Abstract

The thermal properties of soils, as thermal conductivity, have been usually determined by different designs of the quasi-permanent hot wire method. In the present paper the hot disk method was used to determine the effective thermal diffusivity (ETD) and thermal conductivity (TC) of soils derived from volcanic materials (one Ultisol and two Andisols) as a function of temperature from 25C to 280C. The volumetric heat capacity was also calculated from ETD and TC estimations. The TC values at 25C ranges from 0.84-0.94 for Andisols to 1.27 Wm-1K-1 for the Ultisol, and are similar to those reported by the hot-wire method. Values decrease down to 0.28-0.32 for Andisols and 0.67 Wm-1K-1 for Ultisol when heating temperature increases from 25C to 280C. The TC increases when soil density or water content increases, and decreases when soil organic matter content increases. The values of the thermal properties depend on water and organic carbon content, and mineralogy of samples