Effects of the integrated use of organic and inorganic phosphorus sources in micro-doses on the yield and profitability of cowpea (Vigna unguiculata L. Walp) Cultivation

An experiment was conducted in the field to evaluate the effect of phosphorus fertilization in microdose using organic and mineral fertilizers on the yield and profitability of cowpea cultivation. To achieve this, a balanced application of NPK and granular compost was provided to supply the same amount of phosphorus to the cowpea. Three treatments were compared in a split-plot design with three replications, where the treatments were in large plots and the cowpea varieties, numbering four (4), were in small plots. The three treatments are as follows: (i) T0 control treatment without fertilizer application, (ii) T1 application of two grams of NPK per hole, and (iii) T2 application of 9.375 grams of granular compost per hole. The results show a significant difference in yield parameters between treatments (pod yield, grain yield, and straw yield). The mean comparison test revealed that the control treatment and NPK are quite similar for these parameters. Thus, with compost, an increase of 69.17% in grain yield, 55.47% in pod yield, and 41.67% in straw yield was noted compared to the control. The VCR (value-cost ratio) and gross income were significantly improved by compost. The application of organic or mineral fertilizers for cowpea cultivation is profitable due to relatively high VCRs: 3.34 for NPK and 6.79 for compost. Therefore, the use of compost for cowpea cultivation proves to be economically more profitable, as it yields higher returns.