Biological nitrogen fixation and leaf nutrient concentration on soybean as a function of molybdenum and gypsum levels

The economic competitiveness of Brazilian soybeans on the world market occurs, in large part, due to the benefits of biological nitrogen fixation in this crop. The field experiment was carried out in Maracaju, Mato Grosso do Sul State, Brazil, under no-tillage system, in rainfed condition. The aim was to evaluate nodulation, growth, mineral nutrition and grain yield of soybeans under different doses of gypsum and molybdenum. The experimental design used was a randomized block with five replicates and arranged in a split-plot squeme, with the plot represented by four doses of gypsum (0, 1.000, 2.000 and 3.000 kg ha(-1)) and the subplots by four doses of molybdenum (0, 20, 40 and 60 g ha(-1)). There were no interaction effects of Mo x gypsum for grain yield. Gypsum has no influence in the N leaf content and grain yield. Mo increases grain yield and protein levels in the grain.