CO-INOCULATION OF SOYBEAN (Glycine max L. Merril) WITH BENEFICIAL MICROORGANISMS ISOLATED FROM THE AMAZON

The nitrogen requirement of soybean is met by symbiosis with elite strains of Bradyrhizobium, applied through seed inoculation during sowing. Several research have sought to enhance the benefits of this association through the co-inoculation of soybean with beneficial microorganisms. Additionally, the Amazon is recognized as a biome rich in microorganisms with potential benefits to plants. In view of this, we sought to explore the possibilities of using beneficial microorganisms isolated from the Amazon in co-inoculation of soybean. Greenhouse and field studies were conducted during the years 2020 and 2021 in Paragominas and Belém, Pará state. The design was in Completely Randomized Design in the greenhouse and in Randomized Blocks for field experiments, both with factorial schemes of 3 × 2. The first factor was composed of co-inoculation with Trichoderma asperellum and Bacillus amyloliquefaciens, plus standard inoculation with Bradyrhizobium. The second factor was represented by fertilization or not with phosphate source (0 and 100 kg ha-1 of P2O5). We evaluated parameters of growth, leaf nutrition, root system, nodulation, yield and profitability. The root volumes of the plants were 25% and 17% higher than that of the standard inoculation for T. asperellum and B. amyloliquefaciens, respectively. In 2020, co-inoculation with T. asperellum increased yield by 15%, plant height by 27%, and net profit by up to 121 USD compared with standard inoculation. In 2021, there were increases of 7% and 13% in yield, 18% and 7% in the number of pods, 11% and 2% in reproductive branches, 8% and 4% in plant height, and 159 USD and 309 USD in net profit compared to standard inoculation, for T. asperellumand B. amyloliquefaciens, respectively. Our results indicate that the use of regionalized microorganisms, as was the case of isolates from the Amazon used in soybean co-inoculation, can bring great benefits in productivity and profitability, expanding the possibilities of prospecting local biodiversity even if for the use of exotic crops.