Modos de aplicação de nitrogênio na cultura da soja

Abstract

Normally for several crops nitrogen fertilization is used, but specifically for soybean, this is a little used practice due to its ability to perform symbiosis with microorganisms that perform biological nitrogen fixation. The objective of this study was to evaluate the effect of nitrogen, via soil and foliar application, in different stages of growth, vegetative development, nodule formation and yield of two soybean cultivars (TMG 1179 and TMG 132). The experimental design was a randomized complete block (DBC), with four replications, in a 2 x 7 factorial scheme. The first factor was two soybean varieties TMG 132 and TMG 1179. The second factor was the different nitrogen application modes: Witness without Application of nitrogen (only inoculated with Bradhirrhizobium japonicum); 20 kg of N on the groove still open at sowing; 20 kg of N diluted in water, sprayed onto the seeding groove; 20 kg of N in coverage in V2; 20 kg of N in coverage in V4; 20 kg of leaf N in V2; 20 kg of N foliar V4. Totaling 14 treatments and 56 plots. The application of N in the groove reduces the nodulation of soybean plants, reducing plant capacity in the BNF. The application of 20kg.ha-1 of nitrogen from V2 increases the vegetative growth, nodulation and yield of soybean. The foliar application of N, at the dose 20 kg.ha-1, applied via leaf in V2 and V4, is the most efficient way to increase soybean yield.