Variability of Soil Thermal Properties of a Seasonally Cultivated Agricultural Teaching and Research Farm, University of Ibadan, South-western Nigeria
Knowledge of the thermal properties of the soil top layer is of great importance in agricultural meteorology where problems of heat exchange at the soil surface are encountered. The availability of these data is important because of the improvements in wider applications of soil heat and water transport models as well as seed germination and crop growth. This research work therefore intends to determine the variability of soil thermal properties of a seasonally cultivated Agricultural Teaching and Research Farm located within the University of Ibadan campus, South-western Nigeria with a view to have understanding of how different soils warm up in order to allow better planning of planting of crops and have knowledge for the control of thermal-moisture regime of soil in the field and greenhouse. Forty-five points were located for the measurements of thermal properties in cultivated fields of maize, pineapple, cowpea, Okro and vegetables. A KD-2 Pro thermal analyzer was used for the measurements of these thermal properties such as thermal conductivity, thermal resistivity, volumetric specific heat and thermal diffusivity. Samples were collected at each location for the laboratory determination of soil moisture content and bulk density. The variability of soil thermal properties was analysed using classical statistics such as mean, range, standard deviation and coefficient of variation. The results show that for the whole site, the thermal conductivity, volumetric specific heat, thermal diffusivity and temperature ranges from 1.103-2.151 W/mK, 1.247-2.936 mJ/m3K, 0.486-1.000 mm2/s and 23.83-34.49 oC with mean values of 1.672 W/mK, 1.831 mJ/m3K, 0.785 mm2/s and 27.71 oC respectively. Also soil moisture content and bulk density ranges from 0.146-0.223 m3m-3 and 1.260-1.410 mg/m3 with an average of 0.191 m3m-3 and 1.340 mg/m3 respectively. It was found out that the thermal properties of agricultural soils within University of Ibadan vary from one point to the other and th
