Babatunde KM, Adekanmbi OA, Adeyolanu AS and Salau MA
Experiment was conducted to obtain information on seperate and interaction effects of tillage passes and 15-15-15 NPK fertilizer application rates on some growth parameters, N, P and K uptake by Amaranthus viridis, hence the use of a tractor implement with specified specification on sandy clay soil planted with Amaranthus viridis. The research was conducted at vegetable research plot, Department of Agricultural Technology, The Oke-Ogun Polytechnic, Saki, between 2nd July and 30th September, 2015. Soil treatments consisting of three levels of tillage passes (0, 3 and 6) equivalent to 1.7, 1.3 and 1.5 g/cm3 soil bulk density respectively, four levels of 15-15-15 NPK fertilizer rates (0, 100, 150 and 200 kg/ha) and replicated three times in a completely randomized design. The results showed that no-tillage pass had significant effect on bulk density, zero tillage reduced the percent uptake of N(0.58-0.46), P (0.002-0.0005) and K (0.13-0.04), however, statistically, the reduced effects were more pronounced on Nitrogen and Potassium. Fertilizer rates significantly improved percent uptake of N (0.11-0.58), P (0.0004-0.005) and K (0.04-0.07). Interactions (tillage passes × fertilizer rates) effects were observed on plant height, stem girth,fresh weight, root length and percent N, P and K uptake, but T2F2 (6 passes × 150 kg/ha) significantly increasedplant height and improved uptake of Phosphorous, therefore, 6 passes and 150 kg/ha 15-15-15 could be more suitable for optimum production for Amaranthus viridis on a sandy clay soil.