Aplicação de gesso agrícola e de molibdênio na cultura da soja

Abstract

Besides being currently the second largest soybean producer in the world, Brazilian average productivity is high, thus, the correction and fertilization of soils, mainly in tropical savannas, which currently concentrates the largest areas of this legume cultivation, has great relevance, once there is frequent occurrence of high levels of Al and low Ca in this area. As this legume requires large amounts of nitrogen, another factor, which allows the crop to be economically competitive, is the biological nitrogen fixation, efficiently carried out by the bacteria of the genus Bradyrhizobium, once this legume requires great amount of nitrogen to obtain high productivity. The work was conducted under field conditions, no-tillage in rainfed conditions in the city of Maracaju-MS, this work aims evaluate the nodulation, biological nitrogen fixation, the nutrient content, grain yield of soybean under different doses of gypsum and molybdenum, and also the changes in chemical soil properties because of the use of gypsum. It has been used a randomized block design with five replications, arranged in a split plot, and the plots were four rates of gypsum (0, 1,000, 2,000 and 3,000 kg ha-1) and the split, four doses of molybdenum (0, 20, 40 and 60 g ha-1). The cultivar used for the experiment was the BRS Charrua RR. Soil samples were collected six months after treatment. There were no interaction effects on gypsum x Mo in grain yield of soybean. Mo increases the efficiency of biological nitrogen fixation, reflected in increases in foliar N, the dry mass of aerial part of the plant, mass of one hundred grains, grain yield and protein content of grains. The gypsum has promoted increased levels of calcium in the soil up to 60 cm depth, reduced the potassium content in the 0 to 20 cm, reduced levels of aluminum in depths of 40 to 80 cm and had no effect on grain yield soybean.