Major elements of climate

1. Solar radiation:

• Solar radiation performs two essential functions.
• Provide light for direct growth and development functions in the plants.
• Provides heat that governs and indirectly affects various physiological processes in the plant.
• The instrument that is used to measure total incoming radiation is called pyranometer.
• Intensity, duration and quality of solar radiation, which control growth and development in the plants.
• The duration of radiation controls photoperiodism and the intensity and quality control the
• physiological processes in the plants.

2. Temperature:

• Temperature affects the physical and chemical processes within the plants.
• The diffusion rate of gases and liquids change with temperature.
• Solubility of different substances depends upon the temperature.
• The stability of the enzyme system is affected by the temperature.

3. Relative humidity (RH):

• Determines the rate of evaporation and transpiration.
• The higher the relative humidity, the less is the evapo-transpiration and vice versa.
• High humidity favors the growth of fungi and other crop pests.
• About 70-80% RH is considered optimum for crop production.

4. Wind:

• Wind is indirectly responsible for causing rainfall and changing the humidity of a certain places.
• Directly, the gentle wind is responsible for promoting photosynthesis by supplying CO2 in the deeper leaf layer of plant canopy.
• Gentle wind helps to pollinate the crop plants, water uptake, conduct proper metabolism, and regulates the temperature of plant canopy.
• Hot dry wind is harmful for crop plants because such wind accelerates the transpiration and evaporation from the soil causing desiccation of plants.
• It also affects the photosynthesis by the closing of stomata.
• High wind velocity causes lodging of crops, breakage of plant parts, shattering of grains, flower drops and uprooting of whole plant.
• In desert and light soil containing field the high wind velocity causes more soil erosion also.