Inoculação com Bradyrhizobium japonicum associada à adubação nitrogenada na produção do feijão-caupi em solo florestal de Mazagão-AP

Abstract

Cowpea [Vigna unguiculata (L.) Walp] is a legume widely cultivated in family farming due to its rusticity and short cycle, but it has low yield in the Amapá, due to the lack of use of technologies, such as management which can be optimized by inoculating the seeds with nitrogen-fixing bacteria. Thus, the objective was to evaluate the growth and production of cowpea under inoculation with Bradyrhizobium japonicum associated with nitrogen fertilization in the municipality of Mazagão, Amapá. The experiment was carried out in pots, in a greenhouse, at the Federal University of Amapá, Campus Mazagão. The experimental design was completely randomized, with eight treatments, three replications and two experimental units per plot. The treatments consisted of the combination of two cowpea genotypes (‘Branquinho’ and ‘Sempre Verde’) and four forms of nutritional management [I - bacterial inoculation (B. japonicum, semia 5079 and semia 5080 strains) in the seeds; N – nitrogen fertilization (urea); I + N – bacterial inoculant associated with nitrogen fertilization and T – Control, without seed inoculation and without nitrogen fertilization]. Plant growth and production were evaluated, and the data obtained were subjected to analysis of variance by the F test up to 5% probability and Tukey test (p<0.05) for comparison of means in cases of significance by the F test. The regional genotype of cowpea ‘Branquinho’ expresses greater vegetative growth and greater production when compared to the Semper Verde genotype. Inoculation with B. japonicum significantly increases the mass of 100 seeds of the Branquinho genotype, which promotes increased production and larger seed size, dispensing with nitrogen fertilization, being an alternative for use by family farmers in Amapá