PRACTICAL

FUNDAMENTALS OF AGROMETEOROLOGY
AND
CLIMATE CHANGE

Prepared by Ajay Jaishi

Prepared by Ajay Jaishi
PRACTICAL NUMBER 1
SITE SELECTION AND LAYOUT FOR
INSTALLATION OF METEOROLOGICAL
STATION

 A meteorological station is a facility equipped

with instruments to measure atmospheric
conditions such as temperature, humidity, wind
speed, wind direction, rainfall, solar radiation,
and atmospheric pressure.
 Proper site selection and layout are crucial to
ensure accurate and representative data
collection

Prepared by Ajay Jaishi

 Basic Requirements for Meteorological Station Site Selection

1. Open Surroundings, Avoid Obstruction

2. Avoid High Magnetic Field Areas

3. Avoid Pollution Sources and Human Disturbance

4. Flat and Stable Ground

5. Consider Natural Environmental Features

Prepared by Ajay Jaishi

 Instruments and Their Placement
1. Thermometer & Hygrometer –
• Placed in a Stevenson screen (1.25–2 m above ground).
• Height: 1.25–2.0 m above ground.
• Material: White-painted, double-louvered wooden or plastic enclosure.
2. Anemometer & Wind Vane – Installed at 10 m height for standard wind measurements.
3. Rain Gauge
• Positioned 30 cm above ground, away from obstructions.
• Distance: At least twice the height of nearby obstacles (e.g., 4m from a 2m fence).
4. Barometer – Kept indoors or in a stable environment to avoid direct weather effects.
5. Sunshine Recorder (Campbell-Stokes or Pyranometer)
• Height: 1.5 m above ground.
• Location: Fully exposed to sunlight, no shading at any time of day.
6. Soil Temperature Sensors
• Depths: 5 cm, 10 cm, 20 cm, 50 cm, and 100 cm below ground.
• Placement: Bare soil, away from artificial heat sources.
Note: Fencing: If needed, use open wire mesh (not solid walls) to avoid microclimate effects.
Prepared by Ajay Jaishi
 PRACTICAL NUMBER 2
MEASUREMENT OF SOLAR RADIATION AND CALCULATE THE PAR

Prepared by Ajay Jaishi

Q) A pyranometer installed in a field records an average solar radiation
of 600 W/m² over 4 hours (10:00 AM to 2:00 PM). Estimate:
a) Total energy received per m² over the 4-hour period .
b) The PAR energy assuming 45% of total solar radiation is PAR.

Calculate Total Energy Received (in Joules/m²)

Formula:
Energy=Power * Time

Calculate PAR (Photosynthetically Active Radiation)

Given:
PAR = 45% of total solar radiation
PAR Energy=8,640,000 J/m² ×0.45

Prepared by Ajay Jaishi

 PRACTICAL NUMBER 3
MEASUREMENT OF MAXIMUM-MINIMUM AIR TEMPERATURE
AND CALCULATE GDD

•Maximum thermometers use mercury + constriction to trap the highest temp.

•Minimum thermometers use alcohol + index to mark the lowest temp.
•Both are reset manually and provide precise, separate readings for weather stations.
Prepared by Ajay Jaishi
 Max Temp Min Temp
Day Date Base Temp = 10°C
(°C) (°C)

1 April 1 22 12 (22+12)/2 - 10 = 7.0

2 April 2 24 14 9.0
3 April 3 20 10 5.0
... ... ... ... ...

30 April 30 26 16 11.0

31 May 1 28 18 13.0
32 May 2 30 20 15.0
... ... ... ... ...
60 May 30 32 22 17.0
61 May 31 34 24 19.0
62 June 1 35 25 20.0
... ... ... ... ...
90 June 30 36 26 21.0
Prepared by Ajay Jaishi
PRACTICAL NUMBER 4
DETERMINATION OF VAPOUR PRESSURE, RELATIVE HUMIDITY AND DEW POINT
TEMPERATURE USING PSYCHROMETER AND PSYCHROMETRIC CHART.

Prepared by Ajay Jaishi

 Calculation of Vapor pressure and RH

Actual Vapour Pressure (AVP) SVP: Obtained from Hygrometric table

RH = ------------------------------------------- X 100 % / graph at Tw (Wet bulb temperature)
Saturation Vapour Pressure (SVP) AVP = SVP – ½ (Td – Tw)

Td = 27.40 0C
Tw = 23.00 0C

Td – Tw = 4.40
SVP (from Hygrometric Table / Graph) at Tw=23.00
= 21.10 mm Hg

AVP = SVP – ½ (4.40) = 21.10 – 2.20 = 18.90

18.90
RH = AVP / SVP = ---------- X 100 % = 90 %
21.10 Prepared by Ajay Jaishi
Calculation of Dew point from Psychrometric Chart

Prepared by Ajay Jaishi

PRACTICAL NUMBER 5
DETERMINATION OF AVERAGE WIND SPEED AND DIRECTION FROM MEASURED DATA

If the wind direction is reported as 315

degrees, it means the wind is blowing from
the northwest (NW).

Wind direction is measured in degrees

from true north (0°) and increases
clockwise:
0° (or 360°) = North (N)
90° = East (E)
180° = South (S)
270° = West (W)
315° is exactly halfway between West
(270°) and North (360°), placing it in Figure: Wind compass describing wind direction.
the northwest (NW) direction. This compass is based on the 360 degrees found in a
A 315° wind is blowing from the northwest circle.
toward the southeast. Prepared by Ajay Jaishi
 WIND SPEED SCALE

Q) A wind anemometer with radius 0.25 m completes 90 rotations in 3 minutes. Find the
average wind speed in km/h.

Prepared by Ajay Jaishi

PRACTICAL NUMBER 9
PREPARATION OF CROP WEATHER CALENDAR

 Crop weather calendar is a comprehensive guide for farmers.

 It is a tool that provides information on average weather of every week, planting,
sowing and harvesting periods of locally adapted crops in a specific agro-ecological
zone.
 It also provides stage-wise pest disease infestation information.
 Tracks crop stages: sowing → growth → flowering → maturity
 Provides:
i) Ideal weather conditions ii) Weather-based warnings

iii)Water requirements per growth stage iv) Pest/disease risk forecasts

 Supports: crop planning, irrigation, & pest control

Prepared by Ajay Jaishi

 Preparation of crop weather calendars

These crop weather calendars consist of three parts: A, B and C

(A) Meteorological Data
The top section of the Crop Weather Calendar displays average monthly weather data, including temperature,
rainfall, humidity, and sunshine hours. These values are derived from long-term (20+ years) records and are
aligned with standard meteorological weeks.
(B) Crop Growth Stages
The middle section illustrates the crop’s life cycle—sowing, growth, flowering, and maturity—through
horizontal bars. It highlights ideal weather conditions for each phase to maximize yield, accounting for
regional and seasonal variations.
(C) Pest & Disease Alerts
The bottom section identifies weather conditions that trigger pests/diseases, along with vulnerable crop
stages. This helps agrometeorologists issue timely warnings and advisories for effective crop protection.

Prepared by Ajay Jaishi

Prepared by Ajay Jaishi
Crop weather insect pest calendar for rice crop Prepared by Ajay Jaishi
 PRACTICAL NUMBER 13
CALCULATE AND ANALYZE CARBON FOOTPRINT

The carbon footprint is a measure of the amount of greenhouse gas emissions

released into the atmosphere by the activities of a person, company, city or
state.
In essence, it is a measure of how much we contribute to anthropogenic global
warming.
The footprint includes direct emissions caused by burning fossil fuels
(in driving a car engine or heating a building, for example) and indirect
emissions, such as those related to electricity consumed, if it comes
from fossil fuels.
And although by convention it is measured in tons of carbon
dioxide (CO2) per year, it actually includes emissions of all gases that
contribute to global warming.

Prepared by Ajay Jaishi

Step 3: Calculate Emissions
Use the formula:
Carbon Footprint (kg CO₂-eq) = Quantity Used (kg)×
Emission Factor (kg CO₂-eq/kg) Carbon Footprint (kg CO₂-eq)
=Quantity Used (kg)×Emission Factor (kg CO₂-eq/kg)Step 4: Sum Up
Emissions
Direct Emissions (from chemical application, e.g., N₂O from
fertilizers).
Indirect Emissions (from manufacturing, transport).

Prepared by Ajay Jaishi

Calculations:
Urea: 100×5.6=560 kg CO₂
DAP: 50×1.2=60 kg CO₂
Glyphosate: 5×15=75 kg CO₂
Diesel: 10×2.68=26.8 kg CO₂-eq10×2.68=26.8 kg CO₂-eq

Total Carbon Footprint:

560+60+75+26.8=721.8 kg CO₂-eq560+60+75+26.8=721.8 kg CO₂-eq

Prepared by Ajay Jaishi