Nitrogen and potassium fertilizer influenced nutrient use efficiency and biomass yield of two plantain (Musa spp. AAB) genotypes

Nitrogen and potassium are key nutrients for optimum productivity in Musa species. In this study, optimum doses of N and K were determined for two plantain genotypes. The growth and dry matter yield (DMY) of ‘PITA 24’ (a hybrid plantain of the International Institute of Tropical Agriculture) and a landrace, ‘Agbagba’ were evaluated on factorial doses of N (0, 200, 400 and 600 kg.ha-1) and K2O (0, 300, 600 and 900 kg.ha-1). The nutrient use efficiencies of the applied nutrients were also studied. Analysis of variance showed that fertilizer combination significantly (p<0.05) influenced the genotype performance and genotype-by-fertilizer interaction effects. Growth and DMY in both genotypes were superior where both nutrients were applied together. ‘PITA 24’ maintained a better growth, higher DMY, and greater efficiency of nutrient use than ‘Agbagba’. Both genotypes had the best growth where N was applied at 200 or 400 kg.ha-1 in combination with 300, 600 or 900 kg.ha-1 of K2O. The control plants were the poorest. Agronomic efficiency (AE) of applied K+ was high at N200K300, N400K300, and N600K300; similarly, AE of applied N was superior at N200K600, N200K300, and N200K900. The partial factor productivity from the applied nutrients was highest at N200K300, suggesting that it was most economical to grow plantain with 200 kg N and 300 kg K2O ha-1. For optimum performance of plantains in the humid tropics of southeastern Nigeria, results from the study suggest the combined application of 200 to 400 kg N and 300 to 600 kg K2O per hectare, per annum.   Key words: Plantains, dry matter yield, nutrient use efficiency.