Impacts of Residual Phosphorus on the Production of Cowpea in the Cerrado Region

Abstract

Phosphate fertilizers when applied to the soil, besides being harvested by the crops, promote a residual effect that can be offered to subsequent crops. The objective of this research was to evaluate the residual effect of phosphate fertilization applied to maize cultivation on the successor crop, cowpea, in the Cerrado region in Maranhao. The research was carried out in the experimental area of Federal University of Maranhao (UFMA), located in the city of Chapadinha, MA (3 ° 44'30"S, 43 ° 21'37''W). The experimental design was in randomized blocks, with six treatments and four replications. The treatments were composed of the following residual P doses: 0, 60, 70, 80, 90, 100 kg·ha -1 of P 2 O 5 . The cultivation of cowpea (cultivar BRS guariba) was sown at a spacing of 1.0 × 0.20 m. The cowpea proved to be efficient in the use of residual phosphate fertilization, since it promoted grain yield close to the national average. The cultivation of cowpea in previously cultivated areas is feasible, in order to take advantage of the residual phosphate fertilization in the Cerrado of East of Maranhao. The phosphorus dose applied in the predecessor crop corresponding to 80 kg·ha -1 of P 2 O 5 promoted higher grain yield (393.44 Mg·ha -1 ) and a greater profit margin (US $326.26). Thus, it is feasible to grow cowpea in previously cultivated areas, in order to take advantage of residual phosphate fertilization.