Tuesday, March 16, 2010

Heat Capacity Of Soil

Soil heat capacity varies depending on type of soil and soil moisture.


Soil heat capacity measures the amount of energy it takes to raise the temperature of the soil by one degree Celsius or one degree Fahrenheit. The heat capacity of soil varies depending on the amount of moisture and the soil composition. Does this Spark an idea?


Types


The heat capacity of soil is much greater than the heat capacity of air but less than the heat capacity of water. Consequently, wet soils have higher heat capacities than dry soils, so a light dry soil exhibits larger seasonal temperature changes than a wet soil. Other factors affecting heat capacity include the amount of sand, clay, silt and organic matter.


Function


According to the Engineering Toolbox, the average heat capacity at constant pressure of dry soil is 0.8 kilojoules per kilograms Kelvins. The average heat capacity of wet soils, by contrast, is 1.48 kilojoules per kilograms Kelvins. Clay soils typically have higher heat capacities than sandy soils, and increasing the organic matter content typically increases moisture retention and heat capacity.


Considerations


Soil heat capacity is sometimes measured in terms of the volumetric heat capacity, or heat capacity per unit volume. Tilling soil, adding organic matter in the form of mulch and other human actions can alter the heat capacity of soil to some extent.







Tags: heat capacity, heat capacity, organic matter, Soil heat, Soil heat capacity, average heat