ÉPOCAS DE ADUBAÇÃO NITROGENADA COMO ESTRATÉGIA PARA MAXIMIZAR A PRODUTIVIDADE DO SORGHUM BICOLOR L. EM SUCESSÃO A CULTURA DA SOJA

Abstract

Nitrogen fertilization, whether applied at planting or as topdressing, is essential for increasing nitrogen content and leaf chlorophyll, which are directly associated with photosynthetic efficiency and crop productivity. In this context, the objective of this study was to evaluate the response of sorghum to different nitrogen fertilization strategies, with and without splitting, through physiological and productive variables. The experiment was conducted during the second growing season at the experimental field of the Federal University of Mato Grosso do Sul, located in the municipality of Chapadão do Sul, Mato Grosso do Sul, Brazil. A randomized block design (RBD) was used, with four replications and six treatments, totaling 24 plots, as follows: T1 (control – without nitrogen fertilizer), T2 (planting), T3 (planting + 1 topdressing), T4 (planting + 2 topdressings), T5 (1 topdressing), and T6 (2 topdressings). The evaluated variables were total chlorophyll, leaf nitrogen content, and productivity. The results showed that the fertilized treatments, whether at planting or as topdressing, significantly improved total chlorophyll, leaf nitrogen content and sorghum productivity. The control treatment (T1), which received no fertilization, showed the lowest performance, highlighting the importance of nitrogen fertilization for the physiological and productive development of the crop. Nitrogen fertilization was essential for the physiological and productive performance of sorghum, regardless of whether it was applied in split or single doses, indicating that the presence of fertilization had a greater impact than the application strategy.