through complete soil preparation.
Recommendations
Successful turfgrass establishments are closely linked
Timing to responsible nutrient management programs, regard-
Across the mid-Atlantic, the optimum period to seed less of the turfgrass and its use. These nutrient manage-
cool-season grasses is late summer to early fall. This ment recommendations were developed in a cooperative
timing optimizes root development and carbohydrate effort between the turfgrass faculty at Virginia Tech and
storage in the young plants because of more favorable representatives of the Virginia Department of Conser-
environmental conditions that maximize plant develop- vation and Recreation that ultimately resulted in the
ment before summer arrives. Early to midspring is the Virginia Nutrient Management Standards and Criteria
secondary window for seed establishments. Seed read- (2005). Fertility recommendations for establishment
ily germinates as the soil warms, but the root system is consider that the following criteria are met: (1) selec-
rarely developed sufficiently to ensure survival during tion of appropriate grass for the climate and its intended
a hot, dry summer season. Seed is readily available for use, and (2) establishment occurs under optimal plant-
all cool-season grasses. ing conditions.
For seeded warm-season grasses, the ideal establishment Nutrient management strategies for new plantings will
period is midspring to early summer. These grasses per- vary widely depending on the grass and its intended
form optimally during hot weather conditions as long use. For instance, consider the inherent differences in
as they receive adequate moisture to maintain growth. growth rates between grasses, even within the group-
The first winter survival of plants established from seed ings of cool-season and warm-season species. Bermuda-
later than mid-July can be greatly reduced in extreme grass and St. Augustinegrass (warm-season grasses) or
winters; the more mature a warm-season turf is, the bet- tall fescue and perennial ryegrass (cool-season grasses)
ter its chance of surviving the first winter. There are are noted for quick establishment, whereas zoysiagrass
seeded varieties for bermudagrass, zoysiagrass, and and centipedegrass (warm-season) or Kentucky blue-
centipedegrass but not all varieties of these grasses are grass and fine fescue (cool-season) are very slow. Simi-
available from seed (i.e., they must be established veg- larly, consider differences in establishment challenges
etatively by sprigs, plugs, or sod). St. Augustinegrass is between roadside vegetation being seeded on cut-and-
almost exclusively established from sod or plugs (seed fill soils high in B- or C-horizon material versus seeding

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

on completely modified, sand-based systems for golf Nitrogen

and sports turfs. Regardless of the site characteristics,
the newly established sites planted from seed, sprigs Establishing turfgrasses in an environmentally respon-
(i.e., rhizomes or stolons), plugs, or sod have imma- sible manner is a challenge in any situation. When
ture root systems that are limited in both size and depth. possible (or affordable), establishing by sod provides
These limitations in initial root development place an immediate soil stabilization; sediment loss is essen-
even greater importance on the need for soil testing in tially negated. However, seed, sprig, or plug estab-
order to correct chemical deficiencies — especially pH lishments present the challenge of applying relatively
and plant-available phosphorus and nitrogen. Consult large amounts of water and fertilizer to promote quick
with a certified nutrient management planner or with establishment (i.e., reduce sediment loss), but not at the
local cooperative Extension office personnel when expense of leaching or movement of the fertilizer into
developing a suitable nutrient management program for nearby water sources.
turf establishment in your area. Nitrogen amounts during grow-in will vary depending
on the turfgrass, water solubility of the nitrogen source,
Phosphate and Potash soil characteristics, and timing of the establishment.
At establishment, there are at least three factors that
Recommendations for Establishment
require fertility programs to be adjusted for the specif-
Soil testing is appropriate for adjusting soil phosphorus ics of a planting situation:
and potassium levels prior to planting. Table 6.1 details
general phosphate and potash recommendations for 1. All new establishments, even sod, lack a fully
turfgrass establishments. developed root system to efficiently utilize nutri-
ents and water soon after planting.
Table 6.1. Phosphorus and potassium levels 2. The requirement for frequent irrigation during turf
applied at turfgrass establishments on the establishment to sustain the emerging root and
basis of soil testing. shoot systems increases the potential for nutrient
Nutrient needs (lb/1,000 sq ft) loss.
Phosphorus Potassium 3. With seed, plug, or sprig establishments, the lack
Soil test level* (P2O5) (K2O) of a dense turf canopy increases water quality
Low 3-4 2-3 concerns due to the potential lateral movement of
Medium 2-3 1-2
nutrients and sediment.

High 1-2 .5-1 Immediate soil coverage is an inherent advantage in

sod establishments and even where complete installa-
Very high 0 0
tion is not possible due to cost, using sod strips in pre-
*For low soil test levels within a category (e.g., L-), use the dominantly seed establishments is often an affordable
higher side of the range of nutrient needs. For high soil test
levels (e.g., H+) use the lower side of the range of nutrient way to slow the speed of water on slopes and reduce
needs. soil loss (figure 6.13).

Research in Maryland (Turner 2005) has demonstrated

that there are limited advantages in turfgrass establish-
ment at seeding from utilizing traditional high phos-
phorus-analysis “starter fertilizers” (e.g., 5-15-5, etc.),
with the advantages being realized primarily when soil
temperatures are suboptimal for establishment. Simi-
larly, the same advantages in the use of starter fertil-
izers can apply to overseeding, spot renovations, and
sodding as well, but their importance is minimal on
soils with adequate phosphorus and optimal tempera-
ture and moisture conditions for establishment.

Figure 6.13. Adding single strips of sod to seed establishments on sloped

sites is a highly effective means of reducing soil erosion potential.

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

One nitrogen fertility strategy that promotes the devel- there is a great deal of variability in fertilization strate-
opment of newly established turfgrasses with less gies for turfgrass establishments. Successful establish-
potential impact on water quality is to utilize “slowly ments are best achieved by planting grasses during their
available nitrogen” (SAN) sources during grow-in. The optimum establishment windows (late summer to early
Virginia Department of Conservation and Recreations’ fall for cool-season grasses and late spring through
Nutrient Management Training and Certification Regu- midsummer for warm-season grasses). For any grass
lations (4 VAC 5-15) (http://www.dcr.virginia.gov/doc- on any soil type, utilize a soil test to determine lime,
uments/nmtraincertregs.pdf) define SAN as “sources phosphorus, and potassium needs and incorporate all
that have delayed plant availability involving com- needed amendments into the top 4 to 6 inches of the
pounds which dissolve slowly, materials that must be soil profile prior to planting.
microbially decomposed, or soluble compounds coated
First, consider nitrogen-based establishment fertility
with substances highly impermeable to water, such as
programs for cool- or warm-season grasses on heavier-
polymer-coated products, methylene urea, isobutyl-
textured, predominantly silt/clay soils. These programs
idene diurea (IBDU), urea formaldehyde based (UF),
apply to most soils used for golf fairways and roughs,
sulfur-coated urea, and natural organics.” Ideally, these
athletic fields, and sod farms in the region. Up to 1
sources should contain 50 percent or more SAN in
pound of nitrogen per 1,000 square feet can be applied
order to realize the full benefits of sustained nitrogen
in a single application at planting with a 50 percent or
feeding with little nitrogen loss potential. Such sources
greater SAN source that will feed the turf for up to four
should be the focal point of grow-in programs on sand-
weeks. For sources containing predominantly WSN,
based soils. However, it is possible — and sometimes
apply no more than 1 pound of nitrogen per 1,000
desirable due to cost or desired rate of turf coverage —
square feet over the first four weeks by splitting the
to utilize predominantly water-soluble nitrogen (WSN)
applications into regular intervals. At four weeks after
sources during grow-in by way of frequent, low-level planting, apply 0.25 to 0.5 pound of WSN per 1,000
(0.25 to 0.5 pound of nitrogen per 1,000 square feet) square feet per week for the next four weeks.
nitrogen applications. Many times, a successful grow-
in program that combines both desirable turfgrass cov- Next, consider nitrogen-based establishment fertility
erage and quality with environmental protection is one programs for cool- or warm-season grasses on naturally
that employs a range of nitrogen sources with varying occurring or modified sand-based soils. In these highly
degrees of water solubility. leachable soils, it is important to use a 50 percent or
greater SAN source at up to 1 pound of nitrogen per
Grow-In Strategies for Lawns and General Turf 1,000 square feet for the first four weeks of establish-
ment for either type of grass. For warm-season grasses,
Nitrogen applications for establishment of home lawns apply 0.25 to 0.50 pound of WSN per 1,000 square
and general turf areas should not exceed 1 pound of feet per week for the next four weeks. On cool-season
nitrogen per 1,000 square feet at planting, followed by grasses, apply up to 0.25 pound of nitrogen per 1,000
one or two applications initiated at 30 days after plant- square feet per week (or 0.5 pound of a 50 percent or
ing, not to exceed a total of 2 pounds of nitrogen per greater SAN source every two weeks) after germina-
1,000 square feet for the establishment. Slow-release tion is complete for the next eight weeks.
nitrogen sources containing 50 percent or greater SAN
will reduce leaching potential and should be used when- Large-scale grow-ins on golf courses are sometimes
ever possible for establishments on sand-based soils. achieved with fertigation systems (the application of
Split applications of WSN at 0.25 to 0.5 pound per 1,000 low levels of nutrients through an inground irrigation
square feet per application on one- to two-week inter- system). For a properly installed and functioning irriga-
vals will further improve nitrogen-use efficiency, but tion system, fertigation is an extremely efficient method
consider that these applications can be difficult given of nutrient delivery through the irrigation water.
the likelihood of wet soils during the grow-in period.
Irrigation and Water Conservation
Grow-In Strategies for Golf Course, Athletic Strategies for Establishments
Field, or Sod Production Systems Light and frequent irrigation is required for optimal
With the wide range of grasses that can be used and the seed establishments. Keep the seedbed moist but don’t
diversity in soils found across the mid-Atlantic region, apply so much water that the seed might drown or be

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

washed away. A somewhat more aggressive watering general application level is one bale of straw per 1,000
strategy is required for sprig establishments, as these square feet, and it can be applied by hand or by power
tissues are particularly prone to rapid desiccation. Initi- equipment that chops and blows the straw. Avoid using
ate irrigation as soon as possible on newly planted sprigs hay as a mulch source; a clean (weed-free) wheat straw
and keep the sprigs moist but not saturated. Exces- is a preferred mulching material. Straw can simply be
sive watering can drown plants and promote fertilizer mulched right back into the canopy as the new grass
losses, due to either runoff or leaching loss. Even with establishes, and any of the small-grain seed that germi-
immediate irrigation, anticipate a possible total loss of nates can be mowed and will die during the first sum-
color due to leaf desiccation on the sprigs, but don’t let mer season.
this deter watering as healthy sprigs will almost always
There are numerous paper-based and wood-fiber
rapidly initiate new roots and shoots if their planting is
mulches available for mulching as well. Shredded
appropriately timed and irrigation and fertility require-
paper mulch is very popular when turf is established by
ments are met. As establishment progresses, gradually
“hydroseeding” — a motorized, pump-driven planting
reduce irrigation to a deep and infrequent strategy rec-
strategy that applies a fertilizer, seed, mulch, and tacki-
ommended for established turf.
fier slurry to a prepared seedbed. There is also a wide
Sod and rooted plugs provide more flexibility in sup- variety of erosion control blankets that are primarily
plemental irrigation requirements for establishment, designed for vegetation establishments on sloped sites.
not requiring nearly as much attention as seed or sprig These materials and their application strategies are fur-
plantings. As a rule of thumb, sod installations during ther discussed in chapter 11.
optimal establishment periods should receive up to 1
inch of water (either from irrigation or rainfall) during Seeding Levels and Planting Strategies
establishment. However, the ideal water management
approach is to keep the soil moist and not saturated; Seed provides the most popular means of establish-
during periods of low evapotranspiration, supplemental ment because of the availability of improved cultivars
water needs will be greatly reduced. Roots require both for many species and the relative affordability of seed.
water and oxygen to establish properly, and overwater- Many improved varieties of bermudagrass do not pro-
ing sod greatly reduces establishment. Periodically tug- duce viable seed and must be established vegetatively.
ging on the sod or plugs to assess root development is Seed is readily available for many improved varieties of
a good way to monitor moisture needs, and as rooting cool-season turfgrasses. Select certified (blue-tag) seed
progresses, reduce supplemental irrigation to a deep and whenever possible, as this ensures that what is indi-
infrequent strategy as one would for an established turf. cated on the tag is what is in the bag. Apply fertilizers
and lime as detailed above, utilizing soil tests whenever
An important way to conserve moisture and reduce possible to best correct deficiencies. For lawns, seed at
soil-erosion potential for seed establishments (and it the recommended levels detailed in table 6.2, using the
could work for sprig plantings as well) is to mulch the higher seeding levels during suboptimal establishment
seedbed. Small-grain (e.g., wheat, barley, etc.) straw is periods.
an ideal mulch for seed establishments (figure 6.14). A
Establishment Methods
The most common equipment to deliver seed in sur-
face applications to prepared seedbeds is either rotary
(often referred to as “broadcast” or “centrifugal”) or
drop (gravity-fed) spreaders. A rotary spreader can be
used for large-scale plantings because it can cover a
lot of ground in a short period of time. However, uni-
form seed distribution can be disrupted on windy days.
Drop spreaders allow for precision in seed application
because the seed falls precisely over the area covered
by the spreader. Seed distribution is not affected by the
wind, but this delivery method takes a great deal more
Figure 6.14. Mulching newly seeded areas with weed-free straw is time because it covers a much smaller area in a single
very effective in conserving moisture for seed establishments. pass. Apply seed in at least two directions (especially

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

with drop spreaders) to avoid skips. The previously

Table 6.2. Recommended seeding levels for
mentioned method of hydroseeding is an excellent
turfgrasses used in home lawns. means of rapidly covering large areas of prepared soil
Seeding level with a seed, fertilizer, and mulch slurry using water as
Grass (lb pure live seed/1,000 sq ft) a carrier.
Fine-leaf fescue 3-5
There also are a host of mechanized seeders that slice
Kentucky bluegrass 2-3 or lightly till the soil in front of a seed hopper that drops
Perennial ryegrass 3-5 the seed into the soil, thus ensuring soil-to-seed con-
tact. The primary concern with mechanized planters is
Tall fescue 6-8
being sure the seed is not planted so deep in the soil that
Perennial ryegrass 3-5 it cannot emerge. Smaller-seeded grasses (bluegrass,
Bermudagrass .5-1 bermudagrass, bentgrass, zoysiagrass, centipedegrass)
Centipedegrass .25-.50 should be planted on or just below the soil surface.
Larger-seeded grasses (tall fescue, perennial ryegrass,
Zoysiagrass 2-3
fine-leaf fescues) can be planted into the top 0.5 inch
Cool-season Use recommendations on the of soil.
mixtures depend on bag. For example, a 90/10
percent of individual (percent by weight) mixture of
species in mix. tall fescue/Kentucky bluegrass Sodding
is seeded at 3-4 lb/1,000 sq ft. An inherent advantage of sodding is that the soil
attached to the sod serves as a nutrient and moisture
Table 6.3. Recommended establishment levels for reservoir to aid in establishment. Another consideration
specific uses of grasses for golf and sports turfs. in the choice of sod is that it is an extremely effective
means of almost eliminating soil erosion (and poten-
Seeding level tial movement of sediment into waterways) during turf
(lb pure live
establishment. Appropriate use of a high-phosphorus
seed/1,000
Grass and use sq ft) starter fertilizer can benefit initial rooting, but the
responses are not likely to be as significant as those
Creeping bentgrass (golf putting greens .5-1 encountered from seed establishments. Fertilizers can
and tees)
also be applied postestablishment to the sod itself. Sod
Creeping bentgrass (golf fairways) .25-.50 offers significant advantages in lower water require-
Kentucky bluegrass (golf fairways and 2-3 ments (and attention to watering during establishment),
tees, sports fields) has virtually no soil-erosion potential, and provides
Perennial ryegrass (golf fairways and 3-5 almost immediate gratification and use potential. Roll
tees, sports fields) the sod after planting to ensure soil-to-plant material
contact. Water frequently enough to maintain a moist
Perennial ryegrass/Kentucky bluegrass 2-4
mixtures, 90%-10% by weight (golf
(not saturated) sod. Periodically check for rooting by
fairways and roughs, sports fields) tugging on sod to see how well it is tacked to the soil;
reduce irrigation frequency and amount after establish-
Tall fescue (golf roughs) 4-6
ment is complete.
Tall fescue (sports fields) 6-8
Tall fescue/Kentucky bluegrass 2-4 Plugging or Sprigging
mixtures, 90%-10% by weight (golf
Any grass that produces lateral stems (rhizomes and/
roughs)
or stolons) can be established by plugging or sprigging
Tall fescue/Kentucky bluegrass mixtures, 3-4 (planting stems directly into the soil, figure 6.15). How-
90%-10% by weight (athletic fields)
ever, due to the ready availability of seed for many cool-
Bermudagrass (golf fairways and tees, .5-1 season grass varieties and their slower lateral growth
athletic fields) rates, only warm-season grasses are commonly estab-
Bermudagrass (golf roughs) .25-.50 lished by plugs or sprigs. Plugs of 2 inch to 4 inch in
Zoysiagrass (fairways or tees) 2-3
diameter are planted on 6- to 12-inch centers. Rapidly
spreading grasses like bermudagrass and St. Augustine-

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

Table 6.4. Vegetative planting recommendations

for various grasses and their respective uses.
Grass and intended use Stems/sq ft
Bermudagrass (lawns) 10-25
Bermudagrass (golf fairways) 10-50
Bermudagrass (golf greens) 35-50
Zoysiagrass (lawns) 25-35
Zoysiagrass (fairways and tees) 35-50

Winter Overseeding
Figure 6.15. Bermudagrass sprigs (i.e., shredded stems) planted in
rows on a sand-based athletic field. Winter overseeding is defined in this publication as
the early-to-midfall seeding of an adapted cool-season
grass can be planted on 12-inch centers and will achieve
turfgrass into an existing warm-season turfgrass for the
complete coverage within one summer growing season;
purpose of winter color and possibly improved play-
faster coverage rates of 30 to 60 days are likely with plug-
ability of sports fields. Note that overseeding is some-
ging on 6-inch centers. Slow-spreading grasses like cen-
times used as a general term to describe any general
tipedegrass and zoysiagrass should be planted on 6-inch
seeding or renovation event that is conducted on exist-
centers and even then might not cover within one grow-
ing stands of turfgrass.
ing season. Plugs have the advantage of usually being
fully rooted, and therefore, they require less-intensive Most often, the choice in cool-season turf for overseed-
maintenance at establishment. ing is an annual, perennial, or intermediate ryegrass.
For most purposes, only bermudagrass is recommended
The shredded stems used as sprigs require regular and
to be overseeded, because other warm-season grasses
frequent irrigation until the growing points on the stems
are generally not viewed as being competitive enough
have produced a functioning rooting system. The mois-
the following season to outcompete the winter over-
ture requirement for sprigs is very high during the first
seeding. The bermudagrass might be lightly vertical-
seven to 14 days of establishment.
mowed or slightly scalped prior to overseeding in order
For those who have never established turf in this manner, to enhance seed movement through the canopy to the
the first impression is that the stems have died because soil. Obviously, this is potentially detrimental to the
most of the leaf material at planting browns and decays. bermudagrass, and the level of vertical mowing should
Be persistent with providing regular irrigation during be kept to a minimum and not used as a dethatching
this seven- to 14-day window, and new leaves and roots event late in the bermudagrass growing season. Opti-
will emerge. Logically, the more plant material used at mum soil-to-seed contact can be achieved by topdress-
establishment, the quicker the establishment rate. Sprig- ing the overseeded grass with sand or a similar topsoil
ging levels of 10 to 25 stems per square foot are typical material. For winter overseeding of bermudagrass,
planting levels, but higher levels of up to 50 stems per home lawns are seeded at 5 to 10 pounds of pure live
square foot will likely be required to establish slower- seed per 1,000 square feet. Athletic fields or golf fair-
growing grasses, such as zoysiagrass or centipedegrass ways and tees are typically seeded at 10 to 20 pounds
in one growing season (table 6.4). of pure live seed per 1,000 square feet.
It is common for sprigging specifications to be pre- Fertilization strategies for overseeded turfs can be
sented in units of bushels of sprigs per acre. However, problematic in trying to balance the needs of the ger-
there is no clear definition of what constitutes a bushel. minating, cool-season grass seedlings with those of
As a point of reference, numerous custom planting a warm-season grass that will soon enter winter dor-
company personnel equate 25 stems per square foot to mancy. Overly aggressive nitrogen fertilization during
a planting rate of 500 bushels per acre. Specifying a fall overseeding periods can reduce ryegrass establish-
precise number of stems per square foot is the easiest ment by promoting excessive late-season bermuda-
way to quantify a vegetative planting rate of stems per grass competition, and high nitrogen levels can also
unit area. reduce the winter hardiness of the bermudagrass. Using

Urban Nutrient Management Handbook 6-13

 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

reduced nitrogen application levels of 0.25 pound of should be conducted at least every three years on high
nitrogen per 1,000 square feet per week during estab- silt/clay soils and every year on high sand-content soils.
lishment allows the manager to maintain control of Table 6.5 provides recommended fertilization levels for
the growth rates of bermudagrass and the establishing phosphorus and potassium.
ryegrass seedling. Nitrogen fertilization levels totaling
from 0.5 to 1 pound of nitrogen per 1,000 square feet Table 6.5. Phosphorus and potassium levels
in early September should suffice to feed the germinat-
applied to established turf on the basis of
ing ryegrass seedlings while not excessively stimulat-
soil testing.
ing the bermudagrass. Apply an additional 0.5 pound of
nitrogen per 1,000 square feet in October or November Nutrient needs (lb/1,000 sq ft)
and then again in February or March of the following Soil test level* Phosphorus (P2O5) Potassium (K2O)
year. These levels should suffice to promote ryegrass
Low 2-3 2-3
growth with limited effects on the bermudagrass turf.
Medium 1-2 1-2
While overseeding is generally considered to negatively
High .5-1 .5-1
affect the health and quality of warm-season grasses,
there are inherent advantages to its use in grassing sys- Very high 0 0
tems. Color and playability of golf and sports turfs might *For low soil test levels within a category (e.g., L-), use the
warrant the necessity of winter overseeding in some higher side of the range of nutrient needs. For high soil test
levels (e.g., H+), use the lower side of the range of nutrient
golf-turf and sports-turf situations. Another possible rea-
needs.
son to overseed is if the turf is irrigated with reclaimed
water. The ryegrass can effectively serve as a sink for
nutrients applied in the reclaimed water that the dormant Nitrogen
bermudagrass turf otherwise would not utilize. As detailed previously in this chapter describing the
predominant grasses of the region and their uses, the
Maintenance Fertility Programs annual nitrogen requirement varies greatly depending
on the species of grass being grown, site characteris-
Phosphorus and Potassium tics, intended use of the grass, and expectations of the
Applications of phosphorus and potassium in mainte- clientele growing the turf. The following tables detail
nance application programs for cool- and warm-season general seasonal nitrogen fertilization strategies for
turfgrasses should be based on soil tests. Soil tests both cool- and warm-season turfgrasses.

Table 6.6. General seasonal nitrogen fertilization strategies for cool-season turfgrasses.
Relative N rate/
application, per growing
Time of year month Comments
Early spring None to low - Never apply to frozen ground.
(.25 lb N/1,000 sq ft) - If following aggressive fall fertilization, probably not necessary.
Mid-late spring Low to medium - Have been shown to benefit root growth with responsible
(.25-.5 lb N/1,000 sq ft) applications.
- Exceeding these levels promotes shoots at expense of roots.
Summer None to low - In general, refrain from N fertility, but small amounts can aid
(.25 lb N/1,000 sq ft) recovery from stress/pest pressures.
- Avoid applications during high heat/drought pressures.
Late summer Medium to high - Promotes recovery from summer stress with early fall applications.
through early (.5-1 lb N/1,000 sq ft) - Continue program (while grass is still green without much shoot
winter growth) to promote roots, color, turf density, and carbohydrate
levels.

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

Table 6.7. General seasonal nitrogen fertilization strategies for warm-season turfgrasses.
Relative N rate/
application, per growing
Time of year month Comments
Early spring None to low - Never apply to frozen ground.
(.25 lb N/1,000 sq ft), - Ideally, wait until complete greening, but strategy doesn’t fit
pending emergence from standard weed and feed products designed for PRE-crabgrass
winter dormancy control
Mid-late spring Low to medium - Excessive levels promote shoots at expense of roots.
(.25-.5 lb N/1,000 sq ft) - Be aware of average “last frost” dates for the area.
Summer Medium to high - Primary season for fertilization, but still wise to avoid applications
(.5-1 lb N/1,000 sq ft) under severe environmental stress.
Late summer Low - Maintaining active growth until dormancy promotes late-season
to winter (.25-1 lb N/1,000 sq ft) rooting and carbohydrate storage, but N applications terminated
dormancy prior to first frost date.

Lawns and Commercial Turf remember that the seasonal requirements of varying spe-
cies are highly variable and some of the region’s turf-
Cool-season grasses can receive up to 3.5 pounds of
grasses would actually decline in health and/or quality if
water-soluble nitrogen (WSN) per 1,000 square feet or
aggressively fertilized. Table 6.8 details typical seasonal
4 pounds of slowly available nitrogen (SAN) per 1,000
square feet on an annual basis. Warm-season grasses can nitrogen requirements to achieve anticipated levels of
receive up to 4 pounds of WSN per 1,000 square feet desirable turfgrass performance.
or 5.5 pounds SAN per 1,000 square feet. Applications
of water-soluble nitrogen should not exceed 1 pound Golf Courses
of nitrogen per 1,000 square feet every 30 days. When Golf turf is some of the most intensively managed grass
using WSN on sandy soils, split applications to no more grown, requiring maintenance cutting heights as low as
than 0.5 pound of nitrogen per 1,000 square feet every 0.1 inch for some putting greens with expectations to
15 days. Slowly available nitrogen sources (defined as
deliver a dense, smooth-playing surface. Furthering the
any nitrogen source containing 50 percent or more SAN)
need for additional nutrition is that clippings are col-
can be applied at up to 1.5 pounds per 1,000 square feet
lected on all greens, most tees, and even some fairways.
on heavier-textured (high clay or silt) soils per applica-
For sand-based greens and tees, care especially needs
tion at a recommended timing or 1 pound of nitrogen per
1,000 square feet on predominantly sand soils. However, to be taken regarding the potential for leaching loss of
nitrates and phosphates due to the sandy soil and the
Table 6.8. Seasonal nitrogen requirements likelihood that the greens contain subsurface drains that
to deliver satisfactory levels of turfgrass likely channel leachate to a water source. When greens
performance for cool- and warm-season lawns. are mature and healthy, nitrate and phosphate leaching
concerns are minimal. When greens are immature (i.e.,
2.5-5.5 lb N/1,000 sq ft 1-2 lb N/1,000 sq ft
annually annually
being grown-in) or are stressed due to pest or environ-
mental pressures, the potential for nutrient loss is greatly
Kentucky/hybrid bluegrass Fine-leaf fescues
increased. Table 6.9 presents general seasonal nitrogen
Creeping bentgrass Centipedegrass applications for all aspects of golf turf management.
Bermudagrass* Zoysiagrass Consider that while the total annual nitrogen rates stay
Tall fescue* Bermudagrass* the same, the maximum nitrogen rate per application
(and therefore, the number of applications) might vary
Perennial ryegrass Tall fescue*
when 50 percent or more SAN sources are used on
St. Augustinegrass* St. Augustinegrass* heavier-textured (predominantly clay or silt) soils, and
*Certain varieties within species perform well under either levels of up to 1.5 pounds of nitrogen per 1,000 square
annual nitrogen program.
feet can be applied in a single application.

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

Table 6.9. General seasonal nitrogen strategies for golf turf management.
Maximum N rate/
application Total annual N rate
Turf use Grass type (lb/1,000 sq ft)a (lb/1,000 sq ft)b
Greens .5-1 3-6
Tees .5-1 2-5
Fairways Cool-season 1 2-3
(standard management)c Warm-season 1 2-4
Fairways Cool-season .5-1 3-4
(intensive management)d Warm-season .5-1 3.5-4.5
Overseeding fairwayse Warm-season .5 1.5
Roughs 1 1-3
For naturally occurring sand or modified sand-based soils on greens and/or tees, apply no more than 0.5 lb water-soluble
a

nitrogen per 1,000 sq ft every 15 days, or 1 lb nitrogen from sources containing 50 percent or greater SAN every 30 days.
Use the higher levels for intensively managed turf where accelerated growth and/or rapid recovery are required; use lower
b

rates for maintenance of lesser used areas.

Standard management fairways may or may not have irrigation and likely are mowed at heights of 0.75-1.25 inch, one to two
c

times per week.

Intensively managed fairways are irrigated and are likely mowed at heights of 0.75 inch or shorter, three or more times per week.
d

Initiate nitrogen applications of no more than 0.5 lb per 1,000 sq ft after ryegrass is well-established and bermudagrass has
e

entered dormancy. In spring, up to two applications of nitrogen at 0.5 lb per 1,000 sq ft can be used in February or March if
growth and color enhancement are required.

Athletic Fields and the 2005 Virginia DCR Standards and Criteria)
provide general recommendations for nitrogen fertility
There is likely no turf management situation more chal- strategies on cool-season athletic fields in this region.
lenging than maintaining a safe, high-quality playing As stated previously, the maximum nitrogen rate per
surface on an athletic field. A fertility program is only application (and therefore, the number of applications)
one component of a successful management program, might vary when 50 percent or more SAN sources are
because appropriate cultivation, irrigation, and field used on heavier-textured (predominantly clay or silt)
use management strategies have similar importance. soils and levels of up to 1.5 pounds nitrogen per 1,000
However, applying fertilizer at the appropriate levels square feet can be applied in a single application. The
and timing pending the grass, soil, and field use is criti- application timing and frequency would be adjusted
cal to sustain turf coverage and encourage its recovery. accordingly.
The following tables (adapted from Goatley et al. 2008,

Table 6.10. Suggested nitrogen fertility programs for a cool-season athletic field.
Maintenance programa (lb N/1,000 sq ft)
Normal Intensive
Application timing (predominantly silt/clay soil)b (predominantly silt/clay soil)b Sandy or modified sand soilc
After August 15 – .5 .5
September 1 1 1
October 1 1 1
November .5 1 1
April 15-May 15 .5 .5 .5
June 1-15 – .5 .5
Seasonal N total Up to 3 lb Up to 4.5 lb Up to 4.5 lb
Intensively managed native soil- and sand-based fields require supplemental irrigation.
a

These nitrogen levels can be applied with either water-soluble nitrogen (WSN) or slowly available nitrogen (contains 50
b

percent or more SAN) sources.

On sand-based systems, any application more than 0.5 lb nitrogen per 1,000 sq ft should be made with 50 percent or more SAN
c

sources on a 30-day minimum interval. Where WSN is used, levels should not exceed 0.5 lb per 1,000 sq ft every 15 days.

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

Table 6.11 Suggested nitrogen fertility Sod Production Systems

programs for a bermudagrass athletic field. Growing sod is quite simply a specialized form of “pro-
Maintenance Programa
duction agriculture,” with a similar goal (i.e., yield) of
(lb N/1,000 sq ft) any other crop. A harvestable sod of acceptable turf
quality (high density, dark green and uniform color,
Sandy or
pest-free, etc.) is the sign of a successful crop. Revenues
Application Predominantly modified sand
are optimized by achieving rapid coverage of the turf;
timing silt/clay soilb soilc
to accelerate harvest, it is common to net the sod either
April 15-May 15 .5-1 .5 prior to planting or at harvest. As for any growing sys-
June 1 1 tem, proper timing and appropriate application levels of
July .5-1 1 nutrients are crucial to optimize nutrient use efficiency.
Prior to seed or sprig establishment, soil tests should
August .5-1 1 be performed to adjust pH and supplemental nutrient
Sept 1-15d .5-1 – requirements (phosphorus and potassium, etc.) at plant-
Seasonal N 3-5 Up to 3.5 ing using the standard guidelines presented in table 6.1.
total for non- Netted sods can likely be produced within a calendar
overseeded year, whereas non-netted sods will likely require some
fields portion of a second growing season to complete estab-
If overseeded lishment. Recommended nitrogen levels at the estab-
with ryegrasse lishment of both cool- and warm-season turfgrasses
were presented earlier in this chapter. Tables 6.12 and
October- .5 .5-1
November
6.13 detail seasonal nitrogen levels in the production of
cool-season or warm-season sods.
February-March .5-1 .5-1
Seasonal N total 4-6.5 4.5-5.5 Table 6.12. Recommended nitrogen levels for
for overseeded production of a cool-season turfgrass sod.
fields
Timing of planting Actual N (lb/acre)
a
Intensively managed native soil- and sand-based fields
require supplemental irrigation. At seedinga 40-60b
These nitrogen levels can be applied with either water-
b
In seeding year of fall
soluble nitrogen (WSN) or sources containing 50 percent or
plantingc
more SAN.
Any application more than 0.5 lb nitrogen per 1,000 sq ft
c
Nov. 15-Dec. 15 40-60
should be made with a SAN source (containing 50 percent
or more SAN) on a 30-day minimum interval. When WSN First full year of
is used, levels should not exceed 0.5 lb per 1,000 sq ft establishment
every 15 days.
April 1-June 15 20-40
The September application is suitable only if anticipated
d

first fall killing frost date is after Oct. 20. Aug. 15-Oct. 1 40-60
Use the higher nitrogen levels on intensively trafficked
e

fields only. Nov 1-Dec. 1 40

Second yeard 20-40/growing-month
as needed to complete
coverage
a
Fall planting dates are optimal for rapid establishment; for
spring plantings, continue first season fertility in August of
that year.
b
Apply no more than 40 lb of water-soluble nitrogen per
acre in any single application; for levels more than 40 lb,
use materials that are 50 percent or more SAN.
c
Do not apply fertilizer to frozen soil.
d
Second-year fertilization likely only required for non-netted
sod.

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

Table 6.13. Recommended nitrogen levels for Table 6.14. Typical maintenance cutting
production of bermudagrass or zoysiagrass heights for turfgrasses grown in the mid-
sods. Atlantic.a
Bermudagrass Zoysiagrass Species Cutting heights (inches)b
Timing of
application lb N/acrea Creeping bentgrass 0.1-0.19, greens; 0.25-0.75, fairways
Establishment by 40-60 40-60 Fine-leaf fescues 1.5-2.5
seed or sprigs in
Kentucky bluegrass, 1.5-2.5
late spring/early
hybrid bluegrass
summer
Perennial ryegrass 0.75-2
June 40 –
Bermudagrass 0.5-1 on athletic fields, golf
July 40 40
fairways and tees; up to 2 on
August 40 – lawns and general-purpose turf
a
 pply no more than 40 lb of water-soluble nitrogen per
A Centipedegrass 1.5-2.5
acre in any single application; for levels greater than 40 lb,
use materials that are 50 percent or greater SAN. St. Augustinegrass 2-3
Zoysiagrass 0.5-1 on golf fairways and tees;
up to 2 on lawns and general-
Mowing purpose turf

Standard Mowing Heights Tall fescue 2-3

Cutting height recommendations for optimal growing
a
The recommended mowing heights detailed in table
periods.
6.14 are recommendations for optimal growing periods Cutting heights shorter than 1 inch require a reel mower.
b

and will vary depending on the cultivar and the use of

the grass (lawn, golf or sports turf). In almost every
instance, the listed grasses can be mowed taller than Equipment
heights listed. However, maintaining turfgrasses within Rotary mowers are the prevalent cutting units for the
their recommended clipping height range during peri- most acreage because they are generally inexpensive
ods of optimal growth promotes turfgrass density by to both purchase and maintain. Rotary units clip grass
promoting lateral growth through tillers (i.e., daugh- by spinning a metal blade with a sharpened edge at
ter plants), rhizomes (belowground stems), or stolons high speed under a stationary deck. The cut is actually
(aboveground stems). Prior to and/or during environ- more of a “tear,” because the grass blades are removed
mental stress periods, raising the clipping height is a simply by the impact of a solid object striking the leaf
standard recommendation for all grasses in order to blade at a high speed. Maintaining a sharp and properly
enhance survival. Therefore, prior to summer stress balanced blade is crucial to maintaining high turf qual-
periods, the recommendation is to raise the cutting ity and plant health. Mowing with a dull blade creates
heights of cool-season grasses, and for non-irrigated jagged wounds in the leaves that result in a low-quality
turf, it is often suggested to refrain from mowing at turf that has increased potential for disease and envi-
all. For warm-season grasses, raise the cutting heights ronmental stress.
a few weeks prior to an anticipated frost date (and ini- Flail mowers have multiple-levered blades on a spin-
tiation of winter dormancy) in order to promote winter ning horizontal shaft. The blades are not intended to
survival. be sharpened and are designed to “give” if they hit a
The standard recommendation is to never remove more solid object; the deck is fully self-contained with no
than one-third of the leaf blade at any cutting event. discharge point. Flail units are popular in maintaining
Limiting leaf blade removal to this level prevents scalp- unimproved turf areas such as highway rights of way
ing and a drain on carbohydrate reserves to replenish where turf quality is not critical.
the shoot system. The cutting unit that provides the highest quality of cut
is the reel unit that features a cylinder of curved blades
that gathers and pinches leaves between the blade and a
stationary, sharpened bedknife. Reel units are used on the

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 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

highest-quality turf where cutting heights shorter than 1 The ability to chop clippings into very small leaf pieces
inch are desired and the highest level of surface smooth- accelerates leaf decomposition in the soil, thus improv-
ness is required. Maintaining properly adjusted and ing lawn appearance and promoting a healthy soil micro-
sharpened blades and bedknives is crucial to achieving bial population. If the 1/3 rule cannot be followed for a
the high-quality cut desired with this type of cutting unit. mowing event and piles of clippings remain on the lawn
(figure 6.17), it is important to remove them because
Clipping Management they block sunlight and encourage disease due to the
elevated temperature and moisture under the pile. In all
Returning clippings is desirable whenever possible, and cases where clippings are collected, they should be prop-
the only situation where clippings are recommended for erly composted (detailed in chapter 9) rather than piled
collection is in putting green management for golf turf in waste areas and/or bagged for deposit in landfills.
where they would disrupt playability of the putting sur-
face. Clippings are essentially controlled-release fertil-
izer, containing approximately 4 percent nitrogen, 0.5 to 1
percent phosphorus and 2 percent potassium by weight.
A common misconception is that clippings contribute to
thatch — a layer comprised primarily of slow-to-decay
stems that forms between the turfgrass canopy and the
soil surface. Thatch is primarily composed of stems (rhi-
zomes, stolons, and crowns) that resist microbial degra-
dation. Therefore, all grasses capable of lateral growth
by way of rhizomes and/or stolons can become thatchy,
especially if they are aggressively fertilized. If properly
mowed (i.e., following the “1/3 mowing rule” of leaf
removal), clippings readily degrade and do not contrib- Figure 6.17. When the “1/3 mowing rule” is violated, it is important
not to leave the piled clippings on the lawn because they can damage
ute to thatch. However, if mowing is sporadic and the the underlying turf. Collect and compost this material.
turf is allowed to produce seedheads, thatch buildup is
likely to occur over multiple seasons. Another tempting
reason to collect clippings is to reduce the potential of
Literature Cited
spreading weeds or diseases throughout the lawn. How- Goatley, M., S. Askew, E. Ervin, D. McCall, R. Stud-
ever, research has shown that the advantages of return- holme, P. Schultz, and B. Horvath. 2008. Sports
ing clippings far exceed any concerns with promoting Turf Management in the Transition Zone. Blacks-
weed or disease pressure in the turf. burg, Va.: Pocahontas Press.

It is now common that many versions of the standard Goatley, M., G. Mullins, and E. Ervin. 2009. Soil Test-
rotary mowers can serve as “mulching mowers” by way ing for the Lawn and Landscape. Virginia Coop-
of modifications of their decks and blades (figure 6.16). erative Extension Publication 430-540. www.pubs.
ext.vt.edu/430-540.
Turner, T. R. 2005. Nutrient Management Guidelines
for Commercial Turfgrass Seeding. University of
Maryland Technical Turfgrass Update, TT-116.
Virginia Department of Conservation and Recreation,
Division of Soil and Water Conservation. 2005.
Virginia Nutrient Management Standards and Cri-
teria, 96-107.

Figure 6.16. A mulching mower chops turfgrass clippings into fine

particles that are quickly decomposed by microbes in the soil.

Urban Nutrient Management Handbook 6-19

 Chapter 6. Mid-Atlantic Turfgrasses and Their Management

6-20 Urban Nutrient Management Handbook

 Chapter 7. The Ornamental Landscape

Chapter 7. The Ornamental Landscape

Laurie Fox, Research Associate, Hampton Roads Agriculture Research and Extension Center, Virginia Tech

• Overall site goals and objectives.

Introduction
Fertilization is an important part of landscape manage- • Location relative to environmentally sensitive areas
ment. Plants need nutrients to survive, and while many or proximity to storm drainage and bodies of water.
of the essential elements are already in the soil, fertilizer
is often added to supplement those nutrients. Fertiliza- Urban Soils
tion is a common cultural practice often made complex There are many special situations to consider in the orna-
and confusing by the wide variety of fertilizer products mental landscape, and one of the most pressing issues is
on the market. The simple objective is to supply plants the fact that the growing medium is usually a drastically
with nutrients in a form they can use at the time they altered urban soil where much of the native topsoil is
most need them in a way that produces a healthy, attrac- removed during development (see chapter 3). Subsoil
tive landscape while being environmentally sound. — deficient in essential nutrients and lacking desir-
able physical properties — becomes the new topsoil in
Site Assessment and many situations. Or perhaps soil of unknown origin and
composition is brought onto the site. Construction is
Environmental Design also a factor affecting the performance of these soils.
Urban soils tend to be heavily compacted, poorly aer-
Site Assessment ated, poorly drained, and low in organic matter. Fertil-
A site assessment provides critical information for any ization of landscape plants will not be effective until
landscape nutrient management plan. The information these adverse growing conditions are corrected. In fact,
from a site assessment supports short- and long-term unhealthy soil cannot sustain healthy plants and can lead
nutrient planning as well as the environmental sustain- to nutrient pollution of surface and groundwater through
ability of the overall plan. A site assessment should be runoff and leaching of the applied nutrients.
conducted every five to seven years and should include
information that will assist the landscape manager in Site Design
making the best nutrient management decisions. Infor-
Nutrient management is also affected by proper envi-
mation to include in a site assessment:
ronmental design. Plants with similar nutrient needs
• Site boundaries. should be grouped together in the landscape when pos-
sible to avoid improper rates of fertilizer application
• Rainfall amount and distribution throughout the year. and to utilize fertilizer most efficiently. Landscape areas
• Water movement (on and through/off site for runoff with mixed categories of plants are more challenging to
and leaching potential). manage. These areas may need to be subdivided into
smaller management areas based on plant category and
• Management area delineation and size (e.g., turf, nutrient needs, or they may need to be fertilized using
annuals, natural areas, etc.). a “middle-of-the-road” approach where all plants get
• Categories of plants (both existing and future addi- some nutrients but none is managed optimally because
tions; see “Plant Categories,” later in this chapter). of the diverse plant mix.

• Condition of existing plants (healthy, stressed, etc.).

BMPs
• Previous management strategies. Special landscape design features such as buffers, biore-
• Results of soil test(s). tention or rain gardens, and green roofs are commonly
used in landscapes to manage stormwater (see chapter
• Site accessibility. 12). They are called landscape best management prac-
tices (BMPs) and are used to slow down stormwater
• Site management goals, short- and long-term.
and provide an opportunity for it to be filtered by the
• Special landscape situations. plants, soil, and microorganisms before it either runs

Urban Nutrient Management Handbook 7-1

 Chapter 7. The Ornamental Landscape

into natural surface water sources or percolates down Planting

to recharge groundwater sources. Plants in these BMPs
should be fertilized only once when they are planted No amount of fertilizer will improve a plant’s health
(usually in the individual planting hole) in order to get or growth if that plant is installed incorrectly. Correct
them established. These plants act as biofilters, absorb- planting is essential for growing healthy roots and get-
ing nutrients from the stormwater; they DO NOT need ting a plant established quickly in a landscape. Without
any additional nutrient applications. a healthy root system, a plant can’t absorb nutrients effi-
ciently or effectively. In addition, many nutrient appli-
cations are made at the time of planting, either in the
Correct Plant Selection and Planting planting hole or to the planting bed area. See Appen-
dix 7-A, Tree and Shrub Planting Guidelines, Virginia
Plant Selection Cooperative Extension publication 430-295 for details
Correct plant selection is the first critical step to a suc- on correct planting.
cessful landscape.
• Choose plants that are adapted to the environmental Determining the Need to Fertilize
and site conditions. Plants need 17 elements for normal growth. These are
divided into two groups based on the amount of each
• Select plants that naturally have few pest problems or
needed by plants. Carbon, hydrogen, and oxygen are
are pest-resistant.
found in air and water. Nitrogen, potassium, magne-
• Choose plants that meet the landscape goals and sium, calcium, phosphorous, and sulfur are found in
design parameters. the soil. The six elements found in soil are used in rela-
tively large amounts by plants and are called macronu-
• Install plants at the correct spacing to account for
trients. There are eight other elements that are used in
their mature size, avoid crowding, and reduce long-
much smaller amounts and are called micronutrients,
term maintenance.
or trace elements. The micronutrients, which are found
in the soil, are iron, zinc, molybdenum, manganese,
Plant Categories boron, copper, cobalt, and chlorine. All 17 elements —
Following are some basic definitions that apply specifi- both macronutrients and micronutrients — are essen-
cally to landscape plants: tial for plant growth. See chapter 4 for more detailed
information.
• Annuals are plants that complete their entire life
cycle in one growing season. They germinate from Fertilizer should be applied when plants need it, when
seed, flower, set seed, and die in the same year. it will be most effective, and when plants can readily
absorb it.
• Biennials are plants that live for two years. They
usually form vegetative growth in the first year and How and when to fertilize landscape plants depends on
flowers and fruit/seed the second year. factors like:
• Perennials are plants that live for three or more • Maintenance objectives: stimulate new versus main-
years. tain existing growth.
• Bulbs are short, modified, underground stems sur- • Plant age: generally more for younger and less for
rounded by (usually) fleshy, modified leaves that older woody plants.
contain stored food for the shoot within.
• Plant stress levels: stressed plants can sometimes
• Herbaceous plants lack a permanent woody stem benefit from additional fertilizer.
and die back to the ground every winter.
In addition to soil testing (see chapter 5), a visual
• Woody plants have permanent woody stems, are inspection of plants is often used in making fertiliza-
perennial, and go dormant in the winter but do not die tion decisions. Look for:
back to the ground. These plants grow from aboveg-
• Poor or chlorotic leaf color (pale green to yellow).
round stems year after year and include shrubs, trees,
and some vines. • Reduced leaf size and retention.

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 Chapter 7. The Ornamental Landscape

• Premature fall coloration and leaf drop (shrubs and at any time of the year, but it is ideal to apply lime in the
trees). fall and winter months when there are several weeks to
months for the chemical reactions to take place before
• Overall reduced plant growth and vigor.
the next growing season.
Foliar or tissue analysis can also be used to help deter-
If the soil is too alkaline (i.e., high pH), the pH can be
mine whether supplemental fertilization is needed (see
lowered by adding sulfur. It is not practical or advis-
chapter 5). Avoid late-summer or early-fall fertiliza-
able to change the soil pH more than one to two levels.
tion while plants are still actively growing because
Whenever possible, it is best to select plants that grow
this stimulates late-fall growth, which can be killed by
well in the existing conditions.
freezing temperatures.

Soil Tests (See chapter 5.) Factors Affecting Nutrient Uptake

Numerous factors affect nutrient uptake by plants. The
The purpose of a soil test is to provide information to
most important factors include:
make wise choices regarding fertilizer and soil amend-
ment. An initial soil test will provide baseline informa- • Fertilizer form: inorganic, fast-release, or liquid
tion on the condition of the soil and can include soil forms are usually absorbed faster than organic, slow-
type; pH; available phosphorus, potassium, calcium, release, or dry forms.
and magnesium; organic matter; and soluble-salt lev-
• Soil type: clay particles and organic matter adsorb or
els. Soil tests can also provide fertilizer and lime rec-
bind more nutrients than sand, so fertilizer applica-
ommendations based on the specific crop being grown.
tion needs to be more frequent in sandy soils but with
Subsequent tests can be used to monitor changes and
lower rates each time due to leaching potential.
improvements in soil health.
• Soil moisture content and soil temperature: nutrient
For ornamental landscape areas, soil testing should be
uptake is faster in moist, warm soils.
done every three to five years. Each management area
in the landscape should have its own test in order to • Fertilizer placement and application timing and method.
customize the nutrient management plan for that area
and avoid incorrect applications. For example, separate • Plant vigor: plants under stress are less able to take
tests should be done for the turf, perennial beds, tree up available nutrients due to damaged or reduced
and shrub or naturalized areas, and annual beds. Soil root systems.
test guidelines should be closely followed to assure the
greatest plant response with the least chance of plant Fertilizers
damage or possibility of water pollution. Many soils
in Virginia have adequate phosphorus levels, making it Forms (See chapter 8.)
unnecessary to apply more through fertilizers.
All fertilizers are labeled with three numbers that give
Soil sample kits are available at local Extension offices the percentage by weight of nitrogen (N), phosphate
and most libraries. There are private companies that (P2O5), and potash (K2O).
also do soil testing. Fees vary. For best results, care-
1. Nitrogen is important for leaf and stem growth and
fully follow the instructions given in the soil sample
provides the rich green color in a plant.
kit. The accuracy of the test is a reflection of the soil
sample taken. Be sure the sample is representative of 2. Phosphorous (derived from phosphate) provides for
the area to be treated. root, flower, and fruit growth.
Soil pH, a measure of acidity, has a significant impact 3. Potassium (derived from potash) helps build plant
on the plant’s ability to use nutrients. Most ornamental tissue and aids in disease resistance, cold hardiness,
landscape plants prefer a pH range of 5.5 to 7.0. Within and the production of chlorophyll.
this range, the essential nutrients are available to most
plants, and soil microorganisms can carry out their ben- Proper use of nutrients can control rate and character of
eficial functions. plant growth.

If the soil is too acidic (i.e., low pH), the pH can be The analysis, or grade, of a fertilizer refers to the mini-
raised by adding lime. Lime applications can be made mum amounts of nitrogen, phosphorus (in the form

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 Chapter 7. The Ornamental Landscape

P2O5), and potassium (in the form K2O) in the fertilizer. “Combination” products that contain fertilizer mixed
The analysis is always printed on the fertilizer label. with a herbicide, insecticide, or fungicide should be
A fertilizer with a 10-10-10 analysis contains 10 per- considered carefully. Herbicides, insecticides, and
cent nitrogen, 10 percent P2O5, and 10 percent K2O. For fungicides should be selected and applied based on
example, in 100 pounds of 4-8-12, there are 4 pounds the crop being grown and the pest(s) being managed.
of nitrogen, 8 pounds of P2O5, and 12 pounds of K2O. Often, the timing for a fertilizer application does not
coincide with that of another product, and off-target
Fertilizers may be divided into two broad categories:
or unintentional injury to the plant could result from a
natural and synthetic. Natural fertilizers generally
combined application.
originate from unprocessed organism sources such as
plants or animals. Synthetic fertilizers are manmade
or processed. Synthetic fertilizers can be organic (e.g., Placement
urea) or inorganic (e.g., superphosphate). Natural fertil- Because most landscape plant roots grow in the top 12
izers commonly misnamed “organic” can also contain inches of soil, surface or shallow application (6 to 9
inorganic ores such as rock phosphate. inches) is recommended. Fertilizer can be added to an
Most nutrients from living or once-living organisms are individual planting hole, incorporated into the planting
not readily available for plant growth because they are hole backfill or into an entire bed area, or spread over
bound in organic molecules such as proteins and amino the plant’s root zone. With the last method, the fertilizer
acids and in structures such as cell walls. These nutri- should not be concentrated around the stem or trunk of
ents are released only by microorganisms decompos- a plant but where the majority of the absorbing roots
ing the organic matter. Cottonseed meal, blood meal, are actively growing. For annuals, this is from the can-
bone meal, hoof and horn meal, fish emulsion, and all opy edge extended out by 6 inches. For perennials, this
manures are examples of organic fertilizers. Organic is from the canopy edge extended out 6 to 12 inches.
fertilizers usually contain relatively low concentrations For trees and shrubs, fertilizer should be applied over
of actual nutrients, but they perform other important an area extending two to three times the canopy spread.
functions that the synthetic formulations do not. These Research has shown that tree roots grow far beyond the
functions include increasing organic content of the soil, drip line of established trees. Do not concentrate fertil-
improving physical structure of the soil, and increasing izer in holes drilled under the tree canopy, but instead
bacterial and fungal activity. use a broadcast application beyond the tree canopy for
better growth.
“Slow-release” fertilizers may be synthetic or natu-
ral. Because nutrients are released over an extended
period of time, slow-release fertilizers do not have to
Application Timing
be applied as frequently as other fertilizer types. Also, Research shows that plants actively absorb nutrients
higher amounts of slow-release fertilizer can be added from the soil during the growing season and require
at each application without risking injury to plant few nutrients during the dormant winter season. In
roots. Slowly released nitrogen is used more efficiently general, apply fertilizer as soon as plants begin break-
because a higher percentage is absorbed by plants. The ing dormancy in the spring and avoid fertilizing after
higher efficiency of slow-release fertilizers means less the first fall frost, which signals plants to slow growth
nitrogen is available to contribute to pollution of sur- in preparation for winter dormancy. Late-summer and
face and groundwater. While slow-release fertilizers are early-fall fertilization may stimulate new growth that is
generally more expensive, when an analysis is done to not winter hardy.
determine the cost of the nitrogen absorbed by the plant,
Do not fertilize during stressful environmental condi-
the unit cost is actually less for slow-release materials.
tions. Drought causes plants to slow their growth. That,
“Water-soluble” or “liquid” fertilizers (which are not the combined with insufficient soil moisture, reduces nutri-
same) are applied either to the soil or foliage. Numer- ent absorption and could increase the potential for root
ous water-soluble fertilizer formulations are available, injury from fertilizers. Too much rainfall or irrigation
from plant starter, high-nitrogen fertilizers to minor can cause nutrients to run off or leach, potentially con-
element formulations. Chelated iron is used extensively taminating water sources. Incorporate the fertilizer into
for prevention and control of iron deficiency in azalea, the bed or planting hole when there is frequent rain or
rhododendron, and other popular ornamentals. irrigation to avoid runoff or leaching problems.

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 Chapter 7. The Ornamental Landscape

The frequency of fertilization depends on the type of

plants being fertilized and the type of fertilizer used.
Slow-release fertilizers are commonly recommended so
that one application lasts for the entire growing season.
If general-purpose, water-soluble fertilizers are used,
two or three applications applied four to six weeks apart
may be needed to make it through the growing season.
Fertilizer should be applied to newly planted landscape
ornamentals to help them establish quickly.

Application Methods
Five methods — (1) liquid injection, (2) drill hole or
punch bar, (3) surface application or fertilizer stakes or
spikes, (4) foliar spraying, and (5) tree-trunk injection
or implants — are discussed here. Each serves a spe-
cific role depending on the site and plant health. Table
7.1 summarizes the advantages and disadvantages of
the five application methods. Regardless of the method Figure 7.1. Liquid injection drill hole or stake diagram.
selected, the soil should be moist at the time of fertiliza- slowly, soon after application. This method is very
tion to prevent fertilizer injury to the plant. common, but the results can be slow because it takes
1. Liquid injection (primarily for trees). Through liquid time for the nutrients to filter into the soil and to the
injection into the soil, fertilizer solutions are placed absorbing roots.
in the root zone. This is an excellent method for cor- 4. Fertilizer stakes or spikes. Fertilizer in the form of
recting nutrient deficiencies. Injection sites should be stakes or spikes, is driven into the soil in a grid pat-
2 to 3 feet apart — depending on pressure — and 6 to tern similar to that made with liquid injection fertil-
9 inches deep. Fertilizing deeper than 9 inches may izer applications. Because lateral fertilizer movement
place the fertilizer below the absorbing roots, pre- is limited in soil, root system to fertilizer contact is
venting plant use. When using this method in sum- reduced with this method. The general product rec-
mer or during periods of drought, the soil should be ommendation of one or two stakes per inch of trunk
moist before application. diameter often does not provide an adequate fertilizer
2. Drill hole or punch bar (primarily for trees). A major amount or efficient distribution.
advantage of the drill-hole system is the opening of 5. Foliar spraying. Spraying liquid or water-soluble
heavy, compacted soils, which allows air, moisture, fertilizer on the foliage is best for correcting defi-
and fertilizer to move into the soil. The drill holes ciencies of minor elements, especially of iron and
should be placed in concentric circles or in a grid manganese. Absorption begins within minutes after
system around the main stem beginning 3 to 4 feet application, and with most nutrients, it is completed
from the main stem and extending beyond the drip within one to two days. Foliar nutrition can be a
line (see figure 7.1). Space the holes 2 feet apart and supplement at a critical time for the plant but cannot
drill them 6 to 9 inches deep. The recommended rate replace soil fertilization. This method should not be
of fertilizer for the area should be uniformly distrib- used as a means of providing all the nutrients required
uted among the holes and is based on the root-zone by plants. Several applications during a growing sea-
space under the tree (and not the trunk diameter). The son may be necessary. This method is generally not
holes can be filled either with organic material such practical for large landscape trees.
as compost or inorganic materials such as gravel,
6. Tree-trunk injection or implants. The infusion of
sand, or calcined clay.
liquid or implants of fertilizer directly to the tree
3. Surface application. A broadcast application of trunk is often the best method for correcting iron and
granular fertilizer at the appropriate rate and time is manganese problems in large landscape trees. This
made to the ground surface or on top of mulch in method is especially useful in areas of adverse soil
landscape beds. It is best to water the fertilizer in pH, high moisture, or where other means of applica-

Urban Nutrient Management Handbook 7-5

 Chapter 7. The Ornamental Landscape

tion are not practical. The wounds or holes caused

by the injections to the trunk should close within a
Specific Fertility Needs
growing season. Monitoring the wounds until they
are healed is recommended to make sure insects or Annuals and Bedding Plants
diseases do not become a problem. Generally, a slow-release, complete fertilizer at a rate
of 2 to 4 pounds of nitrogen per 1,000 square feet is
Table 7.1. Advantages and disadvantages of incorporated into the bed at planting time for season-
application methods. long nutrients. Sometimes a liquid or water-soluble fer-
tilizer is applied at 0.5-1.0 pound of nitrogen per 1,000
Application
method Advantages Disadvantages
square feet at planting to jump-start the annuals until
the slow-release fertilizer takes effect. Additional over-
Subsurface • Aerates soil. • Special fertilizer the-top fertilizer applications are not recommended
• Convenient. and drilling or
because damage can occur to the plants when fertilizer
soil injection
equipment
contacts the stems, blooms, or foliage.
needed.
Foliar sprays • R
 elieves • T
 emporary Bulbs
symptoms of benefits. Avoid high-nitrogen fertilizers, which can cause foliage
micronutrient • Doesn’t address growth at the expense of blooms. A single fall applica-
deficiencies. underlying soil tion of 1 to 2 pounds of nitrogen per 1,000 square feet
problem. of a slow-release, complete fertilizer incorporated into
Injection and • Relieves • T
 emporary the bed or planting hole at planting time is best. Several
implantation deficiency benefits. formulations of bulb fertilizer are available, like 9-9-6,
symptoms. • W
 ounds create 4-10-6, 5-10-20, or 10-10-20. They often go by names
entry for insects/ like “bulb food,” “bulb booster,” or “bulb tone.” The
diseases. common formulation 9-9-6 is ideal for most types of
Source: Virginia Cooperative Extension publication bulbs, including garden lilies, tulips, etc. For daffodils,
430-018 (VCE 2009a). use slow-release 5-10-20 or 10-10-20, if it is available.
A topdressing of well-rotted manure or compost applied
in the fall is also beneficial for bulbs (see chapter 9).
Overfertilization
Many synthetic fertilizers are salts, much like our famil-
iar table salt, except that they contain various plant nutri-
Perennials
ents. If the concentration of fertilizer is too high, and if Generally, a slow-release, complete fertilizer at a rate of
tender plant roots are close to the fertilizer granules, water 1 to 4 pounds of nitrogen per 1,000 square feet is incor-
is drawn from these roots. Plant cells in these roots begin porated into the bed or planting hole at planting time. If
to dehydrate and collapse. The plant roots are “burned” planting in the fall (September through November), use
or dried out to a point where they cannot recover. Foliar 1 pound of nitrogen incorporated, followed by a sec-
injury, often in the form of marginal leaf burn, is also a ond application of 2 to 3 pounds of nitrogen broadcast
result of too much fertilizer. Newly transplanted orna- the following spring (March or April). Always water
mentals are under stress while they are trying to adapt the bed after applying fertilizer to established plants to
to their new location, and they can be easily injured by wash the fertilizer off the foliage and prevent injury. If
overfertilization. Reduce fertilizer rates when plants are planting in the spring, use 3 to 4 pounds of nitrogen per
growing in restricted areas (sidewalk cuts, parking lot 1,000 square feet incorporated. This should be enough
islands) or where roots of multiple plants overlap. It is to carry plants through the summer. Do not exceed 4
important to apply fertilizer at the proper time and rate. pounds of nitrogen per 1,000 square feet per year.
Overfertilization can cause other problems in addition
to plant injury. Avoid getting fertilizer on sidewalks and Shrubs and Trees
driveways where it can easily wash into storm drains Generally, a slow-release, complete fertilizer at a rate of
and, eventually, into creeks, streams, and rivers. Nutri- 1 to 4 pounds of nitrogen per 1,000 square feet is incor-
ents, particularly nitrogen, become a water quality porated into the bed or planting hole at planting time
problem through leaching or run-off. or surface-applied around the canopy edge or drip line

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 Chapter 7. The Ornamental Landscape

of the plant. If planting in the fall (September through maintenance landscape. As the application rate of fer-
November), use 1 pound of nitrogen per 1,000 square tilizer increases, so does the amount of new growth,
feet, followed by a second application of 2 to 3 pounds which requires more water, more fertilizer, and more
of nitrogen the following spring (March or April). pruning.
Additional applications of 2 to 3 pounds of nitrogen
can be made each spring for the first three to five years, Area
particularly on young trees to encourage establishment To determine how much fertilizer to apply, first measure
and quick growth. For established shrubs and trees, the area to be fertilized. This involves measuring the
use 2 to 4 pounds of nitrogen per 1,000 square feet in length and width of a bed in linear feet and multiplying
the spring (March or April), every three years. Do not the two numbers to obtain the square footage. Landscape
exceed 4 pounds of nitrogen per 1,000 square feet per beds can be addressed individually, or several can be
year. Trees growing in turf areas will obtain nutrients added together for total square footage. Few plant beds
from the fertilizer that is applied to the turfgrass. Do are perfectly square or rectangular, so square off the
not apply excess fertilizer to turf in an effort to fertilize rounded areas to simplify the calculations. See Appendix
trees because injury to the turf may occur. 7-B, Maryland Cooperative Extension publication, How
to Measure Your Yard for additional information (www.
Some species such as roses (Rosa spp.), red-tip pho-
hgic.umd.edu/_media/documents/hg306.pdf).
tinia (Photinia x fraseri), and English laurel (Prunus
laurocerasus) are more demanding, while others like Trees growing within a bed can be included in the bed
ornamental grasses, silver maple (Acer saccharinum), estimate or, if they require special fertilization, estimate
willow (Salix spp.), privet (Ligustrum spp.), forsythia their canopy area by measuring the distance from the
(Forsythia spp.), hollies (Ilex spp.), and junipers (Juni- trunk to the drip line (this is called the radius). Then
perus spp.) require less fertilization. Species like azalea, use the geometric formula for the area of a circle to
dogwood, hemlock, and rhododendron have shallow calculate the area of the canopy (3.14 x radius2). For
root systems that are easily damaged by fertilizers. example, if the distance from the main trunk to the drip
Here, split- or low-rate applications of slow-release line of a tree is 20 feet, the area beneath the canopy is
fertilizers are recommended. A low-rate application (1 3.14 x (20 x 20) = 1,256 square feet. See the guidelines
pound of nitrogen per 1,000 square feet) may also be above for additional recommendations on tree fertiliza-
appropriate for shrubs and trees under stress, such as tion amounts and placement.
from disease, drought, construction, or storm damage.
Plants growing in shade generally require less fertilizer Conversions
than those growing in the sun, while those growing in To convert from actual amount of nitrogen recom-
sandy soils generally require more frequent fertilization mended to amount of fertilizer, divide the amount of
than those in clay soils, due to nutrients leaching from nitrogen desired per 1,000 square feet by the fertilizer
sandy soils. Water-soluble fertilizers should be applied analysis or grade. For example, if you have an 18-6-
in split applications to minimize leaching potential and, 12 fertilizer, how much is needed to apply 3 pounds
where possible, use slow-release nitrogen sources on of nitrogen per 1,000 square feet? Divide 3 pounds of
sandy soils. nitrogen by 0.18 ( percentage of nitrogen in fertilizer)
to get 17 pounds of fertilizer.
Fertilizer Calculations (See chapter 10.)
The quantity of fertilizer applied on established orna- Fertilizer Selection
mentals depends on: Fertilizers differ in nutrient content and release dura-
tion. The type of fertilizer selected is based on:
• The analysis of the fertilizer used.
• Cost.
• The area fertilized.
• The types of plants being fertilized.
• The amount of growth desired.
• The type of growth response desired.
Nitrogen controls vegetative growth, so application
rates are based on this primary nutrient. Low rates of • Time of year.
fertilizer are recommended, particularly for a lower • Application methods.

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 Chapter 7. The Ornamental Landscape

• Equipment cost. Granular slow-release fertilizers can last from three to

• Proximity to water sources. twelve months after application.

• Effect of soil type and pH. Other commonly available, slow-release fertilizers on
the market include Osmocote granules, Osmocote tab-
• Type of deficiency. lets, Jobe’s Spikes, Woodace briquettes, Agriform tab-
• The existing nutrient content of the soil. lets, and Milorganite. These fertilizers generally cost
more per pound than general-purpose granular fertiliz-
To determine whether a granular fertilizer has slow-
ers such as 10-10-10 or 12-4-8, but they also last longer
release properties, check the analysis label. Nitrogen
and don’t need to be applied as frequently. Organic fer-
listed in the form of ammoniacal nitrogen indicates that
tilizer sources such as bone meal, cottonseed meal, and
the product probably isn’t slow-release. If the nitrogen
animal manures can also be used. Compost is another
is listed as being derived from urea, urea-formalde-
good source of slowly available nutrients.
hyde, IBDU (isobutylenediurea), or sulfur-coated urea,
the release duration of the product will be increased. Tables 7.2 - 7.5 will help with fertilizer selection.

Table 7.2. Chemical fertilizers, analysis, speed of reaction, and effect on soil pH.
Pounds of each
fertilizer required
Speed of reaction to get 1 lb N/1,000
Fertilizer Analysis and leaching Soil reaction sq ft
Ammonium nitrate 33-0-0 Rapid Acidic 3.0
Ammonium sulfate 20-0-0 Rapid Very acidic 5.0
Urea 46-0-0 Rapid Slightly acidic 2.0
Ureaformaldehyde 38-0-0 Slow Slightly acidic 2.5
Di-ammonium phosphate 18-46-0 Rapid Acidic 5.5
Calcium nitrate 15-0-0 Rapid Alkaline 6.5
Potassium nitrate 13-0-44 Rapid Neutral 7.5
10-10-10 10-10-10 Rapid Varies with N source 10.0
Osmocote 18-6-12 Slow Acidic 5.5
Source: Virginia Cooperative Extension publication 430-018 (VCE 2009a).

Table 7.3 Average nutrient content of various organic fertilizer sources.

Fertilizer source % Nitrogen (N) % Phosphorus (P2O5) % Potash (K2O)
Blood, dried 13.0 — —
Bone meal, raw 3.5 22.0 —
Bone meal, steamed 2.0 28.0 —
Cottonseed meal 6.6 2.5 1.5
Fish scrap, dried 9.5 6.0 —
Soybean meal 7.0 1.2 1.5
Horse manure 0.7 0.3 0.6
Cow manure 0.6 0.2 0.6
Pig manure 0.5 0.3 0.5
Sheep manure 0.8 0.3 0.9
Chicken manure 1.1 0.8 0.5
Duck manure 0.6 1.4 0.5
Source: Georgia Cooperative Extension bulletin 1065 (2009).

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 Chapter 7. The Ornamental Landscape

Table 7.4. Recommended fertilization rates for newly planted ornamental plants during the
first growing season (use only one of the fertilizers listed at the rate recommended).
12-4-8 16-4-8 10-10-10
Application
Plant type/size Application rate /plant
*
frequency

1-gallon shrubs 1 tsp 1 tsp 1 tbsp March, May, July

3-gallon shrubs 2 tsp 2 tsp 2 tbsp March, May, July
5-gallon shrubs 3 tsp 3 tsp 3 tbsp March, May, July
Trees under 4 feet 1 tbsp 1 tbsp 2 tbsp March, July
Trees 4-6 feet 3 tbsp 3 tbsp 5 tbsp March, July
Trees 6-8 feet 4 tbsp 4 tbsp 6 tbsp March, July
Application rate 100/sq ft
Ground covers, 0.5 lb 0.5 lb 1.0 lb Each 4-6 weeks
annuals, and
herbaceous
perennials
Source: Georgia Cooperative Extension bulletin 1065 (2009).* When using slow-release or soluble fertilizers,
follow label recommendations for application rate.

Table 7.5. Recommended application rates of various general-purpose granular fertilizers on

established ornamental plants in the landscape.
Application ratea
1,000 sq ft 100 sq ft 10 sq ft
Source Pounds Cups Pounds Cups Tablespoons
10-10-10 10.0 20.0 1.0 2.0 4.0
8-8-8 12.5 25.0 0.5 2.5 5.0
13-13-13 6.0 12.0 0.75 1.5 3.0
12-3-6 6.0 12.0 0.75 1.5 3.0
12-4-8 6.0 12.0 0.75 1.5 3.0
12-6-6 6.0 12.0 0.75 1.5 3.0
16-4-8 6.0 12.0 0.5 1.0 2.0
4-12-12 25.0 50.0 2.5 5.0 10.0
5-10-10 20.0 40.0 2.0 4.0 8.0
Source: Georgia Cooperative Extension bulletin 1065 (2009).
a
 his rate will supply 1 pound of actual nitrogen per 1,000 square feet. For optimum growth of young shrubs,
T
ground covers, and trees, three to five applications are recommended at six- to 10-week intervals from March to
August. Application frequency varies with the amount of slow-release nitrogen in the product, so consult the label
for specific recommendations. Established trees and shrubs will benefit from one to two applications during the
growing season. Annual flowers and roses should receive applications at four- to six-week intervals from March
to August. When using slow-release or specialty fertilizers, follow the manufacturer’s recommendation on the
container.

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 Chapter 7. The Ornamental Landscape

Organic and Other Soil Nutrient Deficiencies

Amendments (See chapter 9.) Each of the 17 essential elements has a specific role in
plant growth. A deficiency or an excess of any one will
Amendments can improve soil structure, drainage, and
impair plant growth until the problem is corrected. Iron
nutrient-holding capacity, making the soil a more favor-
and manganese are the micronutrients most often defi-
able place for root development and nutrient uptake.
cient in landscape plants. An adjustment in soil pH usu-
Soil improvement or building is a continual process in
ally corrects deficiencies of the micronutrients. Some
the landscape. The regular addition of manures, com-
symptoms of nutrient deficiency in woody plants are
post, cover crops, other organic matter, and amend-
listed below (North Carolina Cooperative Extension
ments can raise the soil nutrient level to a point where
Service 1996).
the addition of synthetic fertilizers is greatly reduced,
and in some cases, no longer needed. This highly desir-
able soil quality does not come about with a single or
even several additions of organic material, but rather
requires a serious, long-term program.

Table 7.6. Element and foliar deficiency symptoms.

Element Foliar deficiency symptoms
Nitrogen (N) • General yellowish-green; more severe on older leaves.
• Stunted growth with small and fewer leaflets.
• Early leaf drop.
• Dark green to blue-green; slightly smaller leaves.
• Veins, petioles, or lower surface may become reddish-purple, especially when young.
• Death of lower needles in pines.
Potassium (K) • Partial chlorosis of most recently matured leaves in interveinal area beginning at tips,
followed by necrosis.
• Older leaves may become brown and curl downward.
Calcium (Ca) • Death of terminal buds.
• Tip die-back.
• Chlorosis of young leaves.
• Leaves may become hard and stiff.
• Root injury is the first apparent symptom.
Magnesium (Mg) • Marginal chlorosis on older leaves, followed by interveinal chlorosis.
• Margins may become brittle and curl upward.
Sulfur (S) • Uniform chlorosis of new leaves.
• Older leaves are usually not affected.
Iron (Fe) • Interveinal chlorosis of young leaves (sharp distinction between green veins and yellow
tissue between veins).
• Older basal leaves greener, exposed leaves blanched.
Manganese (Mn) • Interveinal chlorosis of young leaves beginning at margins and progressing toward midribs,
followed by necrotic spots.
Zinc (Zn) • Young leaves may be yellow, small, deformed, or mottled with necrotic spots.
• May be a tuft of leaves at shoot tips.
Boron (B) • Terminal growth dies; later growth that develops has sparse foliage.
• Young leaves may be red, bronzed, or scorched.
• Leaves may be small, thick, distorted, or brittle.
Copper (Cu) • Rosetting of foliage, terminal growth may die.
• Leaf symptoms not usually pronounced, but veins may be lighter than blades.
Molybdenum (Mo) • Cupping of the older leaves.
• Marginal chlorosis followed by interveinal chlorosis.

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 Chapter 7. The Ornamental Landscape

Literature Cited
Georgia Cooperative Extension. 2009. Care of Ornamen-
tal Plants in the Landscape. Bulletin 1065. www.caes.
uga.edu/publications/pubDetail.cfm?pk_id=6180.
Maryland Cooperative Extension. 2009. How to Mea-
sure Your Yard. Home and Garden Mimeo No. HG
306. www.hgic.umd.edu/_media/documents/publi-
cations/measure_yard.pdf.
North Carolina Cooperative Extension Service. 1996.
Fertilizer Recommendations and Techniques to
Maintain Landscapes and Protect Water Quality.
Publication No. AG-508-5. www.bae.ncsu.edu/bae/
programs/extension/publicat/wqwm/wqwm127.
html.
Virginia Cooperative Extension. 2009a. Fertilizing
Landscape Trees and Shrubs. VCE Publication
430-018. http://pubs.ext.vt.edu/430/430-018/430-
018.html.
Virginia Cooperative Extension. 2009b. Tree and Shrub
Planting Guidelines. VCE Publication 430-295.
http://pubs.ext.vt.edu/430/430-295/430-295.pdf.

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 Chapter 7. The Ornamental Landscape

Appendix 7-A
Original publication available at: http://pubs.ext.vt.edu/430/430-295/430-295.html

publication 430-295

Tree and Shrub Planting Guidelines

Bonnie Lee Appleton, Extension Specialist
Susan French, Extension Technician, AREC, Hampton Roads; Virginia Tech

Plant and Site Selection growth between the root ball, planting hole, and surround-
ing soil.
Select trees and shrubs well-adapted to conditions of indi-
vidual planting sites. Poorly-sited plants are doomed from Backfill half the soil, then water thoroughly to settle out air
the start, no matter how carefully they’re planted. pockets. Finish backfilling, then water again. Cover any
exposed root ball tops with mulch.
Test soil drainage before planting. Dig a test hole as deep
as your planting hole and fill with water. If water drains at a Incorporate slow-release granular fertilizers into backfill soil
rate of less than one inch per hour, consider installing drain- to provide nitrogen, or if a soil test indicates a need for phos-
age to carry water away from the planting hole base, or mov- phorus or potassium. Avoid using fast-release agronomic
ing or raising the planting site (berm construction). fertilizers that can dehydrate tree roots. Use no more than 1#
actual nitrogen per 1,000 ft. of planting hole surface. (Exam-
Also consider using more water-tolerant species. For trees,
ple - if using 18-6-12 with a 5' diameter hole, incorporate 0.3
try red maple, sycamore, bald cypress, willow oak, or river
oz. per planting hole.)
birch. For shrubs, try inkberry, redtwig dogwood and but-
tonbush. Avoid dogwoods, azaleas, boxwoods, Japanese
hollies, and other plants that don’t like “wet feet” where Tree and Shrub Preparation
drainage is poor. Closely inspect the wrapping around root balls of B&B
(balled and burlapped) trees and shrubs. Growers use many
Examine soil for compaction before planting. If soils are synthetic materials, as well as burlap treated to retard deg-
compacted, consider replacement with a good loam soil, or radation, to wrap root balls. Many of these materials will
incorporation of several inches of an organic material such not degrade. To insure root growth into surrounding soil,
as composted yard waste to a depth of at least 8 inches over remove pinning nails or rope lacing, then cut away or drop
the entire planting area. Do not incorporate small quantities the wrapping material to the bottom of the planting hole,
of sand - compaction will increase and drainage decrease. backfilling over it.
Wire baskets used to protect root balls degrade very slowly
Site Preparation underground. Remove the top 8-12 inches of wire to keep
Dig shallow planting holes two to three times as wide as equipment from getting caught in wire loops, and surface
the root ball. Wide, shallow holes encourage horizontal root roots from girdling.
growth that trees and shrubs naturally produce. Remove all rope, whether jute or nylon, from trunks. Again,
In well-drained soil, dig holes as deep as the root ball. In degradation is slow or nonexistent, and ropes can girdle
poorly-drained heavy clay soil, dig holes one to two inches trunks and roots.
shallower than the root ball. Cover the exposed root ball top Remove plastic containers from container-grown trees and
with mulch. shrubs. For plants in fiber pots, break away the top or remove
Don’t dig holes deeper than root balls or put loose soil the pot entirely. Many fiber pots are coated to extend their
beneath roots because loose soil will compact over time, shelf life, but this slows degradation below ground and
leaving trees and shrubs planted too deep. Widen holes near retards root extension.
the soil surface where most root growth occurs. Score walls If roots are circling around the root ball exterior, cut through
of machine-dug (auger, backhoe) holes to prevent glazing. the roots in a few places. Cutting helps prevent circling
Backfill holes with existing unamended soil. Do not incor- roots from eventually girdling the trunk. Select trees grown
porate organic matter such as peatmoss into backfill for indi- in containers with vertical ribs or a copper-treatment on the
vidual planting holes. Differences in soil pore sizes will be interior container wall. These container modifications and
created causing problems with water movement and root treatments minimize circling root formation.
www.ext.vt.edu
Produced by Communications and Marketing, College of Agriculture and Life Sciences,
Virginia Polytechnic Institute and State University, 2009
Virginia Cooperative Extension programs and employment are open to all, regardless of race, color, national origin, sex, religion,
age, disability, political beliefs, sexual orientation, or marital or family status. An equal opportunity/affirmative action employer.
Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University,
and the U.S. Department of Agriculture cooperating. RIck D. Rudd, Interim Director, Virginia Cooperative Extension, Virginia
Tech, Blacksburg; Alma C. Hobbs, Administrator, 1890 Extension Program, Virginia State, Petersburg.

Urban Nutrient Management Handbook 7-13

 Chapter 7. The Ornamental Landscape

Tree Care After Planting Only stake trees with large crowns, or those situated on windy
sites or where people may push them over. Stake for a maxi-
Remove tags and labels from trees and shrubs to prevent gir- mum of one year. Allow trees a slight amount of flex rather
dling branches and trunks. than holding them rigidly in place. Use guying or attaching
Good follow-up watering helps promote root growth. Drip material that won’t damage the bark. To prevent trunk gir-
irrigation systems and water reservoir devices can facilitate dling, remove all guying material after one year.
watering. Most trees should not have their trunks wrapped. Wrapping
Mulch, but don’t over mulch newly planted trees and shrubs. often increases insect, disease, and water damage to trunks.
Two to three inches of mulch is best - less if a fine mate- Thin-barked trees planted in spring or summer into hot or
rial, more if coarse. Use either organic mulches (shredded or paved areas may benefit from wrapping if a white wrap is
chunk pine bark, pine straw, composts) or inorganic mulches used. To avoid trunk girdling, do not attach wraps with wire,
(volcanic and river rocks). nylon rope, plastic ties, or electrical tape. If wraps must be
Keep mulch from touching tree trunks and shrub stems. used, remove within one year.
This prevents disease and rodent problems if using organic For protection against animal or equipment damage, install
mulches, and bark abrasion if using inorganic mulches. guards to protect the trunk. Be sure the guards are loose-
Don’t use black plastic beneath mulch around trees and fitting and permit air circulation.
shrubs because it blocks air and water exchange. For added
weed control, use landscape fabrics that resist weed root pen-
etration. Apply only one to two inches of mulch atop fabrics
to prevent weeds from growing in the mulch.

DO NOT prune terminal

Prune codominant leaders leader or branch tips

Prune rubbing or
cross branches

Prune narrow crotch angles

and water spouts
DO NOT stake or wrap
trunk unless necessary

Prune broken branches

Remove tags and labels

Prune suckers
2"-3" mulch kept away from trunk
Cut away all balling ropes
Soil well to contain water
Remove top of wire basket
UNAMENDED backfill soil
Partially backfill, water to
Widen and score hole wall settle soil, finish backfilling
Area for water drainage
Remove container and cut circling (pipe or tile could be installed)
roots if container-grown, or as much
burlap as possible if field-grown Leave solid soil pedestal - do not
dig deeper than ball depth

Dig hole 2-3 times root ball width

7-14 Urban Nutrient Management Handbook

 Chapter 7. The Ornamental Landscape

Appendix 7-B
Original PDF file available at: http://www.hgic.umd.edu/_media/documents/hg306.pdf

Home & Garden Mimeo # HG 306

How to Measure Your Yard

To apply the correct amount of fertilizer on your lawn, you How to determine the square footage of some familiar
need to know its surface area. shapes

First, determine the total area of your property. Second, Squares, rectangles
subtract the areas not to be fertilized. The remaining square
footage is the number needed to determine how much Area = Length x width
fertilizer is needed. (See Figure 1)
30’
Length = 50’
Total lot: Lot, 125’ x 100’ = 12,500 sq. ft. Width = 30’
50’
Area: 50’ x 30’ = 1,500 sq. ft.
Subtract: House, 44’ x 26’ = 1,144 sq. ft.
Deck, 12’ x 12’ = 144 sq. ft.
Drive, 40’ x 10’ = 400 sq. ft.
Triangles
Garden, 25’ x 15’ = 375 sq. ft.
Walk, 4’ x 20’ = 80 sq. ft.
Area = .5 x base x height
Total to subtract = 2,143 sq. ft.
80’
Remainder: Yard = 10,357 sq. ft.
Base = 40’
Height = 80’
G Area: .5 x 40’ x 80’ = 1,600 sq. ft. 40’
15’
25’

12’ Circles
12’ D
Area = Ð x r2
100’ (Ð = 3.14) r = 20’
H
26’
44’ r (radius) = 20’
Area; 3.14 x (20’ x 20’) = 1,256 sq. ft.
D
R
I 40’
V
E
125’’
10’

Figure 1.

Educating People To Help Themselves

Local Governments - U.S. Department of Agriculture Cooperating
The University of Maryland is equal opportunity. The University’s policies, programs, and activities are in conformance with pertinent Federal and State laws and regulations on nondiscrimination regarding race,
color, religion, age, national origin, sex, and disability. Inquiries regarding compliance with Title VI of the Civil Rights Act of 1964, as amended: Title IX of the Educational Amendments; Section 504 of the
Rehabilitation Act of 1973; and the Americans With Disabilities Act of 1990; or related legal requirements1 should be directed to the Director of Personnel/Human Relations, Office of the Dean, College of
Agriculture and Natural Resources, Symons Hall, College Park, MD 20742.

Urban Nutrient Management Handbook 7-15

 Chapter 7. The Ornamental Landscape

7-16 Urban Nutrient Management Handbook

 Chapter 8. Fertilizer and Lime Sources for Turf and Landscapes

Chapter 8. Fertilizer and Lime Sources

for Turf and Landscapes
Mike Goatley Jr., Professor and Extension Specialist, Crop and Soil Environmental Sciences, Virginia Tech
Steven Hodges, Professor, Crop and Soil Environmental Sciences, Virginia Tech

The information of most importance to end users in

Introduction fertilizer selection is usually the grade (e.g., 19-19-19)
Soil or tissue test results provide the basis for fertil- and the guaranteed analysis. The grade presents the per-
ity programs in the management of turf and landscape centages by weight of nitrogen, phosphate (P2O5), and
materials. A standard soil test (described in chapter 5) potash (K2O). Note that the grade is not nitrogen, phos-
provides information on soil pH and the levels of the phorus, and potassium; the percentages of the actual (or
macronutrients phosphorus (P), potassium (K), calcium elemental) phosphorus and potassium nutrients can be
(Ca), and magnesium (Mg). The test will also likely determined by multiplying the P2O5 level by a constant
provide levels of the micronutrients iron (Fe), zinc of 0.44, and the K2O level by 0.83. While most soil test
(Zn), copper (Cu), and boron (B). Missing from soil test recommendations for these nutrients will be provided
results by nature of its constant fluctuations from plant- in units of P2O5 and K2O per 1,000 square feet, some-
available to -unavailable forms and back is nitrogen times levels are given in pounds of the actual nutrient
(N). However, depending on the plant material being instead. The guaranteed analysis will detail all nutrients
grown, the soil test will provide a recommendation for in the product (in addition to nitrogen, phosphate, and
nitrogen levels and timing of application.
potash) on a percentage-by-weight basis. These rules
apply regardless of whether the product is a granular or
Defining Fertilizers liquid material.
State regulatory agencies ensure the integrity of fertil- Another common way of defining fertilizers is to clas-
izer sources. For example, in Virginia, the Office of sify them as either inorganic or organic. By definition,
Product and Industry Standards in the Department of “organic” fertilizers contain carbon, and those defined
Agriculture and Consumer Services analyzes samples as “inorganic” contain no carbon. Strictly following
of fertilizer and agricultural lime sources to ensure that these definitions reveals that an organic fertilizer source
labeling guarantees are met and that the product is safe may be composed of naturally occurring animal or
for the environment. A labeled fertilizer has five crite- plant byproducts/waste materials or synthetic products
ria that must be met: brand, grade, guaranteed analysis, such as urea and any urea-based compound (ureaform-
net weight, and name and address of the registrant and aldehyde, methylene urea, isobutyraldehyde urea, etc.).
licensee (figure 8.1). This information applies whether This distinction is very important in both defining and
the source is in liquid or granular form. developing what are commonly referred to as “organic
fertilizer programs.” In almost all instances where
organic fertilizer programs are desirable, the intent for
the program is very likely to be the utilization of “natu-
rally occurring” organic sources and not the synthetic
organic products.
At this time, the U.S. Department of Agriculture
(USDA) does not offer specifications on what defines
a “certified organic program” in turfgrass management
as it does for crop production programs. The Northeast
Organic Farming Association of Connecticut (www.
ctnofa.org) offers a program that certifies organic lawn
care practitioners but not their programs. This program
might be of interest for lawn care managers interested
in defining their overall fertility, cultural, and pest man-
Figure 8.1. The five components required on a fertilizer label. agement programs as “organic.”

Urban Nutrient Management Handbook 8-1

 Chapter 8. Fertilizer and Lime Sources for Turf and Landscapes

Other ways of describing fertilizers include those row crop production systems, slowly available nitrogen
defined as complete or incomplete and balanced or sources often provide sensible management, cost, and
unbalanced sources. There are a host of possibilities environmental advantages to readily available nitrogen
in developing various analyses of fertilizer sources in sources. It is important to understand that all nitro-
terms of nutrient content. gen sources will gradually lower soil pH. However,
readily available nitrogen sources will drop pH much
“Complete” fertilizers contain some level each of nitro-
more quickly than slowly available nitrogen sources
gen, phosphate, and phosphate, while “incomplete” fer-
— a management point that needs to be addressed by
tilizers are designed to address only one or two specific
soil testing. Each source has different strengths and
nutrient needs (45-0-0, 0-20-0, 0-0-50, and 18-46-0 are
all examples of incomplete fertilizers). weaknesses.

A “balanced” fertilizer contains equal amounts of nitro-

Readily Available Nitrogen
gen, phosphate, and potash (products such as 8-8-8,
10-10-10, or 19-19-19 and so forth). Often, balanced Readily available sources are also referred to as “water-
fertilizers are referred to as “garden fertilizers” because soluble,” “quick-release,” or “fast-acting” to designate
they are traditionally used in gardening applications how quickly they become available following appli-
and the plants respond to the additional phosphate and cation. The rapid conversion of the fertilizer to the
potassium in order to optimize bloom or fruit yield. plant-available forms of ammonium (NH4+) and nitrate
An “unbalanced” fertilizer will have varying levels of (NO3-) is why they provide such a quick growth and
nutrients (analyses such as 29-3-7 are common in many color response. As described previously regarding soil
turf-specific products). Unbalanced fertilizers are very test information for nitrogen, these forms are readily
common in turfgrass management programs because transformed by chemical and microbial processes into
nitrogen is the focal point of seasonal fertility programs. plant-unavailable forms as well.
Additional P2O5 and K2O are often not needed and their Readily available sources are less expensive than
applications should be based on soil testing, particu-
slowly available sources of nitrogen and can be applied
larly phosphate, because misapplication and overap-
as either liquid or dry formulations. Light and frequent
plication are possible concerns for water quality. Other
applications of 0.25 to 0.50 pound of nitrogen per 1,000
unbalanced fertilizers are developed for specific uses.
square feet are desirable, but up to 1 pound of nitrogen
Consider the classic “starter” fertilizers, such as 5-15-
per 1,000 square feet in a single application is suitable.
10 (discussed further in chapter 6). Sources that empha-
The level and frequency of the application typically
size P2O5 are ideal for establishing plants because they
depends on the grass being grown, its intended use, the
provide an additional boost of phosphorus that can be
soil, and the climate (detailed in chapters 6 and 7).
important for the developing root system.
In order to optimize nutrient utilization by the turf,
reduce potential injury due to their high salt concen-
Nitrogen Sources trations, and lessen potential environmental impact
Nitrogen sources are frequently categorized according from nutrient leaching (especially the highly leachable
to their water solubility, which will be detailed in this nitrate), an increased frequency of application at lower
chapter as “readily available” and “slowly available.” A levels is often desirable. Excessive salt accumulations
fertilizer label must state the percentage of total nitro- in the soil can damage roots and/or reduce their func-
gen as well as the varying percentages of water-soluble tion; however, because most areas of the mid-Atlantic
and slowly available nitrogen (SAN). Slowly avail- receive periodic rainfall, concerns about salt accumula-
able nitrogen can also be identified as water-insoluble
tions in the soil from quickly available fertilizers are
nitrogen (WIN) or controlled-release nitrogen (CRN),
limited. The primary concern with turf damage from
depending on the nitrogen source. If there is no detail
quickly available, high-salt-content fertilizers is the
regarding SAN, WIN, or CRN, it is assumed that all
potential for “foliar burn” caused by tissue desiccation.
nitrogen is water-soluble.
In this scenario, the water-soluble, typically high-salt-
Because turf and landscape plant materials are usually content fertilizer that remains on the turfgrass leaves
not being grown for yield (the exception being sod and actually attracts water from the cells of the plant; this
container/field landscape production systems) and are causes cell and leaf tissue desiccation in localized areas,
confined to relatively small land areas as compared to resulting in the visual foliar burn.

8-2 Urban Nutrient Management Handbook

 Chapter 8. Fertilizer and Lime Sources for Turf and Landscapes

Some of the most common forms of inorganic, readily eowner clientele to water the applied fertilizer into
available nitrogen sources used in turf and landscape the soil but recognize that this simply does not happen
management are ammonium nitrate, ammonium sulfate, soon enough to minimize foliar burn potential. Due to
potassium nitrate, calcium nitrate, diammonium phos- its high sulfur content (24 percent) and the fact that all
phate, and monoammonium phosphate. The sources nitrogen is in the ammoniacal form, ammonium sulfate
with the highest water solubilities (ammonium nitrate, causes the quickest decline in soil pH.
urea, and ammonium sulfate) are often dissolved in
Potassium nitrate is a popular lawn and landscape fer-
water and are foliar-applied. The water solubilities and
tilizer due to its combination of nitrogen and potassium
salt indices for these sources are provided in table 8.1.
nutrients. This source is frequently used in spring and
fall applications as a treatment to increase potassium
Table 8.1. The grade, salt index, and water
levels in plant material. Potassium — the second-high-
solubility of the most common, readily
est nutrient content in plant tissues that is typically sup-
available nitrogen sources used in turf and plemented by fertilizer applications — regulates water
landscape management fertility programs movement into and out of cells. Its function is often
(after Turgeon 1985). described as the “summer coolant” and “winter anti-
Water freeze” of plants due to its ability to improve environ-
solubilityb mental stress tolerance. Its low water solubility results
Fertilizer Grade Salt indexa [g/l (lb/gal)] in much less foliar burn and leaching potential, but it is
Ammonium 34-0-0 3.2 1810 (15.0) also difficult to dissolve and apply as a liquid.
nitrate
Monoammonium phosphate (commonly called MAP)
Ammonium 21-0-0 3.3 710 (5.9) and diammonium phosphate (DAP) are popular
sulfate
sources for preparing blended fertilizers, but they also
Potassium nitrate 13-0-44 5.3 130 (1.1) are used in turf and landscape applications, particularly
Monoammonium 11-48-0 2.7 230 (1.9) for establishment situations. DAP has the greater water
phosphate solubility of the two, but even its water solubility is so
Diammonium 20-50-0 1.7 430 (3.6) low that it is not a concern for fertilizer burn.
phosphate Urea has the unique property of being a synthetic
Urea 45-0-0 1.7 780 (6.5) organic (i.e., carbon-containing) source with a low salt
The salt index scale is: <1.0 = low, 1.0 to 2.5 = moderate, and
a index. Urea is available in granular and prilled forms
>2.5 = high. that have the same chemical composition, but the gran-
Water solubility expressed in grams per liter (pounds per gallon in ular forms are larger and harder while the prilled forms
b

parentheses).
are softer and easier to blend with other fertilizers. Due
Ammonium nitrate is the most soluble of the quickly to the high nitrogen content and water solubility, urea is
available nitrogen sources, providing the fastest growth often sprayed on turf provided there is adequate mois-
and color response potential due to its rapid conver- ture available following application. In the presence
sion to plant-available ammonium and nitrate. Its high of the enzyme “urease” (commonly present on leaves
water solubility also means it has the greatest potential and dead plant residues), urea is rapidly converted to
for foliar burn and leaching. Ammonium nitrate sup- ammonium-nitrogen. Some volatile losses may occur
plies for the turf and landscape market are restricted under windy or hot, dry conditions if not watered into
because it may also be used as a strong oxidizing agent the soil. Approximately 60 percent will be converted the
for explosives. first day, with the remainder converted within a week.
There is ongoing interest in ways to improve nitrogen-
Ammonium sulfate is significantly less water-soluble
use efficiency of quickly available urea.
than ammonium nitrate and was a popular alternative
to ammonium nitrate in professional lawn care man- Row-crop production systems have had a great deal of
agement long before supplies of ammonium nitrate research devoted to chemical additives with the urea
dwindled. This source provides a rapid growth and that reduces the rate of its conversion to plant-available
color response from two macronutrients — nitrogen nitrogen (nitrification inhibitors) or gaseous loss (vola-
and sulfur. Its lower water solubility is advantageous, tilization). The additives are extremely effective in the
particularly for lawn applicators who ask their hom- laboratory setting, but their levels of effectiveness in

Urban Nutrient Management Handbook 8-3

 Chapter 8. Fertilizer and Lime Sources for Turf and Landscapes

the field are variable and the factors affecting response array of slowly available nitrogen sources that provide
not yet clearly understood. Research in this area contin- very controlled growth and color responses, along with
ues in order to better understand chemical approaches inherent environmental advantages due to the slow-
to improve the nitrogen-use efficiency of urea. While release characteristics. Their use in turf and ornamen-
these products affect the rate of conversion to plant- tal systems is typically more economically viable than
available nitrogen, they do not alter the water solubility in production agriculture systems because “yield” is
of the urea, and they are still defined as readily avail- generally not a consideration (except in sod or nursery
able nitrogen sources. production systems) and quality, appearance, and play-
ability (in the case of turf) are the driving factors in
Slowly Available Nitrogen management programs. The incremental release char-
A unique aspect of nitrogen fertilization programs in acteristics of these materials are particularly valuable
turf and ornamental management is the use of a vast in turfgrass systems with completely modified, sand-

Table 8.2. A list of slowly available nitrogena (SAN) sources, their typical chemical analyses,
and general comments regarding the source.
Typical
Nitrogen source analyses General comments about the fertilizer
Natural organics 6-2-0b, d • Derived from waste byproducts.
• Very low N analyses usually contain some phosphate and other micronutrients.
• Very controlled release that is dependent on microbial activity.
Sulfur-coated urea 32-0-0c • Urea granules coated with molten sulfur.
(SCU) • Analyses and release rate varies depending on amount of coating.
• N release due to osmosis, so moisture and temperature govern release rate.
• Relatively inexpensive compared to other SAN sources.
• Will reduce soil pH.
• H
 andling is important because scratching the coat removes the controlled-
release characteristic.
Polymer-coated 32-0-0c • Polymer coating of urea (sometimes also combined with sulfur).
urea (PCU) • N analyses variable depending on coating thickness.
• N
 oted for very predictable release characteristics, and handling is not as much
of a concern as for SCU.
Isobutylidene 31-0-0 • Most readily available N source with highest water solubility.
diurea (IBDU) • High foliar burn potential, declining availability.
Methylene urea 30-0-0b, d • S ynthetic organic that can have varying levels of SAN defined by their solubility
in hot or cold water.
• N
 -release rates are dependent on the chain length of the carbon polymers
(higher percentage of short chains increases water solubility).
• N availability based on microbial activity.
Ureaformaldehyde 38-0-0 • S ynthetic organic with predominantly long-chain carbon polymers and very
(UF) controlled N release.
• N availability based on microbial activity.
• Very limited response in cold temperatures.
a
Slowly available nitrogen (SAN) is used as a comprehensive term regarding nitrogen availability and includes sources also identified as water-
insoluble nitrogen (WIN) and controlled-release nitrogen (CRN).
b
N analyses vary depending on the source.
c
N analyses vary depending on the coating thickness.
d
The percentage of SAN varies depending on the source.

8-4 Urban Nutrient Management Handbook

 Chapter 8. Fertilizer and Lime Sources for Turf and Landscapes

based soils (e.g., sand-based golf greens, tees, and ath- ity and delivers approximately 1 pound of nitrogen per
letic fields) that possess inherently low cation exchange 1,000 square feet. It is an extremely effective, broad-
capacities (CEC; discussed in chapter 2) and high nitro- spectrum herbicide but is relatively short-lived in its
gen leaching potential. weed control activity.
Slowly available sources of nitrogen are also referred
to as water-insoluble, controlled-release, slow-release, Ureaform and Methylene Urea
and slow-acting to designate their ability to meter out Ureaformaldehyde is made by reacting urea with form-
nitrogen over a certain length of time, similar to timed- aldehyde to produce nitrogen fertilizers that vary in
release cold capsules. Using the Virginia Department release rate. UF products, like natural organic fertiliz-
of Conservation and Recreation’s (VDCR 2005) Nutri- ers, are dependent on microbial activity and subject to
ent Management Training and Certification Regula- similar environmental conditions. Defining these prod-
tions 4 VAC 5-15 criteria, SAN is defined as “nitrogen ucts can become quite technical, but the information
sources that have delayed plant availability involving has value in making an informed decision regarding the
compounds that dissolve slowly, materials that must be selection of these very specialized SAN sources.
microbially decomposed, or soluble compounds coated
The term “water-insoluble nitrogen” (WIN) found on fer-
with substances highly impermeable to water such as
tilizer bags containing UF refers to the amount of cold-
polymer-coated products, methylene urea, isobutyl-
water-insoluble nitrogen (CWIN) and hot-water-insoluble
idene diurea (IBDU), urea formaldehyde based (UF),
nitrogen (HWIN) present in the bag. Both CWIN and
sulfur (S)-coated urea, and natural organics.”
HWIN represent the slow-release portion of the fertilizer.
Slowly available nitrogen sources provide a sustained The CWIN typically releases over several months while
growth and color response that lasts for weeks to months the HWIN can continue to release at a slower rate over
rather than providing a quick surge in growth and several years. Products with the same WIN value can dif-
greening response. Slowly available nitrogen sources fer in the amount of CWIN and HWIN present, which in
also have a very low salt index; hence, they do not turn determines their release characteristics.
contribute to a buildup of soluble salts in the soil that
The activity index (AI) can be used to distinguish dif-
might affect root system development. These sources
ferent UF fertilizers with identical WIN values. The
also have minimal foliar burn potential. Because of the
AI represents the amount of CWIN that is soluble
added steps involved in their production, they are typi-
in hot water. In other words, AI is a measure of rela-
cally more expensive than quick-release fertilizers.
tive solubility with solubility increasing as AI values
The primary SAN sources used in turf management increase. According to the Association of the American
systems and a further description of the products are Plant Food Control Officials (AAPFCO), UF fertilizers
listed in table 8.2. should contain at least 35 percent nitrogen and have an
AI of at least 40 percent.
Natural Organic The remainder of the products are composed of cold-
These fertilizer sources are byproducts of plant and ani- water-soluble nitrogen (CWSN) as free urea (quick-
mal industries or waste products such as municipal sew- release nitrogen) and short-chain polymers that provide
age sludge; hoof, horn, seed, bone, and feather meal; a quick response, yet offer some degree of safety
and chicken and cow manures, among others. They regarding salt injury compared to quick-release fertil-
can be categorized by their low (typically less than 10 izers. Higher AI values represent sources that will pro-
percent) nitrogen content and the presence of mostly vide faster nitrogen responses.
water-insoluble nitrogen. They are highly dependent on
Ureaform is manufactured by reacting urea with form-
microbial activity for breakdown and release of nitro-
aldehyde using a 1.3-1.0 ratio. It consists of equal frac-
gen. For this reason, neutral pH, adequate moisture and
tions of CWSN, CWIN and HWIN. It is often necessary
oxygen, and temperatures above 55 degrees Fahrenheit
to supplement the ureaform with quick-release nitrogen
enhance release.
or increase the rate the first couple of years because of
A specialty organic product that also has activity as a the extremely slow release of nitrogen. This is espe-
pre-emergent herbicide is corn gluten. This product cially true in the cooler portions of the season because
— approximately 8 percent nitrogen by weight — is it might require three to four weeks to achieve a signifi-
applied on the basis of its pre-emergent herbicide activ- cant turf greening response.

Urban Nutrient Management Handbook 8-5

 Chapter 8. Fertilizer and Lime Sources for Turf and Landscapes

Methylene urea is manufactured by reacting urea with contain a nitrogen-to-sulfur ratio of 2-to-1. Nitrogen
less formaldehyde using a 1-9-1 ratio. This results in is released by the microbial degradation of the coating
more CWSN (64 percent) and less CWIN (23 per- and/or diffusion through the coating. Sulfur-coated urea
cent) and HWIN (13 percent). The difference results products without sealants often release slower because
in quicker response yet shorter residual nitrogen com- of the thicker sulfur coating. Release rate increases as
pared to ureaform. coating thickness decreases and temperature increases.
It is the variability in coating thickness and particle
Other UF products are made with higher ratios of urea
size differences that allow for initial greening residual
to formaldehyde. These products contain 35 to 40
percent nitrogen and are classified as “slowly avail- response.
able” by the AAPFCO. They provide a much quicker Breaking of particles (with a spreader, traffic, or
response compared to methylene urea and ureaform, mower) results in the immediate release of nitrogen. A
but the response is shorter. Some products are available seven-day dissolution rate in water (lab procedure) is
in liquid formulation as flowable products (they require commonly used to characterize the quickly available
tank agitation). These products contain no WIN, but fraction of SCU products. Most products have dissolu-
instead contain short-chain reaction products that give tion rates in the range of 25 to 35 percent. Controlled-
a response somewhat comparable to free urea, though release soluble urea nitrogen (CRSUN) is a term used
the chance of salt injury to turf is much less. Products on certain SCU labels and refers to the total percent-
claiming controlled-release nitrogen will also release age of nitrogen as SCU in the product. Another term,
nitrogen quickly. “controlled-release nitrogen,” refers to the amount or
percentage of SCU particles that are not broken and at
IBDU least covered with a sealant.
Isobutylidene diurea is made by reacting isobutyralde-
hyde and urea and is slowly soluble in water. Approxi- Polymer-Coated Nitrogen
mately 90 percent of the nitrogen is in the WIN form. These products are coated with a synthetic polymer
Higher soil moisture and smaller particle size result coating that is sometimes plastic-like in its composition.
in more rapid release. Nitrogen release is somewhat Sometimes the polymer coating is also supplemented
depressed in alkaline soils and is independent of with sulfur coating. Polymer-coated urea products are
microbial activity. For this reason, IBDU will release not microbially dependent because there is no wax
more readily during cooler temperatures than will UF sealant. Nitrogen is released through cracks in the sul-
products. fur and diffusion through the plastic. In plastic-coated
urea, nitrogen is dissolved by water absorbed through
Triazones the coating. Nitrogen is then gradually released through
These products are water-soluble, liquid, cyclic com- the coating by osmosis. Release increases with tem-
pounds derived by combining ammonia with urea and perature and is influenced very little by soil moisture
formaldehyde. Although considered to be slow-release content, irrigation, soil pH, or microbes. Coating thick-
by the AAPFCO, they act much like the “slowly avail- ness determines the release rate for polymer-coated
able” UF products described above rather than IBDU, products.
ureaform, or methylene urea because the greening
response is quicker and the residual time is shorter. The Combinations of Quickly and Slowly
major benefit is that salt injury is lessened using these Available Nitrogen
products compared to using urea. Triazones have not
established a major role in turfgrass fertilization pro- Many manufacturers combine quick- and slow-release
grams, but they have the potential to expand in use in sources of nitrogen to take advantage of the strengths of
the turf and landscape industry. both. The quick-release source provides quick green up,
but it is at a sufficiently low rate to prevent salt injury
and reduce the potential for leaching. The slow-release
Sulfur-Coated Urea source is available to provide a greening response for a
Sulfur-coated urea (SCU) products are made by spray- longer duration.
ing molten sulfur on urea particles. A sealant (wax or
oil) is usually added to seal the imperfections, followed
by a conditioner to reduce stickiness. Particles often

8-6 Urban Nutrient Management Handbook

 Chapter 8. Fertilizer and Lime Sources for Turf and Landscapes

Practical Considerations in Interpreting and this product could be applied at up to 1.25 pounds
per 1,000 square feet in a single application. Note that
and Applying Slowly Available Nitrogen for some states, the only thing required by law on the
Sources label is percentage of total nitrogen, but for most spe-
The slowly available nitrogen sources offer advantages cialty turf fertilizer materials, there likely will be a
from an environmental perspective as well as reduc- listing of the percentages of varying nitrogen sources
tions in application frequency and controlled plant according to their solubilities.
response. In cooperation with the Virginia Department
of Conservation and Recreation, the following applica-
tion criteria were developed for SAN sources (all cat-
egories and combinations of WIN, CRN, etc., apply)
in order to optimize plant nutrient use efficiency and
environmental responses.
If the fertilizer is 50 percent SAN or more, then up to 1.5
pounds of nitrogen per 1,000 square feet is acceptable in
a single application during optimal growing periods.
If the fertilizer is 25 to 49 percent SAN, then up to 1.25
pounds of nitrogen per 1,000 square feet is acceptable
in a single application during optimal growing periods.
If the fertilizer is less than 25, then no more than 1 pound Figure 8.2. A fertilizer label detailing the guaranteed analysis of some
of the various sources of slowly available nitrogen and how it is
of nitrogen per 1,000 square feet should be applied in a defined.
single application during optimal growing periods.
Determining the percentage of SAN in a fertilizer source Phosphorus Fertilizer Sources and
that contains varying forms of water-soluble and slowly
available nitrogen can be tricky. As an example, use the
Fertility Guidelines
guaranteed analysis of a complete, balanced fertilizer As previously defined, phosphorus does not actually
detailed in figure 8.2 to determine its SAN percentage and occur as phosphate in the fertilizer or the soil. (This
a recommended maximum application rate. The material is an artifact from early analytical methods and laws
is 32-4-4 with the two forms of readily available (water- used to assess phosphorus content and regulate fertil-
soluble) nitrogen being ammoniacal (3.5 percent) and izer sales that has remained in use to keep records com-
urea (17.2 percent), for a total of 20.7 percent of the total parable across years.) Most scientific literature now
nitrogen being readily available. For the SAN sources, uses percentage of elemental phosphorus (percentage
5.7 percent is clearly defined as WIN. The remaining 5.6 of phosphorus) instead. To convert from percentage of
percent is where the analysis can be confusing. The top of P2O5 to percentage of phosphorus, multiply by 0.44.
the analysis details the 5.6 percent as “other water-soluble The standard phosphorus fertilizer sources are provided
nitrogen,” and an asterisk indicates that more information in table 8.3. Natural organic fertilizer sources are usu-
is provided in a footnote. The footnote specifies that the ally 0.5 percent to 2.0 percent P2O5 by weight. One of
“other water-soluble nitrogen” is derived from methyl- the most significant changes in lawn fertilization pro-
ene urea. As previously discussed, this SAN source con- grams in the 21st century is the ready availability of
tains highly variable percentages of nitrogen solubilities, phosphate-free fertilizers.
ranging from very slowly available to readily available In most soils, phosphorus quickly binds with other
(which, because it contains readily available nitrogen, is elements to form water-insoluble compounds that are
why it is classified as “other” water-soluble nitrogen). slowly released into the soil solution as phosphate
Therefore, the total SAN in this source is: anions (HPO42- or H2PO4-) on an “as needed” basis due
to plant uptake. Water quality issues bring phosphorus
5.7 percent + 5.6 percent = 11.3 percent SAN. applications to the forefront of environmental con-
cerns due to the potential for eutrophication in water
The percentage of SAN is:
sources affected by phosphorus. Phosphorus is critical
11.3 percent ÷ 32 percent = 35 percent SAN, for energy transformations in plants and root develop-

Urban Nutrient Management Handbook 8-7

 Chapter 8. Fertilizer and Lime Sources for Turf and Landscapes

ment; therefore, it is an extremely important nutrient

to optimize establishment. Typical application rates
Potassium Fertilizer Sources and
for turf and landscape plant establishment might be 1 Fertility Guidelines
to 2 pounds of phosphorus per 1,000 square feet. For The most common forms of potassium fertilizer sources
maintenance of a healthy canopy, it should be applied are presented in table 8.4. Remember that the last of the
as recommended by soil test results. Many soils in the three numbers that appear in the fertilizer grade repre-
southeastern United States are inherently low in phos- sents potash; to convert this value to elemental potas-
phorus, and appropriate phosphorus applications that sium, multiply by 0.83.
support a healthy turfgrass will actually improve water
quality because the turf minimizes sediment losses. Table 8.4. The typical grade, salt index, and
On the other hand, on heavier-textured soils where water solubility of the most common potassium
phosphorus has been regularly applied for many years, sources used in turf and landscape management
additional phosphorus is not likely required. When pres- fertility programs (after Turgeon 1985).
ent in its anionic form, phosphate is highly leachable, Cold water
but due to its immobilization with other compounds, Salt solubilityb
its mobility is much less than that of NO3-. However, Fertilizer Grade index [g/l (lb/gal)]
a

phosphate leaching can and does occur in two situa- Potassium chloride 0-0-60 1.9 350 (2.8)
tions: (1) soils that contain excessive phosphorus lev- (muriate of potash)
els, likely due to persistent overapplication of synthetic
Potassium sulfate 0-0-50 0.9 120 (1.0)
or organic phosphorus sources, and (2) modified sand- (sulfate of potash)
based soils, particularly during turfgrass establishment.
Potassium nitrate 13-0-44 5.3 130 (1.0)
All this being said, the major source of phosphate con-
tamination in our waterways comes from fertilizer mis- The salt index scale is: <1.0 = low, 1.0 to 2.5 = moderate, and
a

>2.5 = high.
applications where granules are erroneously applied
Water solubility expressed in grams per liter (pounds per gallon in
b

to hardscapes. This material quickly and easily enters parentheses).

water supplies through stormwater drains.
Potassium is involved in a host of biochemical responses
Table 8.3. The typical grade, salt index, in a plant but is not a direct component of any organic
and water solubility of the most common compound. In particular, potassium is recognized as the
nutrient that most impacts water relations within the
phosphorus sources used in turf and
plant, sometimes being referred to as the “antifreeze”
landscape management fertility programs
and “coolant” nutrient of the plant world.
(after Turgeon 1985).
Cold-water There are many unrefined and manufactured sources of
Salt solubilityb potassium, but plants always absorb potassium in the
Fertilizer Grade indexa [g/l (lb/gal)] same form: K+. Potassium is required in the second-
highest quantity by plants after nitrogen. As a cation,
Superphosphate 0-20-0 0.4 20 (0.16)
K+ can be temporarily bound and exchanged for other
Treblesuperphosphate 0-45-0 0.2 40 (0.32) cations in soils that contain significant anionic (nega-
Monammonium 11-48-0 3.2 230 (1.8) tively charged) exchange sites (i.e., soils with signifi-
phosphate cant amounts of clay and/or organic matter). Even as a
Diammonium 20-50-0 1.7 430 (3.4) cation, K+ can still leach depending on soil type (espe-
phosphate cially sand-based soils) and under heavy rainfall and/
Rock phosphate 0-30-0c NA NA or irrigation. In general, application rates of potassium
should not exceed 1 pound of K2O per 1,000 square
Bone meal 4-12-0 NA NA feet. Lower rates and more frequent applications are
Note: NA = not applicable. desired on sandy soils low in organic matter.
a
The salt index scale is: <1.0 = low, 1.0 to 2.5 = moderate, and
>2.5 = high. At this time, potassium is not considered to be an envi-
b
Water solubility expressed in grams per liter (pounds per gallon in ronmental concern that negatively impacts water qual-
parentheses).
ity, so it does not receive as much attention as nitrogen
c
Rock phosphate levels of P2O5 can range from 27 to 41 percent.
and phosphorus from this perspective. Potassium

8-8 Urban Nutrient Management Handbook

 Chapter 8. Fertilizer and Lime Sources for Turf and Landscapes

chloride (KCl) is the most commonly used potassium lime. Leaching is primarily limited to sandy soils with
source, primarily because it is a cheaper material. The low CEC and is enhanced by low pH. Applications of
other sources (potassium sulfate, potassium magnesium these nutrients to soils do not result in any known water
sulfate, and potassium nitrate) contain other macro- quality problems in this region.
nutrients that can provide additional desirable plant
Similar to nitrogen, sulfur is highly mobile in the soil
responses. Potassium sulfate has a very low salt index
because its plant-available form is the sulfate (SO42-)
and is less water-soluble than the other sources, mean-
anion. Tissue sampling is usually the best way to diag-
ing it has low foliar-desiccation potential. Potassium
nitrate is a popular spring and fall fertilizer material
used to prepare landscape plants for the environmen- Table 8.5. Common inorganic sources of
tal extremes of the summer and winter. Potassium calcium, magnesium, and sulfur.
magnesium sulfate (commonly called sul-po-mag) is Ca Mg S
somewhat underutilized in turf management programs Material Chemical formula (%) (%) (%)
as compared to production agriculture systems. It pro- Calcium CaCl2 36.0 0.0 0.0
motes turfgrass color without a lot of growth, but it chloride
is a very water-soluble product that must be quickly
Burned CaO 70.0 0.0 0.0
watered in to prevent foliar burn. lime or
calcium
Calcium, Magnesium, and Sulfur oxide
Calcitic CaCO3 32.0 3.0 0.1
Fertilizer Sources and Fertility limestone
Guidelines Dolomitic CaCO3, MgCO3 21.0 6.0 0.3
There are numerous sources of calcium, magnesium, limestone -30.0 -12.0
and sulfur detailed in table 8.5; the table lists the most Gypsum CaSO4 22.0 0.4 17.0
common fertilizer sources. In addition, materials such
Hydrated Ca(OH)2 50.0 0.0 0.0
as bone meal, wood ash, manures, and sludge can con-
lime
tain significant amounts of these elements.
Magnesium MgNH4PO4.6H2O 0.0 15.0 0.0
Many of these sources will be recognized also as chem- ammonium
icals applied to alter pH. Therefore, if calcium, magne- phosphate
sium, or sulfur is required due to nutrient deficiency but Magnesium MgO 0.0 45.0 0.0
a pH change is not desired, standard liming sources and oxide
elemental sulfur should be avoided.
Magnesium MgSO4.7H2O 2.0 10.0 14.0
Calcium and magnesium are often overlooked regard- sulfate
ing their importance as macronutrients because they are Potassium K2SO4.2MgSO4 0.0 11.0 22.0
most commonly associated with adjusting pH levels. magnesium
However, both have important activities in the plant, sulfate
with calcium serving as a primary component of cell Ammonium (NH4)2SO4 0.3 0.0 24.0
walls and magnesium being the central atom of the sulfate
chlorophyll molecule. They behave very much the
Ammonium (NH4)2S2O3 0.0 26.0 0.0
same in the soil due to similar chemical properties, but
thiosulfate
magnesium is typically much lower in soils than cal-
cium. Both are divalent cations (Ca2+ and Mg2+) and are Elemental S 0.0 52.0 0.0
of very similar size. It is important to monitor the bal- sulfur -70.0
ance of magnesium, calcium, and potassium and many Flowable, 90.0
soil test reports will include this information as part of wettable -100.0
their results. The mobility of both calcium and magne- flowers
sium is relatively low, especially compared to anions Potassium K2SO4 0.7 1.0 18.0
or even other cations, such as sodium or potassium. sulfate
Therefore, loss of these two cations through leaching is Sulfuric H2SO4 0.0 0.0 20.0
relatively low, especially when applied in the form of acid -33.0

Urban Nutrient Management Handbook 8-9

 Chapter 8. Fertilizer and Lime Sources for Turf and Landscapes

nose sulfur deficiency, but deficiencies are most com- uptake capability. The inherently low levels of iron in
mon on sand-based, low-organic-matter soils. For high-sand green mixes and some of our native sandy
landscape plants that require an acidic soil pH (for sands, along with the relatively high supply of nitrogen
instance, achieving a certain bloom color of hydran- and phosphorus in these management systems can fur-
gea), elemental sulfur is often used to lower pH. For ther complicate iron uptake.
lawn applications intended to lower pH, elemental sul-
fur applications should not exceed 5 pounds per 1,000 The most popular forms of iron applied in turf and land-
square feet and should promptly be watered in. scape applications are the chelates applied as sprays
over the top of the turf canopy. Granular iron sources
are beneficial in increasing soil iron levels where
Micronutrient Fertility Sources needed, but they do not provide rapid color response.
and Fertility Guidelines These liquid organic chelates are easy to handle, mix,
and apply, and they can be tank-mixed with most
Micronutrients are required in very small quantities but
pesticides. Chelation reduces the rate of complexing
they are equally important to overall plant health as the
of iron into insoluble compounds in the soil, thereby
macronutrients. The list of plant-required micronutri-
improving plant uptake. However, the benefit most turf
ents comprises iron, manganese (Mn), boron, copper,
managers seek from foliar applications of any form
zinc, chlorine (Cl), and molybdenum (Mo). Micronu-
of iron is a rapid, deep-green color without a surge in
trients are rarely deficient in terms of soil quantities
shoot growth. The immediacy of the “iron response” is
with the only exception being very sandy soils (natural
mostly due to “staining” of the foliage, but there also
or modified) with low organic matter or high turnover
will be a promotion of internal chlorophyll production
systems, such as sod farms. Maintaining an appropriate
within the leaves over time. The color response from
soil pH is the most important factor in managing soils
foliar applications is relatively short-lived (might last
to ensure adequate micronutrient availability.
up to two weeks) and is lost as the turf is clipped. Typi-
Iron is by far the most important micronutrient in cal iron application levels are 5 to 10 pounds per acre
turfgrass management programs, having uses in all (0.12 to 0.25 pounds per 1,000 square feet).
segments of the turfgrass industry. The most popular
sources of iron are detailed in table 8.6. Deficiencies of other micronutrients are rare except on
mostly sand soils. Maintaining appropriate soil pH is
Table 8.6. Standard iron fertilizer sources of utmost importance in ensuring satisfactory avail-
ability and/or preventing potential phytotoxicity issues.
used in lawn and landscape settings.
For instance, where copper or galvanized zinc roofs are
Source % iron used, there is the potential for metal toxicity to lawn
Iron sulfates 19-23 and landscape plants, particularly where water from the
Iron oxides 69-73 roof is concentrated near a downspout. The easiest way
to manage the elevated soil copper or zinc content is
Iron ammonium sulfate 14
to reduce their solubility by liming to maintain the pH
Iron chelates 5-14 above 6.0. Where supplemental micronutrient applica-
Whereas nitrogen deficiencies are often uniform across tions are needed (most often indicated by tissue test-
the turf, iron deficiencies are often scattered randomly ing), chelated formulations are very effective.
throughout the turf, and appear more severe on closely
mowed surfaces. The most severe deficiencies occur Liming Materials and Chemical
with warm days and cool nights, when shoot growth
is favored over root growth. Total iron levels in most Composition
mid-Atlantic soils range from 0.5 percent to 5.0 per- Why is there such a constant need for lime in this
cent. Yet iron is the micronutrient most likely to be defi- region? Most of the soils of the mid-Atlantic essen-
cient. Iron occurs primarily as oxides and hydroxides tially act as weak acids, with only a small portion of
that are sparingly soluble in well-aerated soils above their potential acidity present in the active, or soil solu-
pH 4.0. Root exudates from deeply rooted plants are tion, form. Exchangeable aluminum (Al), manganese,
generally able to solubilize sufficient iron to optimize and iron metals, along with pH-dependent charges on
plant growth, but high nitrogen rates and close mowing organic matter and clay edge sites, constitute the major
decrease root growth relative to shoot growth and limit sources of potential acidity (also called the reserve or

8-10 Urban Nutrient Management Handbook

 Chapter 8. Fertilizer and Lime Sources for Turf and Landscapes

total acidity). The reserve acidity, in conjunction with greater than 100 is possible and simply indicates that the
the exchangeable bases, helps to buffer or to enable the material has a higher neutralizing capacity than pure
soil to resist rapid changes in soil solution pH. Plants calcite. Note that the neutralizing values for magnesium
growing in acid soils must be able to contend with high carbonate (MgCO3), dolomitic limestone [CaMg(CO3)2],
levels of aluminum and manganese, and low availability calcium hydroxide (CaOH2), and calcium oxide (CaO)
of phosphorus, calcium, and magnesium. Because most are all greater than 100 percent (table 8.7).
turfgrasses are intolerant of these conditions, acidic soil
Apply this information in the selection and application
must be limed to make the rooting environment hospi-
of the lime source as recommended by the soil test. For
table for root exploration and development.
example, if the soil test recommendation indicates that
A number of materials are available for liming acid 50 pounds of lime is recommended per 1,000 square
soils (table 8.7). The selection of a liming material feet (the recommendation is on the basis of pure cal-
should be based on its ability to neutralize soil acidity, cite) and the lime source available has a CCE of 90
chemical composition, fineness of grind, ease of han- percent, 55.5 pounds of the source (50 pounds per 0.9
dling, and cost. Limestone is a naturally occurring sedi- = 55.5 pounds) per 1,000 square feet will be necessary
mentary rock rich in the minerals calcite (CaCO3) or to achieve the recommended liming rate. Conversely,
dolomite [CaMg(CO3)2]. Most limestone is formed in if dolomitic limestone (with a CCE on the label of 109
thick, compacted deposits of calcareous skeletons and percent) is selected, only 46 pounds (50 pounds per
shells of sea animals on the ocean bed. Relatively pure 1.09 = 46 pounds) per 1,000 square feet are required.
deposits of calcite are called “calcitic” limestone, while
materials containing more magnesium are called “dolo- Fineness of Grind
mitic” limestone. Dolomitic limestone is widely used Because liming materials have a limited solubility, the
as a lime (and magnesium) source in the mid-Atlantic. rate of reaction is largely determined by the amount of
When either calcitic or dolomitic lime is heated, the car- surface area exposed to acid soil. As fineness increases,
bonate is driven off and calcium (magnesium) oxide is the rate of reaction increases. Agricultural lime (hav-
formed. When treated with water, or “slaked,” calcium ing a wide variety of particle sizes) is particularly cost-
oxide forms Ca(OH)2, also called slaked or hydrated effective for new establishment sites where it can be
lime. These are very reactive and caustic materials and incorporated into the seedbed prior to planting. Ag-lime
are seldom if ever used for turf. These materials are is more difficult to apply because of its nonuniform par-
occasionally used when very rapid changes in pH are ticle size. Powdered lime provides a rapid response but
needed, such as immediately prior to planting. is extremely difficult to handle and apply. Pelletized
lime — finely ground limestone made into pellets by
Table 8.7. The neutralizing value (calcium using a binding agent — is commonly used in turf set-
carbonate equivalent, CCE) of the pure tings. The large pellets retain the quick reaction time of
forms of commonly used liming materials. fine particles but without the dust of the powdered form.
Neutralizing Pelletized forms are more expensive than powdered
Lime material value (%) lime, but the ease in handling and application makes it
CaO (calcium oxide) 179 a very popular choice. Pellets break down when wet-
ted to release the finely ground particles. When applied
Ca(OH)2 (calcium hydroxide) 136 to bare ground, pelletized lime should be wetted and
MgCO3 (magnesium carbonate) 119 allowed time for particles to break down prior to till-
CaMg(CO3)2 (dolomitic limestone) 109 age or incorporation. Otherwise, the particles will be in
contact with much less of the soil surface and will not
CaCO3 (calcium carbonate) 100 be as effective in neutralizing soil acidity.
Source: Data from Tisdale, Nelson, and Beaton 1985.

As with most sedimentary materials, limestone varies in Managing Lime Applications

purity and chemical composition. In order to compare The general recommendation is to apply no more than 50
the acid-neutralizing value of various liming materials of pounds of lime per 1,000 square feet at any one time to
differing purity levels, the calcium carbonate equivalent established turf (25 pounds per application to golf putting
(CCE) test uses pure calcite (CaCO3) as the standard, with greens). If the soil test suggests more, then the amount
an arbitrarily assigned value of 100 percent. A CCE value should be applied monthly in incremental amounts.

Urban Nutrient Management Handbook 8-11

 Chapter 8. Fertilizer and Lime Sources for Turf and Landscapes

All the beneficial effects of liming occur only where • S

 upplement the soil test with a plant tissue test when
lime and soil are in contact. Liming materials are spar- necessary.
ingly soluble and react strongly with the soils with
• C
 ore or aerate compacted soil to reduce runoff and
which they come in contact. As a result, lime is rela-
aid phosphorus and lime in entering the soil.
tively immobile in the soil and surface applications
generally affect no more than the surface 2 or 3 inches • M
 inimize fertilizer rates on slopes. If using quickly
during a growing season. For this reason, it is impera- available sources of nitrogen on deep, sandy soils or
tive to adjust the pH of soils prior to establishment and near shallow water tables, use no more than 0.25 to 0.50
to incorporate the lime early enough so that neutraliza- pound of nitrogen per 1,000 square feet per application.
tion of the acidity has time (two to four weeks for finely
ground lime) to take place. Thorough incorporation • E
 stablish and maintain a buffer zone of reduced- to
throughout the rooting zone increases the rate of reac- zero-input vegetation around bodies of water (fig-
tion and treats a larger volume of the soil, maximizing ure 8.3). In some cases, native vegetation might be
the benefits of lime. appropriate, but whatever plant material is selected,
it must persist indefinitely to serve as a functional
Attempting to change the pH in the deep rooting zone buffer zone. Florida has established a very success-
of an established turf is difficult at best. One method ful public awareness campaign called the “Ring of
of getting lime somewhat deeper in established turf Responsibility” that promotes best management
areas is to apply lime in conjunction with core aeration practices in maintaining and fertilizing turf near
events. Applying lime in the fall and winter months is water resources (Florida Department of Environ-
also possible because the foliar burn potential (i.e., leaf mental Protection 2008). In Oklahoma, researchers
desiccation) is very low and the freezing and thawing simulated intensively managed golf fairway turf bor-
of the soil aid in mixing lime throughout the root zone. dering water sources and reported that a graduated
buffer system where turf cutting heights were raised
Overliming from 1 to 2 inches as the slope approached the water
significantly reduced total runoff volume as well
In this region, the target pH for turf and most ornamen-
as nitrogen and phosphorus movement (Moss et al.
tals is 6.0 to 6.5. Overliming dramatically reduces avail-
2006). This approach utilizing a simple graduated
ability of micronutrients and can result in deficiencies
buffer improves water quality protection and still
that are very difficult to correct. Turfgrass areas that
meets playability needs from a golfer’s perspective.
have excessively high pH can be amended over time
with use of an acid-forming fertilizer such as ammo- • C
 onsider using iron as a supplement to nitrogen for
nium sulfate. Where pH is too high, the only alternative greening response.
is to reduce the pH using elemental sulfur or aluminum
sulfate. • U
 se at least 50 percent slowly available sources of
nitrogen on soils subject to leaching.
Lime application should be based on soil tests to ensure
that excessive lime is not added. While a good liming • T
 ime applications carefully. Do not apply fertilizer
program usually provides adequate levels of calcium before a heavy rainfall.
and magnesium, there are times when lime is not rec- • I rrigate lightly (0.10 to 0.25 inch) after each applica-
ommended but additional calcium and/or magnesium tion of quick-release fertilizer so it is washed off the
are required. Sources such as gypsum (calcium sulfate), foliage and moved into the soil.
magnesium sulfate, and potassium-magnesium sulfate
should be used in this instance to supply needed nutri- • Avoid overirrigation.
ents without the addition of pH-increasing lime. • R
 eturn grass clippings to the lawn to improve nutrient
cycling and reduce the amount of fertilizer needed to
Best Management Practices for produce healthy plants (figure 8.4). Use a mulching
mower whenever possible and consider that a mulch-
Water Quality Protection ing mower can even be used to manage fall leaves
The following list details steps that can reduce the impact (Goatley 2006).
of nutrient management practices on water quality.
• W
 hen collected, compost grass clippings rather than
• Base fertilization practices on a soil test. disposing of them in landfills.

8-12 Urban Nutrient Management Handbook

 Chapter 8. Fertilizer and Lime Sources for Turf and Landscapes

• U
 se a drop (gravity) spreader near bodies of water or
impenetrable areas to lessen the chance of spreading
material on these surfaces.
• P
 erhaps the most important best management practice
toward improving water quality is to simply sweep or
blow fertilizers and grass clippings off hardscape sur-
faces and back into the turf (figure 8.5).

Literature Cited
Florida Department of Environmental Protection. 2008.
Florida Friendly Best Management Practices
for Protection of Water Resources by the Green
Figure 8.3. This buffer zone near the water’s edge features low-input
Industries, 32-33. Tallahassee: Florida Depart-
native grasses and shrubs. ment of Environmental Protection. www.dep.state.
fl.us/water/nonpoint/docs/nonpoint/grn-ind-bmp-
en-12-2008.pdf.
Goatley, M. 2006. “Leave” Them Alone: Lawn
Leaf Management. Virginia Cooperative Exten-
sion Publication 430-521. http://pubs.ext.
vt.edu/430/430-521/430-521.html.
Moss, J. Q., G. E. Bell, M. A. Kizer, M. E. Payton, H.
Zhang, and D. L. Martin. 2006. Reducing nutrient
runoff from golf course fairways using grass buf-
fers of multiple heights. Crop Science 46:72-80.
Tisdale, S. L., W. L. Nelson, and J. D. Beaton. 1985.
Soil Fertility and Fertilizers, 500-09. 4th ed. New
York: MacMillan. Turgeon, A. J. 1985. Turfgrass
Management, 164-65. Englewood Cliffs, N.J.:
Figure 8.4. A mulching mower being used to recycle both grass clip-
pings and tree leaves in a single mowing event. Prentice-Hall.
Virginia Department of Conservation and Recreation
(VDCR), Division of Soil and Water Conservation.
2005. Virginia Nutrient Management Standards
and Criteria, 96-107. Richmond: VDCR.

Additional Resources
Hunnings, J. R., and S. J. Donohue. 2002. Soil Sam-
pling for the Home Gardener. Virginia Coopera-
tive Extension Publication 452-129. http://pubs.
ext.vt.edu/452/452-129/452-129.html.
Little, C., and M. Watson. 2002. Understanding Value in
Lime. Ohio State University Extension Fact Sheet
ANR-9-02. http://ohioline.osu.edu/anr-fact/0009.
Figure 8.5. Sweeping or blowing fertilizer and/or grass clippings on html.
hardscapes back into the turf canopy is one of the most important
steps in protecting water quality.

Urban Nutrient Management Handbook 8-13

 Chapter 9. Organic and Inorganic Soil Amendments

Chapter 9. Organic and Inorganic Soil Amendments

Greg Evanylo, Professor, Crop and Soil Environmental Sciences, Virginia Tech
Mike Goatley Jr., Professor and Extension Specialist, Crop and Soil Environmental Sciences, Virginia Tech

Introduction to Organic Table 9.1. Sources of organic amendments.

Amendments Type Examples of byproducts
Organic amendments can be applied to soils to provide Agricultural • Livestock and poultry manures.
nutrients and/or as soil conditioners. The nutrients in • Rotten/unusable plant material such
organic amendments can either be readily available or as feed, hay, silage, and forages.
complexed in organic forms that must first undergo min- • Wood chips.
eralization in order to become plant-available. Because • Slaughterhouse wastes and animal
the nutrient concentrations in many organic amend- mortalities.
ments are often low (relative to inorganic fertilizers)
Municipal • Wastewater sewage sludge/biosolids.
and are typically less than 100 percent plant-available,
• Water treatment residuals.
higher application rates than those of inorganic fertil-
izers are necessary to supply a plant’s nutrient require- • Landscape trimmings such as leaves,
ments. Therefore, organic amendments are often not brush, and grass clippings.
applied to supply a plant’s entire nutrient needs. • Food waste.
• Newspaper and other paper waste.
Organic amendments can also be applied as soil con-
ditioners, relying on the organic matter content to Industrial • Paper mill sludge.
improve such soil physical properties as water-holding • Food processing sludge such as
capacity, plant-available water, aggregation, tilth, bulk poultry dissolved air flotation sludge,
density, porosity, drainage, and hydraulic conductivity. brewery waste, and peanut hulls.
Chemical property improvements from organic matter • Wood shavings, sawdust.
include pH buffering, increased cation exchange capac-
ity, and increased nutrient availability. Organic matter is
also a source of energy for soil microbes that increases
Processes for Generating Organic
aeration, reduces bulk density, and facilitates nutrient Amendments
cycling. Byproducts generated from animal manures and biosol-
ids used in landscapes with public contact must first be
Sources of Organic Amendments treated to eliminate disease-causing organisms (patho-
gens) and vector attraction factors (viz., odors), which
Organic amendments are produced from agricultural, can exacerbate nuisance and health issues. Most biosol-
municipal, and industrial byproducts (table 9.1). Agri- ids applied to agricultural lands are termed “Class B”
cultural sources of organic amendments include poul- and have reduced (but detectable) levels of pathogens.
try and livestock manure and rotten or unusable animal Class B products are generated by processes to signifi-
feed, hay, and forage plants. Municipal wastes include cantly reduce pathogens, such as aerobic and anaerobic
sewage sludge/biosolids, landscape trimmings (e.g., digestion and lime stabilization. The land application of
leaves, grass clippings, brush), and food waste (post- Class B products requires site restrictions to ensure that
consumer or preconsumer). Industrial byproducts such
disease organisms do not pose health or environmental
as paper mill sludge, food processing sludge, and brew-
problems (http://pubs.ext.vt.edu/452/452-302/452-302.
ery waste can also be converted to organic amendments
html).
appropriate for use on turfgrass and landscapes. Such
byproducts require treatment that enables the finished Class A products have undetectable levels of pathogens
amendment to be used in a safe, nuisance-free, and and can be used without restriction as long as regulated
environmentally sound manner in areas where human pollutant concentrations meet appropriate standards.
contact is frequent and/or constituents in the amend- Class A biosolids are treated by processes to further
ment may pose environmental risks if not managed reduce pathogens. Such commonly used processes
correctly. include heat treatment (i.e., pasteurization), drying,

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 Chapter 9. Organic and Inorganic Soil Amendments

advanced alkaline stabilization, and composting. Ani- Composting

mal manures can also be treated by the same processes
to enable their use on lands with high public contact. Composting is the controlled, aerobic, thermophilic,
biological decomposition of organic materials that
Waste residuals that are physically and chemically results in a stable end product that can be used as a
homogenous — such as some manures, biosolids, and soil amendment called “compost.” Compost contains
industrial sludges — are well-suited to be heat-treated, essential plant nutrients in low concentrations and is
dried, and pelletized/granulated or alkaline-stabilized. typically applied as a soil conditioner or mulch.
The end product can be applied at rates marginally
above inorganic fertilizer rates and often with fertilizer-
or lime-spreading equipment. Residuals that are physi- Composition of Organic
cally and chemically heterogeneous, on the other hand, Amendments
are usually processed in large volumes to enable unifor-
mity in the end product. Composting is well-suited for Heat-Treated Biosolids
such treatment processing and application because the
The concentrations of constituents in typical heat-
low-analysis nutrient content of the finished product is
treated biosolids are presented in table 9.2. These mate-
typically applied at considerably higher rates than heat-
rials are very dry (i.e., more than 90 percent solids), and
treated, dried, and pelletized or granulated products.
their fine particle size permits their application as com-
mercial fertilizer. The total Kjeldahl nitrogen (TKN)
Heat Treatment, Drying, and Pelletizing concentrations in such products are usually between
or Granulating 4 and 6 percent, nearly all of which is in the organic
nitrogen form; thus, little of the nitrogen is readily
This process can be used for treating liquid sewage
plant-available.
sludge obtained from a wastewater treatment plant or
from animal manure for the development of an organic Water-insoluble and water-soluble nitrogen are similar
fertilizer pellet or granule. Heat treatment produces indicators of slowly available organic nitrogen forms
an organic fertilizer by combining a dewatered sludge and readily available inorganic nitrogen forms, respec-
with dry fines and simultaneously drying and pelletiz- tively. These residuals are largely organic (40 percent
ing the mixture. Alternatively, animal manures may be carbon, 70 percent organic matter) and possess carbon-
dried and pasteurized by heating and then either pellet- to-nitrogen ratios that favor rapid mineralization of
ized or granulated to produce a fertilizer. Such sludge- the organic nitrogen. Biosolids products are typically
and manure-based products typically have low carbon rich in phosphorus (P), but the phosphorus solubility
(C)-to-nitrogen (N) ratios; thus, a high portion of their is often lower than in manure products because of the
organic nitrogen is rapidly mineralized. presence of high concentrations of phosphorus-binding
iron (Fe), manganese (Mn), and other metal oxides in
Advanced Alkaline Stabilization biosolids. Potassium (K) is low in biosolids products
because the soluble K+ is separated from the solids dur-
This process involves mixing a waste byproduct, typi-
ing wastewater treatment and exits the system with the
cally sewage sludge, with a dry, pH-raising material
treated wastewater effluent. Such materials are usually
such as lime, kiln dust, or fly ash to meet Class A pas-
near-neutral in pH because the heating process drives
teurization criteria (i.e., maintain a pH of 12.0 or more
off pH-elevating ammonia (NH3).
for at least 72 hours, with a temperature of 52°C for
at least 12 hours or with a temperature of 70°C for 30 Electrical conductivity (EC) is an indirect measurement
minutes) via exothermic reaction. A similar process — of soluble-salt concentration. It is lower in heat-treated
except that it does not use heat — can be used to process biosolids than in synthetic fertilizer and similar to that
animal manures into Class A products. In this process, of compost. Organic residuals are good sources of sul-
high concentrations of gaseous ammonia that form at fur (S) and other secondary and micronutrients, includ-
the high pH level disinfect the manure. The resulting ing such regulated plant-essential trace elements as
products contain essential plant nutrients but are often copper (Cu) and zinc (Zn). The byproducts must meet
applied as liming agents. the Code of Federal Regulations Title 40 (40 CFR) Part
503 pollutant concentration limits (PCL) set by the U.S.
Environmental Protection Agency (EPA 1993) for the
inorganic trace elements arsenic (As), cadmium (Cd),

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 Chapter 9. Organic and Inorganic Soil Amendments

chromium (Cr), copper, mercury (Hg), molybdenum

(Mo), nickel (Ni), lead (Pb), selenium (Se), and zinc. Table 9.3. Concentrations of constituents in
typical heat-treated and pelletized manure.
Table 9.2. Concentrations of constituents in Perdue Pelletized
typical heat-treated and pelletized biosolids Agrirecycle poultry litter
Microstarter 60 (Hammac et al.
(Pinegro, Winston-Salem, N.C.; Tuscarora, Leesburg, Parameter Plus 2007)
Va.; Granulite (Synagro), Houston, Texas).
Solids (%) >85.00
Parameter Pinegro Tuscarora Granulite
TKN (%) 3.00 3.51
Solids (%) 93.00 96.00
NH4-N (%) 0.20
pH 7.12 6.00
(NO3-N) (%)
a
0.10
EC (dS/m)a 3.62
Total organic C (%) 36.0
TKNb/total N (%) 5.51 6.00 5.00
C:N ratio 12:1
(NH4-N)c (%) 0.26
P (%) 2.00 2.45
Organic N (%) 5.25
WSPb (%) 0.25
Water-soluble N (%) 0.56 1.00 1.00
K (%) 3.00
Water-insoluble N (%) 4.95 5.00 4.00
Ca (%) 2.50
Total organic C (%) 40.00
Mg (%) 0.50
C:N ratio 7.30:1
SO4-S (%) 0.76
P (%) 2.32 2.62 1.30
Fe (%) 0.13
K (%) 0.17 0.50
Cu (ppm) 0.07
Ca (%) 2.26 2.00 1.00
Zn (ppm) 0.07
Mg (%) 0.36 0.40
Mn (%) 0.07
(SO4-S)d (%) 1.68 2.25 0.40
a
NO3-N = nitrate nitrogen.
Fe (%) 2.86 1.00 1.00 b
WSP = water-soluble phosphorus.
Cu (ppme) 262 300
Zn (ppm) 1,830 200 400 All heat-dried, pelletized or granulated products are
Mn (ppm) 1,030 100 100 very dry, permitting easy spreading with fertilizer
equipment. Nitrogen and phosphorus contents are simi-
a
dS/m = deciSiemens per meter.
lar, but manures are significantly higher than biosolids
b
TKN = total Kjeldahl nitrogen.
c
NH4-N = ammonium nitrogen. in potassium. It is difficult to estimate plant-available
d
SO4-S = sulfate sulfur. nitrogen (PAN) in organic fertilizers that do not list
e
ppm = parts per million. various inorganic and organic nitrogen fractions, but
the nitrogen availability should be similar to that of
unpelletized manure (Hammac et al. 2007). Manure
Heat-Treated Manures products usually contain less iron and, thus, bind phos-
With the excessive concentrations of nutrients, espe- phorus less strongly than biosolids. Manure products,
cially phosphorus, in areas dominated by confined- like heat-dried biosolids, contain other macronutrients
animal feeding operations, manure is frequently being (e.g., calcium, magnesium, sulfur) and micronutrients
processed via heating, drying, pasteurizing, and pellet- (e.g., copper, zinc, iron, manganese, etc.).
izing or granulating. This is particularly true for poultry
manures, which contain especially unbalanced concen- Advanced Alkaline-Stabilization
trations of nitrogen and phosphorus that necessitate their
transport from regions with phosphorus-saturated soils. Products
The analytical data for typical pelletized poultry litter • A
 dvanced alkaline-stabilized (AAS) products have
in table 9.3 can be used to compare and contrast with high pH values (i.e., more than 12.0) due to their
the composition of heat-dried biosolids (table 9.2). strong alkalinity.

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 Chapter 9. Organic and Inorganic Soil Amendments

• Much of the content of such materials that utilize

Table 9.4. Typical composition of N-Viro
calcium oxide (CaO) as the liming agent is calcium.
One such example is N-Viro Soil (table 9.4), whose
Soil (advanced alkaline-stabilized biosolids)
calcium concentration can be as high as 40 percent of produced in Toledo, Ohio.
the product. Property Value
pH 12.2
• The carbon concentration of AAS biosolids is about
half that of digested biosolids due to dilution by the N (%) 1.0
liming agent. P (%) 0.2-1.1
K (%) 1.0
• Nearly all of the nitrogen in AAS products is in the
organic form because the inorganic nitrogen has been Ca (%) 10.0-40.0
driven off as ammonia due to the high pH. Mg (%) 1.0
S (%) 5.0
• Phosphorus is present as a mixture of organic phos-
phorus and calcium phosphates. Na (%) <0.2
As (ppm) 27.4
• Potassium content can vary widely depending on the
Cd (ppm) <1.4
potassium content in the source of alkalinity used to
treat the biosolids. Cr (ppm) 65.4
Cu (ppm) 74.0
• Sulfur is present as a combination of gypsum and
Hg (ppm) <0.7
organic sulfur.
Mo (ppm) 9.2
• Trace element concentrations are lower than digested Ni (ppm) 61.1
biosolids due to the dilution of the biosolids by the
Pb (ppm) 28.4
liming agent and are typically lower than 40 CFR
Part 503 pollutant concentration limits (EPA 1993; Se (ppm) 8.5
table 9.5). Zn (ppm) 188.0
Calcium carbonate 45.0
• The calcium carbonate equivalent of such AAS
equivalent (%)
products typically ranges from 40 to 50 percent.

Table 9.5. Biosolids trace element pollutant

Compost Properties and Quality concentration limits (EPA 1993) and mean
Standards concentrations from the National Sewage
Compost is used primarily as a soil conditioner and Sludge Survey (NSSS; EPA 1990).
secondarily as a supplier of nutrients. Thus, the prop- Class A products must meet pollutant concentration
erties of compost that are usually tested and listed limits in order to be deemed “exceptional quality” for
include those that improve soil conditions for plant uses in areas of frequent public contact.
growth and environmental effects (e.g., water quality; Pollutant PCL (ppm) NSSS (ppm)
table 9.6). Composting is a pH-neutralizing process;
As 41 10
therefore, most high-quality composts have pH values
near 7.0 (table 9.7). Stabilized organic matter tends to Cd 39 7
buffer soil pH, so adding compost to soil often reduces Cu 1,500 741
the need for frequent liming. Only where acid-loving Pb 300 134
plants are grown are such compost application effects Hg 17 5
not desirable.
Mo *
9
Electrical conductivity can vary greatly in compost, Ni 420 43
depending on the source of the feedstock(s) (table 9.6). Se 100 5
Composts produced primarily from animal manures are
Zn 2,800 1,202
usually higher in soluble salts and hence, higher in EC
than yard and woody waste-based composts (table 9.7). No current federal EPA pollutant concentration limits
*

(PCL), but the Virginia Department of Environmental

High soluble salts and EC can impair the growth of sen-
Quality has adopted a limit of 40 parts per million.
sitive plants, particularly seedlings; thus, it is important

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 Chapter 9. Organic and Inorganic Soil Amendments

to limit the portion of high soluble-salt-containing

compost mixed with soil when seeding or transplanting Table 9.6. Typical and preferred values of
will occur soon after soil amending. compost properties.
Property Typical Preferred
The higher the concentration of organic matter in com-
post, the greater will be the beneficial soil physical and pH 5.0-8.5 6.0-7.5
chemical property effects. The water-holding capacity EC (dS/m) 1-10 ≤5
of the compost can vary depending on the quality and
Organic 30-70 ≥50
particle size distribution of the organic matter (table matter (%)
9.6). The compost’s water-holding capacity is directly
proportional to the water-holding capacity of compost- Water-holding 75-200 ≥100
capacity (%)
amended mineral soil. Bulk density of the compost
is an indirect measure of the proportion of organic to Moisture 30-60 40-50
mineral matter in the compost (mineral matter having a content (%)
higher specific density than organic matter) and parti- Bulk density 700-1,200 800-1,000
cle size distribution. An intermediate bulk density will (lb/cu yd)
have a balance between coarse and fine particles. Nutrients 0.5-2.5% N No minimum
Because the primary purpose of compost used in land- 0.2-2% P required for ideal
scapes is as a soil conditioner, there are no ideal con- compost.
0.3-1.5% K
centrations of nutrients. Normal landscape application
Inorganic As, Cd, Cu, Hg, Mo,
rates of compost do, however, provide considerable
trace elements Ni, Pb, Se, and Zn
amounts of nutrients, even at the low concentrations that must meet 40 CFR
typically occur in compost (table 9.6). For instance, 1 Part 503 pollutant
inch of compost (3 cubic yards or approximately 1,350 concentration limits.
pounds of dry matter per 1,000 square feet) having a
Stability Should be measured
nitrogen-to-phosphorus-to-potassium ratio of 1-to-1-to as “stable” to
1 (1:1:1) will provide 13.5 pounds each of nitrogen, “highly stable” by
phosphorus, and potassium per 1,000 square feet. Only appropriate tests.
a small portion of the nitrogen — but most of the phos-
Growth Should pass seed
phorus and potassium — will be plant-available.
screening germination and
Carbon-to-nitrogen ratios can provide useful informa- plant growth assays.
tion (e.g., potential degree of nitrogen mineralization
or immobilization) about compost and other organic
waste byproducts, although by themselves, they are
not good indicators of compost quality. Most stabi-
lized composts that are produced from well-designed
starting recipes have carbon-to-nitrogen ratios between
12:1 and 20:1.

Table 9.7. Properties of various composts.

Water-
No. of EC Soluble P soluble N
Feedstocks samples pH (dS/m) (mg/kg) (mg/kg) C:N ratio
Biosolids and woodchips 6 6.20 5.49 236 1,936 14.9:1
Yard waste 1 6.75 6.40 139 534 32.2:1
Dairy manure 3 7.50 8.52 204 448 14.6:1
Poultry litter 5 7.53 19.80 1,092 979 9.9:1
Various combinations of manures, 11 6.57 11.50 94 1,359 12.9:1
yard and woody waste
Source: Data from John C. Bouwkamp and Catherine Ku. Unpublished data. University of Maryland.

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 Chapter 9. Organic and Inorganic Soil Amendments

Most feedstocks contain concentrations of inorganic contain phytotoxic concentrations of ammonia and
trace elements (e.g., heavy metals, arsenic, and sele- unstable, oxygen-depleting carbon.
nium; see tables 9.5 and 9.6) that will not pose a food
Various chemical tests or bioassays can be used to eval-
chain, phytotoxicity, or direct ingestion concern, but
uate compost or soil-compost mixes for the media’s
the concentrations of these potential pollutants should
potential to support plant growth. There are several quick
be reported for all composts, particularly those pro-
test methods that measure carbon dioxide and ammonia
duced from manure, biosolids, and other sludges. The
production, such as the Solvita compost maturity test
concentrations of these pollutants should be lower than
(www.solvita.co.uk/products/compost-maturity-test-kit.
the EPA (1993) 40 CFR Part 503 pollutant concentra-
htm). Specialized compost laboratories offer tests for
tion limits (table 9.5).
stability and growth screening in addition to the previ-
Because the ultimate purpose of compost application ously discussed physical and chemical properties. A list
to soil is often to improve plant growth response, com- of some compost laboratories can be found on the U.S.
post quality can also be assessed by the product’s abil- Composting Council website at www.compostingcoun-
ity to support plant growth (i.e., biological properties). cil.org/programs/sta/labs.php. These laboratories are
Incomplete and/or improper composting can generate a also certified to perform analyses for the Composting
product with properties that can adversely affect plant Council’s Seal of Testing Assurance Program (www.
growth and vigor. Incompletely composted material compostingcouncil.org/programs/sta/), a compost-
may possess bioactive carbon and a high carbon-to- testing, labeling, and information-disclosure program
nitrogen ratio; its continued decomposition upon addi- designed to provide information needed to maximize
tion to soil can deplete plant root-zone oxygen (O2) and/ benefit from the use of compost.
or immobilize plant-available soil nitrogen via rapid Woods End Research Laboratory (www.woodsend.
microbial respiration. org/index.html) also performs testing of compost and
The biological property “stability” should be assessed natural soil amendments for certified organic farming
to ensure that only stabilized compost is used where acceptance. The Organic Materials Review Institute in
plant growth is important. Stability is a measure of Oregon conducts an independent review process accord-
the degree of decomposition of carbon, where greater ing to the standards established in the U.S. Department
decomposition (i.e., greater stability) prevents high of Agriculture’s (USDA) National Organic Program of
rates of oxygen-depleting, carbon-dioxide-producing October 2002.
(CO2) microbial respiration and net soil nitrogen immo-
bilization. Stability can be tested via various microbial Factors That Affect Nutrient
respiration techniques that measure oxygen assimila-
tion or carbon dioxide production. The Dewar’s self- Availability
heating test employs an insulated container to measure
the difference in temperature between ambient air and Nitrogen
a compost sample maintained under conditions condu- Nitrogen in organic residuals is present in organic and
cive to microbial activity (i.e., 50 to 60 percent mois- inorganic (ammonium nitrogen: NH4-N; nitrate nitro-
ture, optimal bulk density, and porosity). The extent of gen: NO3-N) forms. Inorganic nitrogen is immediately
temperature change between ambient air and the “fin- plant-available, although nitrogen in the ammonium
ished” compost provides an indirect test of the respira- (NH4) form can be lost via volatilization as ammonia
tory potential of the organic matter. (NH3) if the residual has an alkaline pH and is applied
to the soil surface.
A second biological assessment method involves direct
measure of such plant-growth parameters as seed ger- Most of the nitrogen in heat-treated residuals and nearly
mination and seedling vigor. Electrical conductivity was all of the nitrogen in compost is organically complexed.
previously discussed as an abiotic property that could Such nitrogen requires the organic matter to be mineral-
reduce plant vigor. Feedstocks being composted under ized in order to transform the nitrogen into plant-avail-
anaerobic (i.e., oxygen-free) conditions can produce able nitrogen. The main factor that affects the portion
simple organic acids such as acetic (vinegar), butyric of the organic nitrogen that mineralizes to PAN is the
(rancid butter), and propionic that are the products of byproduct carbon-to-nitrogen ratio, which is inversely
fermentation rather than composting. Such organic related to the fraction of PAN. Typically, net nitrogen
acids can be phytotoxic. Immature compost may also mineralization occurs at a carbon-to-nitrogen ratio of

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 Chapter 9. Organic and Inorganic Soil Amendments

less than 20:1, and net nitrogen immobilization occurs relative to plant needs, than nitrogen. The application of
at a carbon-to-nitrogen ratio of more than 30:1. Little- organic wastes at rates to supply a plant’s nitrogen need
to-no mineralization/immobilization occurs between will usually supply more phosphorus than required by
carbon-to-nitrogen ratios of 20:1 and 30:1. the plant. Therefore, organic waste byproducts must be
applied judiciously to prevent soil phosphorus buildup
The form of the carbon in the residual also affects the to concentrations that promote phosphorus runoff and
extent and rate of mineralization. The mineralization resulting surface-water impairment.
rate decreases in relation to the stability of the organic
matter in the residual. For example, the organic nitro-
Other Macronutrients and
gen in sewage sludges that have undergone waste acti-
vation and biosolids that have been decomposed by Micronutrients
microbial (anaerobic, aerobic) digestion processes will Organic wastes, being the eventual products of plant
mineralize slower than the organic nitrogen in livestock materials, contain every plant-essential element. The
and poultry manures that have not first been subjected application of organic waste byproducts is rarely based
to microbial decomposition. Composted manures and on fertilizer elements other than nitrogen, phospho-
sludges undergo intensive decomposition that reduces rus, or sometimes lime. However, there can be value
mineralization rates even further. to vegetative growth and quality by increasing the soil
content of potassium, calcium, magnesium, sulfate sul-
The data in table 9.8 summarize measured values for
fur (SO4-S), and micronutrients with such byproducts.
carbon-to-nitrogen ratios and calculated (estimated)
One caveat is that byproducts could contain elements in
values for total plant-available nitrogen (100 percent
concentrations that may be phytotoxic (e.g., boron).
of inorganic nitrogen forms plus the plant-available
fractions of the organic nitrogen in the various residu-
als). The higher PAN fractions are found in residuals Uses of Organic Amendments
that have a higher portion of their nitrogen in inorganic
forms and a lower portion of their carbon in less decom- Pelletized and Granulated Products
posed (stable) forms. Heat-treated, dried, and pelletized or granulated prod-
ucts are essentially low-grade, organic fertilizers that
Table 9.8. Typical carbon-to-nitrogen can be applied in the same manner as inorganic fer-
ranges and first-year organic nitrogen tilizers. Because such materials have fixed nitrogen-
mineralization rates of organic residuals in to-phosphorus-to-potassium ratios (unlike specially
the mid-Atlantic states. blended inorganic fertilizers), care must be taken not to
Nmin* overapply phosphorus when applying these products to
Residual C:N ratio (first year %) meet nitrogen needs.
Manure, uncomposted 6:25 35-60
Biosolids, uncomposted 5:16 25-35
Advanced Alkaline-Stabilized Materials
Advanced alkaline-stabilized products can be used as
Biosolids and manure, 6:8 35-50
heat-treated, dried, and
liming agents, as topsoil blends, and to supply essen-
pelletized or granulated tial plant nutrients. These products are often physically
granular and can be applied with standard fertilizer
Compost 12:20 5-15
applicators.
* Nitrogen mineralization rate.
Compost and Blended Products
Phosphorus
Phosphorus in organic byproducts is largely 100 percent Compost as a Soil Amendment
plant-available, but the phosphorus in byproducts that Residential soils are typically low in organic matter and
contain considerable amounts of iron, manganese, and have high bulk density because their topsoil has usually
aluminum will be less-available than the phosphorus in been removed and the underlying soil horizons com-
byproducts containing lower amounts of these phos- pacted by earth-moving equipment. Such soils typi-
phorus-binding elements. The phosphorus in organic cally support poor vegetation, even when fertilized and
wastes is typically present in greater concentrations, watered (figure 9.1). For incorporation into disturbed or

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 Chapter 9. Organic and Inorganic Soil Amendments

degraded soils as a soil conditioner and nutrient source aeration and moved into the holes by raking or dragging
for establishment of turfgrass, ornamentals, trees, and a chain. Such use of compost promotes seed germination
shrubs, a thickness of 1 to 2 inches of compost (3 to 6 and improves soil properties by placing compost several
cubic yards per 1,000 square feet or 135 to 270 cubic inches into the soil (figure 9.7).
yards per acre) is recommended. Such rates can be sur-
In a review of 21 short- and long-term research studies,
face-applied (figures 9.2 and 9.3) and incorporated into
Shiralipour, McConnell, and Smith (1992) summarized
the soil surface prior to planting (figure 9.4). Turfgrass
the quantitative soil benefits of applications of 10 to 30
and other plants can then be established by seeding,
tons of mature municipal solid waste (MSW) compost per
sprigging, sodding, or transplanting. Seed germination
acre. The physical and chemical properties of most soils
and seedling vigor are typically improved with the use
were improved with MSW (table 9.9; McConnell, Shira-
of compost (figure 9.5).
lipour, and Smith 1993). These studies demonstrate the
Compost can replace topsoil, peat, sand, and woody fines consistent beneficial effects of compost as a soil amend-
mix in conjunction with core aeration and reseeding or as ment, especially for degraded environments. Additional
a topdressed treatment only (figure 9.6). Compost should benefits have been summarized by Alexander (2001).
be applied at a depth of 0.125 inch to 0.250 inch after

Figure 9.2. Applying compost to disturbed soil using a hand-operated

spreader. Photo courtesy of Greg Evanylo.

Figure 9.1. Ramifications of poor soil quality.

Upper: Poor soil preparation.
Lower: Poor turf establishment.
Photos courtesy of John Sloan, Texas A&M.
Figure 9.3. Close-up of compost application.
Photo courtesy of Greg Evanylo.

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 Chapter 9. Organic and Inorganic Soil Amendments

Figure 9.4. Applying turfgrass seed to compost-mulched disturbed soil. Figure 9 7. Topdressing compost after core aeration is a good practice
Photo courtesy of Greg Evanylo. for getting organic matter into soil under established turfgrass.
Photo courtesy of Ron Alexander, Alexander and Associates.

Table 9.9. Effects of various rates of

municipal solid waste (MSW) on soil
properties (McConnell, Shiralipour, and
Smith 1993).
Compost
application rate
(cubic yards/ Change in
Soil property 1,000 sq ft) soil property
Organic matter 1.0-6.5 6.0-163.0% ↑
Cation exchange 2.5-10.5 31.0-94.0% ↑
capacity
pH 1.0-6.5 0.8-1.4 ↑
Figure 9.5. Comparison of turfgrass establishment on disturbed soil Bulk density 1.0-6.5 4.0-71.0% ↑
with various compost and standard treatments.
Photo courtesy of Greg Evanylo.
Water-holding 0.5-6.5 5.0-143.0% ↑
capacity
Essential plant 1.0-20.0 0-500.0% ↑
elements

Composts and other organic amendments have also

been shown to provide beneficial biological effects,
particularly suppression of plant disease. Nelson
and Boehm (2002) summarized the results of studies
that quantified turfgrass disease control from various
organic amendments (table 9.10). While the maximum
disease-control percentages were often high, there was
considerable variation in control among different com-
post feedstocks, different batches of the same feed-
stock, and at different experiment locations.
Compost can be used as an amendment for various in-
ground infiltration and filtration systems, such as biore-
Figure 9.6. Effect of compost on athletic field. Inset showing compost
being topdressed. Main picture showing difference between turfgrass
tention systems and pervious pavement. Bioretention
color with and without compost. Photos courtesy of Mike Goatley. systems are shallow, landscaped depressions designed

Urban Nutrient Management Handbook 9-9

 Chapter 9. Organic and Inorganic Soil Amendments

to receive and filter stormwater runoff (figure 9.8).

Table 9.10. Turfgrass disease control Such systems are typically incorporated into parking
by various organic amendments lot islands and residential landscapes. As the stormwa-
(Nelson and Boehm 2002). ter infiltrates the bioretention media, pollutants such as
Disease Maximum % sediment, nutrients, polycyclic aromatic hydrocarbons,
Amendment controlled control heavy metals, and bacteria are removed by filtration,
Activated sewage Dollar spot 99 adsorption, ion exchange, biological degradation, and
sludge volatilization (Davis 2007). Bioretention rain gardens
are commonly composed of a natural well-drained
Composted Brown patch 42
soil (sandy loams or loamy sands are best) underlaid
biosolids Dollar spot 40 with coarse sand or gravel and covered with an organic
Pythium root rot 63 mulch layer (compost). The role of the compost is to
Red thread 51 protect the soil bed from erosion, provide a medium
Typhula blight 70 that holds moisture in the plant root zone for vegeta-
tive growth, biological decomposition, volatilization of
Composted Brown patch 25
organics, treatment of bacteria, and pollutant filtering.
brewery sludge Dollar spot 15
Pythium root rot 68 Use of pervious pavement is a practice for increasing
the permeability of surfaces in residential and urban
Red thread 36
areas to increase infiltration and reduce stormwater
Typhula blight 70 runoff. Compost can be used as a partial amendment
Composted cow Brown patch 25 in pervious pavement for reducing erosion and filtering
or horse manure Dollar spot 73 pollutants (figure 9.9).
Pythium root rot 31
Red thread 9
Typhula blight 55
Composted Brown patch 75
poultry litter Dollar spot 55
Necrotic ringspot 86
Pythium root rot 94
Red thread 79
Typhula blight 15
Composted yard Brown patch 39
trimmings Dollar spot 5 Figure 9.8. Bioretention rain garden.
Photo courtesy of A. P. Davis, University of Maryland.
Red thread 0
Composted grass Brown patch 50-80
clippings

Spent mushroom Brown patch 25

compost Dollar spot 0
Red thread 0
Uncomposted Brown patch 75
organic fertilizer Dollar spot 74
(consisting of
soybean meal, Necrotic ringspot 96
feather meal, Pythium root rot 56
blood meal, bone Red thread 57
meal, etc.)
Typhula blight 0 Figure 9.9. Compost can be used as partial growth and filtering me-
dium in pervious pavement.
Photo courtesy of Dwayne Stenlud, MnDOT.

9-10 Urban Nutrient Management Handbook

 Chapter 9. Organic and Inorganic Soil Amendments

Using Compost as Landscape Mulch

Compost can be used to mulch landscape vegetation to
conserve soil moisture and prevent runoff and erosion.
As an alternative to ground wood pallets, mulch com-
post conserved soil moisture and increased soil organic
matter equally well as the woody waste; however, the
soil nitrogen mineralization rate, plant-available nitro-
gen, and plant growth were higher with the compost
(Lloyd et al. 2002). The benefits of compost were due
largely to its lower carbon-to-nitrogen ratio (20:1) than
that of the ground pallets (100:1).
Other well-researched uses of compost as mulch are for
erosion and sediment control and as a cellulosic hydro-
mulch substitute for highway roadsides. Roadsides and Figure 9.10. Compost applied pneumatically to steep slopes adjacent
construction site “cut and fill” areas often leave steep, to highway to establish medium for erosion controlling and hillside
stabilizing vegetation. Photo courtesy of Greg Evanylo.
erosion-prone, low-fertility soils that can be difficult to
vegetate and to physically stabilize. Applying compost
(figure 9.10) at thicknesses of 1 to 2 inches to such sites
can provide erosion- and runoff-reducing mulch whose
organic matter and nutrient content reduce the long-
term risk of vegetation establishment and maintenance
failure (figure 9.11).
Even level, disturbed soils can be difficult to vegetate
owing to the poor physical and chemical properties of
such soils. Compost has also been used successfully
to revegetate such highway roadsides with application
thicknesses of 1 to 2 inches (figure 9.12).

Using Compost as Filtering Amendment

Due to its high organic matter content and variable dis-
tribution of particle-sized fractions, compost possesses
Figure 9.11. Compost-mulched roadside hill.
a suite of attributes (e.g., porosity, chemical adsorption, Photo courtesy of Greg Evanylo.
biological activity) that permit its use as a filtering and
processing agent for waterborne pollutants.
Filter berms are small windrows that can be constructed
around disturbed land to reduce the transport of sus-
pended and dissolved inorganic and organic solids and
biological agents (figure 9.13). Compost filter berms
can be used as recyclable, biodegradable, “living” filter
silt fence substitutes. Upon stabilization of the adja-
cent disturbed land, compost berms present no disposal
costs and are excellent growth media for vegetating the
site perimeter.
Filter socks are mesh (sausage-like) containment sys-
tems into which can be stuffed compost possessing
the appropriate physical and chemical properties to
permit water flow, suspended solids filtering, and dis-
solved constituents’ adsorption and biological degrada- Figure 9.12. Applying compost to highway roadside to revegetate
tion (figure 9.14). The EPA has touted such products poorly established turfgrass. Photo courtesy of Greg Evanylo.

Urban Nutrient Management Handbook 9-11

 Chapter 9. Organic and Inorganic Soil Amendments

Table 9.11. Filtrexx International-certified

results for a specific compost product used
as a filtering medium in a Filtrexx Soxx
product.
Parameter Numeric value
Flow-through rate 16 gpm*
Leach test NPK: none
Chemical removal Total N: 29.0% reduction
Figure 9.13. Compost filter berms can reduce the transport of sus- Total P: 14.0% reduction
pended and dissolved water-borne constituents.
Illustration courtesy of Ron Alexander, Alexander and Asssociates. Total K: 14.0% reduction
Motor oil test 98.5% reduction
(absorption)
Turbidity 27.0% reduction
Large solids removal 100.0% reduction
Suspended solids removal 52.0% reduction
Suspended solids w/ 96.0% reduction
floculant
*gpm = gallons per minute.

The U.S. Composting Council (1996) published a valu-

able field guide for using compost, but the guide did not
account for concentrations of potentially water-impact-
ing nutrients that could be transported to surface water.
Because composts produced from different feedstocks
have different concentrations of soluble and potentially
soluble carbon, nitrogen, and phosphorus, the compo-
sition of total and readily available, potentially water-
Figure 9.14. Compost in filter socks reduces runoff and protects impairing nutrients in the compost and the proximity to
stormwater quality.
water bodies must be assessed prior to planning appli-
Photos courtesy of Rod Tyler, Filtrexx International LLC.
cation rates.
revolutionized by Filtrexx International LLC (www.
An understanding of how compost use affects soil prop-
epa.gov/waste/conserve/rrr/greenscapes/projects/fil-
erties that influence nutrient transport is also important.
trexx.htm). The environmental value of a specific com-
For instance, despite the application of considerably
post source used in these systems is quantified in table
higher-than-needed phosphorus in five consecutive
9.11, where certified test pollutant reductions have been
years of compost application, Spargo et al. (2006)
listed. The compost removed most of the suspended sol-
measured no significant increase in runoff phosphorus
ids and significant portions of dissolved pollutants via
compared to a control treatment fertilized according to
filtering and adsorption, while allowing a flow rate ade-
soil testing recommendations because the high rates of
quate to prevent excessive ponding behind the Soxx.
compost increased infiltration and decreased runoff and
Additional uses of compost from yard waste can be erosion.
found in The Virginia Yard-Waste Management Manual
The conversions in table 9.12 can be used to estimate
(VCE publication 452-055).
the volume of compost needed to apply varying thick-
nesses of compost to a given area. The required mass
Compost Application Rates of compost can be calculated from the measured bulk
Desirable application rates for compost vary depending density, which normally varies between 700 and 1,200
on the purpose for its use and the cost of the product. pounds per cubic yard. A general rule of thumb is that

9-12 Urban Nutrient Management Handbook

 Chapter 9. Organic and Inorganic Soil Amendments

there are approximately 2 cubic yards in 1 ton of com-

post. Additional conversions are listed in The Field
Organic Byproduct Summary
Guide to Compost Use (U.S. Composting Council With Regard to Water Quality
1996). 1. The slow nitrogen-release nature of organic amend-
ments can either reduce or increase water contami-
Table 9.12. Compost use estimator. nation risk. Although nitrogen from most organic
Compost Cubic byproducts will not be supplied in such high concen-
thickness yards/1,000 Cubic yards/ trations in the soil water as nitrogen from inorganic
(inches) sq ft acre fertilizers, organic sources may continue to slowly
0.25 0.75 34.00 release nitrogen during the season (i.e., winter) when
plant uptake is greatly reduced or has ceased.
0.50 1.50 67.00
1.00 3.00 134.00 2. Organic amendments typically supply more phos-
phorus than is required by the growing vegetation
2.00 6.00 269.00
when the amendment is applied at a rate to supply the
plant’s nitrogen needs. This can result in an accumu-
How compost quality affects its fitness for use lation of soil phosphorus at concentrations that may
Although use of the highest quality compost will increase the risk of phosphorus runoff and surface-
ensure the fewest agronomic/horticultural problems, water impairment.
all uses do not require compost of the highest quality. 3. The increase in soil organic matter with the appli-
The information in table 9.13 shows the relative impor- cation of organic amendments increases soil tilth
tance of quality attributes for various compost uses. (including aggregation), infiltration, and water-
For example, compost properties that influence plant holding capacity, which reduces runoff volume and
growth are very important if the compost will be used decreases the risk of surface water impairment by
where establishing vegetation is the primary purpose sediment, nitrogen, and phosphorus.
(e.g., land reclamation, soil amendment for horticul-
tural crop), but such properties are not important if the 4. The increase in soil infiltration and water-holding
primary purpose of the compost is as a vegetation-free, capacity with the application of organic amendments
soil-erosion-controlling mulch. Conversely, particle increases vegetative biomass production and nutrient
size is important when considering compost as mulch, utilization, thus decreasing the risk of water impair-
but not so for amending drastically disturbed soils for ment by nitrate leaching and nitrogen and phospho-
reclamation purposes. rus runoff.

Table 9.13. Relative importance of quality Inorganic Materials for Amending

attributes for various uses.
Soils
Soil
amendment There are a variety of inorganic materials used to
for amend soils, with the most common source being sand
Land horticultural (Bigelow 2006). Based on particle size, sand is classi-
Attribute reclamation crop Mulch fied into five textural classes: very fine, fine, medium,
Plant ++ ++ — coarse, and very coarse (see chapter 3). There are many
growth possibilities in both composition and particle shape
that further define sand and its particular uses. In the
Nutrient + + —
mid-Atlantic, calcareous and silica sands predominate,
content
and they have varying shapes ranging from spherical
pH and + + — to angular. Sand composition and shape is extremely
soluble salts important when selecting sands for completely modi-
Maturity — + — fied root zones for golf putting greens or athletic fields.
Particle size — + + Consult the U.S. Golf Association’s USGA Recommen-
dations for a Method for Putting Green Construction
++ = very important, + = important, — = not important
(2004) if interested in putting green construction, or refer
to a book such as Sports Fields: Design, Construction

Urban Nutrient Management Handbook 9-13

 Chapter 9. Organic and Inorganic Soil Amendments

and Maintenance (Puhalla, Krans, and Goatley 2010) should be applied as a topdressing application, and the
for recommendations in building a sand-based sports crumb should be sized to no more than 10- to 20-mesh
field. material. It can float to the surface during heavy rain
events and it is not a replacement strategy for imple-
Calcined and vitrified clays (also called porous ceram-
menting regular, hollow-tine, core cultivation programs
ics) are naturally occurring materials that are mined in
to relieve compaction.
various parts of the country. The clays are heat-treated
in a rotary kiln where they expand to significantly larger Incorporating crumb rubber into the existing soil has
end products, similar to the size of sands. The end prod- not been as successful as its benefits when used as sur-
ucts are physically very stable and both retain some face topdressing. The best results on reducing surface
degree of cation exchange capacities (e.g., nutrient- compaction have been obtained when it is used preven-
holding capacity), but the temperature differences in tively (pre-traffic) rather than as a curative (post-traffic)
their formation result in very different moisture-reten- treatment. Given its black color, the heating of crumb
tion properties. Calcined clays, fired to temperatures up to rubber from radiant energy can benefit early- and late-
760° C, are noted for strong water-absorption properties. season turfgrass growth but can result in excessive heat-
On the other hand, vitrified clays, fired at temperatures ing in thin turfgrass canopies during the hottest months
up to 1,100° C, have significantly less water-holding of the year, especially on cool-season turfgrasses.
capacity. Combinations of these products as wetting
and drying agents are the staple for managing the skin
(grass-free) areas of baseball and softball fields with
Inorganic Amendment Use
calcined clay products serving as a wetting agent and Strategies
vitrified clays serving as a drying agent. These materi- Based on its comparatively large particle size, it is
als can also be used in completely modified, sand-based logical that sand can be added to fine-textured soils
soils if they meet particle size specifications. to improve drainage and soil aeration. Many potential
mistakes and/or concerns exist about amending soils
Zeolites are either synthetic or naturally occurring
with inorganic materials. What is the size and unifor-
mined aluminosilicates that provide greater cation
mity of the proposed amendment? In general, uniform
exchange capacity than calcined clays but not quite as
medium-to-coarse-textured amendments are desired,
high a water-holding capacity. Zeolite compounds have
and well-graded materials (e.g., concrete sand that con-
been used as amendments in modified sand-based soils
tains equal percentages of fine-, medium-, and coarse-
since the mid-1980s and their ability to capture and
textured materials) are discouraged.
hold NH4+ and K+ ions enhance turfgrass establishment
and reduce nutrient leaching. Next, just how much of the amendment is required to
achieve the desired results? The only way to precisely
Diatomaceous earth is mined from deposits of the fos-
determine this is to conduct a physical analysis of mix-
silized shell remains of diatoms — single-celled aquatic
tures of the existing soil material and proposed amend-
organisms whose shells are primarily silica. These fos-
ments, something that will likely have to be done by
silized remains contain a high percentage of micropo-
consulting with a soil testing laboratory.
res and have the ability to hold significant amounts of
water. The physical stability of diatomaceous earth is The most common mistakes in modifying existing soils
questionable if used as an amendment on heavily traf- with sands (or other coarse-textured amendments) are
ficked soils, but calcining the product improves its (1) using an inappropriately sized material, and (2) not
strength. adding enough coarse-textured amendment to affect
the desired changes in porosity. As a rule of thumb,
Another inorganic amendment that has application
uniform, medium-to-coarse-textured inorganic mate-
primarily on sports turfs but could be utilized on any
rials are desirable for amending soils. Well-graded
heavily trafficked area is crumb rubber. Use of crumb
amendments such as “concrete sand” have very limited
rubber presents a recycling opportunity because it is
potential in increasing porosity when added to heavier-
produced from ground-up tires. Developing a turfgrass
textured soils because the relatively equal percentages
canopy up to a 0.75-inch depth has improved turf wear
of fine, medium, and coarse aggregates are intended to
tolerance, reduced surface compaction, and improved
produce a firm medium.
shear resistance of the sod (Sorochan and Vanini 2003;
Goddard et al. 2008). However, no more than 0.25 inch A quick review of the soil textural triangle (figure 9.15)

9-14 Urban Nutrient Management Handbook

 Chapter 9. Organic and Inorganic Soil Amendments

demonstrates how specified ranges in the percentages doubles the percentage of plant-unavailable water
of sand, silt, and clay are used to define soil texture. (water is held so tightly by the calcined clay particles
Soils that are very high in percentage of silt and clay that plants cannot utilize it) but increases the percent-
will require large additions of sand to change their tex- age of total porosity. The sand-modified soil has virtu-
tures; for any soil to even have “sand” in its textural ally no change in the percentage of plant-unavailable
name (sandy clay, sandy clay loam, etc.), it will have to water and an actual decrease in the percentage of total
contain approximately 50 percent sand by volume. porosity (table 9.14). The data reveal the difficulty in
predicting how adding what seems to be an appreciable
amount of coarse-textured amendment actually affects
the physical properties of the soil. A physical soil test is
required to precisely determine how much amendment
is needed to blend with a specified depth of the existing
soil. Even with these data, the actual performance of the
blended soil in the field will still be greatly influenced
by how thoroughly the mixing of amendment and exist-
ing soil is conducted.

Topdressing With Inorganic

Amendments
Periodic (one to two times annually), light (0.25-inch
depth or less) topdressing (i.e., surface applications) of
inorganic amendments offers the potential benefits of
surface smoothing and improved thatch control in turf.
It is ideal to conduct the topdressing event with hollow-
tine core aeration events in order to better incorporate
Figure 9.15. The soil textural triangle. the material into the soil profile. Topdressing is a cul-
tural practice that is quite common on sand-based golf
Table 9.14 demonstrates how adding up to 40 percent greens and athletic fields. Although not common in
by volume of either a uniform medium-textured sand lawn turf management, the benefits are the same. Due
or calcined clay to a silt loam soil alters porosity and to economics, sand is the logical inorganic material of
water-holding capacity. In this example, adding either choice. In general, a uniform, medium-to-coarse-tex-
the medium sand or the calcined clay essentially doubles tured material is preferable, but even well-graded con-
the percentage of air porosity and reduces the percent- crete sands have been successfully used in topdressing
age of plant-available water by one-third as compared lawn turf if they are applied one to two times annually
to the silt loam soil. However, the two amendments at depths of 0.25 inch or less. The possibilities of top-
vary widely in their effects on the percentage of plant- dressing with crumb rubber on heavily trafficked sites
unavailable water and total porosity. The calcined clay are detailed above.

Table 9.14. Alterations in soil porosity and available water percentages of a silt loam topsoil
amended with inorganic materials.
Amendment added Air porosity Plant-available water Plant-unavailable water Total porosity
(% by volume) (%) (%) (%) (%)
None 9 35 9 53
40% medium sand 18 22 8 48
40% calcined clay 16 25 20 61
Source: Data provided by D. V. Waddington, professor emeritus of soil science, Pennsylvania State University.

Urban Nutrient Management Handbook 9-15

 Chapter 9. Organic and Inorganic Soil Amendments

Lloyd, J. E., D. A. Herms, B. R. Stinner, and H. A. J.

Literature Cited Hoitink. 2002. Comparing composted yard trim-
Alexander, R. 2001. Compost utilization in landscapes. mings and ground wood as mulches. BioCycle 43
In Compost Utilization in Horticultural Cropping (9): 52-56.
Systems, ed. P. J. Stoffella and B. A. Kahn, 151-75.
Boca Raton: Lewis Publishers. McConnell, D. B., A. Shiralipour, and W. H. Smith.
1993. Compost application improves soil proper-
Bigelow, C. A. 2006. Making amends: Here’s what to ties. BioCycle 34 (4): 61-63.
expect when choosing an amendment for soils.
Grounds Maintenance 41 (7): 35-39. Nelson, E. B., and M. J. Boehm. 2002. Compost induced
suppression of turf grass diseases. BioCycle 43
Davis, A. P. 2007. Bioretention and rain gardens. Pre- (6): 51-55.
sentation at 2007 Mid-Atlantic Composting Asso-
ciation Conference. Beltsville, Md. http://preview. Puhalla, J. C., J. V. Krans, and J. M. Goatley Jr. 2010.
tinyurl.com/25se3zv. Sports Fields: Design, Construction, and Main-
tenance. 2nd ed. Hoboken, N.J.: John Wiley &
Environmental Protection Agency (EPA). 1990. Sons.
National sewage sludge survey: Availability of
information and data, and anticipated impacts on Shiralipour, A., D. B. McConnell, and W. H. Smith.
proposed regulations. Proposed Rule 40 CFR, Part 1992. Physical and chemical properties of soils as
503. Federal Register 55 (218): 47,210-283. affected by municipal solid waste compost appli-
cation. Biomass and Bioenergy 3 (3-4): 261-66.
Environmental Protection Agency (EPA). 1993. Stan-
dards for the use or disposal of sewage sludge: Sorochan, J. C., and J. T. Vanini. 2003. Managing fields
Final rules. Code of Federal Regulations. Title 40 using crumb rubber and varietal selection. Sports-
Parts 257, 403, and 503; 9,248-415. Turf 19 (5): 14-16.

Evanylo, G. K., C. A. Sherony, J. H. May, T. W. Simpson, Spargo, J. T., G. K. Evanylo, and M. M. Alley. 2006.
and A. H. Christian. 2003 (reviewed 2009). The Vir- Repeated compost application effects on phos-
ginia Yard-Waste Management Manual. 2nd ed. Vir- phorus runoff in the Virginia Piedmont. Journal of
ginia Cooperative Extension Publication 452-055. Environmental Quality 35:2342-51.
http://pubs.ext.vt.edu/452/452-055/452-055.pdf. U.S. Composting Council. 1996. The Field Guide to
Goddard, M. J. R., J. C. Sorochan, J. S. McElroy, D. Compost Use. Alexandria, Va.: U.S. Composting
E. Karcher, and J. W. Landreth. 2008. The effects Council.
of crumb rubber topdressing on hybrid Kentucky U.S. Golf Association. Green Section. Revised 2004.
bluegrass and bermudagrass athletic fields in the Recommendations for a Method of Putting Green
transition zone. Crop Science 48 (5): 2,003-09. Construction. Far Hills, N.J.: U.S. Golf Associa-
Hammac II, W. A., C. W. Wood, B. H. Wood, O. O. tion. http://tinyurl.com/36rjqau.
Fasina, Y. Feng, and J. N. Shaw. 2007. Determina-
tion of bioavailable nitrogen and phosphorus from
pelletized broiler litter. Scientific Research and
Essay 2 (4): 89-94. www.academicjournals.org/
SRE (http://preview.tinyurl.com/2g2lsu2).

9-16 Urban Nutrient Management Handbook

 Chapter 10. Equipment Calibration and Fertilizer Application Methods

Chapter 10. Equipment Calibration

and Fertilizer Application Methods
Michael Goatley Jr., Professor and Extension Specialist, Crop and Soil Environmental Sciences, Virginia Tech
Steven Hodges, Professor, Crop and Soil Environmental Sciences, Virginia Tech

The next step to consider is the basic calculation of how

Introduction much product is needed to deliver the desired amount of
After determining the source and form of nutrients that nutrient. The three numbers that make up the fertilizer
best fit the situation, it is necessary to have an accurate grade on the label represent the percentages of nitrogen
assessment (size, surrounds, plant materials, etc.) of the (N), phosphate (P2O5), and potash (K2O) by weight, and
area planned for fertilization. Square footage of areas the label will list any other nutrients contained within
can usually be calculated by assessing site character- the fertilizer on a percentage-by-weight basis as well.
istics for typical shapes and using some basic geomet-
ric formulas for the different shapes detailed in figure
10.1 to calculate square footage. For example, using the Dry Fertilizer and Application
formula for the circle below, one could calculate the Methods
square footage of a circular courtyard with a diameter
Fertilizers are available in either dry or liquid formula-
of 25 feet as having a total square footage of
tions. First, consider dry formulations and their standard
3.14 x (12.5)2 = 490.6 square feet. delivery methods. For dry formulations, the percent-
age of each nutrient by weight will be indicated in the
Guaranteed Analysis section of the label. To determine
the amount needed for a given area, use the following
basic formula (and note that nitrogen is generally used
because it is usually the most limiting nutrient).

Pounds of fertilizer per area

Pounds of N needed per area
=
N from fertilizer formula as a decimal
(i.e., the number divided by 100)

Example: Using a 16-4-8 fertilizer to supply 1 pound

of nitrogen per 1,000 square feet gives:

Pounds of fertilizer per area

1 lb of N per 1,000 sq ft
=
0.16
= 6.25 lb of fertilizer per 1,000 sq ft

Because the numbers on the fertilizer grade represent

their percentage by weight, the amounts of phosphate
and potash that would be delivered to the area would be:
6.25 x 0.04 = 0.25 lb of P2O5 per 1,000 sq ft
6.25 x 0.08 = 0.50 lb of K2O per 1,000 sq ft

Notice that the proportion of the nutrients remains con-

stant: A 16-4-8 product has a 4-1-2 proportion of nitro-
gen to phosphate to potash.
Figure 10.1. Mathematical formulas for calculating the square footage
of various shapes found in turf and landscape management situations. Product requirements for larger or smaller areas can
simply be made by calculating standard proportions.

Urban Nutrient Management Handbook 10-1

 Chapter 10. Equipment Calibration and Fertilizer Application Methods

Using the basic algebraic steps of “cross multiply, To calibrate the spreader, you will need to collect and
divide, and solve for the unknown” is a popular way weigh the amount of product actually dropped in a
to perform fertilizer calculations. For example, for the known area at a given spreader setting. It is strongly
proportion of 1/2 = Y/4, cross-multiplying results in: recommended to apply material at one-half the desired
rate in perpendicular directions to reduce the possibil-
(1 x 4) = (2 x Y)
ity of skips and to avoid fertilizer application disasters
4 = 2Y such as the example in figure 10.3.
Dividing each side by 2 results in Y = 2. Apply this
same proportion concept to fertilizer calculations with
the only requirement being that the units in the numera-
tors (top number in the proportion) and the denomina-
tors (bottom number of the proportion) must match.
Assume the goal is to deliver 1 pound of nitrogen per
1,000 square feet to a 10,000-square-foot area with
the 16-4-8 fertilizer previously considered. The previ-
ous calculation determined that 6.25 pounds of 16-4-8
total are needed to deliver a desired level of 1 pound
of nitrogen per 1,000 square feet to the 10,000-square-
foot area. Carefully keeping the proportion rules for
similar units in numerators and denominators in place, Figure 10.3. Striping is evidence of either a poorly calibrated drop spread-
er or an inexperienced operator who did not properly apply the fertilizer.
the basic proportion is:

6.25 lb of 16-4-8 Y lb of 16-4-8 Steps in Drop Spreader Calibration

x
1,000 sq ft 10,000 sq ft 1. Determine a known area for the calibration: Measure
52,500 = 1,000 Y the width of your spreader (feet) and the distance
you will walk during the calibration process (fig-
Y = 62.5 lb of 16-4-8
ure 10.4). For this example, assume a 2-foot-wide
Drop Spreader Calibration spreader (drop width, not overall width of spreader)
and plan on walking a 50-foot length for a calibra-
Drop spreaders (figure 10.2) allow granules to drop out tion area of 2 feet by 50 feet = 100 square feet.
of a hopper by gravity and provide the most accurate
distribution because the material falls directly below its 2. Prepare a collection device: A huge timesaver in
release point. Wind is of minimal concern with distri- calibrating a drop spreader is to hang a “catch pan”
bution uniformity, but applications take longer because from the base of the spreader frame to collect all
only limited areas are being covered in a single pass. product that falls through the hopper. A catch pan
Drop spreaders are preferred when applying very fine made by cutting an appropriate length of 4-inch-
material or a mix of nutrients of differing sizes, and they diameter PVC pipe and fitting it with two end caps
are ideal to use around impervious surfaces as a means is shown in figure 10.5. An alternative method to
of ensuring that the product is kept off hardscapes. collect product is to drop the material on a piece of
plastic or on a clean, hard surface that can be swept
to collect the product after it is dropped. (Note: For
lengths longer than 10 feet, you will want to use
a catch pan rather than dropping it on plastic or a
hard surface and collecting.)
3. Ensure normal spreader operation: Place enough of
your dry product in the spreader to completely cover
the base and make sure the particle size is small
enough to readily flow through the spreader. Spe-
cialty turf fertilizers usually work well, but many
agricultural-grade materials (for example, 10-10-
Figure 10.2. A typical 3-foot-wide drop (gravity-fed) spreader. 10) are too large to flow through a drop spreader.

10-2 Urban Nutrient Management Handbook

 Chapter 10. Equipment Calibration and Fertilizer Application Methods

4. Make the calibration “run”: Select a low-to-medium

setting on the spreader (figure 10.6). Begin walk-
ing a few paces behind the calibration starting point
in order to establish a consistent speed. Open the
spreader as you reach the starting point and walk
the desired, known length. Collect the product in
the catch pan, sweep it off the hard surface or col-
lect it off the plastic, and place it in a container of a
known weight.
5. Weigh the product (figure 10.7) and calculate the
amount of product (total weight minus weight of
the container) being delivered per unit area: If the
amount delivered does not match the amount you
Figure 10.6. Adjusting the setting on the spreader will increase or
are trying to apply, adjust the spreader setting and decrease the size of the openings at the base of the spreader.
repeat the calibration steps until you collect the
desired amount. Note: One of the biggest limita-
tions when using a small area for calibration is the
accuracy of the scales. Accurate calibrations are
possible in small areas with very precise scales
as pictured in figure 10.7, but if you want to use
standard scales from around the house, the calibra-
tion area (and therefore, the amount of product col-
lected) will have to be much larger.

Figure 10.7. Scales that measure in units of ounces or grams allow for
accurate spreader calibration on relatively small areas.

Example: The fertilizer selected for application is a

6-2-0 organic material (containing 6 percent nitrogen,
2 percent phosphate, and 0 percent potash by weight).
Figure 10.4. A calibration run length of 20 feet has been marked with The desired level of application for this slowly avail-
paint in this photo.
able nitrogen source is 1.5 pounds of nitrogen per 1,000
square feet, so the formula is 1.5 ÷ 0.06 = 25 pounds
of 6-2-0 fertilizer required per 1,000 square feet. The
spreader is 2-feet wide (and is equipped with a catch
pan) and a length of 25 feet has been measured, result-
ing in a 50-square-foot calibration area (25 feet in
length x 2-foot drop spreader width = 50 square feet of
area covered in a single pass). The setup for the propor-
tion is:

25 lb of 6-2-0 x Y lb of 6-2-0
1,000 sq ft 50 sq ft
1,250 = 1,000 Y
Figure 10.5. A homemade catch pan made from a piece of PVC pipe. Y = 1.25 lb of 6-2-0

Urban Nutrient Management Handbook 10-3

 Chapter 10. Equipment Calibration and Fertilizer Application Methods

Continue to adjust the setting on the spreader until 1.25

pounds of 6-2-0 is collected during the calibration run.
(If you want to work in ounces or grams, the calcula-
tions will be 1.25 pounds x 16 ounces per pound = 20
ounces of the product, or 1.25 pounds x 454 grams per
pound = 567.5 grams.)
To avoid skips in application, it is recommended to
calibrate for one-half rate and make two perpendicu-
lar passes over the treatment area in order to improve
application uniformity. Therefore, the calibration for a
one-half-rate application that will be made in two direc-
tions would be:
1.25 ÷ 2 = approx 0.63 lb of 6-2-0
Figure 10.8. A broadcast spreader can hold relatively large volumes
of fertilizer and is a useful tool to rapidly apply granular fertilizers to
Broadcast (Rotary) Spreader large areas.

Calibration Steps in Broadcast (Rotary) Spreader

Broadcast spreaders (figure 10.8) deliver product by
Calibration
dropping a dry granule onto a spinning impeller. The
spread pattern of a broadcast spreader is not as precise 1. Ensure that the spreader is operating normally:
as a drop spreader but it is usually the preferred means Place enough product in the spreader to completely
to rapidly deliver fertilizer to a large area. A consistent cover the base of the spreader.
walking speed is important to optimize uniform deliv- 2. Determine uniformity and the effective spreader
ery, and wind is much more of a concern for distribution width (ESW): Product can be propelled 15 feet
uniformity — especially with lightweight materials. or more in a semicircle around the spreader, with
The potential for materials landing on hardscapes is the amount delivered decreasing with distance
much greater with broadcast spreaders due to the wide from the spreader. It is important to know how the
throw of the materials in the spread pattern. Particular spreader distributes product. Use catch pans (inex-
care needs to be taken when using these spreaders near pensive aluminum baking pans as pictured in figure
sidewalks, streets, etc., to ensure that product does not 10.9) spaced uniformly every 2 to 3 feet from the
land on hardscapes and potentially end up in a nearby center of the spreader and perpendicular to its line
water source. Many of these spreaders have deflector of motion. Depending on the size of the spreader,
attachments that should be employed around hard- anticipate product spread distance to range from
scapes to minimize the potential for fertilizer ending 12 to 20 feet. Begin walking a few paces behind
up on the hard surfaces; however, even when deflectors the calibration starting point in order to establish a
are used, the site should be inspected after application consistent walking speed prior to opening the hop-
and product should be swept up or blown back onto the per (figure 10.10). Open the spreader in time to dis-
turf. tribute product across the catch pans and close it as
soon as you pass the line of pans.
Spreading mixed materials of different sizes can be a
problem because larger, heavier particles are thrown 3. Collect results: Collect the fertilizer that is captured
farther than smaller particles, thus reducing even distri- in each pan and place the product in small clear
bution of nutrients. As with drop spreaders, application cups or tubes to make a visual evaluation of the
uniformity can often be improved by applying one-half spreader pattern (figure 10.11). Be sure to keep the
rates in two directions (detailed in the following). samples in the same order — by distance from the
spreader — as the pans. The desired distribution for
a standard application should be essentially a bell-
shaped pattern, with the largest amount of prod-
uct in the middle catch pan and uniform amounts
extending away from the center.

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 Chapter 10. Equipment Calibration and Fertilizer Application Methods

width can be determined as being that distance

where the fertilizer product is approximately 50
percent of the total collected from the center catch
pan. Using the example in figure 10.11, that point
occurs at approximately 6 feet, so in this example,
the ESW is 6 feet on either side of center, for a total
ESW of 12 feet. The application strategy will be to
overlap distribution by 6 feet in order to uniformly
achieve 100 percent coverage. If the distribution is
not uniform, the spreader might need an adjustment
or repair or the nonuniform distribution will have
to be accounted for in the delivery of the product.
Note that some professional spreaders intentionally
have adjustments and/or shields to deflect granular
Figure 10.9. Fertilizer catch pans are being placed at regular intervals
in order to determine the fertilizer’s effective distribution width. products from being discharged in a certain direc-
tion (e.g., in order to restrict fertilizer from being
thrown onto a hardscape).
5. Calibrate weight delivered: Now that the ESW
and the overlap width of the spread are known, the
spreader will be calibrated to determine an appropri-
ate setting to deliver a desired amount of material.
The use of a collection bag — an attachment that
encloses the impeller and captures the product as it
is being delivered (figure 10.12) — greatly speeds
the calibration process and prevents product from
repeatedly being delivered to an area during the
calibration run. Consider the goal in this example
is to deliver a total of 1 pound of nitrogen per 1,000
square feet using urea (45-0-0). If possible, per-
Figure 10.10. Establish a consistent walking speed prior to fertilizer
delivery in the calibration run. form the calibration using a calibration run length
that results in 1,000 square feet of coverage. If the
ESW is 12 feet, then the desired calibration length
is 83.3 feet (1,000 square feet ÷ 12 feet ESW = 83.3
feet in length). If 45-0-0 is the fertilizer of choice,
the formula for how much product is needed is (1 x
100) ÷ 45 = 2.2 pounds urea per 1,000 square feet
to deliver 1 pound of nitrogen per 1,000 square feet.
Set the spreader setting to a low-to-medium range;
establish a comfortable, repeatable walking speed
that is initiated several feet before the beginning of
your calibration course; and collect fertilizer in the
collection bag over the 83-foot distance. Weigh the
material collected and adjust the spreader setting
up or down depending on the amount collected.
Figure 10.11. The collection of fertilizer from catch pans at 2-foot Repeat the process until approximately 2.2 pounds
spacing from the center demonstrates an effective spreader width of of urea are collected. Just as for drop spreaders,
12 feet in this example.
the uniformity in distribution can be improved
4. Evaluate spread pattern and determine effective by applying the fertilizer in two directions. If this
spreader width: By visually evaluating the fertilizer strategy were employed, the calibration run would
collected from the catch pans, the effective spreader collect 1.1 pounds of urea (one-half the full rate).

Urban Nutrient Management Handbook 10-5

 Chapter 10. Equipment Calibration and Fertilizer Application Methods

uct, collect it with a broom and dust pan, and weigh to

determine a rate of product per unit area covered in the
calibration run. Because all the product is collected, it is
not necessary to start with a known quantity. As before,
keep adjusting the spreader settings until the appropri-
ate amount of product is delivered per unit area.
Finally, a fourth method of delivery that does not
involve calibration is what is sometimes referred to as
the “exercise method.” For this method, divide the lawn
up into logical areas of known square footage. Next,
weigh precise amounts of fertilizer to cover the known
area. For example, if an area measures 5,000 square
feet and the goal is to deliver 2.2 pounds of urea per
Figure 10.12. This rotary spreader is equipped with a collection bag to
1,000 square feet (i.e., 1 pound of nitrogen per 1,000
capture all granular product that is applied during calibration. square feet), then 11 pounds of urea are needed for the
lawn based on the following proportion:
In the absence of a collection bag, it is possible to sim-
ply weigh out a known amount of fertilizer to place 2.2 lb of 45-0-0 x Y lb of 45-0-0
in the hopper, apply product to a length of at least 25
1,000 sq ft 5,000 sq ft
feet, and then determine how much fertilizer remains
in the hopper in order to determine the level of nutri- 11,000 = 1,000 Y
ent applied. For example, 2 pounds of urea is placed in Y = 11 lb of 45-0-0
the fertilizer hopper with a previously determined ESW
of 12 feet and a calibration run length of 25 feet. The Weigh 11 pounds of urea and place it in the spreader.
total area covered in a single pass is 12 feet x 25 feet = Select a very low spreader setting and cover the lawn in
300 square feet. It was previously determined that 2.2 multiple directions until the spreader hopper is emptied.
pounds of urea per 1,000 square feet was required to No calibration is required, but the only way to ensure
deliver 1 pound of nitrogen per 1,000 square feet. The uniform spread is to get plenty of exercise covering the
proportion would be: lawn in multiple directions, delivering small amounts of
product. This method is very suitable for someone who
2.2 lb of 45-0-0 x Y lb of 45-0-0 infrequently fertilizes small lawn areas but obviously is
not an efficient use of time for professional applicators
1,000 sq ft 300 sq ft
who may be fertilizing several acres per day.
660 = 1,000 Y
Y = 0.66 lb of 45-0-0 Spread Patterns
Choose a low spreader setting, apply the fertilizer over The spread pattern with a rotary spreader will never be
the 25-foot calibration run length, and collect and weigh completely uniform because of the variability in spread
the remaining fertilizer in the hopper. If 2 pounds of due to wind, speed, equipment operation, and for some
urea was placed in the hopper before the application, fertilizers, the different sizes and weights of particles.
then the desired amount remaining in the hopper is 2.00 To manage the lack of spread uniformity, most text-
pounds – 0.66 pounds = 1.34 pounds of urea. Repeat the books suggest calibrating the spreader to deliver one-
process until you determine the appropriate spreader half the desired rate of product and apply the product in
setting. The obvious disadvantage of this method is the two passes at right angles to each other. Other published
application of product in the calibration area. information suggests that similar (if not better) delivery
results can be obtained by applying granular products
Another method is to apply the dry product to a clean, at one-half application rates in a parallel delivery pat-
paved area where the product can be collected by sweep- tern (figure 10.13).
ing after delivery. Again, determine a suitable length
based on the ESW. Of course, having to sweep up prod-
uct over an 83.3-foot length is quite labor intensive;
therefore, a shorter length is typical but some preci-
sion in calibration is likely sacrificed. Apply the prod-

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 Chapter 10. Equipment Calibration and Fertilizer Application Methods

lar forms of fertilizers are highly water-soluble and can

be quickly dissolved in water to make their own spray
solution, while others are quite insoluble and unsuitable
for liquid feeding (see the water solubility information
in tables 8.1, 8.3, and 8.4 in chapter 8).
Before adding different fertilizers and/or pesticides to
a tank, check the label very carefully for specific com-
ments regarding tank mixing and/or conduct a test of
the compatibility of the two products by adding small,
proportional amounts of the products that simulate what
will be added to the spray tank. If the product blends
into a uniform solution, mixing in the tank should be
fine. If the combination becomes a sludge-like consis-
tency, tank-mixing should be avoided.

Sprayer Components
All spray systems will have a tank, a pump, a boom,
nozzles, and sprayer tips. The system will logically be
mobile, whether it is by way of someone walking or
a motorized vehicle. While it is beyond the scope of
this handbook to provide exhaustive detail on all these
components, there are some basic elements about the
sprayer components that will suffice in obtaining accu-
Figure 10.13. Standard right-angle application method (top) and the rate calibration. Additional information is available
overlap delivery method (bottom).
in Fine Tuning a Sprayer with “Ounce” Calibration
Method, Virginia Cooperative Extension publication
Final Thoughts on Spreader Calibration 442-453 (Grisso et al. 2009).
Several national lawn product retailers sell spread- The pump is used to create pressure (whether the pump
ers specifically designed for their products. Part of is powered by hand or by an engine), and it is impor-
the advantage of using these specialty products is the tant that the pressure be optimal for the system and the
“cookbook” nature of the application instructions. product and that it is consistent and repeatable. Most
However, it is still wise to use their recommended set- products will have pressure and spray-volume recom-
tings only as guidelines for beginning your own cali- mendations on their labels.
bration steps rather than taking the suggested spreader
settings and application levels as guarantees. Not all Next, choose an appropriate nozzle and tips for the
spreaders deliver product alike, and over time (and with system and the application. Again, this information is
use), spreader performance is likely to change. Record usually provided on the product label or as a recom-
all information involved in calibration steps (amount mendation provided by the sprayer system and/or the
and type of product, spreader settings, etc.) for future nozzle and tip supplier. True foliar feeding of nutrients
reference. This will make future calibrations that much that are intended to primarily enter a plant through the
quicker and easier. leaves is accomplished with spray volumes of 45 gal-
lons per acre (GPA) or less. In other situations where
a liquid fertilizer might be mixed with an insecticide
Liquid Fertilizers and Sprayer intended to enter the soil in order to control a ground-
Calibration borne pest, the recommended volume of liquid delivery
might be 100 to 200 GPA.
Many specialty products are marketed as liquid formu-
lations that quickly go into solution or are easily sus- Other factors to consider when selecting and optimiz-
pended in water. Many micronutrient formulations are ing the use of nozzles and tips for multinozzle booms
sold as chelates — organic forms of the nutrient that are (often used in golf turf management) are their appropri-
in a liquid formulation. Also, several common granu- ate spacing and height off the ground. Some tips require

Urban Nutrient Management Handbook 10-7

 Chapter 10. Equipment Calibration and Fertilizer Application Methods

up to a 33 percent overlap of the spray pattern to ensure The “Ounce” Calibration Method
100 percent coverage. The manufacturers of the noz-
zles and tips provide helpful charts for these criteria, This method of calibration is very popular because it
with much of the information being available on the eliminates a lot of the math in the calibration calcula-
Internet. tions. A gallon equals 128 ounces, so if a sprayer is cali-
brated on an area of 1/128th of an acre (1 acre = 43,560
Routinely check the system and its components to square feet ÷ 128 = 340 square feet), then the ounces
ensure proper working condition. Check that hoses and collected during calibration equate to gallons per acre.
fittings are securely attached, nozzles and tips are not
clogged, and spray pressure generated by the pump is Begin by measuring the nozzle spacing on the boom
constant. A great place to run a preliminary inspection (figure 10.16) because this determines the course length
of the system is to conduct a sprayer test by applying required to cover 1/128th of an acre. For example, with
water on a driveway or parking lot that makes it easy to a 20-inch nozzle spacing as depicted in figure 10.16
evaluate that boom height, nozzle selection, and nozzle (20 inches equals 1.67 feet), the calculation will be 340
spacing are all appropriate to provide uniform appli- square feet ÷ 1.67 feet nozzle spacing = approximately
cation (figure 10.14). After this initial check, gather 204 linear feet (see table 10.1 for course lengths based
all the equipment you will need for the calibration: a on standard nozzle spacing). When calibrating a sin-
stopwatch, measuring tape or wheel, flags to mark your gle nozzle such as for a hose end or backpack sprayer,
course, and containers to collect and measure the liquid determine the spray width (in feet) for the single nozzle
discharge (figure 10.15). and divide this into 340 square feet to determine the
course length for calibration.

Figure 10.14. Evaluating nozzle and tip performance prior to calibra-

tion is easily accomplished by spraying water on a road or driveway Figure 10.16. Nozzles should be equally spaced on the boom accord-
to evaluate boom nozzle height and overlap. ing to manufacturer recommendations. By measuring the spacing,
you can then calculate the test course length in order to calibrate the
sprayer according to the ounce calibration method.

Table 10.1. Course lengths required to

calibrate 1/128th of an acre (340 square feet).
Boom nozzle spacing Course length
(inches) (feet)
12 340
16 255
20 204
24 170
28 146
32 127
36 113
Figure 10.15. The basic equipment needed for sprayer calibration.
40 102

10-8 Urban Nutrient Management Handbook

 Chapter 10. Equipment Calibration and Fertilizer Application Methods

If the boom has 20-inch nozzle spacings, then table 10.1 In the example presented, the 40 ounces of discharge
indicates that a course length of 204 feet is required to collected for the known time period equates to a
cover 1/128th of an acre. Fill the tank at least half way sprayer calibrated to deliver 40 GPA. Catch the output
with water, determine an optimum speed for the ter- from at least three nozzles for the required duration to
rain and product delivery (usually 3 to 4 mph), set the ensure that all nozzles are performing comparably. If
power takeoff (PTO) at an appropriate rate of RPMs for a nozzle does not deliver an output that is within plus/
the pump to deliver the desired pressure and volume minus 5 percent of the average nozzle output, check the
of spray solution, and operate the sprayer system as if filter and tip to see if they are clogged and/or damaged.
product was being applied. Be sure the test course ter- Replace any suspect nozzle or tip.
rain is comparable to the area that you will be treating
so your calibration run equates well with the actual area Example of How Much Product to Add
to cover.
The label of a popular 15-0-0 liquid fertilizer that is
Time how long it takes to travel the 204 feet for this also 4 percent sulfur and 6 percent iron by weight rec-
particular spray system setup. Then, operate the sprayer ommends an application range of 2 to 8 fluid ounces
in a stationary position, capturing the discharge from a per 1,000 square feet. If 4 ounces per 1,000 square feet
single nozzle for the time period it took to drive the 204- is selected, how much is added to the sprayer system
foot test course in this example (figure 10.17). Using a that was just calibrated in the preceding example?
measuring cup marked in ounces, what is collected in
ounces simply equals gallons per acre. If relatively large areas are to be treated, it is logical to
prepare full tanks of spray solution. Assume the system
has a 100-gallon tank. As calibrated at 40 GPA, then a
full tank can cover 100 gallons ÷ 40 GPA = 2.5 acres.
How many square feet are in 2.5 acres? One acre is
43,560 square feet, so 2.5 x 43,5460 = 108,900 square
feet. Using a basic proportion, the setup is:

4 fluid oz of product x Y fluid oz of product

1,000 sq ft 108,900 sq ft
435,600 = 1,000 Y
Y = approx 436 fl oz of product
436 fluid oz 
= approx 3.4 gal of 15-0-0
128 fl oz/gal
Figure 10.17. Capture the discharge from a nozzle for the same time So, 3.4 gallons is the amount of 15-0-0 liquid fertilizer
duration it took to drive the test course.
to be added to the tank of a sprayer calibrated to deliver
40 GPA. To prepare a full tank, fill the tank partially
with water, add the fertilizer, and then add the remain-
ing water to bring the tank to the 100-gallon level.
What if the goal were to cover only 20,000 square feet
of area? It was just calculated that a full sprayer hold-
ing 100 gallons will cover 108,900 square feet. There
would be no point in mixing a full tank but instead, just
enough to cover 20,000 square feet. A simple propor-
tion would be:

100 gal Y gal

x
108,900 sq ft 20,000 sq ft
2,000,000 = 108,900 Y
Figure 10.18. The amount captured in ounces equals the gallons per
acre the sprayer is delivering. In this example. the sprayer is calibrated Y = approx 18.4 gal of water
to deliver 40 GPA.

Urban Nutrient Management Handbook 10-9

 Chapter 10. Equipment Calibration and Fertilizer Application Methods

How much fertilizer is needed to treat the 20,000-square- 18.4 gallons of total spray volume to treat 20,000
foot area using a rate of 4 fluid ounces per 1,000 square square feet. Fill the tank with approximately 9 gallons
feet? of water, add the 11.2 pounds of urea (stirring or agitat-
ing to ensure the product fully dissolves), and bring the
4 fluid oz of product x Y fluid oz of product final tank volume to approximately 18.4 gallons. The
1,000 sq ft 20,000 sq ft sprayer is calibrated to deliver 0.25 pound of nitrogen
per 1,000 square feet.
80,000 = 1,000 Y
Y = 80 fluid oz of product
Other Considerations With Sprayable
Add a few gallons of water to the tank, add the 80 fluid Fertilizers
ounces of fertilizer, and then fill the tank to a final vol-
Because of the high volumes applied and the relatively
ume of approximately 18.4 gallons.
dilute concentration of nutrients, liquid fertilizer appli-
How about adding dry products or powders? Many cations are often very uniform and precise. However,
commercially available powdered fertilizers are highly you should pay very close attention to the label rec-
water-soluble and even some bulk fertilizer materials ommendations regarding spray volume, nozzles, and
may be sufficiently soluble to deliver in liquid form (see tips and the requirement for sprayer agitation. Also, be
chapter 8, table 8.1). For example, up to 6.5 pounds of sure to record your own observations regarding sprayer
urea is soluble in a gallon of water (from table 8.1; note performance and plant response for future reference.
that rapid mixing and even heat may be needed to speed Watering in of many liquid fertilizers may be recom-
dissolution of some materials unless dilute solutions mended after application to reduce leaf burn potential
are desired). Consider an example where the goal is to or to improve uptake efficiency. Be very careful regard-
use the calibrated sprayer above to provide a nitrogen ing the compatibility of tank mixtures of fertilizers,
level of 0.25 pound per 1,000 square feet (using urea) pesticides, and other spray additives because they can
to 20,000 square feet of turf. cause undesired changes in physical and/or chemical
properties of the materials.
It will take 0.25 pounds of nitrogen ÷ 0.45 = 0.56 pounds
of urea per 1,000 square feet to deliver the desired level
of nitrogen. The area to be covered is 20,000 square
Literature Cited
feet. Grisso, R., P. Hipkins, S. D. Askew, L. Hipkins, and D.
McCall. 2009. Nozzles: Selection and Sizing. Vir-
0.56 lb of 45-0-0 x Y lb of 45-0-0 ginia Cooperative Extension Publication 442-032.
1,000 sq ft 20,000 sq ft http://pubs.ext.vt.edu/442/442-032/442-032.html.
11,200 = 1,000 Y Grisso, R., M. Weaver, K. Bradley, S. Hagood, and
Y = 11.20 lb of 45-0-0
H. Wilson. 2009. Fine Tuning a Sprayer with
“Ounce” Calibration Method. Virginia Coopera-
It was previously determined (see above) that a sprayer tive Extension Publication 442-453. http://pubs.
calibrated to deliver 40 GPA would need approximately ext.vt.edu/442/442-453/442-453.html.

10-10 Urban Nutrient Management Handbook

 Chapter 11. Soil-Water Budgets and Irrigation Sources and Timing

Chapter 11. Soil-Water Budgets and

Irrigation Sources and Timing
W. Lee Daniels, Professor, Crop and Soil Environmental Sciences, Virginia Tech
Greg Evanylo, Professor, Crop and Soil Environmental Sciences, Virginia Tech
Kathryn Haering, Research Associate, Crop and Soil Environmental Sciences, Virginia Tech
Laurie Fox, Research Associate, Hampton Roads Agricultural Research and Extension Center, Virginia Tech
David Sample, Assistant Professor, Biological Systems Engineering, Virginia Tech

with local climate — particularly rainfall intensity and

Introduction snowmelt — resulting in different infiltration and run-
The successful establishment and management of turf- off rates.
grass and landscape plantings are highly dependent on
the maintenance of adequate soil moisture over time, In this chapter, we will focus on understanding how
water applied as rainfall or irrigation moves into and
particularly during periods of drought. Ideally, the soil’s
out of the soil profile on a local (e.g., home lot) basis.
physical properties allow for rapid infiltration and reten-
Greater detail on larger scale (e.g., subdivision or water-
tion of rain and applied irrigation waters. When adverse
shed level) stormwater and nutrient runoff issues and
soil properties such as excessive compaction and lack
best management practices is presented in chapter 12.
of aggregation (see chapters 2 and 3) limit soil infiltra-
tion rates, valuable water is lost to runoff and may carry
excess nutrients away with it in stormwater discharge. The Hydrologic Cycle and Soil-
Conversely, when excess soil water percolates down Water Budgets
through the soil profile, particularly during the winter, A basic understanding of the hydrologic cycle (illus-
it may also carry away soluble nutrients such as nitrate- trated in figure 11.1) is necessary to understand nutrient
nitrogen to local groundwater. Thus, the relative risk of loss mechanisms and to develop management strategies
nutrient movement to groundwater and surface waters to reduce nutrient losses to groundwater and surface
in any managed soil landscape is strongly controlled water. The primary components of the hydrologic cycle
by the physical nature of the soil profile coupled with that are most important to nutrient transport in surface
the nature of the vegetation and associated manage- water and groundwater are:
ment practices. These site-specific factors then interact • P
 recipitation.
• I nterception of rainfall on plants.
• S
 urface runoff.
• E
 vapotranspiration (evaporation
plus plant transpiration).
• N
 et leaching to groundwater and
eventual discharge into streams
(base flow).
Nutrients move into the groundwa-
ter system via leaching and to sur-
face water via runoff or groundwater
discharge to springs and seeps. Any
contaminants dissolved in surface
runoff, such as nitrate (NO3-) or
ortho-phosphorus, can contribute
to surface water contamination. In
addition, discharge of groundwater
Figure 11.1. The hydrologic cycle. Figure by Kathryn Haering. into surface water often occurs in

Urban Nutrient Management Handbook 11-1

 Chapter 11. Soil-Water Budgets and Irrigation Sources and Timing

stream beds and tidal portions of the Chesapeake Bay vegetation goes dormant for the winter. Long-term
system. average rainfall by month does not vary significantly
throughout the year for most areas, but it is slightly
Precipitation higher in the late summer and early fall due to infre-
quent (but extreme) effects of hurricanes. Evapotranspi-
Long-term annual precipitation averages range from ration, however, is much greater during the late spring,
35 inches to more than 50 inches in different areas of summer, and early fall because water use by vegetation
the mid-Atlantic region. Although timing and amount is much higher during this period (see figure 11.2).
of precipitation will vary in each individual year,
these deviations from the average cannot be reliably
predicted. Leaching and Groundwater Discharge
Water that infiltrates upland soils during the growing
season is largely removed by evapotranspiration (figure
Interception
11.2); water losses beyond the rooting zone to ground-
From 5 percent to 40 percent of precipitation is inter- water are very rare. Consequently, the risk of leach-
cepted by the leaves of plants, depending on the inten- ing or runoff losses of water and soluble nutrients is
sity of rainfall and the morphology of the canopy. This much less during the summer than during the winter.
water never reaches the soil surface to contribute to However, during the late fall and winter, any added or
either infiltration or runoff, but it does cool and wet the remaining soil water — particularly that held in large
plant’s leaves, which can decrease transpiration losses macropores — is subject to leaching below the rooting
over the short term. Higher interception rates are asso- zone and will eventually reach groundwater.
ciated with light rains falling on dense multistoried
canopies (e.g., mature woody trees over complete her- During leaching, soluble nutrients such as nitrate per-
baceous groundcovers), while lower interception rates colate through the soil with water because they are not
are associated with heavy rains on thinly vegetated sur- readily bound to soil surfaces. The relative amounts of
faces, such as newly established lawns. surface runoff, interception, and leaching from an area
are influenced by storm intensity, storm duration, slope,
soil type, type of vegetation, and amount of plant or
Surface Runoff crop residue on the soil surface.
Precipitation that falls onto the soil surface in excess of
the infiltration rate will run off to lower portions of the During the winter months, the amounts of rainfall
landscape or to surface streams. Soil infiltration rates and snowmelt that infiltrate most upland soils greatly
vary widely, from several inches of rainfall per hour exceeds the rate of evapotranspiration. During this
on gently sloping, well-vegetated, and aggregated sur- period (nominally November to March), water leaches
faces to less than 0.10 inch per hour on sloping, com- completely through the soil profile and contributes to
pacted, clayey, poorly vegetated areas. Infiltration is local groundwater “recharge.” Groundwater that infil-
also affected by whether or not the soil surface is wet trates upland soils as recharge eventually discharges
or dry at the start of the rainfall event (antecedent mois- into local streams and is also termed “base flow.”
ture conditions). Figure 11.3 depicts an example of a landscape-level
water budget and net groundwater discharge to streams
Evapotranspiration for a typical Ridge and Valley Province watershed. In
this area, long-term leaching and discharge accounts
Evapotranspiration (ET) is the sum of surface evapora-
for about 5 inches per acre of watershed area, while
tion of moisture (from puddles, ponds, etc.) plus the
direct-surface runoff losses account for 7 inches per
removal of soil moisture by the root uptake and sub-
acre annually. Surface runoff contributions to stream
sequent transpiration of water through the leaves of
water occur during and after rainfall events or snow-
living vegetation. For example, ET accounts for 25 to
melt and are therefore highly variable over time.
40 inches of the total precipitation in Virginia and is
highest in Eastern Virginia, where the long growing In contrast, base flow is usually a continuous contribu-
season and higher air temperatures combine for maxi- tor to stream flow throughout the year. During dry
mum plant water demand. The removal of soil water by periods, base flow is the primary contributor to stream
ET decreases significantly when air temperatures drop flow, which vividly demonstrates the interconnection
below 45 degrees Fahrenheit (F) and/or when the active of groundwater and surface waters.

11-2 Urban Nutrient Management Handbook

 Chapter 11. Soil-Water Budgets and Irrigation Sources and Timing

Figure 11.2. The soil water budget. This figure depicts the overall balance of water inputs (as precipitation) and losses (as runoff, evapotranspira-
tion, and leaching) for a typical upland soil in the mid-Atlantic region. The annual period shown here runs from September (S) to September. Note
that while average precipitation inputs are fairly even across the year, net evapotranspiration demand varies directly with the season as driven by
temperature and day length. In midsummer (J, J, and A), potential evapotranspiration greatly exceeds rainfall and the difference between the two
results in a soil water deficit that must be made up via supplemental watering/irrigation for optimal plant growth. By late fall (N and D), however,
evapotranspiration drops with falling temperatures and the soil holds and stores water against leaching up to its water-holding capacity as soil stor-
age. Once that capacity to retain water is exceeded, additional infiltrating rainwater and snowmelt is transmitted down through the soil and is lost
as leaching to groundwater recharge. Figure by Kathryn Haering; based on data from Carroll County, Va.

Watering Basics for Turf and

Landscape Plantings
As pointed out in the preceding section, plant transpi-
rational demands for water during the summer usually
exceed rainfall, which can lead to water stress, poor
plant growth, and even death of established turf and
landscape plantings. Water stress is amplified in urban
soils that are limited by compaction and poor aggrega-
tion/infiltration (chapter 3) and in very sandy or rocky
native soils with inherently low water-holding capaci-
ties (chapter 2). Therefore, we commonly supplement
rainfall with watering/irrigation during the summer and
Figure 11. 3. General water budget, Upper South Fork of the Shenan- early fall months.
doah River (adapted from Virginia Department of Conservation and
Recreation 1993).

Base flow and subsurface seepage of groundwater con- Water Application Rate, Timing, and
tribute more than surface runoff to surface water bod- Frequency
ies in the Atlantic Coastal Plain Province due to much The amount of water needed by established turf or
flatter terrain, highly permeable soils, and relatively ornamental plants depends on the type of turf or plant,
high water table levels. In some areas of the Coastal the soil type, the amount of existing moisture in the
Plain, groundwater discharge may account for as much soil, and the time of year. Overwatering is a leading
as 80 percent of total annual contributions to surface cause of problems with landscape plants and can also
water. Groundwater in the Coastal Plain Province typi- damage established turf — especially when applied to
cally moves in a downwardly arcing path from uplands soils with limited permeability that locally perch shal-
toward discharge points at a rate of several inches to as low, saturated zones in soils (see chapter 3) or cause
much as 2 feet per day. local ponding. Where feasible, rain sensors should be

Urban Nutrient Management Handbook 11-3

 Chapter 11. Soil-Water Budgets and Irrigation Sources and Timing

installed on large or commercial irrigation systems to Slow, deep, soaking applications once a week are best
prevent overwatering and waste and to reduce costs. for landscaping plants. Avoid short, frequent, shallow
applications that can actually stress landscape plants
Application Rate or cause a buildup of ions or salts from the water in
One-time irrigation rates for turf should be sufficient the soil that may be toxic to certain plants. Newly
to wet, but not saturate, the entire rooting depth as installed plants may require more frequent irrigation.
described below. This may vary from 0.5 to 1.5 inches This depends mainly on the plant species, soil type, and
or more of water per event, depending on the poros- mulch.
ity, aggregation, and bulk water-holding capacity of the
In general:
soil. An easy way to check this is to use a shovel to
examine the wetting depth approximately 30 minutes • W
 ater annuals every two days for the first two
after the irrigation event ends. Obviously, the applica- weeks.
tion rate will also need to be managed to ensure com-
plete infiltration and limited runoff. • W
 ater perennials and woody plants every three to
four days for the first three weeks.
As a general guide, water should be applied to land-
scape plantings at the rate of 1.0 inch per week (60 gal- • I rrigation frequency should return to once a week as
lons per 100 square feet) in a single application. This needed after the plants have been established.
amount will wet most soils to a depth of about 12 inches
(the area containing 80 percent of the roots of most Water Reuse: Using Reclaimed
landscape plants). Because water moves readily within
the plant, you do not need to water the entire root zone. Water for Irrigation
Twenty-five percent of the root area can absorb enough “Reclaimed water,” also known as “recycled water,” is
water for the entire plant. Irrigation should stop when water recovered from domestic, municipal, and indus-
water begins to run off. If necessary, 0.5 inch of water trial wastewater treatment plants that has been treated
can be applied, followed by an additional 0.5 inch sev- to standards that safely allow most uses except human
eral hours later to prevent runoff. This rate is a general consumption (figure 11.4). “Wastewater” (untreated
recommendation for established annuals, perennials, liquid industrial waste and/or domestic sewage from
and woody plants in landscape beds.
residential dwellings, commercial buildings, and indus-
trial facilities) is not reclaimed water. “Gray water,” or
Application Timing untreated wastewater from bathing or washing, is one
The best time to water is in the early morning, form of wastewater. Wastewater may be land-applied,
whether using a hand-held hose, drip or trickle sys- but this is considered to be land treatment rather than
tem, microsprinklers, soaker or ooze hose, or overhead water reuse.
sprinklers. As much as 30 percent of the water applied
overhead during midday can be lost to interception and
evaporation. Also, overhead applications made early in
the day allow time for the foliage to dry, which prevents
diseases.

Application Frequency for Landscaping Plants

For established turfgrass, the watering regime should
be managed to provide enough water to wet the soil
throughout the normal rooting zone (i.e., 6 to 12 inches)
but not more than twice per week to avoid overwater-
ing. Deep, infrequent watering promotes downward
turfgrass root proliferation while more frequent, shal-
low irrigation events are detrimental to long-term turf
rooting patterns and the sod’s inherent ability to with- Figure 11.4. Water reclamation process at a wastewater treatment
stand drought in the absence of watering. facility. (adapted from Environmental Protection Agency [EPA] 2004).

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 Chapter 11. Soil-Water Budgets and Irrigation Sources and Timing

How Is Reclaimed Water Produced? disease risks to acceptable levels, reclaimed water must
meet certain disinfection standards by reducing the con-
During primary treatment at a wastewater treatment centrations of constituents that may affect public health
plant, inorganic and organic suspended solids are and/or limiting human contact with reclaimed water.
removed from plant influent by screening and settling.
The decanted effluent from the primary treatment pro- The EPA (2004) recommends that water intended for
cess is then subjected to secondary treatment, which reuse should:
involves biological decomposition of organic material • B
 e treated to achieve biochemical oxygen demand
and settling to further separate water from solids. If a and total suspended solids levels of less than 30 mil-
wastewater treatment plant is not equipped to perform ligrams per liter (mg/l) during secondary or tertiary
advanced treatment, water is disinfected and discharged treatment.
to natural water bodies following secondary treatment.
• R
 eceive additional disinfection by means such as
Advanced treatment or tertiary treatment consists of chlorination or other chemical disinfectants, UV
further removal of suspended and dissolved solids, radiation, ozonation, and membrane processing.
including nutrients, and disinfection. Advanced treat-
ment can include: Biochemical oxygen demand (BOD) is an indicator of
the presence of reactive organic matter in water. Total
• N
 utrient (nitrogen and/or phosphorus) removal by suspended solids (TSS) are measures of the amount of
biological or chemical methods. organic and inorganic particulate matter in water.
• R
 emoval of organics and metals by carbon adsorption In Virginia, water reuse means direct beneficial reuse,
or chemical precipitation. indirect potable reuse, or a controlled use in accordance
• F
 urther removal of suspended and dissolved solids by with the Water Reclamation and Reuse Regulation (9
filtration, coagulation, ion exchange, reverse osmo- VAC 25-740-10 et seq.; available at the Virginia Admin-
sis, and other techniques. istrative Code website at http://leg1.state.va.us/000/
reg/TOC09025.htm, chapter 740).
• R
 emoval of organic chemicals by oxidation with
hydrogen peroxide or ozone. The Virginia Water Reclamation and Reuse Regulations
are designed to protect both water quality and public
Water that has undergone advanced treatment is dis- health while encouraging the use of reclaimed water.
infected prior to being released or reused. Reclaimed The primary determinants of how reclaimed water of
water often requires greater treatment than effluent that varying quality can be used are based on treatment pro-
is discharged to local streams or rivers, because users cesses to which the water has been subjected and on
will typically have more direct contact with undiluted, quantitative chemical, physical, and biological stan-
reclaimed water than with undiluted effluent. dards. Further detail on the water reclamation process
and reclaimed water quality standards can be found at
Why Reuse Water? http://pubs.ext.vt.edu/452/452-014/452-014.html.

The demand for fresh water can potentially exceed sup-

ply during times of even moderate drought. The poten- Reclaimed Water Quality
tial for developing new sources of potable water is Considerations for Irrigation
limited. Conservation measures such as irrigating with Water quality must be considered when using reclaimed
reclaimed water are one way to help ensure existing water for irrigation. The following properties are criti-
water supplies are utilized as efficiently as possible. cal to plant and soil health and environmental quality.

Water Reuse Regulations Salinity Levels

There are no federal regulations governing reclaimed Salinity, or salt concentration, is probably the most
water use, but the Environmental Protection Agency important consideration in determining whether water
(EPA; 2004) has established guidelines to encourage is suitable for reuse (EPA 2004). Water salinity is the
states to develop their own regulations. The primary sum of all elemental ions (e.g., sodium, calcium, chlo-
purpose of federal guidelines and state regulations is ride, boron, sulfate, nitrate) and is usually measured
to protect human health and water quality. To reduce by determining the electrical conductivity (EC; units =

Urban Nutrient Management Handbook 11-5

 Chapter 11. Soil-Water Budgets and Irrigation Sources and Timing

deciSiemens per meter [dS/m]) or total dissolved solids concentrations. Specific toxic concentrations will
(TDS; units = mg/l) concentration of the water. Water vary depending on plant species and type of irrigation
with a TDS concentration of 640 mg/l will typically method used. Levels of boron as low as 1 to 2 mg/l
have an EC of approximately 1 dS/m. in irrigation water can cause leaf burn on ornamental
plants, but turfgrasses can often tolerate levels as high
Most reclaimed water from urban areas is slightly saline
as 10 mg/l (Harivandi 1999). Very salt-sensitive land-
(TDS ≤ 1,280 mg/l or EC ≤ 2 dS/m). High salt concen-
scape plants such as crape myrtle (Lagerstroemia sp.),
trations reduce water uptake in plants by lowering the
azalea (Rhododendron sp.), and Chinese privet (Ligus-
osmotic potential of the soil. For example, residential use
trum sinense) may be damaged by overhead irrigation
of water adds approximately 200 to 400 mg/l dissolved
with reclaimed water containing chloride levels more
salts (Lazarova, Bouwer, and Bahri 2004a). Plants dif-
than 100 mg/l, but most turfgrasses are relatively toler-
fer in their sensitivity to salt levels, so the salinity of the
ant to chloride if they are mowed frequently (Harivandi
particular reclaimed water source should be measured
1999; Crook 2005).
so that appropriate crops and/or application rates can be
selected. Most turfgrasses can tolerate water with 200 to
800 mg/l soluble salts, but salt levels above 2,000 mg/l Nutrient Levels
may be toxic (Harivandi 2004). For further information Reclaimed water typically contains more nitrogen and
on managing turfgrasses when irrigating with saline phosphorus than drinking water. The amount of nitro-
water, see Carrow and Duncan (1998). gen and phosphorus provided by the reclaimed water
can be calculated as the product of the estimated irriga-
Many other crop and landscape plants are more sen-
tion volume and the nitrogen and phosphorus concen-
sitive to high soluble-salt levels than turfgrasses and
tration in the water. To prevent nitrogen and phosphorus
should be managed accordingly. See Wu and Dodge
leaching into groundwater, the Virginia Water Recla-
(2005) for a list of landscape plants with their relative
mation and Reuse Regulation requires that a nutrient
salt tolerance and Maas (1987) for information on salt-
management plan be written for bulk use of reclaimed
tolerant crops.
water not treated to achieve biological nutrient removal
(BNR), which the regulation defines as treatment which
Concentration of Sodium, Chloride, and achieves an annual average of 8.0 mg/l total nitrogen
Boron and 1.0 mg/l total phosphorus. Water that has been sub-
Specific dissolved ions may also affect irrigation water jected to BNR treatment processes contains such low
quality. For example, irrigation water with a high con- concentrations of nitrogen and phosphorus that the
centration of sodium (Na) ions may cause dispersion reclaimed water can be applied at rates sufficient to
of soil aggregates and sealing of soil pores. This is a supply a crop’s water needs without risk of surface or
particular problem in golf course irrigation (Sheikh groundwater contamination.
2004), because soil compaction is already a concern
due to persistent foot and vehicular traffic. The sodium Other Plant Growth and Water Quality
adsorption ratio (SAR), which measures the ratio of Concerns
sodium to other ions, is used to evaluate the potential • H
 igh suspended solids (TSS) concentrations may clog
effect of irrigation water on soil structure. For more irrigation systems and can fill pore spaces near the
information on how to assess and interpret SAR levels, soil surface, resulting in reduced drainage. Accept-
see Harivandi (1999). able TSS levels will vary depending on the type of
High levels of sodium can also be directly toxic to suspended solids and type of irrigation system. Gen-
plants, both through root uptake and accumulation of erally, TSS levels less than 50 to100 mg/l are safe for
plant leaves following sprinkler irrigation. The specific drip irrigation.
concentration of sodium that is considered to be toxic  ree chlorine (Cl2) is necessary for disinfection, but
• F
will vary by plant species and type of irrigation system. can damage plants at high concentrations (> 5 mg/l).
Turfgrasses are generally more tolerant of sodium than Storage for a short time reduces the residual free-
most ornamental plant species. chlorine concentration in water.
Although boron (B) and chlorine (Cl) are neces- • H
 igh or low pH is an indicator of the presence of
sary at low levels for plant growth, dissolved boron phytotoxic ions, and pH should be approximately 6.5
and chloride ions can cause toxicity problems at high to 7.0, if possible.

11-6 Urban Nutrient Management Handbook

 Chapter 11. Soil-Water Budgets and Irrigation Sources and Timing

• H
 igh bicarbonate (> 120 ml) and carbonate (15 mg/l) • The total amount available.
levels can clog sprinklers and cause white lime
• The time of year, when available.
deposits on plant leaves; it may increase soil pH and
decrease permeability. • A
 vailability of water storage facilities for the non-
growing season.
• H
 eavy metals can be a concern in wastewater that has
high industrial input, but such metals (for example, • Delivery rate and type.
cadmium, copper, molybdenum, nickel, and zinc) are
typically strongly bound to the solid fraction, or bio-
solids portion, of the wastewater and are rarely found
Literature Cited
in high enough concentrations to pose a reclaimed Carrow, R. N., and R. R. Duncan. 1998. Salt-Affected
water quality problem. Turfgrass Sites: Assessment and Management.
New York: John Wiley & Sons.
(Harivandi 1999; Landschoot 2007; Lazarova et al.
2004a) Crook, J. 2005. St. Petersburg, Florida, dual water sys-
tem: A case study. In Water Conservation, Reuse,
and Recycling. Proceedings of an Iranian-Ameri-
Application Rates can Workshop. Washington, D.C.: The National
Irrigation rates for reclaimed water are site- and crop- Academies Press.
specific and will depend on the following factors (EPA
2004; Lazarova, Papadopoulous, and Bahari 2004b). Environmental Protection Agency (EPA). 2004. Guide-
lines for Water Reuse. EPA 645-R-04-108. Wash-
1. Seasonal irrigation demands must be determined. ington, D.C.: EPA. www.epa.gov/ORD/NRMRL/
These can be predicted with: pubs/625r04108/625r04108.pdf.
• A
 n evapotranspiration estimate for the particular Harivandi, M. A. 1999. Interpreting Turfgrass Irriga-
crop being grown. tion Water Test Results. Publication 8009. Oakland:
• Determination of the period of plant growth. University of California, Division of Agriculture
and Natural Resources. http://anrcatalog.ucdavis.
• Average annual precipitation data. edu/pdf/8009.pdf.
• D
 ata for soil permeability and water-holding Harivandi, M. A. 2004. Evaluating Recycled Waters
capacity. for Golf Course Irrigation. U.S. Golf Association
Green Section Record 42(6): 25-29. http://turf.lib.
Methods for calculating such irrigation requirements
msu.edu/2000s/2004/041125.pdf.
can be found in the U.S. Department of Agricul-
ture’s (USDA) National Engineering Handbook at Landschoot, P. 2007. Irrigation Water Quality Guide-
http://www.info.usda.gov/CED/ftp/CED/neh-15.htm lines for Turfgrass Sites. Department of Crop
(USDA 2003) and in Reed, Crites, and Middlebrooks and Soil Sciences, Cooperative Extension. State
(1995). Turfgrass irrigation rates in Virginia can also College: Penn State University. http://turfgrass-
be calculated using the website http://www.turf.cses. management.psu.edu/irrigation_water_quality_
vt.edu/Ervin/et_display.html. These calculations are for_turfgrass_sites.cfm.
more complicated for landscape plantings than for
Lazarova, V., H. Bouwer, and A. Bahri. 2004a. Water
agricultural crops or turf because landscape plant-
quality considerations. In Water Reuse for Irriga-
ings consist of many different species with different
tion: Agriculture, Landscapes, and Turf Grass, ed.
requirements.
V. Lazarova and A. Bahri, 31-60. Boca Raton, Fla.:
2. The properties of the specific reclaimed water to be CRC Press.
used, as detailed in the section above, must be taken
Lazarova, V., I. Papadopoulous, and A. Bahri. 2004b.
into account because these may limit the total amount
Code of successful agronomic practices. In Water
of water that can be applied per season.
Reuse for Irrigation: Agriculture, Landscapes, and
3. The availability of the reclaimed water should also Turf Grass, ed. V. Lazarova and A. Bahri, 104-150.
be quantified, including: Boca Raton, Fla.: CRC Press.

Urban Nutrient Management Handbook 11-7

 Chapter 11. Soil-Water Budgets and Irrigation Sources and Timing

Maas, E. V. 1987. Salt tolerance of plants. In Vol. 2 of Virginia Department of Conservation and Recreation.
CRC Handbook of Plant Science in Agriculture, 1993. Nutrient Management Handbook. 2nd ed.
ed. B. R. Christie, 57-75. Boca Raton, Fla.: CRC Richmond: VDCR.
Press.
Wu, L., and L. Dodge. 2005. Landscape Plant Salt
Reed, S. C., R. W. Crites, and E. J. Middlebrooks. 1995. Tolerance Guide for Recycled Water Irrigation.
Natural Systems for Waste Management and Treat- Slosson Research Endowment for Ornamental Hor-
ment. 2nd ed. New York: McGraw-Hill. ticulture, Department of Plant Sciences, University
of California-Davis. http://ucce.ucdavis.edu/files/
Sheikh, B. 2004. Code of practices for landscape and
filelibrary/5505/20091.pdf.
golf course irrigation. In Water Reuse for Irriga-
tion: Agriculture, Landscapes, and Turf Grass, ed.
V. Lazarova and A. Bahri, 152-161. Boca Raton,
Fla.: CRC Press.
U.S. Department of Agriculture (USDA). 2003. Irriga-
tion water requirements. In National Engineering
Handbook, 2-i-2-284. Part 623, Section 15, Chap-
ter 2. Washington, D.C.: USDA Natural Resources
Conservation Service. www.info.usda.gov/CED/
ftp/CED/neh-15.htm.

11-8 Urban Nutrient Management Handbook

Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Chapter 12. Principles of Stormwater Management for

Reducing Nutrients From Urban Landscaped Areas
David Sample, Assistant Professor, Biological Systems Engineering, Virginia Tech
Laurie Fox, Research Associate, Hampton Roads Agricultural Research and Extension Center, Virginia Tech

• T
 ype and condition of soil: Water infiltrates clay soils
Introduction slower than sandy soils.
The objective of this chapter is to provide a summary of
current urban stormwater management issues and prac- • S
 oil saturation level at the time of the precipitation:
tices relevant to the mid-Atlantic region. One of the goals More runoff from pervious areas can occur if soil is
of a nutrient management plan is to reduce nutrient loads already saturated before precipitation.
in stormwater runoff from urban landscaped areas. Nutri- • V
 egetative canopy layers and coverage: Runoff is
ent management efforts have typically addressed agricul- reduced on sites with a higher percentage of vegeta-
tural, industrial, and commercial sites and impervious or tive coverage and multiple canopy layers.
paved surfaces. There appeared to be very little, if any,
overlap with urban stormwater management. • Extent and steepness of slopes.
However, Virginia’s regulatory approach to stormwa- Figure 12.1 describes a simplified hydrologic cycle for
ter management now includes urban stormwater runoff a residential lot. Precipitation, usually in the form of
from both pervious and impervious areas, so many of the rainfall, falls on the land. On pervious areas, infiltration
newer, “greener” stormwater management practices may occurs until soil saturation has been reached. Runoff
become part of the landscape of an average urban site. occurs almost immediately from impervious surfaces
Thus, a background in stormwater quantity and quality and after saturation from pervious land. Living vegeta-
may be beneficial for the nutrient management planner. tion creates water vapor that is released to the atmo-
sphere; this is known as evapotranspiration (ET).
This chapter provides an introduction to stormwater
and discusses aspects related to stormwater quality, Evapotranspiration
with an emphasis on nutrient loading to downstream
receiving waters. The current regulatory approach and Precipitation
available practices for managing urban stormwater run-
off are summarized. A list of practices and an assess-
ment tool to examine the risk of urban water quality
problems from a single site are provided in appendix B
of this chapter. Runoff

Introduction to Stormwater
Management Soil
Infiltration

What Is Stormwater?
Stormwater is a hybrid term used to describe runoff (usu- Water Table
ally from urban areas) caused by precipitation in the form
Rock
of rain, snow, or ice. In urban areas, runoff can occur
from both impervious and pervious areas, although much Figure 12.1. Simplified hydrologic cycle of a residential lot.
more runoff comes from impervious areas.
Factors that affect stormwater runoff: Where Does Stormwater Go?
Figure 12.2 illustrates the water pathways in a typical
• Quantity and intensity of precipitation.
urban system. Potable water is shown entering homes
•A
 mount of impervious surface on the site (rooftops, drive- (blue water system) while wastewater is shown leav-
ways, patios and decks, roadways, parking lots, etc.). ing homes. Wastewater from laundry, bathroom sinks,

Urban Nutrient Management Handbook 12-1

 Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

and showers is often classified as “gray water” and can as a “combined sewer overflow.” The more common
be recycled; however, in most homes, gray water is type of system is a “separate storm sewer system.”
discharged to the wastewater or “black water” system. Here, one pipeline conveys stormwater from storm
Typical stormwater from streets and impervious areas drains directly into receiving waters, which are usually
enters a catch basin and is transported to a storm sewer. smaller streams and/or lakes, wetlands, bays, estuar-
In some cases, stormwater is also classified as a gray ies, or reservoirs. A separate pipeline conveys sanitary
water system. wastewater — household water and waste from toilets,
sinks, and showers — to a wastewater treatment facil-
ity. Wastewater receives treatment and is discharged to
receiving waters as authorized with permit conditions
in the National Pollutant Discharge Elimination Sys-
WATER (Blue water) tem (NPDES). Stormwater discharges from urbanized
areas are also regulated via an NPDES permit; a system
Household Household SEWER of this type is known as a “municipally separate storm
Gray water Black water sewer system,” or MS4.
STORM SEWER
(Gray water)
Figure 12.2. Definitions of urban water systems.
Watersheds
A key concept necessary for understanding how water
Many people who live in urban areas believe that flows to receiving waters is a watershed. A watershed
stormwater flows through storm drains to a treatment is a contiguous portion of land that sheds water into a
facility. This is only the case in a “combined sewer sys- single lowest point called an outlet or pour point. Rid-
tem” (CSS), where one pipeline is used to convey both
gelines or areas of higher elevation separate one water-
stormwater and wastewater (gray and black water).
shed from another.
This type of system is often found in older urban areas.
A major problem of a CSS is overflows of partially Figure 12.3 illustrates a typical watershed. All upstream
treated wastewater that occur when peak runoff exceeds land uses and practices contribute to downstream water
storage capacity in the system. This discharge is known quality. Parks, open spaces, “low-impact development”

Figure 12.3. Watershed model. Green = positive factors; red = negative factors. Source: Potomac Conservancy 2007.

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Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

(LID) areas, riparian buffers, streams, and wetlands con- nature of these sources, they have not previously
nect aquatic and forested ecosystems within the water- been regulated. In order to achieve the goals of the
shed. This connected natural system is also known as CWA, pollution from urban runoff is now becom-
“green” infrastructure. In essence, urban nutrient plan- ing more strictly regulated through the municipally
ners are stewards of the green infrastructure system. separate storm sewer system NPDES stormwater
permits. Other nonpoint source pollution problems
For more information on watersheds, see What is a
have also been addressed through a variety of incen-
Watershed? (Gilland et al. 2009), Virginia Cooperative
tive programs.
Extension publication 426-041, in appendix 12-A of this
chapter or at http://pubs.ext.vt.edu/426/426-041/426-041.
pdf. Stormwater Quantity Issues
Figure 12.4 illustrates one of the most fundamental con-
Stormwater Quantity and Quality Issues cepts in urban stormwater — a hydrograph — which is
a plot of stream discharge over time during a rainfall
In undisturbed areas, stormwater runoff is generally
event. Urban development causes multiple impacts on
not an issue because rainwater is quickly absorbed into
the stormwater hydrograph.
the soils or utilized by vegetation. Water that infiltrates
the soil is either released into the atmosphere by plants 1. The peak runoff rate increases due to lack of
through the evapotranspiration process or percolated infiltration.
down through the soil profile to recharge the ground-
2. Water travel time decreases, resulting in a shortening
water aquifers.
of the hydrograph when compared to predevelop-
During urban development, the land is impacted in two ment hydrology.
ways:
3. After the storm event is over, base flow does not
1. During site preparation, when vegetation is stripped recover when comparing postdevelopment with pre-
away leaving exposed soils that easily erode during development curves. This is due to the lack of infil-
rainfall events, causing an increase in sediment load- tration and recharge from impervious areas.
ing and downstream deposition. Sediment- and ero-
Traditional stormwater management functions by pro-
sion-control practices and products are used at this
viding a facility with additional storage volume that
stage of development.
slowly releases water at the predevelopment rate of dis-
2. During construction, as impervious surfaces are cre- charge. However, the volume of this discharge is greater
ated (roofs and paved surfaces), infiltration is reduced than before development. This is shown as the dotted
and runoff is increased. Best management practices green line in figure 12.4. The increased stormwater vol-
(BMPs) are used at this stage of development to off- ume causes an increase in sheer stress as it reaches a
set the increased runoff. Because runoff is the pri- stream, which then causes erosion and increased trans-
mary transport mechanism for pollutants including port capacity for pollutants. Low-impact development
sediment and nutrients, these pollutants will increase attempts to replicate the predevelopment hydrograph
with the runoff increase if nothing is done to prevent by increasing infiltration volume. A perfect LID system
it. would therefore be very close to the blue line on figure
12.4 or the predevelopment hydrograph.
Both point and nonpoint source pollution are regulated
under the federal Clean Water Act (CWA).
• “Point sources” may be classified as publicly owned
treatment works, privately owned treatment facili-
ties, industrial discharges, and sometimes, agricul-
tural operations. Point sources are regulated through
the National Pollutant Discharge Elimination System
permitting program.
• “Nonpoint sources” consist primarily of runoff from
urban, suburban, and developing areas and some agri- Figure 12.4. A typical urban hydrograph.
culture sites. Because of the numerous and diffuse

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Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Figure 12.5 illustrates the net impact of these changes Stormwater Quality Issues
across an annual hydrologic cycle in Virginia. The hor-
izontal portion shows the continuum of urbanization Higher stream flows cause increased stream erosion
from left to right, with natural groundcover on the left, and higher loads of sediment, nutrients, and other pol-
moving through suburban, then urban development to lutants in downstream receiving waters. The pollutants
75 to 100 percent imperviousness on the right. The top are present due to practices on the land but are carried
part of the figure shows the annual change in the typi- by storm runoff and adversely impact downstream
cal year’s water budget. Significant changes occur with receiving waters. When receiving waters deteriorate to
the point of not meeting their designated use, they are
recharge decreasing from 11 to 2 inches and runoff
listed as “impaired.” A current map of impaired streams
increasing from 4 to 23 inches. A moderate decrease in
for Virginia is provided in figure 12.7.
ET from 17 to 13 inches occurs.
For each of these impacted streams, the Virginia
Figure 12.6 illustrates the subsequent geomorphic
Department of Environmental Quality (VDEQ) has or
effects of urbanization on a receiving stream. A con-
is establishing a Total Maximum Daily Load (TMDL)
tinuum of urbanization is shown from left to right. As
of the identified pollutant to the receiving stream. Once
development increases, significant changes occur in
a TMDL has been established, the VDEQ develops an
stormwater runoff peak flows and frequencies. The
allocation amount for each of the identified sources for
resultant stream shape changes are also shown. Urban
the pollutant in the upstream watershed. VDEQ then
streams are subjected to more frequent and increased
revises the surface water discharge permits from identi-
peak flows and have much higher sheer stresses during
fied point sources at the time of permit renewal. Then,
bankfull events. This results in increased erosion of the
the Virginia Department of Conservation and Recre-
channel. Also, urban streams tend to dry out due to the
ation (VDCR) develops an implementation plan for
lack of recharge, resulting in a loss of stream length.
how these allocations will be achieved for nonpoint
The urban stream widens, deepens, and dries out, seri-
sources, including stormwater discharges.
ously impacting or destroying aquatic ecosystems and
associated green infrastructure.

Figure 12.5. Virginia average annual water budget with urbanization. Source: Potomac Conservancy 2008.

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Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Figure 12.6. Urbanization and its effect on stream geomorphology. Source: Ministry of Water, Land and Air Protection, Copyright 2002
Province of British Columbia. All rights reserved. Reprinted
with permission of the Province of British Columbia.

Figure 12.7. Currently impaired water bodies, Virginia. Source: Virginia Department of Environmental Quality 2008.

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 Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Regional water quality issues can also significantly Nitrogen and phosphorus are the primary nutrients of
affect local water quality programs. The Chesapeake concern. As a benchmark, for illustrative purposes,
Bay receives runoff from most of Virginia, including existing loadings from various land uses were com-
the watersheds associated with the Shenandoah, Poto- puted from the Chesapeake Bay Nutrient and Sedi-
mac, Rappahannock, James, and York rivers. These ment Reduction Tributary Strategies (Commonwealth
watersheds are shown in figure 12.7. The bay also of Virginia 2005) and disaggregated for Virginia. Fig-
receives runoff from the states of Maryland, Pennsyl- ures 12.11 and 12.12 depict nitrogen and phosphorus
vania, Delaware, and New York, creating a watershed loadings, respectively, from different land uses, with
of 64,000 square miles. urban areas separated into impervious and pervious
(or landscaped) areas. These figures show that while
An assessment of the health of tributary streams to the
urban impervious areas are the source of increased
bay is provided in figure 12.8. Once a rich and productive
flows, urban pervious areas may be a source for excess
estuary, the Chesapeake Bay has declined due to pollu-
nutrients, on par with loadings from agricultural areas.
tion generated from urban and industrial development and
Thus, nutrient management in the landscape should
agricultural practices. Within the bay, sediment, nutrients,
reduce loadings from urban areas and eventual pollu-
and other pollutants cause a variety of problems such
tion to receiving waters and the Chesapeake Bay.
as excess algae growth, reduced dissolved oxygen lev-
els, and decreased water clarity. These conditions cause
changes in aquatic organisms, often decimating desirable
species and creating dead zones in the bay (figure 12.9). A
recent assessment of water quality and ecosystem health
of the bay estuary is provided in figure 12.10.

Figure 12.9. Chesapeake Bay dead zones, August 2005. Figure 12.10. Chesapeake Bay Report Card 2008: Bay Health Index.
Source: Chesapeake Bay Program 2005. Source: University of Maryland Center for Environmental Science
(UMCES) and EcoCheck 2008.

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 Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Figure 12.8. Chesapeake Bay Report Card 2008: Tributary Streams and Watershed Health.
Source: University of Maryland Center for Environmental Science (UMCES) and EcoCheck 2008.

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Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Managing Urban Stormwater

The Virginia Stormwater Management Program
(VSMP) is the regulatory program by which the state
and local governments control nonpoint source pol-
lution stemming from urban development. In 2009,
in response to the issue of adverse impacts to receiv-
ing waters from urban runoff, the VDCR revised the
VSMP regulatory program. The program focus shifted
from mitigating peak runoff during urban development
to managing stormwater volume and water quality.
A new process known as the Virginia Runoff Reduc-
tion Method (VRRM) was developed by the Center
for Watershed Protection (2009) in collaboration with
VDCR. The intent of the VRRM is to fundamentally
alter the land design process used in urban develop-
ment through a three-tiered strategy that includes:
Environmental site design (ESD) practices. These
are intended to minimize impervious surface area and
maximize conservation practices. ESD practices can be
Figure 12.11. Average annual nitrogen washoff loadings for Virginia
employed to reduce runoff by restoring soil infiltrative
land uses. Source: Commonwealth of Virginia 2005. capacities, restoring and/or preserving riparian buffers,
and providing conservation subdivisions to protect
critical habitats. The net impact from a stormwater per-
spective is that impervious surfaces and urban runoff
are minimized.
Runoff reduction (RR) or volume control. This consists
of implementing a variety of low-impact, density-based
source controls on a site. Runoff reduction practices seek
to reduce runoff prior to flowing offsite through a variety
of mechanisms, predominately infiltration.
Pollutant removal (PR). This means using tradi-
tional, larger-scale best management practices to treat
the reduced amount of runoff to remove nutrients and
sediments.
Figure 12.13 illustrates the use of Virginia Runoff
Reduction Method strategies in urban design, with the
goal of increasing nutrient removal performance of a
site after development.
Table 12.1 in appendix B lists the VDCR-approved
BMPs. Each practice includes a brief description, dia-
gram, photograph, and performance data, as well as
Figure 12.12. Average annual phosphorus washoff loadings for Virginia
land uses. Source: Commonwealth of Virginia 2005.
their characterization as an ESD, RR, and/or PR device.
The BMPs listed in this table are compiled from several
sources, predominately the VDCR specifications from
the Virginia Stormwater BMP Clearinghouse website
(VDCR 2011), and are for public use. Most of these
BMPs are intended for use in landscaped areas, so
some familiarity with their functions may be beneficial.

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 Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Figure 12.13. Virginia’s runoff reduction methodology. Source: Center for Watershed Protection 2008.

Proprietary BMPs consist of systems developed by spe- practices that can be beneficial, and present a risk-based
cific manufacturers that utilize a variety of treatment assessment tool for an owner or contractor to evaluate
technologies to remove pollutants from urban runoff, practices at a single lot scale. This information is based
usually at a smaller scale than public-use BMPs. Propri- on Shelton and Feehan (2008), Thacker (2009), and the
etary BMPs should be examined individually because Washington Environmental Council (2009).
limited unbiased information is available.
Source Control or Reducing Pollutants
Managing Stormwater on a in Runoff
Residential Lot One of the most effective means of reducing pollutants
Until recently, stormwater management focused exclu- in runoff is source control. Addressing the following
sively on management of impervious areas. As the questions and issues may assist in the characterization
understanding of nonpoint source pollution from urban of the relative risk a single site poses on downstream
areas has improved, it has become apparent that a sub- urban water quality issues.
stantial portion of the pollutants may come from per-
vious or landscaped areas. So, programs have shifted Where Does Stormwater Go?
toward management of both pervious and impervious In order to assess a site, develop a site plan using the
urban areas at both watershed and single-lot scales. following steps:
Many practices are available to reduce nonpoint source 1. Measure lot boundaries and buildings or obtain a
pollution at the residential level. Water and nutrient copy of a recent survey of the site. An example of
use in both turf and ornamental bed areas should be
a simple site plan without topography is provided in
addressed. These practices require participation from
figure 12.14.
the homeowner, which can sometimes be challeng-
ing. The following sections provide an overview of the 2. Include topographical information if it is available,
steps to characterize and reduce runoff and pollutants but a visual survey of the high and low spots on the
at a residential scale, identify landscape management site can suffice.

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 Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Keeping Yard and Garden Wastes

Disposing of leaves, grass, branches, and other yard
debris in ditches and storm drains is a common prac-
tice that clogs drainage systems, causes flooding, and
increases organic loading downstream. Previously, it
was explained that for the most part, urban runoff is
discharged untreated to receiving waters. As the organic
matter from yard debris decomposes in streams, lakes,
and estuaries, it depletes oxygen in water that can cause
fish kills. Excess nutrients cause algal blooms and
aquatic weed growth that lead to an imbalance in the
ecosystem. To avoid these problems:
• S
 weep/collect yard debris off streets, sidewalks, and
driveways.
• D
 ispose of debris in a compost pile or through a curb-
side pickup service.
• U
 se a mulching mower to return grass clippings and
their nutrients to the lawn.
• Use compost instead of fertilizer.

Handling Pesticides Safely

A wide variety of pesticides are available for use in
Figure 12.14. Site planning. Source: Shelton and Feehan 2008. landscapes.

3. Identify impervious areas such as buildings, parking • K

 eep an updated inventory list of the products stored
areas, sidewalks, patios, pools, decks, and driveways on site.
and how they drain (or if a drain is present). • Store products in a dry, locked place.
4. Show areas of steep slopes. • A
 lways follow the label instructions. The label is the
law!
5. Identify soil types based on soil test information or
local soil maps. • H
 ire certified pesticide applicators when necessary,
especially when applying products near bodies of
6. Mark and characterize landscaped and vegetated water.
areas.
• A
 void applications before a rain or irrigation cycle to
7. Identify sensitive areas such as creeks, ditches, lakes, prevent runoff contamination.
wetlands, storm drains, buffers, etc. Usually these
would receive runoff from the site. • I mmediately clean up any spills or residues on imper-
vious surfaces and dispose of them properly.
8. Mark stormwater runoff paths and flow directions.
• P
 urchase only what is needed to avoid storing large
9. Identify where the runoff leaves the site to adjacent amounts.
receiving waters, storm drains, and neighboring
• T
 reat only when necessary with the least-toxic
sites.
product.
It is always a good practice to reduce runoff, but it can • C
 onsider alternative management practices to
also be a good social practice when water flows onto pesticides.
neighboring sites.
• P
 romote beneficial insects and natural predators in
the landscape to minimize pesticide applications.

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Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Fertilizers Animal Waste Disposal

An example of nutrient contamination can sometimes Domestic animals and pets provide companionship and
be seen in properties adjacent to stormwater ponds. recreation. However, animals produce waste that can
Excess or misapplied fertilizer runs off before plants contain high concentrations of nitrogen, phosphorus,
can absorb it and causes algae blooms and aquatic weed and harmful pathogens. When this waste is exposed to
growth. These plants typically have short life cycles, rainfall, it can easily contaminate runoff and potentially
and when they die and decay, they deplete oxygen cause human health hazards for recreational and drink-
needed for aquatic organisms and sometimes release ing waters downstream. The economic impact on a com-
substances that are toxic to aquatic organisms. Respon- munity is significant when drinking water resources are
sible fertilizer use can avoid many of these problems. compromised or recreational activities involving water
are banned and beaches closed. Fortunately, this issue is
• See pesticide list above.
easily resolved through good housekeeping practices.
• T
 est soil to determine the fertilizer need (every three
• P
 ick up pet waste and dispose of it properly. Many
years is recommended).
communities have “scoop the poop” programs.
• U
 se a slow-release fertilizer instead of multiple appli-
cations of a quick-release product. • C
 ompost animal waste. Compost systems are good
for treating waste from many animals or from larger
• A
 pply the total amount recommended in a split animals such as horses.
application.
• A
 pply at the correct time for the plants to use it most Salt or Other De-Icing Products
efficiently. In order to cope with winter weather, salt and de-icing
• Don’t use a complete fertilizer if it isn’t necessary. products are often used. These can be toxic to aquatic
organisms and plants. Salts can be corrosive to water
• C
 onsider an organic product instead of a synthetic pumps and pipes and build up in receiving waters.
product. Because most salts are untreated except for dilution,
• R
 emove fertilizer from impervious surfaces such as they can cause issues in drinking water supplies down-
driveways and sidewalks. stream. Simple practices can be used to minimize these
impacts.
• C
 ontact the local cooperative Extension office for
information on plants, environmental conditions, and • M
 anually clear snow from impervious surfaces and
educational programs. drains.
• Use alternative products such as sand or kitty litter.
Are Car and Truck Wastes Being Carried
Away by Stormwater? Landscape Site Management for
Fluids and residues from our vehicles can be significant Control of Runoff
pollutants. Used oil from a single oil change can contami-
nate a large quantity of runoff. Antifreeze is toxic to aquatic There are many practices that can be used in residential
organisms and can shut down the kidneys of mammals. landscapes to reduce pollutants in runoff. The follow-
Brake dust and tire bits contain toxic metals. Soaps used ing questions are designed to assist in assessing their
in car washing contain surfactants that threaten aquatic need and the relative risk of a site for urban water qual-
habitat. These issues are easily addressed. ity issues from erosion and other pollutants.

• Maintain vehicles to prevent leaks. Are There Areas of Bare Soil?

• Immediately and thoroughly clean up spills. Soil left exposed without vegetation easily erodes.
When erosion occurs, sediment is transported down-
• W
 ash vehicles on the lawn or at a car wash with envi-
stream through runoff. Excess sediment clogs storm
ronmentally friendly products.
drains and reduces channel conveyance capacity, caus-
• C
 ollect spent fluids, waste oils, solvents, etc., and dis- ing flooding. It also buries and destroys downstream
pose of properly. Many communities have household underwater habitats, depriving fish of their food sources
hazardous waste collection days for these materials. and living areas. These issues can be easily avoided.

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Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

• O
 verseed bare spots. Aeration may be necessary on flows increase, along with the potential for downstream
compacted areas. degradation.
• Use groundcovers if turf will not grow. • D
 isconnect gutters and drain them onto a vegetated area
or into a rain barrel or rain garden (appendix B, table
• U
 se mulch if vegetation will not grow or is not
12.1, BMP Nos. 1, 6, and 9). The rain barrel can provide
desired.
a supplemental irrigation source during dry periods.
• V
 egetative buffers can be used along sloped or down-
• I nstall a green roof (appendix B, table 12.1, BMP No.
hill portions of the site (appendix 12-B, table 12.1,
5). Most buildings cannot be retrofitted for a green
BMP No. 2).
roof without structural improvements, so this prac-
tice applies mainly to additions or new buildings.
Can the Landscape Layout Be Changed to
Reduce Runoff? Can Paved Surfaces Be Reduced?
Reference the site analysis (figure 12.14). Determine On most sites, the controllable impervious areas include
if there are problem areas where the runoff is too con- walks, porches, patios, decks, and driveways.
centrated (i.e., many arrows coming together). There
are many practices that can be used to slow down and • Reduce the total square footage of the impervious area.
spread out the runoff.
• C
 onsider a driveway that uses pavement for the tire
• I mprove the soil to improve water infiltration (appen- tracks only, with turf or gravel in between.
dix 12-B, table 12.1, BMP No. 4).
• U
 se permeable pavement and/or paver systems
• T
 errace slopes and/or add swales (appendix 12-B, (appendix B, table 12.1, BMP No. 7). There are many
table 12.1, BMP Nos. 3, 10, and 11). new products available that allow water infiltration
through the pavement or joints.
• I ncrease vegetation and/or canopy layers. Add
buffers. • C
 onsider using steppingstones or mulched or veg-
etated paths or walks. Some groundcovers can toler-
• I ncorporate a rain garden (appendix 12-B, table 12.1,
ate foot traffic.
BMP No. 9).
• U
 se wider seams or joints on decks and patios for
Adding a rain garden is an excellent BMP that can
better water infiltration.
reduce runoff flows, treat contaminants in runoff, and
encourage infiltration. Rain garden resources include:
Self-Assessment Tool
• R
 ain Gardens Technical Guide: A Landscape Tool to
Appendix 12-B, table 12.2 is a self-assessment tool con-
Improve Water Quality, Virginia Department of For-
structed by Shelton and Feehan (2008) that is designed
estry. www.dof.virginia.gov/mgt/resources/pub-Rain-
to evaluate a single site and identify water quality con-
Garden-Tech-Guide_2008-05.pdf.
cerns for that site. The tool analyzes the relative safety
• R
 ain garden design templates, The Low Impact of stormwater and landscape management practices
Development Center. www.lowimpactdevelopment. using risk scoring and assists the user in determining
org/raingarden_design/templates.htm. which practices are safe and which need modification.
Choose the description that best characterizes the site.
• U
 rban Water Quality Management: Rain Garden Plants,
Each choice has an associated risk level and corre-
Virginia Cooperative Extension publication 426-043.
sponding score according to the following formula:
www.pubs.ext.vt.edu/426/426-043/426-043.pdf.
• Low risk (1): Ideal, but might not always be practical.
Does Roof Water Flow Onto Pavement or • M
 oderate-low risk (2): Provides reasonable water
Landscaped Areas? quality protection.
The impact of a roof on the drainage of a site cannot be
• H
 igh-moderate risk (3): Does not provide adequate
overstated. In many cases, roofs provide the majority
water quality protection.
of impervious areas. When roofs are directly connected
via gutters and downspouts to pavement, runoff peak • High risk (4): Poses a serious danger to water quality.

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Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

The lower the individual and total scores, the better. Sample, D. 2009. Stormwater Management Research:
Higher individual scores and a higher total score suggest Assessing Improvements in Design and Operation
that the site could be improved relative to stormwater on Performance. Virginia Tech College of Agricul-
management and the risk the site poses to downstream ture and Life Sciences, Approved Hatch Proposal
contamination. 200-2015.
Shelton, D. P., and K. A. Feehan. 2008. Stormwater
Acknowledgements Management on Residential Lots. University of
Figures 12.1, 12.2, 12.3, and 12.5 were constructed Nebraska-Lincoln Extension Publication EC707.
using symbols courtesy of the Integration and Smith, D. R. 2006. Permeable Interlocking Concrete
Application Network, University of Maryland Cen- Pavement: Selection, Design, Construction, Main-
ter for Environmental Science (http://ian.umces. tenance. 3rd ed. Herndon, Va.: Interlocking Con-
edu/symbols/). crete Pavement Institute.
Thacker, P. 2009. Stormwater Management. Training
Literature Cited session for Prince William County, Va.
Center for Watershed Protection. 2008. The Runoff
University of Maryland Center for Environmental
Reduction Method. Technical Memorandum. www.
Science (UMCES), Integration and Application
vwrrc.vt.edu/swc/documents/pdf/TechnicalMemo.
Network, and EcoCheck. 2008. Chesapeake Bay
pdf.
Report Card 2008. (EcoCheck is a partnership
Chesapeake Bay Program. 2005. Map: Chesapeake between UMCES and the National Oceanographic
Bay Record Dead Zone, August 2005. and Atmospheric Administration.) http://ian.umces.
www.chesapeakebay.net edu/pdfs/ecocheck_newsletter_209.pdf.
Christian, A. H., and G. K. Evanylo. 2009. Compost: Virginia Department of Conservation and Recreation
What Is It and What’s It to You. Virginia Coopera- (VDCR) and Virginia Water Resources Research
tive Extension Publication 452-231. http://pubs. Center (VWRRC). 2011. Virginia Approved Storm-
ext.vt.edu/452/452-231/452-231.html. water BMP Standards and Specifications. Available
at the Virginia Stormwater BMP Clearinghouse
Commonwealth of Virginia. Department of Conserva-
Website. www.vwrrc.vt.edu/swc.
tion and Recreation. 2005. Chesapeake Bay Nutri-
ent and Sediment Reduction Tributary Strategy for Virginia Department of Conservation and Recreation
the Shenandoah and Potomac River Basins. www. (VDCR). 2010. Stormwater Design Specifications.
dcr.virginia.gov/soil_and_water/documents/tssh- Version 1.9.
enpoall032805.pdf.
Virginia Department of Environmental Quality (VDEQ).
Gilland, T., L. Fox, M. Andruczyk, S. French, and L. 2008. Final 2008 305(b)/303(d) Water Quality
Swanson. 2009. What Is a Watershed? Virginia Assessment Integrated Report.
Cooperative Extension Publication 426-141.
Washington Environmental Council. 2009. Stormwa-
http://pubs.ext.vt.edu/426/426-041/426-041.pdf.
ter Management: One Backyard at a Time. Video
Potomac Conservancy. 2007. State of the Nation’s Workshop, Sept. 15, 2009. www.wecprotects.org.
River: Potomac Watershed 2007. From U.S. Envi-
ronmental Protection Agency, Office of Wetlands,
Oceans and Watersheds. Adapted from: Pollution
Probe. 2004. The Source Water Protection Primer.
www.potomac.org/site/state-of-the-nations-river/.
Potomac Conservancy. 2008. State of the Nation’s
River 2008: Potomac Stormwater Runoff. From:
U.S. Environmental Protection Agency, Office of
Wetlands, Oceans and Watersheds. www.potomac.
org/site/state-of-the-nations-river-2008.

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12-14 Urban Nutrient Management Handbook

Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Appendix 12-A
Original publication available at: http://pubs.ext.vt.edu/426/426-041/426-041.html

publication 426-041

Urban Water-Quality Management

What Is a Watershed?
Traci Gilland, Extension Agent, Portsmouth
Laurie Fox, Horticulture Associate, Hampton Roads Agricultural Research and Extension Center
Mike Andruczyk, Extension Agent, Chesapeake
Susan French, Extension Agent, Virginia Beach
Lynnette Swanson, Extension Agent, Norfolk

A Watershed Defined
A watershed is an area of land that drains to a lake, river, wet-
land, or other waterway. When precipitation occurs, water
travels over forest, agricultural, or urban/suburban land areas
before entering a waterway. Water can also travel into under-
ground aquifers on its way to larger bodies of water. Together,
land and water make up a watershed system.

Watersheds can be any size, but generally, the larger the body
of water the larger the watershed. For example, the Chesapeake
Bay Watershed covers 64,000 square miles and drains from
six states, including Virginia. Smaller, local watersheds drain
much smaller areas. Even a local stream has a watershed as-
sociated with it, perhaps only a few acres in size.

Virginia Watersheds There are nine major watersheds in Virginia. Some flow to the
Chesapeake Bay. Some go directly into the Atlantic Ocean. Others
No matter where you live in Virginia you are part flow to the Albemarle Sound in North Carolina. Some rivers in Virginia
of one the state’s nine major watersheds. You may even flow to the Mississippi River and then to the Gulf of Mexico.
1. Shenandoah-Potomac
have even noticed signs identifying the boundar-
2. Rappahannock
ies of each watershed while traveling through the 3. York
state. 4. James
5. Eastern Shore of the
Virginia’s watersheds ultimately drain into three Chesapeake Bay and
main bodies of water. Nearly two-thirds of Virginia coastal rivers
drains into the Chesapeake Bay. Southeastern and 6. Chowan
7. Roanoke
south-central Virginia drain into the Albemarle
8. New
Sound in North Carolina. Rivers in Southwest 9. Tennessee
Virginia flow to the Mississippi River and on to -Big Sandy
the Gulf of Mexico.

www.ext.vt.edu
Produced by Communications and Marketing, College of Agriculture and Life Sciences,
Virginia Polytechnic Institute and State University, 2009
Virginia Cooperative Extension programs and employment are open to all, regardless of race, color, national origin, sex, religion,
age, disability, political beliefs, sexual orientation, or marital or family status. An equal opportunity/affirmative action employer.
Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University,
and the U.S. Department of Agriculture cooperating. Rick D. Rudd, Interim Director, Virginia Cooperative Extension, Virginia
Tech, Blacksburg; Alma C. Hobbs, Administrator, 1890 Extension Program, Virginia State, Petersburg.

Urban Nutrient Management Handbook 12-15

Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Why Are Watersheds Human Impacts on

Important? Watersheds
Healthy watersheds are a vital component of a healthy Nearly all watersheds have something in common; they
environment. Watersheds act as a filter for runoff are populated by humans. With humans comes devel-
that occurs from precipitation and snowmelt, provid- opment and, unfortunately, pollution. As development
ing clean water for drinking, irrigation, and industry. encroaches on natural areas, the filtering system of the
Recreation and leisure are important components of watershed is replaced by impervious surfaces such as
watersheds, with many Virginians taking advantage concrete and asphalt. Water runs off these surfaces in
of boating, fishing, and swimming in our waterways. sheets, carrying with it a variety of pollutants. This
Watersheds also support a variety of plant and wildlife type of pollution is called non-point source pollution
communities. because it comes from multiple sources over a large
area. Anything on the impervious surface, such as
Scientists and community leaders recognize the best automobile fluids, litter, leaves, debris, sediments, or
way to protect our water resources is to understand and animal feces is swept away by the run-off. It is carried
manage them on a watershed basis. Human activities directly into a waterway by storm drains and culverts.
as well as natural events that occur in a watershed can These non-point source pollutants can have devastat-
affect water quality throughout the entire system. ing effects on the health of Virginia waterways.

Unhealthy System
Healthy System Nutrients Toxicants
Sediments

Water Column Habitat

• Clear water
• Algal growth balance
• Oxygen levels adequate
• Finfish abundant Algal Blooms

Human Health
Low Disolved Concerns
Oxygen
Food Chain
Effects
Poor Water Clarity

Aquatic Plant Habitat

Flourishes Aquatic Plant
Growth Inhibited

Fish, Shellfish, and other

Organisims Stressed

Bottom Habitat
Healthy

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Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Fertilizer runoff from lawns and landscapes is an- For more details about watersheds and what you can
other part of non-point source pollution. The overuse to do to help, please refer to the following agencies.
and incorrect use of fertilizers account for this type of
pollution. The adage “if a little is good, then more is • Virginia Department of Conservation and
better” is not only false, but has serious detrimental Recreation
effects on water quality. Excess fertilizer in the lawn http://www.dcr.state.va.us/sw/index.htm
is easily washed off by rain or irrigation. It travels into • Alliance for the Chesapeake Bay
waterways, causing algal blooms that block sunlight, http://www.alliancechesbay.org
smother aquatic plants, and increase bacterial decay.
As a result, dissolved oxygen is decreased and the • Chesapeake Bay Program
water is unable to provide a healthy environment for http://www.chesapeakebay.net/
aquatic life.
Virginia Cooperative Extension offers a wide variety
of publications regarding proper fertilizer and pesticide
How can you help? use, plant selection and buffers. Please see our website,
http://www.ext.vt.edu, or contact your a local Extension
If everyone in Virginia would do a few simple things, agent for more details.
we can greatly improve how our watersheds function
in protecting water quality. Below are just a few ways
you can help. Editorial Contributors
Barry Fox, Extension Specialist, Virginia State
• Reduce your daily water usage. University
• Never dispose of anything by dumping into a storm Leanne Dubois, Extension Agent, James City
drain. Storm drains lead directly to waterways. Peter Warren, Extension Agent, Albemarle County
• Use the correct amounts of fertilizer at the correct
time for your grass species.
• Reduce your use of pesticides and fertilizers by re-
placing grass with hardy trees and shrubs.
• Follow label directions carefully on all chemicals
and use them only when necessary.
• Clean up after your pets.
• Maintain home septic systems.
• Create buffers along waterways on your property.
• Know your watershed address.
• Volunteer for clean up, restoration, and conserva-
tion programs.
• Promote sustainable land stewardship throughout
your community.

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Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

12-18 Urban Nutrient Management Handbook

Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Appendix 12-B
Table 12.1. Descriptions of best management practices (BMPs).
Rose ranges reflect current observations in the literature, not VDCR specifications and design practices.
Source: VDCR 2011. Efficiency ranges provided in Center for Watershed Protection, 2008. The Runoff Reduction Manual, Technical Memorandum.

# Name/Performance Description Diagram or Photograph Diagram or Photograph

Treatment 
Type

1 Impervious Surface Disconnection This is one of the simplest means of reducing 
urban runoff from residential lots, and involves 
100% taking rooftop runoff and redirecting it from 
impervious areas.  The redirected runoff must 
be infiltrated, filtered, treated, or reused, prior 
80%
to discharge into a storm drain system.  If 
sufficient land area with good soils is available, 
Runoff Reduction

60% simply disconnecting rooftop drains, and 
allowing them to sheet flow across the lot or 
40% directing flow to a grass channel or other BMP 
is acceptable.  In other cases, with limited 
space, rooftop disconnection is combined with 
20% soil restoration, bioretention, a cistern, or a 
tree planter.  
0%
P N
Source: VDCR Stormwater Design Specification Number 1: Rooftop 
(Impervious Surface) Disconnection Version 1.9, 2011.

2 Sheetflow to Open Space Vegetated filter strips, also known as filter 
strips, grassed filters, and grass strips) are 
densely vegetated, uniformly graded areas that 
intercept sheet runoff from impervious 
surfaces.  Turf grass is the most common 
100% planting, however, vegetation can also consist 
of meadows or small forest plantings.  A filter 
strip can accept runoff from small contributing 
80%
Runoff Reduction

impervious areas; larger areas with higher 
flows are accommodated by the use of a gravel 
60% trench or other level spreader. Filter strips trap 
sediments very effectively, have some modest 
40% runoff reduction potential from infiltration, and 
reduce the velocity of the runoff by increasing 
surface roughness.  Filter strips are frequently 
20% used  to pretreat small areas, prior to discharge 
to a larger BMP such as a filters or bioretention 
0% system. 
P N Source: VDCR Stormwater Design Specification Number 2:  Sheet Flow to  Source:  US EPA, 2009.  Chesapeake Bay Program, 
Filter Strip or Conserved Open Space, Version 1.9, 2011. http://www.chesapeakebay.net/photosearch.aspx?menuitem=14870.

3 Grass Channels Grass channels are open channels with grass 
sides that can carry runoff  with modest 
velocities. Grass channels provide treatment 
100% via filtering through vegetation and are 
Runoff Reduction//Pollutant Removal

considered part of a conveyance system.  
80% When compared with curb and gutter, inlets 
and pipes, grass channels provide a modest 
amount of runoff reduction and pollutant 
60%
removal, the extent of which varies depending 
on the underlying soil characteristics.  Unlike 
th d l i il h t i ti U lik
40% dry swales, they do not include a soil media 
and/or specific storage volume.  When used as 
20% an alternative to traditional systems such as 
stormwater pipes and curb and gutter, a grass 
swales can provide significant environmental 
0%
benefits.
P N Source: VDCR Stormwater Design Specification Number 3: Grass Channels, 
Source: Fairfax County Department of Public Works and Environmental 
Version 1.9, 2011.
Services, 2011.

4 Soil Restoration/Soil Amendments Soil restoration is the technique of using 
compost to amend soils to improve their 
100%
Environmental Site Design/Runoff Reduction

porosity and improve their nutrient retention.  
Mature compost contains a mixture of complex 
80% organic matter that reduces soil compaction 
and enhances soil structure, infiltration, 
rooting and water holding capacity.  Normal 
60%
calculations for lawn areas that undergo soil 
restoration and do not receive runoff from 
40% other areas can absorb as much as 75% of 
runoff.  Compost‐amended soils may be used 
20% in conjunction with impervious surface 
disconnection, grass channels, and filter strips.  

0%
P N
Source: VDCR Stormwater Design Specification Number 4: Soil Compost  Source: Christian, AH., G.K. Evanylo, R. Green, (2009) Compost: What Is It 
Amendment, Version 1.9, 2011. and What's It To You, VCE Publication 452‐231.

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Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Table 12.1. Descriptions of best management practices (BMPs). (cont.)

# Name/Performance Description Diagram or Photograph Diagram or Photograph
Treatment 
Type

5 Vegetated Roofs Vegetated roofs, which are also known as 
green roofs, are roofs that are designed and 
constructed to support living vegetation.  There 
are two main types of vegetated roofs, 
100%
extensive, and intensive.  Both roofs add 
weight to the structural load.  Intensive green 
80% roofs have thicker media and can support long 
rooted shrubs and trees.  The increased weight 
Runoff Reduction

60% and associated structural load of the media can 
be high.  The most common vegetated roof, 
the extensive roof, has a shallower media and 
40% smaller plantings, and is typically constructed 
of replaceable modular forms.  For extensive 
20% roofs, rainfall is intercepted by the plantings, 
infiltrated into the media, and used by plants.  
Extensive vegetated roofs typically provide 0.5 
0%
inches of storage.
P N

Source: VDCR Stormwater Design Specification Number 5: Vegetated Roof,  Source: Fairfax County Government Center, 2010, photo taken by D. 

Version 1.9, 2011. Sample.

6 Rainwater Harvesting                                      Rainwater harvesting systems, also known as 
Based mainly upon its Runoff Reduction  rain barrels and/or cisterns intercept, divert, 
credits, receives a 40% of the credited  store and release rainfall for later use as a 
volume (must determine credited  water supply.  These systems may also provide 
volume through simulation). pollution reduction through stormwater 
volume control.  Most systems are covered to 
avoid contamination and eliminate evaporative 
losses.  In a typical system, rainfall falls on the 
roof, runs off, is captured in gutters, and flows 
Runoff Reduction

to a simple device which eliminates the first 
flush containing organic materials that washes 
off the roof.  Once the first flush volume is 
exceeded, the water enters a storage tank 
located either above or below ground.  Once 
the tank's capacity is exceeded, water is 
diverted through an overflow near the top of 
the tank.  Because a tank may remain full 
between rain events, water quality benefits 
may be reduced due to the potential for 
spillage.
Source: Sample, D. (2009) Stormwater Management Research, Assessing 
Improvements in Design and Operation on Performance, approved VT‐CALS  Source: Wetland Studies and Solutions, Inc., Gainesville, VA, 2009., 
Hatch Proposal 2010‐2015. photo taken by D. Sample.

7 Permeable Pavement Permeable pavement is a modified form of 
asphalt or concrete whose top layer is pervious 
to water due to voids within the mix design.  
Permeable or porous pavements include 
100% pervious concrete, porous asphalt, grid pavers
pervious concrete, porous asphalt, grid pavers 
and interlocking concrete pavers.  These 
Runoff Reduction/Pollutant Removal

80% pavements consist of several layers, including 
the top pervious layer, an underlying storage 
layer composed of gravel or stone. This layer 
60% provides the storage reservoir needed for 
stormwater management.  The depth and 
40% materials are determined by the amount of 
peak runoff and structural concerns. Runoff 
20% infiltrates, enters the lower layer, and either 
exfiltrates into the nearby soils or is collected 
in an underdrain system and later discharged 
0% to a conveyance system.  Porous pavements 
P N are efficient for removal of sediments, 
nutrients, and some metals.  However,  Source: Smith, D. (2006) Permeable Interlocking Concrete Pavement‐
Selection Design, Construction and Maintenance. Third Edition. Interlocking 
sediment clogs the pores of these systems,  Concrete Pavement Institute. Herndon, Virginia, cited in VDCR Stormwater 
Source: Wetland Studies and Solutions, Inc., Gainesville, VA, 2009, photo 
leading to failure. Vacuum sweeping can  Design Specification Number 7: Permeable Pavement, Version 1.9, 2011.
taken by D. Sample.
remove sediment and  restore clogged 
8 Infiltration Infiltration practices provide temporary surface 
or subsurface storage, allowing exfiltration of 
100% runoff into soils.  Implementation consists of 
an excavated trench filled with gravel or stone 
backfilled to the surface.  Temporary storage 
Runoff Reduction/Pollutant Removal

80% volume is provided within pore spaces or voids 
between the stone.  Sediment can be easily 
60% trapped within the pores and clog them, so 
pretreatment for sediment removal is advised.  
Designs can include or exclude a perforated 
40%
drainage pipe near the bottom of the stone 
layer, depending upon the quality of the runoff 
20% and the infiltration rate; a minimum value of 
0.5 inches/hour is recommended.  These 
0% systems can reduce significant quantities of 
P N runoff by infiltration, and also provide filtration 
Source: Virginia DCR Stormwater Design Specification Number 8:  
and adsorption of pollutants within the media  Infiltration, Version 1.9, 2011. Source: Wetland Studies and Solutions, Inc., Gainesville, VA, 2009.
and soil column.  Infiltration practices should 
be avoided in industrial areas and other "hot 
spots" to avoid contamination of groundwater.

12-20 Urban Nutrient Management Handbook

Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Table 12.1. Descriptions of best management practices (BMPs). (cont.)

# Name/Performance Description Diagram or Photograph Diagram or Photograph
Treatment 
Type

9 Bioretention Bioretention cells, (small informal versions 
often called rain gardens), are stormwater 
BMPs consisting of a depression with a 
vegetated layer, a mulch layer, several layers of 
100% sand, soil, and organic media known as a filter 
Runoff Reduction/Pollutant Removal

bed, an overflow, and an optional underdrain.  
They typically small treat catchment areas of 5 
80% acres or less.  Within a bioretention cell, 
treatment is performed by filtration, 
60% infiltration, detention (overflow weir), 
adsorption, plant uptake and 
40%
evapotranspiration.  An underdrain consists of 
a perforated pipe in a gravel layer installed 
along the bottom of the filter bed; an upturned 
20% outlet promotes partial anaerobic conditions 
within the fluctuating water table which results 
0% in denitrification.  In nonindustrial settings 
P N where soils have high infiltration rates, 
removal of the underdrain may be considered, 
Source: Sample, D. (2009) Stormwater Management Research, VT‐CALS 
thus increasing runoff reduction by exfiltration. Hatch Proposal 2010‐2015.  Diagram shows optional upturned elbow. Source: Wetland Studies and Solutions, Inc., Gainesville, VA, 2009.

10 Dry Swale A vegetated swale is a shallow, gently sloping 
channel with broad vegetated side slopes, and 
low velocity flows.  A dry swale provides 
100%
temporary storage and filtering of a design 
Runoff Reduction/Pollutant Removal

treatment volume within vegetation and soil 
80% media.  Dry swales are similar to bioretention 
except they are configured as linear channels.  
60% Dry swales are always located above the water 
table to provide drainage capacity.  In highly 
permeable soils, typically no underdrain is 
40% used, while the reverse is true in impermeable 
soils.  Underdrains are constructed with a 
20% perforated pipe fit within a gravel layer at the 
bottom of the swale.  Vegetation species can 
include turf, meadow grasses, woody covers, 
0%
and trees.  Treatment processes generally 
P N
include settling, adsorption and filtering, 
infiltration into native soils (if permeable), and  Source: VDCR Stormwater Design Specification Number 10:  Dry Swales, 
Source: Wetland Studies and Solutions, Inc., Gainesville, VA, 2009.
Version 1.9, 2011.
plant uptake. 
11 Wet Swale A wet swale is a shallow, gently sloping 
channel with broad vegetated side slopes, and 
low velocity flows.  Wet swales typically stay 
100% wet by intercepting the shallow groundwater 
table.  Vegetation is primarily wetland and 
80% other hydrophilic species.  Wet swales function 
moval

similar to linear constructed wetlands, and 
area functioning part of the stormwater 
Pollutant Rem

60%
conveyance system.  Treatment is provided by 
settling filtering and biological processes, 
40% associated with microbial organisms.  Soils are 
typically saturated; water depths do not usually 
20% exceed 6 inches.  Because they are normally 
flat or gently sloped and exist in areas of high 
water table, wet swales are applicable only to 
0%
coastal plain installations. Source: VDCR Stormwater Design Specification Number 11: Wet 
P N Source: VDCR Stormwater Design Specification Number 11: Wet Swales, 
Version 1.9, 2011. Swales, Version 1.9, 2011.

12 Filtering Practices A stormwater filtering practice, also known as a 
stormwater filter captures, temporarily stores, 
and treats stormwater runoff by passing it 
through an engineered filter media, collecting 
100% it in an underdrain and then discharging the 
effluent to the stormwater conveyance system. 
80% Typical filter designs  include a settling 
chamber and a filter bed chamber, which 
contain multiple layers of differing media.  
Pollutant Removal

60%
Common media types include various layers of 
sand, gravel, organic matter, geotextiles, 
40% packed bed, and/or ion exchange resins.  
Stormwater filters are  useful for treating  
20% runoff from small, highly impervious sites, 
including "hot spots".  Stormwater filters can 
work on most commercial, industrial, 
0%
institutional or municipal sites and can be 
P N located underground if surface area is not 
available. 

Source: VDCR Stormwater Design Specification Number 12: Filtering 
Practices, Version 1.9, 2011. Source: Center for Watershed Protection, Photo courtesy of David 
Hirschman, 2011.

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Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Table 12.1. Descriptions of best management practices (BMPs). (cont.)

# Name/Performance Description Diagram or Photograph Diagram or Photograph
Treatment 
Type

13 Constructed Wetlands Constructed wetlands, also known as 
stormwater wetlands, are BMPs that use 
100% wetland vegetation to provide physicochemical 
and biological treatment of urban stormwater.  
80% Constructed wetlands vary substantially in 
their microtopography from depressions of less 
Pollutant Removal

than one foot  to deeper micropools several 
60%
feet deep.  This variability diversifies wetland 
vegetation.  There are several subtypes of 
40% constructed wetlands, including shallow marsh, 
extended detention, pond/wetland systems, 
20% pocket wetlands, and forested wetland 
systems.  Treatment is provided by settling, 
filtration, adsorption, and biological uptake. 
0%
Stormwater wetlands can be very effective at 
P N pollutant removal.
Source: VDCR Stormwater Design Specification Number 13: Constructed 
Wetlands, Version 1.9, 2011. Source:  Hession, C., 2010, Biological Systems Engineering, Virginia Tech.

14 Wet Ponds/Retention Ponds Wet ponds (also known as stormwater ponds 
or retention ponds) are stormwater 
100% impoundments that have a permanent pool of 
water that is controlled to a specified elevation 
by an outfall structure.  Treatment consists of 
80%
settling of solids and biological uptake of 
nutrients.  Inflow enters the pond and partially 
Pollutant Removal

60% displaces water collected during previous 
storms.  If additional freeboard is available 
40% above the outfall threshold, then attenuation 
of stormwater peak flows may also be provided 
through extended detention, which helps meet 
20%
channel protection requirements.  Because of 
their placement at the lowest point of a 
0% drainage area, wet ponds are the final 
P N treatment opportunity available.  Therefore,  Source: Fairfax County Department of Public Works and Environmental
Source: VDCR Stormwater Design Specification Number 14: Wet Ponds,  Services, 2011.
other opportunities for runoff reduction and/or  Version 1.9, 2011.
water quality treatment should be explored 
prior to resorting to this BMP.
15 Extended Detention An Extended Detention (ED) Pond provides 12‐
24 hours of storage during peak runoff events.  
Releases from the ED Pond are controlled by  
100% orifices and/or weirs within the pond's outlet 
Runoff Reductiion/Pollutant Removal

structure.  As the outflow is restricted, water 
backs up into the ED Pond.  The pool slows flow 
80%
velocities and enables particulate pollutants to 
settle.  Treatment of settleable nutrients and 
60% sediment is good, however, resuspension of 
the settled pollutants can occur, and dissolved 
40% nutrient removal is poor. ED Ponds have the
nutrient removal is poor.  ED Ponds have the 
lowest overall pollutant removal rate of any 
stormwater treatment option, so they are 
20%
often combined with other upstream LID 
practices to better maximize pollutant removal 
0% rates. 
P N Source: VDCR Stormwater Design Specification Number 15: Extended  Source: Center for Watershed Protection, Photo courtesy of David 
Detention Pond, Version 1.9, 2011. Hirschman, 2011.  

12-22 Urban Nutrient Management Handbook

Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Table 12.2. Site assessment tool.

Stormwater Management on Residential Lots: Assessing the Risk of Surface and Groundwater Contamination
1. F or each category listed in the first column that is appropriate to your property, read across and circle the
statement that best describes conditions on your property. If there is not a descriptive statement that exactly fits
your situation, use your judgment to select the risk level that best applies. (Skip and leave blank any categories
that don’t apply to your property.)
2. L ook above the description you circled to find your “Risk Level Number” (1, 2, 3, or 4) and enter that number
in the right-hand column under “Your Risk Score.”
Your
High Risk High-Moderate Risk Moderate-Low Risk Low Risk Risk
Practice (Risk Level 4) (Risk Level 3) (Risk Level 2) (Risk Level 1) Score
Potential Contaminants in Runoff
Grass Grass clippings, Grass clippings, – Grass clippings,
clippings, leaves, and other leaves, and other leaves, and other
leaves, and yard wastes are yard wastes are left yard wastes are
other yard dumped down a on driveways, streets, swept off paved
waste storm drain or near a and other paved surfaces and onto
surface water body. areas to be carried lawns away from
off by stormwater. water flow routes.
Leaves and other
yard wastes are
composted.
Handling Spills are not Granules, etc., are – Spills are cleaned
and use of cleaned up. Products left on driveway, up immediately,
pesticides, are used in greater sidewalks, or other particularly on
fertilizers, amounts than what paved areas to paved surfaces.
and outdoor is recommended on be carried off by Recommended
chemicals the label. stormwater. amounts of
chemicals are
applied according to
label instructions.
Timing of Application is made Application is made Application is made Application is made
pesticide, when heavy rain is when heavy rain is when light rain is when no or only
fertilizer, forecast within the forecast within the forecast within the light rain is forecast
and outdoor next 24 hours and next 24 hours and next 24 hours and within the next
chemical use on saturated soils or on unsaturated soils on saturated soils or 24 hours and on
areas where runoff is or areas with little areas where runoff is unsaturated soils
likely. slope. likely. or areas with little
slope.
Storage of Chemicals are stored Chemicals are Chemicals are Chemicals are
pesticides, in nonwaterproof stored in waterproof stored in waterproof stored in waterproof
fertilizers, containers outdoors. containers outdoors, containers outdoors, containers in a
and other but within reach of out of the reach of garage, shed, or
potentially stormwater. stormwater. basement that is
harmful protected from
chemicals stormwater.

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Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Table 12.2. Site assessment tool. (cont.)

Your
High Risk High-Moderate Risk Moderate-Low Risk Low Risk Risk
Practice (Risk Level 4) (Risk Level 3) (Risk Level 2) (Risk Level 1) Score
Potential Contaminants in Runoff (cont.)
Automotive Used oil, antifreeze, Used oil, antifreeze, Drips and spills are Oil drips and fluid
wastes or other wastes are or other wastes are not cleaned up. spills are cleaned up.
dumped down a dumped in a ditch or Car parts and other Dirty car parts and
storm drain or on a on the ground. vehicle wastes are other vehicle wastes
paved surface. left on unpaved areas are kept out of reach
outside. of stormwater runoff.
Vehicle Cars, trucks, or other Cars, trucks, or other Cars, trucks, or other Cars and trucks
washing items are washed on items are washed on items are washed on are taken to a
a driveway, street, or a gravel or rocked a lawn. commercial car
other paved area. area. wash.
Animal and Animal and pet Animal and pet Animal and pet Animal and pet
pet wastes wastes are left on wastes are left to wastes are left to wastes are flushed
paved surfaces or decompose on grass decompose on grass down the toilet or
dumped down a or soil. Wastes are or soil. Wastes are wrapped and placed
storm drain. concentrated in a scattered over a wide in the garbage for
small area, such as area. disposal.
a pen.
Landscaping and Site Management
Landscaping There is no No areas are Yard is landscaped Yard is landscaped
landscaping to slow landscaped to and soils are and soils are
the flow of runoff. encourage water to amended to slow the amended to slow the
Soils are compacted, soak in, and soils flow of stormwater flow of stormwater
limiting infiltration. are compacted. Yard and provide areas and provide areas
Yard is hilly, allowing is relatively flat, where water soaks where water soaks
runoff to occur. reducing the amount into the ground. Yard into the ground. Yard
of runoff that occurs. is hilly, allowing is relatively flat and
some runoff to occur. little runoff occurs.
Yard and Large areas of yard Small areas of yard Grass or other Bare spots in the
gardens or garden are left or garden are left ground cover is lawn are promptly
without mulch or without mulch or used, but is spotty, seeded and topped
vegetation for long vegetation for long particularly on with a layer of straw
periods. periods. slopes. or mulch. Bare soil
in gardens is covered
with mulch
Paved Large areas are Some small areas are Alternatives such as Alternatives such
surfaces paved for walkways, paved for walkways, gravel, rock, paving as wood chips or
patios, and other patios, and other blocks, brick, or mulch are used for
areas. areas. flagstone are used walkways, patios,
for walkways, patios, and other areas.
and other areas.

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Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

Table 12.2. Site assessment tool. (cont.)

Your
High Risk High-Moderate Risk Moderate-Low Risk Low Risk Risk
Practice (Risk Level 4) (Risk Level 3) (Risk Level 2) (Risk Level 1) Score
Landscaping and Site Management (cont.)
Roof Most or all Most or all eave drip Most or all eave drip Most or all eave drip
drainage downspouts are lines or downspouts lines or downspouts lines or downspouts
connected directly to discharge onto paved discharge water onto discharge water onto
storm drains. surfaces where water grassy or mulched a grassy or mulched
runs off. areas where some area or rain garden
water runs off. where water soaks
into the ground.
Lot during Soil is left bare Soil is left bare Soil is left bare Bare soil is seeded
construction until construction is until construction is until construction is and mulched as
completed and no completed. Sediment completed. Sediment soon as possible
sediment barriers are barriers are installed, barriers are installed (before construction
used. but are poorly and maintained to is completed).
maintained allowing detain muddy runoff Sediment barriers
some muddy runoff until grass covers are used until grass
to leave the site. soil. covers soil.
Buffer strips Bare soil, sand, or Spotty mowed Mowed grass exists Buffer strips of thick .
gravel exists next vegetation exists next next to stream bank vegetation are left
to a stream bank or to a stream bank or or lakeshore. along a stream bank
lakeshore. Stream lakeshore. or lakeshore.
banks or lakeshores
are eroding.
Source: Shelton and Feehan 2008

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Chapter 12. Principles of Stormwater Management for Reducing Nutrients From Urban Landscaped Areas

12-26 Urban Nutrient Management Handbook

 Chapter 13. Turf and Landscape Nutrient Management Planning

Chapter 13. Turf and Landscape

Nutrient Management Planning
David Kindig, Soil and Water Conservation, Virginia Department of Conservation and Recreation
Timothy Sexton, Soil and Water Conservation, Virginia Department of Conservation and Recreation

Introduction Assessment of Planned Areas

This chapter will emphasize the actual steps that a cer-
tified nutrient management planner will use to develop Land
and implement a nutrient management plan (NMP). The obvious place to begin is with the land. This will
Utilizing the data and recommendations provided in vary from small management areas like an urban or res-
an NMP promotes water quality protection. However, idential setting to perhaps several hundred acres, such
an equally important result of an NMP is its value as as golf courses, large parks, and recreation facilities.
a comprehensive tool in planning fertilizer selections Planned areas will represent an area that will be man-
and application strategies in terms of optimizing plant aged and fertilized as one distinct unit. It will usually
responses, nutrient-use efficiency, and economics. be defined by the type of planting it contains, such as
While these criteria were specifically developed for the turf, bedding plants, etc. How many planned areas will
Commonwealth of Virginia, the principles will apply to be needed to address various plant species? How much
any mid-Atlantic state. area is in each of these planned areas? What is the pres-
ent use of these areas? If they are being used for turf or
The primary steps for nutrient management planning are:
annual or perennial bedding plants, will that use con-
1. Collect and evaluate information about the overall tinue or will the areas be renovated to something else?
area to be planned.
2. Determine realistic expectations of the planting’s Equipment Resources
performance with known conditions, such as soil fer- Once you know what is normally done (or expected) in
tility levels and adaptation of plant species to the area each planned area, knowing what type of equipment,
and for the intended use. if any, your client has will be helpful when develop-
ing recommendations. Does your client have seeding
3. Establish nutrient requirements for the plant species
equipment, fertilizer spreaders, aerators, sprayers, or
in each area to be planned.
tillage equipment? What are the limitations of these
4. Evaluate planting area limitations based on environ- machines? You need to consider the availability of
mental site sensitivity or other plan implementation equipment when recommending certain management
concerns. operations and, if unavailable, is there an alternative
operation that will be acceptable?
5. Allocate purchased and any on-site nutrient sources,
if any, to available planned areas.
Past Methods of Fertilizer Application
6. Identify nutrient timing and placement methods to
The use of commercial fertilizer is a similar consideration.
maximize nutrient use by plantings and minimize
You need to know the client’s current fertilization program.
environmental losses.
The rate and timing of applications are important consider-
Prior to initiating plan development, it is critical to ations for plan development. Also, be certain to determine
obtain some information about the current management how much custom application is done and by whom. If the
practices used by your client. This process of inven- landowner is a steady customer of a particular dealer, his
torying your client’s resources and needs is critical to application capabilities and limitations should be consid-
developing an implementable plan, based on sound ered, if possible, when developing the final plan.
agronomics, that improves water quality.
Soil Resource Assessments
The most important resource to consider when develop-
ing a plan is the soil, or combination of soils, and the
location within the landscape of each planned area. For

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 Chapter 13. Turf and Landscape Nutrient Management Planning

undisturbed areas, a soil survey is used to determine the Environmentally Sensitive Sites
predominant soils in the planned areas. Consider the
expected outcomes in trying to grow the various plant An important item to consider in evaluating your cli-
species your client wants. If the soils in the planned ent’s operation is the presence of environmentally sen-
area have been heavily excavated, what type of soil is sitive sites. An environmentally sensitive site is any
present and how deep is it? This may come down to managed area that is particularly susceptible to nutri-
identifying the soil by its texture and physically assess- ent loss to ground or surface water because it contains
ing the soil horizons and any restrictive characteristics (or drains to areas that contain) sinkholes, or where at
that will limit or even prohibit successful plantings. least 33 percent of the area in a specific management
area contains one, or any combination of, the following
Steep slopes that are prone to erosion or light-textured features:
soils subject to leaching are two possible examples.
These types of factors obviously affect satisfactory 1. Soils with high potential for leaching based on soil
seeding but are also additional considerations in devel- texture or excessive drainage.
oping a thorough plan. Of course, a current soil test will 2. Shallow soils less than 41 inches deep that are likely
also be important as part of this evaluation. to be located over fractured or limestone bedrock.
3. Subsurface tile drains.
Nutrient Resources
Soil testing is critical to nutrient management planning 4. Soils with high potential for subsurface lateral flow
in determining the plant’s likely response to applied based on soil texture and poor drainage.
nutrients and the pH of the soil for lime needs. The use 5. Floodplains as identified by soils prone to frequent
of water-soluble fertilizer, slow-release materials, and flooding in county soil surveys.
even manures, wastewater, and biosolids needs to be
considered in your recommendations regarding timing 6. Land with slopes greater than 15 percent.
and rate of applications. You will have preferred mate-
Existing best-management practices (BMPs) installed
rials you would like used; however, your client may
to protect such areas should be noted to ensure their
have products in stock or a source of these materials he
protection and maintenance. The plan writer should also
has to use. Know the options you have available to use
consider the need for recommending additional mea-
various materials in the following years and educate
sures to protect water quality whenever necessary. It is
your client about the advantages and disadvantages of
critical that an actual site visit be made to all planned
available materials for his operation. Ultimately, what
areas that will receive any type of nutrient applications.
is used will be the client’s decision, so to facilitate plan
This is necessary to check for environmentally sensi-
implementation, try to use as many client-preferred
tive areas and to check the general terrain of the appli-
materials as possible.
cation sites. Maps in the plan should clearly identify all
environmentally sensitive sites.
Nutrient Requirements for Species in
Each Planned Area Allocation of Nutrients to Planned Areas
Once soils are tested, nutrient recommendations for the After considering nutrient needs for each planned area
plant species in each planned area can be determined and the environmentally sensitive areas, fertilizer appli-
by utilizing the tables in Virginia Nutrient Management cations should be made to meet nutrient needs or to sup-
Standards and Criteria, revised October 2005 (Virginia plement deficiencies in meeting the nutrient needs when
Department of Conservation and Recreation-VDCR). If other sources of nutrients have been applied first.
the plant species is not contained in Standards and Cri-
teria, use Virginia Cooperative Extension publications Plans shall be written on a nitrogen (N) and phosphorus
or other sources that specifically address management (P) basis. It is important that nutrient applications be
of that species. When a publication is used for this pur- prioritized to meet plan requirements. Nitrogen recom-
pose, it should be noted in the plan narrative or noted mendations should not exceed the need determined by
as a recommendation source on the worksheet for the the Virginia Nutrient Management Standards and Cri-
plan. There are numerous examples of plant materials teria (2005) or other appropriate resource as discussed.
and their anticipated nutrient requirements presented in Soil test levels should be used to make phosphorus and
preceding chapters of this manual. potassium (K) recommendations.

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 Chapter 13. Turf and Landscape Nutrient Management Planning

and let them know this may take several hours or more
Initial Client Visit so that they can schedule the time required. Also let
them know what information you will need so they can
Collecting Background Information have it ready when you arrive. The following pages
This visit is very important. The complete and detailed contain an example of an approach for collecting back-
information you collect at this time will reduce the ground information (figures 13.1-13.4). It may not be
number of return visits or calls needed. Plan ahead and necessary in all cases but could be helpful when work-
be organized. Make an appointment with your clients ing with a client for the first time.

General Information
Date of visit _____ /_____ / _____

Owner name ______________________________________________

Phone _____________________________ E-mail _____________________________

Manager/superintendent _____________________________________

Phone _____________________________ E-mail _____________________________

Address _________________________________________________________________________________________

City/state/zip _____________________________________________________________________________________

Extension agent ____________________________________________

Phone _____________________________ E-mail _____________________________

Fertilizer supplier __________________________________________

Phone _____________________________ E-mail _____________________________

Salesman _________________________________________________

Phone _____________________________ E-mail _____________________________

Consultant ________________________________________________

Phone _____________________________ E-mail _____________________________

Are you scheduled to receive biosolids or other organic nutrient sources? o Yes o No

If yes, supplier: ___________________________________________________________________________________

Field representative: ________________________________________

Phone _____________________________ E-mail _____________________________

Who takes soil samples? o Client o Fertilizer dealer o Consultant o Other

At what interval are soil samples taken? o 1 year o 2 years o 3 years

Do you have current samples of all areas to be included in plan? o Yes o No

What lab is used? o VT o A&L o Spectrum o Waters o Other

Who makes recommendations? o Extension o Laboratory o Fertilizer dealer o Consultant o Yourself

Are tissue samples taken? o Yes o No

What plant species? ________________________________________________________________________________

Figure 13.1. Sample form to collect background information.

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 Chapter 13. Turf and Landscape Nutrient Management Planning

Nutrient Application
Plant species Rate/month Rate/month Rate/month Rate/month
Bermudagrass
Turf-type tall fescue
Flowering annuals

Figure 13.2. General nutrient application for each plant species (pound per acre plant food).

Management Area Information

Owner: ___________________________________________________________ Date _____ /_____ / _____

Operation name: _________________________________ Location: ___________________________________

Last lime
Management area Present plant Renovate to new application
designation ID Sq ft or acres species species rate (month/year)

Figure 13.3. Clearly define and label each management area.

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 Chapter 13. Turf and Landscape Nutrient Management Planning

necessary to include it in the narrative.

Components of a Nutrient
Management Plan Plan Map
A nutrient management plan designates proper manage- Use a copy of an aerial photograph whenever possible.
ment of nutrients using proper application rates and tim- Generally, these photographs will show established,
ing specific for the species of plant in each management planned area boundaries and should be a good refer-
area. Following the plan will result in a cost-effective ence to identify these areas as they are listed in the plan.
and environmentally sound use of plant nutrients. A plan If aerial photos are not available, take the time to draw
may also be used to document the proper rate and timing a clear, neat map. This map should show planned area
of nutrient applications. This is used to report the urban identification designations, environmentally sensitive
community’s progress in protecting and improving water areas (e.g., wells, erosion control structures, drainage-
quality. A description of the components of an NMP is ways, etc.), and any other features of the landscape that
outlined in Virginia’s Nutrient Management Training need to be addressed in the plan to minimize the impact
and Certification Regulations (available at www.dcr.vir- of nutrient application to the environment.
ginia.gov/soil_and_water/nutmgt.shtml). The following
information offers a brief outline and explanation of the
various parts of a plan. All plans must be written to the
Plan Map Legend
criteria set forth in the regulations. Use a legend to explain any symbols used on the plan
map. It can be on the map itself or included on a sepa-
rate sheet directly following the map.
Plan Identification Sheet
The plan identification sheet is a page at the front of the Soil Map
plan that contains information such as the client’s name
and address, the planner’s name and certificate num- Include soil maps for the operation when there is con-
ber, and the county and watershed code for the opera- siderable acreage in the plan and the land, for the most
tion. Information about the square footage or acreage of part, is undisturbed. Delineate the outside boundaries of
each plant species is included to give a snapshot view the operation matching those used on the plan maps.
of the plan.
Nutrient Application Window
Narrative Timing of nutrient applications is very important.
Spring and Summer Lawn Management Considerations
Use this section to describe the operation and to assist
for Cool-Season Turfgrasses, Virginia Cooperative
with tailoring the plan to the individual.
Extension (VCE) publication 430-532 (VCE 2009a),
• Describe the type of operation (athletic field, golf and Spring and Summer Lawn Management Consider-
course, recreation area, etc.). ations for Warm-Season Turfgrasses, VCE publication
• Describe the location, naming common landmarks 430-533 (VCE 2009b) are two publications that give
or route numbers; this will be helpful to identify the the client a quick view of when various operations in
operation on a map or for another planner to drive turf maintenance should occur throughout the year.
to the operation. This information may be helpful when clients are put-
• Include a general description of the management of ting together a plan implementation strategy.
each plant species in the operation.
• Make note of the proximity of management areas Organic Nutrient Sources
to streams, erosion control, environmentally sensi-
Calculating nutrient availability from land-applied
tive areas, etc., and what precautions address each
organic materials is an important component of an NMP.
issue.
Most organic materials will either be animal manures or
• Give directions on where additional help can be obtained
biosolids. A detailed discussion and examples of calcu-
for other operation management and water quality
lating nutrient availability is covered in Standards and
objectives that are beyond the scope of this plan.
Criteria, pages 109-10, and 117 (VDCR 2005). Refer
• Write clear, concise statements that are to the point.
to this section to become familiar with the formulas and
If some information is already included on the bal- proper coefficients to be used on each planned manage-
ance sheet (e.g., timing, testing, renovation), it is not ment area receiving organic nutrient sources. Once the

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 Chapter 13. Turf and Landscape Nutrient Management Planning

plant-available nitrogen, phosphate, and potash have • Identification of the managed area. The managed area
been calculated, the nutrients supplied from the organic identification needs to exactly match the labeling as
material application are deducted from the nutrient it appears on the plan map. Areas can be grouped in
needs for the plant species to which the material was any order you think best suits the client’s operation.
applied, and subsequent residual nitrogen credit is Separate recommendations should be made for each
given to following spring plant species nitrogen needs. individual planned area unless two or more areas are
managed similarly and soil test levels are similar.
Nutrient Application Worksheet Header • The area of the space identified, either per 1,000
(figure 13.4) square feet or per acre.
• The property owner’s name.
• The plant species in the management area, as either
• The date the plan is prepared and the date it expires. turf or landscape materials.

Nutrient Application Worksheet

Name: ____________________________________________________________________________________________

Prepared: ____ /____ / ____ Expires: ____ /____ / ____

Management Area Identification: _____________________________________________________________________

Square Feet: _______________________________________________________________________________________

Landscape Plants: __________________________________________________________________________________

Turf Species: _______________________________________________________________________________________

Column 1* 2 3 4 5 6 7 8
Nutrient Fertilizer
needs material % slowly Lime recom-
N-P2O5-K2O Application N-P2O5-K2O available Nitrogen P2O5 K2O mendation
(lb/1,000 sq ft) month/day† (lb/1,000 sq ft) nitrogen (lb/1,000 sq ft) (lb/1,000 sq ft) (lb/1,000 sq ft) (lb/1,000 sq ft)

Notes:

†
 he month and day designations may not always be followed due to weather, etc. Apply as close to the month as possible, using the day
T
designation to determine the interval between applications.

Figure 13.4. Worksheet used to provide client with a ready reference for nutrient management recommendations.

* Row of column numbers added for ease of identification; it is not on worksheet.

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 Chapter 13. Turf and Landscape Nutrient Management Planning

Nutrient Application Worksheet Table 6. P2O5 (lb/1,000 square feet or lb/acre): This is the
amount of plant-available phosphorus — expressed
The columns used in the worksheet table (figure 13.4) as phosphate — that is supplied by the designated
are explained below. All recommendations should be fertilizer material application.
designated on a “per 1,000 square feet” or “per acre”
basis. 7. K2O (lb/1,000 square feet or lb/acre): This is the
amount of plant-available potassium — expressed as
1. Nutrient needs: This is where nutrient needs are potash — that is supplied by the designated fertilizer
shown. The nutrient needs represent the total nitro- material application.
gen, phosphate, and potash for an annual applica-
tion. Recommendations should be based upon soil 8. Lime recommendation (lb/1,000 square feet or lb/
test results for phosphorus and potassium for each acre): This is the amount of lime recommended for
plant species. Nitrogen recommendations should be the management area. Most times this recommenda-
based on those contained in Standards and Criteria tion may be the only material application designated;
(VDCR 2005) or a referenced resource document. thus, it will have its own “application month/year”
because it will probably be applied at a different time
2. Application month/day: There may be several appli- than fertilizer materials.
cations of nutrients per year depending on the spe-
cies being fertilized. This column allows the planner 9. Notes: Special considerations regarding nutrient
to designate the months in which the nutrient appli- application, special conditions in the managed area,
cations should be applied and allows the planner to tillage practices, etc., can be footnoted here.
use the worksheet in two ways:
a. If the management areas are small and will receive Assistance Notes
the same applications for each year of the plan, These notes record what transpired during your first and
only the month and day for the application needs follow-up client visits. Write about such things as alter-
to be entered, along with a note on the worksheet natives you provided, decisions made based on unusual
explaining that this annual application program is circumstances, progress on plan implementation, or
applicable for all the years of the plan. unusual circumstances anyone should be familiar with
when visiting the client. These notes will help you or
b. If the recommendations will vary from year to
your successor understand what has already been dis-
year, then each year of the plan should be entered
cussed and what needs further discussion. These notes
into the “Prepared” and “Expires” dates. This will
should only be kept in your copy of the NMP.
probably increase the number of worksheets in the
plan, but it is acceptable when needed to convey
the specific applications needed to achieve desired Personal Plan Notes
soil fertility levels in the management area. This is where your personal notes and calculations
should be recorded. This will be important and very
Note: The month and day designations may not
helpful to you because in some cases you may not
always be followed due to weather, etc. Apply as
update plans for two or three years, depending on the
close to the month as possible, using the day designa-
plan’s expiration date. You may need some reminders
tion to determine the interval between applications.
of how and why you wrote the plan. You should keep
3. Fertilizer material N-P2O5-K2O: This column iden- a record showing details of how the recommendations
tifies the fertilizer material and the rate that it should were derived. Any special condition or unusual circum-
be applied at the designated time period. stances that existed at the time the plan is written should
be documented so the information can be referred to
4. Percent slowly available nitrogen: This column
when you review the plan at a later date or to justify
is used to identify the amount of slowly available
specific recommendations during an inspection. These
nitrogen in the material recommended (Note: slowly
notes should only be kept in your copy of the NMP.
available N is defined in chapter 8 of this manual).
5. Nitrogen (lb/1,000 square feet or lb/acre): This is the
amount of plant-available nitrogen supplied by the
designated fertilizer material application.

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 Chapter 13. Turf and Landscape Nutrient Management Planning

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 Chapter 13. Turf and Landscape Nutrient Management Planning

Sample Nutrient Management Plan

Nutrient Management Plan Identification

Owner
Fairfax County
1100 Cub Run Lane
Manassas, VA 22025
(804) 555-1212

Land Manager
Mr. William DuPont

Watershed Summary
Watershed: PL45
County: Prince William

Nutrient Management Planner

John Smith
Courthouse Plaza, Suite #5
Hanover, VA 22555
Certification code: 100

Acreage Use Summary

Total acreage in this plan: 15
Athletic fields: 3.5
Supporting areas: 2
Picnic/recreation: 7
Other turf: 2.5

Plan written 3/18/10

Valid until 3/18/13

Planner signature: ________________________________

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 Chapter 13. Turf and Landscape Nutrient Management Planning

Narrative for
Cub Run Valley Park
Manassas, Virginia

Cub Run Valley Park is located off Rt. 29 in Fairfax County between Rt. 609 and Rt. 620. The park entrance is off
of Stillfield Place Road. This park is open to the public from March 1 through November 30. The park consists of
three athletic fields — two baseball and one football field, a primitive picnic area, and an adjoining recreation
area maintained for the public to use for recreational activities such as pick-up games, Frisbee tossing, and
general exercise and play activities. No pets are allowed in the park. Cub Run stream runs through the park and
Field No. 3; the football field is accessed from the parking areas by a large cement culvert crossing over the
stream. This crossing is used by cars, maintenance equipment, and foot traffic to access this area of the park.
The athletic fields are mainly used for community Little League baseball and elementary football games on
weekends, with practices being conducted throughout the season. Field No. 1 has restricted use and is used
mainly for weekend games through early summer. Field No. 3 is used for baseball practice in the late summer,
with the majority of the baseball season games played on Field No. 2. During the football season, Field No. 2
is used for practices as well. These fields are managed at a high level, with special attention given to mowing
heights and intervals, weed control, and compaction. Soil tests are taken regularly to monitor nutrient needs,
and nitrogen is applied on a set schedule to keep grass growing as vigorously as possible through the open
season. When possible, play is rotated to different areas of the fields to minimize damage to the field in any one
area due to concentrated use.
The recreation area is used for all activities while the park is open to the public.
Condition of the athletic fields is usually good at the opening of the park and remains fairly good through the
season. If the field conditions deteriorate too much, the park may be closed earlier in November to minimize
damage done to the grass stands and keep costs down to renovate and re-establish fields for the next year.
A buffer area of 50 feet on each side of Cub Run is untreated and is mowed occasionally at about 6 to 8 inches
to discourage activities in the buffer area.
Because very little excavation was done to build the fields and other park areas, the native soils are still in place
for the most part. Athletic Field No. 1 is constructed on Dulles silt loam, which is somewhat poorly drained.
Athletic Field No. 2 is constructed on Ashburn silt loam, which is moderately well-drained. The paved parking
lot is built on Jackland and Haymarket soils, which are very stony; fortunately, the entrance area to the park runs
through a Dulles silt loam.
Field No. 3, the overflow parking area, and the picnic/recreation area are on a Rowland silt loam. This soil is
environmentally sensitive because it is listed as “frequent” for the chance of flooding. Application of nutrients in
these areas are not scheduled when heavy rainfall events are expected within a week’s time. Any soil disturbance
associated with renovation or construction is usually stabilized with straw mulch covered with anchored netting
after final grading and seeding are completed. In areas where water flow could possibly be more concentrated,
soil stabilization blankets may be installed to protect the planting until the grass is fully established.
The park is maintained by the county, which has a minimal budget for fertilizer, lime, and reseeding. Nutrient
applications, particularly fall nitrogen applications, may be slightly reduced to save money — especially if the
turf has a good appearance.
The worksheets in this plan represent recommendations for each management area for the next three years.
Applications will be repeated each year at the same designated times. Lime recommendations are only for one
application and the designated date includes the year to be applied. This plan is written for a three-year period
and will need to be revised at that time to remain current. Revising a plan takes some time, so the process
should begin at least four weeks or more prior to the plan expiration date.

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 Chapter 13. Turf and Landscape Nutrient Management Planning

The following management practices should be utilized where appropriate to protect water quality and enable
the client to better implement a nutrient management plan.
1. Soil samples should be analyzed at least once every three years for pH, phosphorus, potassium, calcium,
and magnesium in order to maximize the efficient utilization of nutrients. A representative soil sample
of each management area should be composed of at least 20 cores randomly sampled from throughout
the area. Soil sampling core depth will be 6 inches from the surface. Soil pH should be maintained at
appropriate agronomic levels to promote optimum plant growth and nutrient utilization.
2. Spreader calibration is extremely critical to ensure proper application rates.
3. A protective cover of appropriate vegetation should be established and maintained on all disturbed areas.
Vegetation such as trees, shrubs, and other woody species are limited to areas considered to be appropriate,
such as wind breaks or visual screens.
4. This nutrient management plan should be revised at least once every three years to make adjustments
for needed renovations, re-establishment of turf around construction projects, and updated soil test
information.
5. If clippings are collected, they should be disposed of properly. They may be composted or spread uniformly
as a thin layer over other turf areas or areas where the nutrient content of the clippings can be recycled
through actively growing plants. They should not be blown onto impervious surfaces or surface waters,
dumped down stormwater drains, or piled outside where rainwater will leach out the nutrients, creating the
potential for nutrient loss to the environment.
6. Iron applications (particularly foliar applications) may periodically be used for enhanced greening as an
alternative to nitrogen. These applications are most beneficial if applied in late spring through summer for
cool-season grasses and in late summer/fall applications for warm-season grasses.
7. Do not apply fertilizers containing nitrogen or phosphorus to impervious surfaces (sidewalks, streets, etc.).
Remove any granular material that lands on impervious surfaces by sweeping and collecting it, and either
putting the collected material back in the bag or spreading it on the turf and/or using a leaf blower, etc., to
return the fertilizer back to the turfgrass canopy.
8. These conditions do not override any local or county ordinances that may be more restrictive.

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 Chapter 13. Turf and Landscape Nutrient Management Planning

Cub Run Valley Park

Soil Test Summary Report
Lab: Virginia Tech
Sample date: March 9, 2010

Area P2O5 K2O

Managed area I.D. (sq ft) (lb/ac) (lb/ac) Soil pH Buffer index Turf species
Athletic Field No. 1 52,800 14/M 40/L 6.2 — Bluegrass
Athletic Field No. 2 52,800 33/M+ 161/M+ 6.3 — Bermudagrass
Athletic Field No. 3 57,600 35/M 148/M 5.9 6.18 Bermudagrass
Support area 85,120 10/L+ 59/L+ 6.2 — Bermudagrass
Overflow parking 108,900 8/L 51/L+ 5.7 6.12 K-31 fescue
Picnic/recreation area 101,360 14/M- 78/M- 6.0 6.21 Tall fescue
Entrance area 1,000 10/L+ 73/L+ 5.8 6.14 Perennials

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 Chapter 13. Turf and Landscape Nutrient Management Planning

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 Chapter 13. Turf and Landscape Nutrient Management Planning

Nutrient Application Worksheet

Fairfax County
Name: ____________________________________________________________________________________________

3 /____
Prepared: ____ 18 /10
____ 3 /____
Expires: ____ 18 / ____
13
Athletic Field No. 1
Management Area Identification: _____________________________________________________________________

52,800 - 7,000* (infield) = 45,800

Square Feet: _______________________________________________________________________________________

Bluegrass
Landscape Plants: __________________________________________________________________________________

none
Turf Species: _______________________________________________________________________________________

Nutrient Fertilizer
needs Appli- material Lime recom-
N-P2O5-K2O cation month/ N-P2O5-K2O % slowly Nitrogen P2O5 K2O mendation
(lb/1,000 sq ft) day† (lb/1,000 sq ft) available N (lb/1,000 sq ft) (lb/1,000 sq ft) (lb/1,000 sq ft) (lb/1,000 sq ft)
18-24-12
4/15 50% 0.5 0.66 0.33 —
2.76 lb
18-24-12
6/1 50% 0.5 0.66 0.33 —
2.76 lb
3.5-2.0-3.0
18-24-12
8/15 50% 0.5 0.66 0.33 —
2.76 lb
23-0-23
9/1 50% 1 0 1 —
4.35 lb
Notes:

*7,000 square feet deducted from treated area for infield,

which does not receive any fertilization.
†
 he month and day designations may not always be followed due to weather, etc. Apply as close to the month as possible, using the day
T
designation to determine the interval between applications.

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 Chapter 13. Turf and Landscape Nutrient Management Planning

Nutrient Application Worksheet

Fairfax County
Name: ____________________________________________________________________________________________

3 /____
Prepared: ____ 18 /10
____ 3 /____
Expires: ____ 18 / ____
13
Athletic Field No. 2
Management Area Identification: _____________________________________________________________________

52,800 - 7,000* (infield) = 45,800

Square Feet: _______________________________________________________________________________________

Bermudagrass
Landscape Plants: __________________________________________________________________________________

none
Turf Species: _______________________________________________________________________________________

Nutrient Fertilizer
needs material Lime recom-
N-P2O5-K2O Application N-P2O5-K2O % slowly Nitrogen P2O5 K2O mendation
(lb/1,000 sq ft) month/day† (lb/1,000 sq ft) available N (lb/1,000 sq ft) (lb/1,000 sq ft) (lb/1,000 sq ft) (lb/1,000 sq ft)
18-24-12
4/15 50% 0.5 0.66 0.33 —
2.76 lb
30-6-10
6/1 50% 1.0 0.20 0.33 —
3.33 lb
30-6-10
7/1 50% 1.0 0.20 0.33 —
3.33 lb
18-24-12
9/1 50% 0.33 0.44 0.22 —
4.5-1.5-1.0 1.83 lb
40-0-0
9/15 85% 0.50 0.00 0.00 —
1.25 lb
Overseed
10/1 ryegrass — — — — —
2 lb
40-0-0
10/15 85% 0.5 0.00 0.00 —
1.25
Notes:

*7,000 square feet deducted from treated area for infield,

which does not receive any fertilization.
10/15 application date is approximate; nitrogen should be
applied as soon as ryegrass has germinated and there is ade-
quate moisture to promote vigorous growth.
 he month and day designations may not always be followed due to weather, etc. Apply as close to the month as possible, using the day
T
†

designation to determine the interval between applications.

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 Chapter 13. Turf and Landscape Nutrient Management Planning

Nutrient Application Worksheet

Fairfax County
Name: ____________________________________________________________________________________________

3 /____
Prepared: ____ 18 / 10
____ 3 /____
Expires: ____ 18/ ____
13
Athletic Field No. 3
Management Area Identification: _____________________________________________________________________

57,600
Square Feet: _______________________________________________________________________________________

Bermudagrass
Landscape Plants: __________________________________________________________________________________

none
Turf Species: _______________________________________________________________________________________

Nutrient Fertilizer
needs material Lime recom-
N-P2O5-K2O Application N-P2O5-K2O % slowly Nitrogen P2O5 K2O mendation
(lb/1,000 sq ft) month/day† (lb/1,000 sq ft) available N (lb/1,000 sq ft) (lb/1,000 sq ft) (lb/1,000 sq ft) (lb/1,000 sq ft)
18-24-12
4/15 50% 0.5 0.66 0.33 —
2.76 lb
Pulverized
5/1 lime
— — — — 57 lb
30-6-10
6/1 50% 1.0 0.20 0.33 —
3.33 lb
30-6-10
7/1 50% 1.0 0.20 0.33 —
3.33 lb
4.5-1.5-1.5 18-24-12
9/1 50% 0.33 0.44 0.22 —
1.83 lb
40-0-0
9/15 85% 0.50 0.00 0.00 —
1.25 lb
Overseed
10/1 ryegrass — — — — —
2 lb
40-0-0
10/15 85% 0.5 0.00 0.00 —
1.25 lb
Notes:

10/15 application date is approximate; nitrogen should be

applied as soon as ryegrass has germinated and there is ade-
quate moisture to promote vigorous growth.
†
 he month and day designations may not always be followed due to weather, etc. Apply as close to the month as possible, using the day
T
designation to determine the interval between applications.

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 Chapter 13. Turf and Landscape Nutrient Management Planning

Nutrient Application Worksheet

Fairfax County
Name: ____________________________________________________________________________________________

3 /____
Prepared: ____ 18 / ____
10 3 /____
Expires: ____ 18 / ____
10
Support Area/Overflow Parking
Management Area Identification: _____________________________________________________________________

194,020
Square Feet: _______________________________________________________________________________________

Tall Fescue
Landscape Plants: __________________________________________________________________________________

none
Turf Species: _______________________________________________________________________________________

Nutrient Fertilizer
needs material Lime recom-
N-P2O5-K2O Application N-P2O5-K2O % slowly Nitrogen P2O5 K2O mendation
(lb/1,000 sq ft) month/day† (lb/1,000 sq ft) available N (lb/1,000 sq ft) (lb/1,000 sq ft) (lb/1,000 sq ft) (lb/1,000 sq ft)
10-20-15
9/1 — 1.0 2.0 1.5 —
10 lb
30-6-10
10/1 50% 1.0 0.2 0.33 —
3.33 lb
3.0-2.5-2.0 11/1 40-0-0
50% 1.0 0.00 0.00 —
2.5 lb
69 lb
Pulverized Overflow
4/11/10 limestone — — — —
parking
only
Notes:

 he month and day designations may not always be followed due to weather, etc. Apply as close to the month as possible, using the day
T
†

designation to determine the interval between applications.

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 Chapter 13. Turf and Landscape Nutrient Management Planning

Nutrient Application Worksheet

Fairfax County
Name: ____________________________________________________________________________________________

3 /____
Prepared: ____ 18 / ____
10 3 /____
Expires: ____ 18 / ____
10
Picnic/Recreation Area
Management Area Identification: _____________________________________________________________________

101,360
Square Feet: _______________________________________________________________________________________

Tall Fescue
Landscape Plants: __________________________________________________________________________________

none
Turf Species: _______________________________________________________________________________________

Nutrient Fertilizer
needs material Lime recom-
N-P2O5-K2O Application N-P2O5-K2O % slowly Nitrogen P2O5 K2O mendation
(lb/1,000 sq ft) month/day† (lb/1,000 sq ft) available N (lb/1,000 sq ft) (lb/1,000 sq ft) (lb/1,000 sq ft) (lb/1,000 sq ft)
10-20-15
9/1 — 1.0 2.0 1.5 —
10 lb
23-0-23
10/1 50% 1.0 0.00 1.0 —
4.3 lb
3.0-2.0-2.0
40-0-0
11/1 50% 1.0 0.00 0.00 —
2.5 lb
Pulverized
4/1/11 limestone — — — — 46 lb
Notes:

†
 he month and day designations may not always be followed due to weather, etc. Apply as close to the month as possible, using the day
T
designation to determine the interval between applications.

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 Chapter 13. Turf and Landscape Nutrient Management Planning

Nutrient Application Worksheet

Fairfax County
Name: ____________________________________________________________________________________________

3 /____
Prepared: ____ 18 /10
____ 3 /____
Expires: ____ 18 / ____
10
Entrance Plantings
Management Area Identification: _____________________________________________________________________

1,000
Square Feet: _______________________________________________________________________________________
Herbaceous Perennials
Landscape Plants: __________________________________________________________________________________
none
Turf Species: _______________________________________________________________________________________

Nutrient Fertilizer
needs material Lime recom-
N-P2O5-K2O Application N-P2O5-K2O % slowly Nitrogen P2O5 K2O mendation
(lb/1,000 sq ft) month/day† (lb/1,000 sq ft) available N (lb/1,000 sq ft) (lb/1,000 sq ft) (lb/1,000 sq ft) (lb/1,000 sq ft)
10-10-10
3/1 — 0.5 0.5 0.5 —
5 lb
Pulverized
3/15 limestone
— — — — 39 lb
1.25-1.0- 10-10-10
4/15 — 0.5 0.5 0.5 —
1.0 5 lb
30-6-10
5/30 50% 0.75 0.15 0.25 —
2.5 lb
Pulverized
6/15 limestone
— — — — 39 lb
Notes:

A 3-1-1 fertilizer ratio is suggested, but based on low soil test

results for phosphorus and potassium, this ratio for P and K
was increased based on an annual N rate of 1.25 lb. Lime
applied in two applications to adjust pH to 6.2.
†
 he month and day designations may not always be followed due to weather, etc. Apply as close to the month as possible, using the day
T
designation to determine the interval between applications.

References: Perennials: Culture, Maintenance, Propagation; Fertilizing Landscape Trees and Shrubs.

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 Chapter 13. Turf and Landscape Nutrient Management Planning

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 Chapter 13. Turf and Landscape Nutrient Management Planning

Plan Discussion fertilizer materials on hand that they want to use before
buying other products, so you may be forced to use some
The following information is NOT part of an actual analysis that does not exactly match your recommen-
plan; its purpose is to help the reader understand what
dations. Try to use as few products as possible to make
information was used to write this plan and the reason-
the plan a little easier for your client to follow. To aid in
ing behind some of the recommendations.
understanding the recommendations in the example plan,
When you begin to work with clients, they may have some the specimen labels that follow (figure 13.5) were used.

40-0-0 Slow-Release Nitrogen Fertilizer 23-0-23

Guaranteed Analysis Guaranteed Analysis
Total Nitrogen (N)* 40% Total Nitrogen (N) 23%
Urea Nitrogen 6% Urea 11.5%
Slowly Available Water Soluble 20% Coated Slow Release 11.5%
Water Insoluble Nitrogen 14% Water Insoluble Nitrogen 0%
Derived from: methylene urea Water Soluble Nitrogen 0%
*20% slowly available Nitrogen from methylenediurea Ammoniacal Nitrogen 0%
and dimethylenetriurea. Total Phosphate Acid (P2O5) 0
10-20-15 Available Potash (K20) .23%
Guaranteed Analysis Iron Sulfate (FE) .2%
Total Nitrogen (N) 10% 30-6-10 50% SCU
Ammoniacal Nitrogen 7.8% Guaranteed Analysis
Urea Nitrogen 2.2% Total Nitrogen (N) 30%
Available Phosphorus (P2O5) 20% Urea 13.1%
Soluble Potash (K20) . 15% Coated Slow Release 15%
Iron (Fe) .1% Ammoniacal N 1.9%
Water-Soluble Iron (Fe) 0.1% Total Phosphate Acid (P2O5) 6%
Derived From: Ammonium Phosphate, Urea, Muriate Available Potash (K2O) .10%
of Potash, Ferric Oxide, Iron Sulfate (FE) 0%
Ferrous Sulfate Sulfate Sulfur (S) 0%
Chlorine (CL) not more than 13%
Notice: This product contains the secondary nutrient
iron. Iron may stain concrete and should be removed
from these areas promptly after application by
sweeping or blowing. Do NOT wash off with water.
18-24-12 50% SCU
Guaranteed Analysis
Total Nitrogen (N) 18%
Urea 0%
Coated Slow Release 9%
Water Insoluble Nitrogen 0%
Water Soluble Nitrogen 0%
Ammoniacal Nitrogen 9%
Stabilized Urea Nitrogen 0%
Total Phosphate Acid (P2O5) 24%
Soluble Potash (K2O) 12%
Iron Sulfate (FE) 0%
Sulfate Sulfur (S) 0%

Figure 13.5. The five sample specimen labels, as stated earlier, may not be part of a plan you would take back to your clients. They are provided
here as a reference to help in your understanding of how to interpret the information contained in them to make recommendations.

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 Chapter 13. Turf and Landscape Nutrient Management Planning

How do I know if my fertilizer material is considered be under the recommendations. Because plans cannot
slowly available, and if so, how do I calculate the per- exceed the nitrogen or the phosphorus nutrient needs,
centage of slowly available nitrogen to use in making it was easiest to come close to the nitrogen needs while
recommendations? To determine this, divide the per- not exceeding the phosphorus needs.
centage of slowly available nitrogen material by the
Lime applications are shown on the worksheets as well.
percentage of total nitrogen listed on the label. Slowly
It was easy to list the lime material and show the appli-
available nitrogen will be listed on the label as “coated
cation rate in the far-right column.
slow release,” “water insoluble nitrogen,” etc.
Because the recommendations for each year of the
Looking at the materials used on Athletic Field No. 2 and
three-year plan were going to be similar, one worksheet
from the label information, here are the calculations:
was developed for each managed area and labeled to be
18-24-12: 9% ÷ 18% = 50% good for three years — see “prepared” and “expires”
dates in the first column of the header section of the
30-6-10: 15% ÷ 30% = 50% worksheet. IF the managed areas would have had sig-
40-0-0: (20% + 14%) ÷ 40% = 85% nificantly different fertility for each of the three years,
then the planner may choose to develop a worksheet for
In the last fertilizer, there are two different materials each management area for each year. Using the work-
making up the slowly available component of the total sheets for either option is acceptable; fill them out so it
nitrogen. (Note: A complete discussion on slowly avail- is clear to the client what needs to be done and when.
able nitrogen sources, their characteristics, and their
uses is provided in chapter 8 of this manual.) The worksheet on the entrance plantings area is fairly
simple. It basically shows a nitrogen application and
For athletic fields No. 1, 2, and 3, the nutrient needs the phosphorus and potash recommendations based on
were determined using the Virginia Nutrient Manage- a soil test. While perhaps not necessary, this adds to
ment Standards and Criteria (2005; available through the plan in that the planner is addressing possible fertil-
the Virginia Department of Conservation and Recre- izer applications to all managed areas of the property.
ation website at www.dcr.virginia.gov/soil_and_water/ Again, talk with your client about what they do in these
nutmgt.shtml). The nitrogen program followed the areas and how satisfied they are with their performance
“intensive” maintenance program shown on page and/or appearance. Although you may find they do not
102 of Standards and Criteria. How an area is man- have any formal program in place, your interest in man-
aged determines whether you should use the normal or aging such areas will improve the overall appearance of
intensive program. You determine how an area is man- the property, which increases the value of your service
aged by talking to your client about the nitrogen rate to your client.
they have been using, how much play the fields have to
A map of the property showing the various features
handle, and how quickly they heal in season and post-
described in the nutrient management regulations is
season. The phosphorus and potash recommendations
required to be part of the plan; however, the soils map
are from soil test results. Those recommendations for
and legend may be useful information in the plan, but
athletic fields are found on page 104 of Standards and
the soils map and legend needs to be information con-
Criteria.
tained in the client’s office file.
Because the financial budget is always tight at the
county and the fields look good late in the season, it Plan Implementation
was decided — in consultation with the client — not
to make the third fall nitrogen application. Such deci- After the initial plan has been delivered, the client
sions are acceptable but should be made with the cli- should begin to implement it. The degree to which it is
ent’s full understanding of what it is being done and implemented will depend on several factors. The most
why. Otherwise, the recommendations in the plan do obvious is whether it will benefit the client either in
not match those in Standards and Criteria, making it cost savings or improved appearance of the managed
area(s). Secondly, how easily can changes suggested
appear that the planner did not completely follow the
in the plan be adapted to the client’s current methods
Standards and Criteria recommendations.
of operation? If the recommendations in the plan are
In general, the nitrogen rates are close to the nutrient similar to what is already being done, the client is
needs. In some areas, the phosphorus applications may more likely to follow them. A well-written plan that

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 Chapter 13. Turf and Landscape Nutrient Management Planning

addresses the specific needs of a property with a practi-

cal and realistic approach is also more likely to be suc-
Plan Revision
cessfully implemented. Finally, the client’s acceptance Several factors can and will result in the need for revising
of the plan, willingness to change, and trust in the plan the nutrient management plan. The most obvious is that the
writer will strongly affect the degree of plan adoption. life of the plan has expired. Plans can be written for up to a
three-year period. Start working with clients well ahead of
For those plans (or portions thereof) that are adopted, the expiration date so your client will have a current plan in
three tasks are important to its ongoing success. place at all times.
Even the best-written plan can be refined to take advan-
1. Future Nutrient Testing tage of what has been learned in the last season. For
Where appropriate, the soil and tissue testing described that reason, plans will always be going through some
earlier are key tools to manage the application of nutri- degree of evolution. Some specific factors may result in
ents. Without these measures of nutrient availability the need for significant revisions. Changes in the pre-
balanced with plant needs, it will be difficult to accu- dominant land use on (or adjacent to) the managed areas
rately determine plant nutrient needs and to develop rel- may require modification of the existing plan. If man-
evant, justifiable recommendations. The client should aged areas are dramatically changed by renovations to
be strongly encouraged to maintain this test-critical the landscape or construction of new buildings, roads,
information. Not only is it needed for developing cred- etc., such changes may require the plan to be revised.
ible nutrient management plans, it is also important in
the operation management decision-making process. Summary
The number of factors that can alter a nutrient manage-
2. Equipment Calibration ment plan is substantial. For that reason, a sincere effort
Equipment calibration represents another area critical on the part of the client who manages a sizeable opera-
to plan implementation. The plan recommendations tion may be needed to reassess decisions made when the
will do little to save money and protect water quality plan was first developed. Follow-up visits are important
if they cannot be followed due to inaccurate nutrient to the success of the planning process. Because the per-
application. Calibration of all application equipment formance of various managed areas varies due to season
conditions, it is important to continue to follow up until
should be checked on a regular basis, especially if your
the client is comfortable with the plan implementation.
client owns his own application equipment. Without
Once the client has an understanding of the concepts and
the necessary adjustments indicated by calibration,
is capable of interpreting the plan, the amount of support
the result may be to apply either too little or too much
required should significantly lessen. Having your clients
plant nutrients. The first may result in an unacceptable
increase their understanding of nutrient management
turf durability and turf/landscape appearance. The lat-
and its importance creates a desire to do their best to fol-
ter may be costly, not only because of the unnecessary
low the plan. More importantly, it indicates that you are
expense, but also because of a negative impact on water
delivering a good and beneficial service to your clients.
quality. Equipment calibration is detailed in chapter 10
of this manual.
Literature Cited
Virginia Cooperative Extension (VCE). 2009a. Spring
3. Application and Maintenance Records
and Summer Lawn Management Considerations for
A final area to emphasize during plan implementation Cool-Season Turfgrasses. VCE Publication 430-532.
is record keeping. Without good records, it is impos- http://pubs.ext.vt.edu.430/430-532/430-532.html.
sible to know what has been done and if any progress or
improvements are being made. Examples of important Virginia Cooperative Extension. 2009b. Spring and Sum-
information to retain are soil tests; spreader calibration mer Lawn Management Considerations for Warm-
settings; dates of fertilizer application and rates applied; Season Turfgrasses. VCE Publication 430-533.
seeding or renovation of specific areas; and any usual http://pubs.ext.vt.edu.430/430-533/430-533.html.
stresses on the areas due to disease, drought, etc., that Virginia Department of Conservation and Recreation
would also impact the health and appearance of the (VDCR). Division of Soil and Water Conservation.
turf. This information provides the background needed 2005. Virginia Nutrient Management Standards and
for fine-tuning future plan updates or revisions. Criteria.

Urban Nutrient Management Handbook 13-25

www.ext.vt.edu PUBLICATION 430-350
Produced by Communications and Marketing, College of Agriculture and Life Sciences, Virginia Polytechnic Institute and State University, 2011
Virginia Cooperative Extension programs and employment are open to all, regardless of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation,
or marital or family status. An equal opportunity/affirmative action employer. Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University,
Virginia State University, and the U.S. Department of Agriculture cooperating. Alan L. Grant, Dean, College of Agriculture and Life Sciences, and Interim Director, Virginia Cooperative
Extension, Virginia Tech, Blacksburg; Wondi Mersie, Interim Administrator, 1890 Extension Program, Virginia State, Petersburg.