Thermal Properties of a Soil Based Upon Field and Laboratory Measurements

Abstract The thermal properties of Yolo silt loam were analyzed on the basis of laboratory and field measurements. Values of the apparent thermal conductivity of the soil, measured as a function of soil water content using a line heat source probe at several soil depths, compared favorably with those values predicted by a theoretical model of de Vries. Values of the apparent thermal diffusivity based upon phase and amplitude relations of the diurnal temperature fluctuation at several soil depths agreed with those obtained from a numerical analysis using temperature data from 13 depths below the soil surface recorded at 10‐min intervals. Measured values of the apparent thermal conductivity divided by measured values of volumetric heat capacity were compared with the above diffusivity values. Whenever the soil‐water content was approximately uniform with depth, an acceptable agreement between values from all methods was obtained. Use of the numerical analysis has the advantage that no corrections are needed for deviations from periodicity of the temperature wave of the upper soil boundary.