Performance of Soilwat Model for Soil Physical Properties Simulation in Auchi, Edo State

The physical properties of soils are dominant factors affecting the use of a soil which determine the availability of O₂ in soils, the mobility of water into and through soils and case of root penetration and also the chemical and biological behavior of soil. The aim of this paper was to investigate the performance of soil physical properties data that was OILWAT model in the prediction of soil physical properties adapted from previous study in the Department of Agricultural and Bio-Environmental Engineering Technology. SOILWAT performed poorly in simulating volumetric moisture content, the equation of the line obtained is y = 0.0403x + 15.428, with the R² = 0.0274, the RMSE value is 4.21 which is quite large compare to the model’s ability to simulate bulk density and saturated hydraulic conductivity. When compared with the measured data, SOILWAT significantly simulated Bulk Density (BD) for Sandy loam and sandy clay loam soil having a perfect agreement between the observed and simulated values (R² = 0.90, p<0.05; RMSE of 0.033 and regression equation given as; y = x – 0.33). The model significantly predicted the Saturated hydraulic conductivity, with R² value of 0.92 and root mean square error (RMSE) 0.03, the equation of best fit obtained is y = x+0.21, since sample environment (confinement and overburden) are not represented in laboratory procedures, laboratory data may not always agree with field data.