Foliar inoculation with Methylobacterium symbioticum SB23 enhances nitrogen fixation and maize productivity under different edaphoclimatic conditions

Biological nitrogen fixation (BNF) is a sustainable alternative to reduce dependence on nitrogen fertilizers. This study evaluated the agronomic efficiency of foliar inoculation with Methylobacterium symbioticum SB23 in maize (Zea mays) under different edaphoclimatic conditions. Field trials were conducted in four regions of Brazil during the 2021 and 2022 growing seasons, using a randomized block design. Seven treatments were evaluated, combining reduced nitrogen doses with inoculant application. Statistical analysis was performed using ANOVA and Duncan’s test (p?0.05). M. symbioticum SB23 inoculation significantly increased shoot biomass and foliar nitrogen accumulation, especially in treatments with a 25% and 50% reduction in nitrogen fertilization. The highest yield gain occurred with a 50% nitrogen reduction, resulting in a 53.7% increase compared to the control. No phytotoxicity symptoms were observed. These findings indicate that M. symbioticum SB23 is a viable strategy to optimize maize nitrogen nutrition, increasing yield while reducing synthetic fertilizer use, contributing to a more efficient and sustainable agriculture.