Crop production depends directly and indirectly on weather condition. The Effects of Weather on Crop Production depends on Solar Radiation, Air Temperature, Precipitation/Rainfall, Relative Humidity, Wind Movement, Atmospheric Pressure and Clouds. The effects of weather on crop production is described as following:
Table of Contents [hide]
- 1 The Effects of Weather on Crop Production
- 1.1 Solar Radiation:
- 1.2 Air Temperature:
- 1.2.1 The Effects of Weather on Crop Production – Temperature
- 1.3 Precipitation/Rainfall:
- 1.3.1 Effects of Precipitation/Rainfall
- 1.4 Winds:
- 1.5 Atmospheric Pressure:
- 1.6 Clouds:
The Effects of Weather on Crop Production
- Direct Solar radiation. It is the amount of radiation received directly from the Sun. The radiation scattered by the suspended particles is called diffused In diffused radiation, about 65 percent is photosynthetically active radiation (PAR) compared to 45 percent in direct radiation. As clouds are very effective reflectors, little solar radiation reaches the earth surface on a cloudy day. Snow is also a very effective reflector (especially when it is fresh). Water surfaces and sea are poor reflectors and thus serve as a good sink for solar energy. Rocks, sand and vegetation reflect 10 t0 30 percent of the incident solar radiation. This explains why photosynthetic activity is > rabi season> kharif-2> kharif -1
- Influence of Sunlight. Photoperiodism Photo/day neutral plants (No relationship bet flower formation and day length): BR-3, maize, soybean, eggplant, tomato, sunflower, banana, papaya Short day plants (critical 11-12 hrs plants that flower below the critical period. E.g. Jute 11.5hrs): Jute, T.Aman, tobacco, sweet potato Long day plants ( critical period 12-14hrs– Long day i.e. short night is required for flowering):Cabbage, potato, lettuce, radish ( eg Spinach flowers above 13 hrs day length or more but not less).
Temperature is defined by the degree of hotness or coldness of a substance, determined by the extent of its molecular activity.
The Effects of Weather on Crop Production – Temperature
- Germination: Proper temperature is essential for seed germination. Too high and too low temperature prohibits seed germination. Different crops have different term requirement for germination and complete life cycle.
- Photosynthesis: Occurs within -6 to 370 Growth, development and yield: Production of dry matter occurs when soil temperature ranges bet 20-30 0C.
- Flower initiation: Certain crops require low temperature for flower initiation and Flowering. E.g. Cabbage, cauliflower, carrot turnip etc flower in low temperature.
- Life span: rabi> kharif-2> kharif-1 due to comparatively reduced respiration rate.
- Transpiration/evaporation: kharif-1> kharif-2> rabi due comparatively higher temperature.
- Insects, pests/diseases/weeds: Transpiration/evaporation: kharif-1> kharif-2> rabi due comparatively higher temperature.
- Product quality: better quality in relatively low temperature (depending on crops)
- Yield: rabi> kharif-2> kharif-1 due to comparatively reduced respiration rate and higher net photosynthetic rate
The falling off any type of condensed moisture to the ground is called precipitation. Rainfall is precipitation in the form of liquid drops larger than 0.5mm in diameter is falling on the earth.
When water droplets in a cloud grow in size and become heavy enough, they fall in the form of rains. Ordinarily, rain drop size varies from 0.5 to 4 mm in diameter.
Effects of Precipitation/Rainfall
Effects of precipitation or rainfall are most important among The Effects of Weather on Crop Production.
- Germination: Proper moisture is essential for seed germination. Different crops have different moisture requirement for germination and complete life cycle. Wheat seed requires 55% water absorption compared to its weight for germination. Mustard requires less water absorption. T. Aman and jute requires more rainfall to grow. Chili and Potato seed damages with higher rainfall.
- N Fertilization: Atmospheric N added to the soil through rainfall.
- Tillage and intercultural operations: Better performed under field capacity and wet condition depending on crops. Upland farming needs special practices.
- Insects, pests/diseases/weeds: kharif-1> kharif-2> rabi due comparatively higher rainfall and excess moisture.
- Photosynthesis: Less Net photosynthesis in more cloudy days.
- Growth, development and yield: rabi> kharif-2> kharif-1 due to comparatively controlled moisture contents.
- Soil erosion: higher in excessive rainfall and open field.
- Product quality: rabi> kharif-2> kharif-1 due comparatively controlled.
- Moisture contents: Grapes ate sour in rainy seasons.
The wind is air in the horizontal motion which travels from a high-pressure area to a low-pressure area. Variations in incident solar radiation due to earth’s position and angle of incidence cause low and high-temperature regimes in different areas. Air from high-pressure areas rushes to the low-pressure areas causing horizontal movement of wind. Wind direction and velocity is important for agricultural crop production. Wind velocity is measured by the anemometer.
The Pressure exerted by the atmosphere of the earth’s surface is called atmospheric pressure. Generally, in areas of higher temperature, atmospheric pressure is low and in areas of low-temperature pressure is high. Atmospheric pressure has no direct influence on crop growth. It is, however an important parameter in weather forecasting. Instruments for measuring atmospheric pressure are aneroid barometer and barograph.
Solar radiation provides energy for evaporation. Evaporation supplies water vapor to the air. Air rises upwards on account of increasing temperature. As the mass of air goes up, it expands due to low pressure and cools. If the cooling proceeds up to saturation, water vapor condenses and cloud formation takes place. Clouds are also formed when a current of warm air strikes a parcel of cool air, or when a moist air from sea blows over cold land. Thus, the cloud is an aggregate on minute drops of water suspended in the air at higher altitude. Clouds are at a basic height of 1950 m. If it is formed above that height, the word, ‘alto’ is associated. If the cloud is associated with rains, word, “nimbus” is associated.
Thunderstorms: Cumulo-nimbus. These clouds develop from cumulus that has developed into tremendous towering clouds with a vertical range from base to 3 to 8 kilometers. When grown to this height, such clouds form the well-known thunderstorms. Thunderstorms help in fixing atmospheric N into the soils in the form fertilizer. We can not control All The Effects of Weather on Crop Production.
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