Specific Heat and Volumetric Heat Capacity of Some Saudian Soils as affected by Moisture and Density

The ability to monitor soil heat capacity is an important mean in managing the soil temperature regime, which in turn, affects its ability to store heat. The effect of water content and bulk density on the specific heat and volumetric heat capacity of two Saudian soils (sand and loam) was investigated through laboratory studies. These laboratory experiments used the calorimetric method to determine specific heat of soils. For the type of soils studied, specific heat increased with increased moisture content. Also, volumetric heat capacity increased with increased moisture content and soil density. Volumetric heat capacity ranged from 1.55 to 3.50 for loam and from 1.06 to 3.00 MJ/m3 / o C for sand at moisture contents from 0 to 0.20 (kg/kg) and densities from 1200 to 1400 kg/m3 . Specific heat ranged from 1140 to 2090 for loam and from 800 to 1530 J/kg/ oC for sand at moisture contents from 0.01 to 0.20 (kg/kg) and soil density of 1200 kg/m3 . The volumetric heat capacity and specific heat of soils observed in this study under varying moisture content and soil density were compared with independent estimates made using derived theoretical relations. The differences between the observed and predicted results were very small. Loam soil generally had higher specific heat and volumetric heat capacity than sandy soil for the same moisture content and soil density.