In-Situ Spatial Variability Of Thermal Conductivity And Volumetric Water Content In A Silty Topsoil

Abstract

Studies of spatial variability of thermal conductivity and volumetric water content of silty topsoil were conduct-ed on a 0.6 ha site at Abeokuta, South-Western Nigeria. The thermal conductivity (k) was measured at depths of up to 0.06 m along four parallel profiles of 200 m long and at an average temperature of 25 C, using a micro-processor-based thermal meter. The volumetric water content (Vw) was determined by gravimetric method. The values of k increased with bulk density and Vw. The mean values of k and Vw were 0.41  0.26 W m-1 K-1 and 0.044  0.028 m3m-3, respectively. The effective range of k was 25.20 m with nugget to sill ratio of 0.28, but was 26.01 m with nugget to sill ratio of 0.25 for Vw. The semi-variance of the data for k and Vw were fitted to exponential models where the spatial structures variability ranged from weak to moderate.

Journal of Applied Science and Technology Vol. 12 (1&2) 2007: pp. 52-57