Agrometeorology - Microclimate And Plant Growth

By TamilNadu Agricultural University on 28 Dec 2018 | read
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Micro Climate in Relation to Crop Production

Soil Temperature Dynamics
Soil temperature and its importance in crop production

  1. Soil temperature is an important environmental parameter for plant growth.
  2. Variation in soil temperature is much more pronounced because of varying characteristics and composition of soil.

Image titleDrip Irrigation

Image titleMicro-Sprinkler

Image titleTrash Mulching

Soil temperature and plant

  1. Soil temperature extremes influence the germination of seeds, functional activity of root system (Rice – 10° C; Wheat – 3° C).
  2. Excessive high temperature is harmful to roots and also causes lesions of stem.
  3. Extreme low temperature impede intake of nutrients.
  4. Soil moisture intake by the plants stops when the soil temperature is at a temperature of below 1° C.
  5. Day time soil temperature is more important because it is necessary to maintain favourable internal crop water status in the light of the high evaporation rate.
  6. High soil temperature causes degeneration of the insets in potato optimum soil temperature for this crop is 17° C, tuber formation is practically absent above 29°C.
  7. Crop yield increases linearly as the 10 cm depth soil temperature increases from     15° C to 27° C for maize.
  8. Extreme low and high temperature influences the soil microbial population and rate of organic matter decomposition.
  9. Rate of decomposition is high under high soil temperatures.
  10. Soil temperature controls the nutrient availability (eg., Nutrient release and N fixation)

Factors affecting soil temperature:

Slope:

  1. Slope an important factor in temperate regions.
  2. In the northern hemisphere a south – facing slope is always warmer than a north facing slope (or) plains.   

Tillage:

  1. Shallow tillage and creating ‘dust mulch’ reduces the heat flow between the surface and sub soil.
  2. Cultivated soil has greater temperature aptitude compared to uncultivated soil.
  3. The air temperature an inch above the soil is 5 to 10°C higher in cultivated soil compared to uncultivated soil during noon.

Soil Moisture:

  1. Availability of optimum soil moisture maintains the soil temperature at required level.

Soil texture:

  1. Sandy soil warm up more rapidly than clay soils, because of lower heat capacity of sandy soils.
  2. Sandy soils have higher temperature in winter.

Organic matter:

    1. Organic matter reduces the heat capacity and thermal conductivity of soil, increased absorptivity due to dark colour.
    2. When organic soils are dry they become warmer than mineral soil in summer and cooler
 

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