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Current Category » Agricultural Meteorology

Untitled Document

Thermal Properties Of Soils

1. Specific heat (Mass specific heat):
It is the amount of heat required to raise the temperature of one gram of substance by 1 0C.  The values for most minerals present in the soil are between 0.18 to 0.20 cal/gm.               

2. Heat capacity (volume specific heat):

It is the amount of heat required to raise the temperature of one cubic centimeter substance by 1 0C .Most soils have a heat capacity in the range of 0.3 to 0.6 cal/Cm3.

3. Thermal conductivity:

It is defined as the quantity of heat transmitted through unit length of substance per unit cross section, per unit temperature gradient per unit time.
Thermal conductivity is the ability of the substance to transfer heat from molecule to  molecule to molecule.  For this reason it is sometimes called inolcular conductivity.  It varies with porosity, moisture content and organic matter content of soil. It is expressed in Jm-1 s-1 K-1

4. Thermal diffusivity:

Thermal diffusivity is the ratio of the thermal conductivity to volume specific heat.
Thermal diffusivity =   Thermal conductivity/ Volume specific heat

Current Category » Agricultural Meteorology