THERMAL-CONDUCTIVITY OF SOILS AS A FUNCTION OF TEMPERATURE AND WATER-CONTENT

Apparent thermal conductivities of loamy sand, loam, and silty clay loam soils were measured with a cylindrical heat probe at several water contents and temperatures. Values of thermal conductivity ( lambda ) were also calculated with the D. A. de Vries model. Results show that the model may be used satisfactorily to calculate lambda . The heat probe method of measuring the thermal conductivity requires a correction factor to allow for errors due to the entrapment of air at the surface of the heat probe, when used at water contents ranging from 0 to about 30% of saturation.