Efeito do uso de Methylobacterium symbioticum SB23 como fixador foliar de nitrogênio na cultura da soja

Abstract

Soybean is a crop of great economic importance, standing out for its high oil and protein content. Due to the high nitrogen demand required to achieve high yields, as a result of the protein content in its composition, inoculation with nitrogen-fixing bacteria is essential. The species Bradyrhizobium japonicum and Azospirillum brasilense are commonly used in seed or in-furrow inoculation, while Methylobacterium symbioticum has been studied as a promising specie for foliar fixation. This study aimed to evaluate the effects of M. symbioticum SB23 inoculation on soybean yield, the impact of foliar application at different phenological stages, and analyze its effect when associated with other nitrogen-fixing bacteria inoculated in seed. The experiment was carried out in Uberlândia-MG, during the 2024/25 growing season, using the Olimpo IPRO cultivar, in four trials arranged in a randomized block design with eight replications. Trials E1, E2, and E3 consisted of two treatments each, while E4 included four treatments. The results showed that all treatments with M. symbioticum SB23 significantly increased yield compared with the control. In treatments with the association of the three species – B. japonicum, A. brasilense, and M. symbioticum SB23 – higher yields were observed compared with the others. Regarding the application stage, the V8 stage presented the best results.