Effects of NPK Fertilizer Application on the Growth and Seed Yield of Cowpea in Ilorin, Southern Guinea Savanna Zone Of Nigeria
To forestall wastage and determine the optimum level of complete fertilizer needed for better production of cowpea, the application of NPK 16:16:16 fertilizer on the growth and yield of the crop was investigated. The field experiment was conducted on the Teaching and Research Farm of the Faculty of Agriculture, University of Ilorin. A medium-maturing cowpea variety IAR- 48 was tested with five NPK fertilizer rates viz: 200kgNPK/ha, 400kgNPK/ha, 600kgNPK/ha, 800kgNPK/ha and 0kgNPK/ha as the control. The experiment was laid out in a randomized complete block design, replicated twice. Data were collected on plant height, number of leaves, leaf area, number of branches, number of pods per plant, number of seeds per pod, weight of 100seeds and grain yield per treatment. All data were subjected to Analysis of Variance (ANOVA) using GENSTAT package while separation of significant means was done using Least Significance Difference (LSD) at 5% probability level. Results showed that NPK fertilizer at the rate of 200kg/ha improved pod production, weight of 100seeds, pod weight and final grain yield per hectare. It could, therefore, be inferred that, subject to further research, if NPK 16:16:16 is applied at rate of 200kgNPK/ha or less, better yield and reduction in the cost of production will be achieved with cowpea variety IAR- 48 in Ilorin, a location in the Northern Guinea Savanna Zone of Nigeria.
Keywords: Complete fertilizer, cowpea, vegetative growth, yield potential and yield improvement