Foliar Azospirillum brasilense inoculation and phosphorus application for sustainable maize production in tropical cropping systems

Introdution Climatic variability during the growth of off-season maize, the primary maize cycle in Brazil, creates stresses that limit yields and demand sustainable management strategies that reduce the reliance on excessive nitrogen (N) inputs. Methods This study evaluated foliar inoculation with A. brasilense and foliar phosphorus (P) application as strategies to improve off-season maize nutrition and yield under reduced N fertilization at six sites in Brazil. Results and Discussion The combined application of A. brasilense and foliar P increased leaf N and P concentrations, stalk diameter, the number of grains per ear, 100-grain weight, and grain yield (GY). Across sites, GY was highest under the combined application at the full N application rate, but combined application under a 25% lower N application rate produced GYs similar to those under the full N rate without inoculation or foliar P. Reducing the N rate by 25% led to a proportional decrease in N 2 O emissions without compromising GYs when combined with inoculation and P supplementation. Thus, managing off-season maize with foliar Azospirillum brasilense inoculation combined with foliar P application represents a sustainable alternative to optimize nutrient use efficiency and maintain productivity with reduced N input. In addition to agronomic benefits, this practice contributes to mitigating N 2 O emissions, making it a sustainable alternative for large-scale off-season maize production in Brazil.