The effects of various soil treatments on crop yield in Southeastern Nigeria

In this study, a PVC drip irrigation system was designed to investigate the effect of different soil treatments on crop yield, using Oba Super 13 maize variety as test crop, on three major plots, each representing a different tillage method. Each plot has three levels of each of the three soil treatments involved including irrigation deficit, tillage method and NPK Application rate, totaling 27 subplots. The three levels of irrigation treatments were 50%, 30% and 10% management allowable depletion levels; tillage treatments were conventional tillage, conservative tillage and no tillage methods, while the NPK application treatments were 400 kg/ha, 500 kg/ha and 600 kg/ha rates, and experimentally designed using the Central Composite Design (CCD) in Design Expert 11 software. The crop yield for all the subplots were determined, and maximum crop yield of 2540 kg/ha was obtained at conservative tillage with 10%MAD, and 600 kg/ha NPK application rate, while minimum tillage of 1234.67 kg/ha was obtained at no tillage, 50%MAD and 400 kg/ha NPK application rate. Controllable variables were optimized using response surface methodology (RSM) with crop yield for all the subplots. The optimum values based on the run gave irrigation deficit as 11.594%, NPK Application rate as 596.406 kg/ha, best tillage method as conservative tillage, crop yield of 2543.589 kg/ha. The highest maize yield was obtained in conservative tillage and the results confirm the viability of obtaining high yield in the study area using drip irrigation system during the dry season.