Effect of Phyisco-chemical Parameters on the Thermal Diffusivity and Soil Heat Flux over Ayadi, Ondo State, Nigeria

This study assesses the effect of some soil physical properties on the thermal diffusivity and soil heat flux over Ayadi in Ondo State, Nigeria. Physical properties of the soil at different depths were determined using laboratory techniques. In-situ measurement of air temperature and surface soil temperature were carried out. The phase lag method was used to determine the thermal diffusivity of the soil, while the subsoil heat flux was determined from values obtained for the thermal diffusivity. The result showed that the subsoil heat flux values during the dry season ranged between 0.58 and 52.84 W/m2, while that of the wet season ranged between -0.77 and 98.50 W/m2. The average thermal diffusivity values at the different depths had values between 0.74 × 10-7 and 238.7 × 10-7 m2/s for the dry season, while the wet season had a range of 1.97 × 10-7 to 238.7 × 10-7 m2/s. Keywords: soil moisture content, air temperature, soil temperature, soil heat flux, thermal diffusivity.