The relationships among thermal resistivity, water content and a stony sandy soil

Developing soil macro-porosity could be considered to be a direct effect of physical, chemical and eco-pedological processes where the soil matrix has contact with coarse elements. Hence, macro-porosity acquires a special importance affecting the liquid phase as well as the gas phase, and therefore the soil thermal properties as well. The aim of this research is to evaluate the effect of the coarse elements on the total thermal resistivity (Rho) for a sandy soil. The experiment was carried out with several gravel masses (kg(gravels)center dot kg(soil)(-1)) mixed with soil, and repacked in a soil column device. The method used for measuring the thermal resistivity was the heat pulse, based on ASTM D5334-08. The water content (theta) was determined using capacitor probes (FDR probes). The experimental device was maintained inside a thermal chamber for controlling a minimal thermal drift. The Rho(theta) relationship presented higher variability when 35% of coarse elements were added and the water content was close to saturation.