Thermal Diffusivity Variations at Ministry of Agriculture Akure South, Ondo State, South–West Nigeria

Thermal diffusivity variations of different soil types in a tropical location, Akure, Nigeria at three different depths over dry and wet seasons are presented. The time lag method was used to estimate the thermal diffusivity (D) of the experimental site using the hourly and mean weekly temperature distribution alongside soil properties such as moisture content, bulk density, porosity and soil heat capacity, at the depths of 30, 40, and 50 cm. Soil type include sandy clay for the 30 cm depth and sandy loamy clay for the 40 and 50 cm depths. Results obtained show a larger variation of thermal diffusivity, having an average value of 59.68 x 10 -7 m2/s in the wet season as compared to 1.41 x 10-7 m2/s for the dry season. Strong correlation exists between the diurnal variation of soil temperature modeled based on different depths and the measured values.