Influence of N:K Ratios in Soils on Growth, Nutrient Availability and Yield of Maize (Zea mays L.) in Southern Nigeria

This study was undertaken to determine the influence of N:K ratios applied to soils and the availability of N, K on yield of maize in two distinct ecological zones of Edo state of Nigeria. The sites used were Rubber Research Institute of Nigeria (RRIN) Iyanomo (Forest) and the Teaching and Research Farm of Ambrose Alli University, Emaudo, Ekpoma (Derived Savanna). The soils of the two experimental sites were analyzed for both physical and chemical properties before the commencement of the experiments. The experiments were carried out as pot experiments in the screen house and field experiments. Each of the experiments had ten treatments (adjusted ratios) that were fitted into randomized complete block design and replicated three times. Maize was used as the test crop. Results from the screen house revealed that N/K ratio 4:1 had the highest dry matter yield for both locations, (RRIN; 2.60 g/pot and Emaudo; 2.75 g/pot) but these values were not significantly different (P < 0.05) from what were obtained from N/K ratio 3:1 and 2:1, respectively. The N:K ratio in soil had influence on the availability of N and K. Under field conditions, N/K ratio 4:1 had the highest grain yield for both locations (RRIN; 3.46 ton/ha and Emaudo; 3.33 ton/ha), and the highest cob field weight (RRIN; 9.92 ton/ha and Emaudo; 9.33 ton/ha), hence its recommendation.