Agronomic Efficiency of Bacillus spp. Co-Inoculation Associated with Phosphorus Fertilization Levels in Soybean and Maize Cultivation

Abstract

The co-inoculation of Bacillus megaterium (CCT 2482) and Bacillus subtilis (CCT 3131) may improve plant phosphorus nutrition and agronomic performance under field conditions. This study evaluated the agronomic efficiency of co-inoculation via seed treatment, combined with different phosphate fertilizer doses, in the morphophysiological and productive performance of corn and soybean under distinct edaphoclimatic conditions. Eight trials (four per crop) were conducted during the 2023/2024 season in a randomized block design with eight treatments and four replications. In soybean, co-inoculation increased leaf phosphorus content, grain mass, number of pods per plant, thousand-grain weight, and yield, even with a 25% reduction in phosphate fertilization. In corn, it improved shoot and root biomass, grains per row, thousand-grain weight, and productivity. These results suggest that co-inoculation may contribute to phosphate fertilization management, although direct comparisons across fertilization levels indicate that its effect depends on crop, variables, and the environment. The bacterial strains exhibited strong potential for phosphate solubilization and plant growth promotion across varied environmental conditions, confirming their adaptability. Therefore, this approach may serve as a complementary strategy for phosphate fertilization management, contributing to improved agronomic performance and more sustainable agricultural production systems.