Factors affecting soil temperature

Temperature of the soil surface is affected by rate of heat gain by radiation & its loss, thermal conductivity of the lower layers. Soil temperature is affected by following factors;

1. Amount of radiation received by soil:
2. Albedo of soil
3. Texture of soil
4. Soil moisture and air content
5. Organic matter on soil
6. Rainfall characteristics of the area

Diurnal variation in soil temperature

• Due to absorption of solar radiation, heat is generated inside the earth surface and temperature increases.
• As radiation falls in the soil surface, heat is transfer to the soil profile by the process of conduction.
• The incoming energy available at the soil surface varies with position of the sun, so there appears diurnal variation of soil temperature on soil profile

Annual variation in soil temperature

• As compared to diurnal change, annual temperature fluctuations extends much deeper into the soil profile.
• The surface layer begins to warm up from February and attains maximum at the time of May last or June first. And then it gradually decreases and is minimum at around January.
• In March, the warming is accelerated on the surface and the cooling of lower depths is arrested. Then the flow of the heat is downwards.
• After attaining maximum temperature around first of June, the soil temperature decreases due to the commencement of monsoon from 3rd week of June but the flow of heat still remains downwards.
• Due to heavy rainfall, high water table condition and seasonal change, upper surface of soil profile start cooling. In month of November, the cooling is accelerated and continued to January when profile as a whole suffer the most rapid cooling and cycle once again commences.