Nitrogênio e micronutrientes na produção de grãos de feijão-caupi inoculado1

Abstract

This work aimed to study the effect of nitrogen and micronutrients addition on nodulation and on the productivity of cowpea inoculated with strain INPA 03 11B. The study was carried out in the experimental area of Universidade Federal do Piauí, Bom Jesus, PI. The experiment was a complete randomized block, with four replications and a 5 x 2 factorial arrangement. Treatments consisted of five nitrogen doses (0, 35, 70, 105, 140 kg ha1), associated with and without foliar micronutrients application (300 g ha1 boric acid; 500 g ha1 copper sulphate, manganese sulphate, zinc sulphate and 60 g ha1 ammonium molibdate). Nodulation, shoot, root and total dry mass, relative efficiency, components of yield and crop productivity, besides N accumulation in shoot and grains were evaluated. Fresh and dry mass of nodules reduced linearly with the increase of N doses. Yield components were not affected by nitrogen and micronutrients fertilization. The application of micronutrients in the absence of nitrogen promoted an increase of 12.4% in grain yield of cowpea inoculated.