SIMULATING THE IMPACT OF TILLAGE FOR SUSTAINABLE AGRICULTURAL DEVELOPMENT ON BIOPHYSICAL PARAMETERS IN RIVER OYUN CATCHMENT AREA, KWARA STATE

Abstract

Agricultural practices have been increasingly criticized for contributing to the deterioration of the nation's water resources. The aim of this study was to simulate the impact of different tillage types on some biophysical parameters in the lower catchment area of River Oyun using Soil Water Assessment Tool (SWAT) model. This model was designed to predict the impact of land management practices on water, sediment, and varying tillage types in watersheds over two planting seasons. Traditional heap(T), Plough/Harrow(PH), Plough/Harrow/Ridge(PHR) and No-till tillage(NT) methods commonly used in the study area were applied to experimental plots at Unilorin Teaching and Research Farm (UTRF) and National Center for Agricultural Mechanization (NCAM), Idofian. Using Randomized Complete Block Design (RCBD), each treatment had three replicates making 12 experimental plots at each location for 2015 and 2016 planting season. The study showed that four out of the eight biophysical factors examined (sediment yield-10.54 metric tons/ha, groundwater amount-174.45GWQmm, organic nitrogen- 62.62kg/ha, and nitrogen in surface runoff -5.15kg/ha) were higher on conservative tillage plot, and while three variables (surface runoff amount- 374.42SURQmm, evapotranspiration-752.78ETmm and soil loss-1.05USLE_LS) were higher on Plough/Harrow and Plough/Harrow/Ridge plots. The study concludes that the different tillage methods impact on the selected biophysical parameters and recommends the need for appropriate technology for monitoring over time, how farm management practices affect water and soil degradation. In addition, the study stresses the need for cooperation in research; the establishment of data banks operating on a unified information system; and the eminence of education, training, and extension to farmers in Nigeria.