Cowpea growth and yield performance as influenced by phosphorus nutrition in the southern Guinea Savanna Zone of Nigeria
The major constraint to increasing on-farm production of cowpea, getting the optimum yield and the widespread cultivation of the crop in the forest and savannah region is the limitation posed to it by phosphorus nutrition. Therefore, this study was carried out to determine the optimum level of phosphorus for better growth and yield of cowpea. The experiment was conducted at the Teaching and Research farm of the Faculty of Agriculture, University of Ilorin. Five levels of phosphorus fertilizers (0kgP/ha, 30kgP/ha, 60kgP/ha, 90kgP/ha, 120kgP/ha) were used in the study and the experiment was laid out in a Randomized Complete Block Design with three replications. Data on plant height, number of leaves, number of
branches, number of flowers and number of pods were taken. All the data collected were analyzed using analysis of variance and significant means were separated using LSD with the aid of GENSTAT 5.2 statistical package. The results showed that phosphorus fertilizer at the rate of 30kgP/ha and 60kgP/ha could significantly improve number of leaves, number of branches, number of flowers and grain yield of cowpea at P < 0.05. It is therefore, recommended that application of phosphorus fertilizer at 30kg/ha be used to enhance grain yield because it is more economically viable than 60kgP/ha to achieve the same objective.
Key words: Cowpea, phosphorus nutrition, soil fertility, growth and yield improvement.