Respostas da soja à inoculação com Bradyrhizobium japonicum e Azospirillum brasiliense

Abstract

One of the reasons for carrying out this work was to see the effects of Bradyrhizobium japonicum and Azospirillum brasiliense on soybean, both on growth and productivity. Soybeans do not need nitrogen fertilization, as inoculation with Bradyrhizobium japonicum supplies the total nitrogen demand for the plant. Another inoculant that can be used in soybean is Azospirillum brasiliense, which helps in nitrogen fixation, however, its main function is to promote greater root development. This work sought to analyze the effects of Bradyrhizobium japonicum and Azospirillum brasiliense on soybean. The experiment had four treatments: Soybean inoculated with Bradyrhizobium japonicum; Soybean inoculated with Azospirillum brasiliense; co-inoculated soybean, which is the inoculation with both microorganisms simultaneously; and the control treatment, which is without inoculation. The parameters analyzed were plant height (assessed at phenological stages V3 and R5); shoot dry mass and N content in leaf tissue (analyzed in R6); the productivity; number of pods per plant; and weight of a thousand seeds. Each Treatment had 3 useful lines, spaced at 0.45 m each, and 5 m long. Each treatment had 4 replicates. According to the results, it was observed that the weight of a thousand seeds and the N content in the plant were not influenced by inoculation, with no difference between treatments. The results of plant height and shoot dry mass had a significant influence, and the co-inoculated treatment had higher height and shoot dry mass. In the evaluation of the number of pods per plant, the treatment with coinoculation was superior to all treatments. In productivity, the co-inoculation treatment was superior to the control treatment, therefore, co-inoculation is recommended, as it increases the profit of the soy producers.