IMPACT ASSESSMENT OF TILLAGE ON CROP YIELD IN THE GUINEA SAVANNAH PART OF KWARA STATE, NIGERIA

Abstract

Land and water resources are central focus to agriculture and are linked to environmental challenges like erosion, soil degradation, water pollution, climate change adaptation, destruction of ecosystems and habitat destruction among others. The major driver of these challenges is the use of inappropriate tillage pratices. This study investigated the environmental impact of tillage methods on crop yield and also model the impact associated with tillage methods on crop yield in the guinea savanna ecological zone, Kwara State, Nigeria. 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. Soil Water Assessment Tool (SWAT) was used to simulate the impact of the tillage methods on crop yield in watersheds over two planting seasons. The result findings reveal that crop yield (kg/ha) parameters had PH yield > NT yield (P (0.015) ˂ 0.05) > T yield (P (0.04) ˂ 0.05) and > PHR yield (P (0.046) ˂ 0.05) for UTRF and NCAM sites in 2015 while in 2016, PH yield > T yield (P (0.026) ˂ 0.05) > PHR yield (P (0.046) ˂ 0.05) and no statistical difference between PH and NT at both locations. Also, in the UTRF site, plant height, number of leaves, leave length and leave width explained 59.3% and 43.3% in 2015 and 2016 of the variance in the yield of maize respectively, while in NCAM site, these variables explained 54.7% and 1.1% in 2015 and 2016 respectively. The study concludes that the different tillage methods impact on the crop yield, however, Plough/Harrow had comparatively favorable effect on the soil environment, contribution to surface runoff and crop yield. It is therefore recommended that PH should be adopted for a sustainable environment.