The effect of soil moisture on thermal properties in some typical Japanese upland soils

Abstract

The effects of soil moisture on thermal properties of some typical Japanese upland soils were studied. Thermal properties which were studied here were volumetric heat capacity, thermal conductivity, and thermal diffusivity. Sample taken at various horizons of volcanic ash (Yachimata) soil, alluvial (Kiyosu) soil, and diluvial (Toyoilashi) soil were used. The results are summarized as follows. 1) Volumetric heat capacity (C): The C values are about 0.1 cal/cm30C for the volcanic ash soils and 0.2 cal/cm30C for the alluvial and diluvia1 soil at the oven dried state. 2) Thermal conductivity (λ): Linear relations are recognized between thermal conductivity and water ratio in all the samples. The coefficients of correlations are very high. The slopes and intercepts of the lines increased with the solid ratio. From these results, a simple model of the mechanism of heat conduction was introduced. 3) Thermal diffusivity (K): The values of K change with water ratio but linear relations between K and water ratio are not recognized. The K values vary between about 1˜2 × 10-3 cm2/sec for the volcanic ash soils, 3˜4.5 × l0-3cm2/sec for the alluvial soils and 4.5˜6 ×10-3 cm2/sec for the diluvial soils. The K values of volcanic ash soil are very small and nearly equal to that of peat soils. © 1975 Taylor & Francis Group, LLC.