ASSOCIAÇÃO DE BACTÉRIAS SOLUBILIZADORAS DE FOSFATO E FUNGOS MICORRÍZICOS ARBUSCULARES NO DESENVOLVIMENTO DA SOJA

Abstract

Bacteria belonging to the genera Bacillus and Azospirillum release organic acids that increase phosphorus (P) availability and stimulate plant growth. Arbuscular mycorrhizal fungi (AMF) establish a mutualistic association with plant roots, enhancing nutrient uptake. Thus, both microorganisms improve phosphorus utilization and increase the efficiency of agricultural systems. Therefore, the aim of this study was to evaluate the use of phosphate-solubilizing bacteria and arbuscular mycorrhizal fungi inoculants, applied either individually or in combination, on soybean growth and yield. The study was conducted under field conditions during the 2024/2025 growing season at the experimental area of the Federal University of Mato Grosso do Sul, Chapadão do Sul Campus, Brazil. The experimental design was a randomized complete block design with eight treatments and four replications, totaling 32 plots. Inoculants based on arbuscular mycorrhizal fungi and phosphate-solubilizing bacteria were applied either individually or in combination, as follows: 1) Control (without AMF or phosphate-solubilizing bacteria inoculation); 2) Arbuscular mycorrhizal fungi (AMF) (consortium of four AMF species: Glomus mosseae, Glomus aggregatum, Glomus intraradices, and Glomus etunicatum); 3) Azospirillum brasilense (AZO); 4) Bacillus (BAC) (consortium of Bacillus amyloliquefaciens and Bacillus megaterium); 5) AMF + AZO; 6) AMF + BAC; 7) AZO + BAC; and 8) AMF + AZO + BAC. At the flowering stage, shoot dry matter (SDM, g) was evaluated. At the end of the crop cycle, growth parameters (plant height, first pod insertion height, number of pods per plant, and number of grains per pod) and grain yield (kg ha⁻¹) were assessed. No significant differences among treatments were observed for plant height, first pod insertion height, number of pods per plant, or number of grains per pod. The AMF + AZO combination increased the number of pods per plant, number of branches per plant, shoot dry matter, and grain yield. The AMF-based inoculant showed positive effects only when associated with one or more phosphate-solubilizing bacterial inoculants, particularly for grain yield, number of pods per plant, and number of branches per plant.