Nutrição mineral do feijoeiro em influência de nitrogênio e palhadas de milheto solteiro e consorciado com feijão-de-porco

Abstract

This study was carried out to evaluate the effect of straws of millet (Pennisetum typhoides (Burm.) Stapf) and millet plus jack bean (Canavalia ensiformes (L.) DC.) intercropping and nitrogen fertilization levels on bean mineral nutrition in a no-till system. The experiment was carried out in a randomized blocks design and four replications in a split-plot arrangement, with the straws in the plots and nitrogen levels at sowing (30 and 60 kg ha-1) and at topdressing (0, 40, 80 and 120 kg ha-1) as a 2 x 4 + 1 factorial in sub-plots, plus an additional treatment with 30 kg ha-1 at sowing, without topdressing, and seed inoculation with Rhizobium tropici with Co and Mo foliar application. The millet plus jack bean straw provide the highest N and Mg contents. N topdressing levels increased N foliar concentration up to 116 kg ha-1, providing a linear effect in K and S contents and differenced effects on Mg concentration, depending on the N level at sowing and straw combinations. The additional treatment increased the N concentration only in millet straw, K and Cu in two straws, and reduced the Ca and Mg contents, under millet and millet plus jack bean straws, respectively. The topdressing levels increased the grain yield, with the bigger response in 30 kg ha-1 at of N sowing.