Republic of the Philippines

UNIVERSITY OF RIZAL SYSTEM

Rodriguez Campus
T. Reyes St., Amity Ville, San Jose, Rodriguez, Rizal Email Address: ursrodriguezcoa@gmail.com

MODULE 1- Soil: Components and Functions

This module aims to give you as a learner a basic ground of soil as a medium for
plant growth. Module 1 provides the foundation for understanding soils in relation
to agriculture. We will focus on the different definitions of soil, its components,
and functions

Learning Outcomes
At the end of the module, student should be able to:
1. Identify key terminologies in defining the soil
2. Compare the different conditions of soil in terms of volume of water and air
content
3. Describe the soil as a medium for plant growth and in terms of other essential
functions

Course Content
• Soil defined: Edaphological and pedological
• Fields of specialization in soil science
• Soil components: Mineral, organic, water and air
• Essential functions of the soil

Lesson 1 –Definition of Soil and Its Components

Soil is:
• A dynamic natural body composed of mineral and organic solids, gases, liquids,
and living organisms, which can serve as medium for plant growth.
• A valuable non-renewable natural resource capable of supporting plant growth and
has properties resulting from the integrated effects of climate and living organisms,
acting upon its parent material, as conditioned by topography, over periods of time.
• A complex biogeochemical material on which plants may grow and has structural
and biological properties that distinguish them from materials from which it
normally originates.

Fields of Study in Soil Science

There are eight fields of study in soil science which are the following:
• Soil Chemistry is a branch of soil science that deals with chemical
composition, chemical properties, and chemical reactions of soils.
• Soil Conservation and Management deals with best practices in
using and preserving the soil.

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 Republic of the Philippines
UNIVERSITY OF RIZAL SYSTEM
Rodriguez Campus
T. Reyes St., Amity Ville, San Jose, Rodriguez, Rizal Email Address: ursrodriguezcoa@gmail.com

• Soil Fertility deals with the amounts of available essential nutrients

for plant growth.
• Soil Microbiology is the study of organisms in the soil, their
functions, and how they affect soil properties
• Soil Mineralogy is concerned with the inorganic minerals found in
the pedosphere and to the depth of weathering.
• Soil Physics is the study of the state and movement of energy and
mass in the continuum that includes the soil, plants, and surface
boundary layer of the atmosphere
• Soil Survey and Classification is a systematic study of the soil of
an area including classification and mapping of the properties and the
distribution of various soil units.
• Land Use is the study of the various ways in which human beings
make use and manage the land and its resources

Soil Components
There are four soil components which are air, water, mineral matter, and organic
matter. In terms of composition by volume, mineral matter comprises the 45%,
organic matter is 5% and 50% of it are the pore spaces being occupied by
25% air and 25% water for an ideal soil (Figure 1)

Mineral Matter

25 Organic matter

45
Water

25
5 Air

Figure 1. Ideal soil component distribution by volume (%)

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 Republic of the Philippines
UNIVERSITY OF RIZAL SYSTEM
Rodriguez Campus
T. Reyes St., Amity Ville, San Jose, Rodriguez, Rizal Email Address: ursrodriguezcoa@gmail.com

During dry season, soils might be dried up because of insufficient rainfall. The
soil might have 5% water and 45% air (Figure 2).

Mineral Matter

Organic matter

45 45
Water

5 5 Air

Figure 2. Dry soil component distribution by volume (%)

On the other hand, during wet season, soils might become too wet, especially
those soils that are prone to waterlogging. Soil might have 45%water and only 5%
air (Figure 3).

Mineral Matter

5
Organic matter

45
45 Water

5 Air

Figure 3. Wet soil component distribution by volume (%)

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 Republic of the Philippines
UNIVERSITY OF RIZAL SYSTEM
Rodriguez Campus
T. Reyes St., Amity Ville, San Jose, Rodriguez, Rizal Email Address: ursrodriguezcoa@gmail.com

Minerals are derived from the weathering of rocks in which the clay
minerals are the most important weathering products. Minerals are the inorganic
component of the soil comprising the sand, silt and clay fractions or particles,
which is more that 90% of the soil solids. There are the three major fractions of
soil (Figure 4). The sand particles have a size between 2 to 0.05 mm. The silt
particles have 0.05 to 0.002 mm size and the clay particles have less than 0.002
mm size.

Figure 4. Three major fractions of the soil and its relative sizes

Organic matter (OM) encompasses the all organic components of a

soilwhich are the in different stages of decomposition:
• Fresh residues, that can be <10% by volume (examples are the fresh fallen
leaves)
• Decomposing OM or the active fraction, that can be 33 to 50% by volume
(example is actively decomposing animal manure)
• Stable OM which is the completely decomposed organic matter or the humus,
that can also be 33 to 50% by volume, and the
• Living organisms, that can be <5% by volume (this can be macro and
microorganisms leaving in the soil

Soil water/soil solution contains the soluble salts, organic solutes, and
suspended colloids. This component of the soil is controlled by the size of the
pore spaces. The small pores or the meso or micropores of the soil have great
affinity for water. Large pores or macropores allow water to escape easily. Soil
water also includes small but significant quantities of soluble inorganic
compounds, which can be the essential elements for plant growth.

Essential Nutrient Elements

There are 18 essential elements for plant growth that can be
generally divided into two. These are:

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UNIVERSITY OF RIZAL SYSTEM
Rodriguez Campus
T. Reyes St., Amity Ville, San Jose, Rodriguez, Rizal Email Address: ursrodriguezcoa@gmail.com

• Macro elements which are needed by plants in large amounts.

Some of these can be found in are such as carbon, hydrogen, and
oxygen. The macro elements that can be found from the soil are
nitrogen phosphorus, potassium, calcium, magnesium, and sulfur.
These nutrients from the
soil could be found in combination with other compounds, or
in the complex structure of minerals or in salts in the soil
solution.
• Micro elements are needed by plants in small amounts such as
iron, manganese, copper, zinc, boron, molybdenum, cobalt,
chlorine, and nickel.

Acidity/alkalinity is a critical property of the soil solution because:

• Chemical and biological reactions are dependent on the levels of H +
and OH- ions present in soil water and
• This Influences solubility/availability of several essential elements.

Soil aircontains more CO2 but less O2 than the atmosphere. It is

because the respiring organisms in the soil consume O2 and produce CO2.It
always, has a relative humiditynear100%, because respiration releases water
which evaporates more slowly in the soil than on/above the soil.

Supplementary Activities

• Video to watch: https://youtu.be/ZuqprXXg2D0

• Book to read: Baxter & Williamson 2001, Know your Soils – Introduction to Soils
http://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/0d08cd6930912d1e4a2567d20
02579cb/71de891c76430335ca2576cb00031fdd/$FILE/NRE%20Soil%20Book%
201_LR.pdf

• Link to read:
https://courses.lumenlearning.com/boundless-biology/chapter/the-soil/

Major Activities

1. Quiz 1

Directions –Open this link once your professor tells you to do so.

https://docs.google.com/forms/d/1s9h7OGkiKp8Oed6rxmSZFmXX4aUgraUqFRD0uo -AVI0

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 Republic of the Philippines
UNIVERSITY OF RIZAL SYSTEM
Rodriguez Campus
T. Reyes St., Amity Ville, San Jose, Rodriguez, Rizal Email Address: ursrodriguezcoa@gmail.com

Quiz 1 Rubric

Scor Assessment
e
9-10 • Understands and responds well to all or most questions.
Excellent!

7-8 • Understands and responds well to all or most questions.

Satisfactory.
• Shows above average knowledge about the lesson.

6 • Understands and responds to most questions. Good.

• Shows average knowledge aboutthe lessons

≤5 • Needs improvement.

2. Field and Laboratory Exercise1

Deadline: September 17, 2020
Directions:
• Accomplished the activities included in Page 8-11
• Submit through my email account at ursrodriguezcoa@gmail.com

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 Republic of the Philippines
UNIVERSITY OF RIZAL SYSTEM
Rodriguez Campus
T. Reyes St., Amity Ville, San Jose, Rodriguez, Rizal Email Address: ursrodriguezcoa@gmail.com

Field and Laboratory Exercise 1 Rubric

Criteria & Points Missing or Serious Below Expectations Meets Excellent Work Points
Assigned Problems Expectations Earned
0 1 2 3
Relevance of The essay did not Answer is incomplete. Answer is brief Answer is almost
answers to the answer the question. Excessive discussion with insufficient complete or complete;
question of unrelated issues detail. Unrelated sufficient detail
and/or significant issues were provided to support
errors in content. introduced and/or assertions; answer
minor errors in focuses only on issues
content. related to the question;
factually correct
Thoroughness of None of the relevant Serious gaps in the Most of the basic Deals fully with the
answer details were included basic details needed. details are included entire question.
but some are
missing.
Organization and Weak organization; Minor problems of Clear and logical
logic of answer sentences rambling; organization or logic; presentation; good
ideas are repeated. Needs work on development of an
creating transitions argument;
between ideas Transitions are
smoothly.
Mechanics of Major problems with Frequent problems Clear, readable,
writing (spelling, mechanics of with mechanics of prose. Good use of
punctuation, language; Awkward language; Occasional transitions; no
grammar, clarity sentence construction; awkward sentences problems with
of prose) Poor or absent and poor transitions; spelling,
transitions; Frequently reduce readability punctuation, or
difficult to understand. grammar.
Republic of the Philippines
UNIVERSITY OF RIZAL SYSTEM
Rodriguez Campus
T. Reyes St., Amity Ville, San Jose, Rodriguez, Rizal Email Address: ursrodriguezcoa@gmail.com

(Adapted from the University of West Florida)

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 Republic of the Philippines
UNIVERSITY OF RIZAL SYSTEM
Rodriguez Campus
T. Reyes St., Amity Ville, San Jose, Rodriguez, Rizal Email Address: ursrodriguezcoa@gmail.com

Field and Laboratory Exercise 1 Soil Components

Name: Score:
Course/Year/Section:

Objective: To be familiar with the different soil components

Materials to Prepare:
✓ Spade
✓ Beaker or Transparent glass or Transparent Jar (with volume capacity
of 1 liter or 1,000ml))
✓ Relatively dry and undisturbed soil clod
✓ 1000ml of water

Directions: Accomplish Activity 1 and 2 while recording a video. Print and accomplished
this worksheet (hand-written) and submit together with the recorded video.

Activity 1
1. Go to the field and observe the soil.
2. List down all the things you can see above the soil surface. Take a photo.
Identify the soil component you can observe.
3. By using a spade, collect at least 2 inches diameter of soil. As much as
possible, do not disturbed its structure. Take a photo and identify the soil
components.

Activity 2
1. Put the soil you collected from the field to the beaker.
2. Fill the beaker with water until it reaches the highest scale of your beaker.
3. Take a photo. Observe and list down the soil components.

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 Republic of the Philippines
UNIVERSITY OF RIZAL SYSTEM
Rodriguez Campus
T. Reyes St., Amity Ville, San Jose, Rodriguez, Rizal Email Address: ursrodriguezcoa@gmail.com

Accomplish the following:

Activity 1

A. Photo of soil surface. Label the soil components. (Print and paste, then label)

Soil air is
Rocks as
invisible, we can mineral
say that air is water
present there since
there are cracks
which can serve as
a passage through
air

B. Photo of the collected soil using spade. Label the soil components.
(Print and paste, then label)

Rocks
represents as
mineral water

Humus as
organic matter

The cracks tells

that there’s a
presence of air

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 Republic of the Philippines
UNIVERSITY OF RIZAL SYSTEM
Rodriguez Campus
T. Reyes St., Amity Ville, San Jose, Rodriguez, Rizal Email Address: ursrodriguezcoa@gmail.com

Activity 2. Photo of the soil in a beaker with water. Label the soil components.
(Print and paste, then label)

AIR

WATER

ORGANIC
MATTER

MINERAL
WATER

Answer the following questions:

1. What are the four soil components? Describe each one.

The four soil components are Air, Water, Organic Matter and Mineral Matter. The largest
component of soil is the mineral portion, which makes up approximately 45% to 49% of the
volume. Water is the second basic component of soil. Water can make up approximately 2% to
50% of the soil volume. Water is important for transporting nutrients to growing plants and soil
organisms and for facilitating both biological and chemical decomposition. Soil water availability
is the capacity of a particular soil to hold water that is available for plant use. Organic matter is
the next basic component that is found in soils at levels of approximately 1% to 5%. Organic
matter is derived from dead plants and animals and as such has a high capacity to hold onto
and/or provide the essential elements and water for plant growth. Air is the next basic
component of soil. Because air can occupy the same spaces as water, it can make up
approximately 2% to 50% of the soil volume. Air is essential for root and microbe respiration,
which helps support plant growth

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 Republic of the Philippines
UNIVERSITY OF RIZAL SYSTEM
Rodriguez Campus
T. Reyes St., Amity Ville, San Jose, Rodriguez, Rizal Email Address: ursrodriguezcoa@gmail.com

2. What does an ideal soil composed of? What happens to the composition of the soil
by volume when there is drought? Typhoon?

An ideal has soil has 45% of mineral matter, a 25% air, 25% of water and a 5% of organic
matter composition. But if there is drought and typhoon, the percentage of components changes.
If there is drought, the soil has 45% of air, a 45% of mineral matter, a 5% of water and a 5% of
organic matter. And if there is typhoon, the soil has 45% of mineral matter, a 45% of water, a 5%
of air, and a 5% of organic matter

3. What composes the mineral matter of the soil?

Based on the activity I've done, there are minerals like small rocks that may be caused by
weathering and also there is a presence of coal. And these minerals holds an organic chemicals
which are good for the soil.

4. What composes the organic matter of the soil? Identify the different components of
soil organic matter you found on the surface soil you observed. Is there any
difference on the soil organic matter components above and below the soil?

There are humus present there which can be considered as Stable Organic Matter

5. Can you see or feel the soil water or soil solution in your sample from Activity 1?
What do you think is the percentage by volume of soil water from your sample?

Since the soil is drowned in water and compacted, I think there is a 45% of water inside the soil.
But if the soil becomes loose because of the water, I think the water sinks inside the soil and can
make the water percentage inside the soil higher.

6. Based on your observation on Activity 2, what is the indication that air is present in
the soil?

When the soil putted in a watered container, there are bubbles pop up which indicates the
presence of air inside the soil

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 Republic of the Philippines
UNIVERSITY OF RIZAL SYSTEM
Rodriguez Campus
T. Reyes St., Amity Ville, San Jose, Rodriguez, Rizal Email Address: ursrodriguezcoa@gmail.com

7. Based on Activity 2, can you identify the stage of decomposition of the organic
matter present on the top of the water?

The organic matter present in the soil is a Stable Organic Matter. As you can see on the picture
on page 10 and 11, there are black twigs which can be considered as humus.

Bonus Question: What do you think is the importance of familiarizing yourself with the
different components of the soil?

It is very important to know the components of the soil because it will tell you if the soil is healthy
and suitable for planting. If the soil is nutritious, therefore it can be a good medium for plant
growth. But if it is not nutritious, then you should not plant any plants.

Prepared and adapted by:

DR JERICHO M INARDA, PAE

Subject Instructor

Gratitude to Ms LOVELY LUAR for the materials.

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