Validation of universal soil loss equation for selected soil locations in Northcentral Nigeria using a rainfall simulator

Abstract

Erosion control in Nigeria must be met with high standards to attain a sustainable agricultural practice to meet the demand of the growing population in terms of food production. The study is aimed at estimating soil loss using a locally maderainfall simulator and ascertaining the performance of the Universal Soil Loss Equation (USLE) model in predicting soil loss in the study location. For this to be investigated, experiments were conducted using rainfall simulators, which are readily unavailable in Nigeria due to their high cost. The drop velocities (DV) of the constructed rainfall simulator were 8.101 m s-1 and 2.443 m s-1, respectively, when operated at maximum and minimum intensity. The performance test revealed that the experimental coefficient of uniformity (CU) was 79.86% at 31.79 mm h-1. In comparison, the rainfall intensity for the simulator equals 78.03% at 16.08 mm h-1, respectively, for the maximum and minimum concentration. Two experimental plots of vegetative and bare plots to estimate soil losses. The maximum soil loss of 0.515 kg m-2 experienced from bare plot at maximum rainfall simulator intensity. Measurements and analysis in this experiment showed a strong correlation over a short term between erosivity index, R, and observed soil losses, which confirms the validity of Universal Soil Loss Equation (USLE) under the conditions of the experiment. Coefficient of determination (R2) between erosivity index R and corresponding soil losses showed a weak correlation for vegetative plot due to the insufficient data of factors but a good correlation for bare land over a short term. The overall results confirmed the validity of USLE under the condition of this experiment within this study area was for a short period.