INOCULATION AND MINERAL FERTILIZATION IN COWPEA: EFFECTS ON NODULATION, PLANT GROWTH AND YIELD

Abstract

The nodulation and growth of legumes have influences of nutrients contained in the soil, mainly P, K and Mo. The present study aimed to evaluate, in field, the effect of inoculation with Bradyrhizobium elkanii and soil fertilized with P, K and Mo on nodulation, plant growth and yield in cowpea (BRS Guariba). The experiment was carried out in an experimental area at Teresina, PI. The treatments were disposed in a completely randomized block with six treatments and four repetitions. The treatments consisted of presence and absence of soil fertilization with P, K and Mo and planted with seeds inoculated or non-inoculated. In the treatment with inoculation, an inoculant was used containing Bradyrhizobium elkanii, strain BR 3262. The sowing was conduced out in plots of 3.2 m x 5.0 m and the collect of data was conduced to the 35 and 50 days after plant emergence (DAE) for the determination of nodulation and plant growth. The yield was determined 58 DAE. Differences were not verified among the treatments to root and shoot dry weight and increase in N at 35 DAE, to root dry weight at 50 DAE and to grain yield. In soil with appropriate P, K content, the inoculation with Bradyrhizobium elkanii plus P, K and Mo fertilization not contributed to increase in the nodule number and dry weight and nor either of the grain yield of cowpea.