Agronomic Efficiency and Phosphate Solubilization of Pseudomonas fluorescens and Bradyrhizobium japonicum in Leaf-Spray Inoculation and Seed Treatment in Soybean

The use of plant growth promoting bacteria (PGPB) that can solubilize phosphorus (P) has shown potential to improve nutrient availability in many crops such as soybean. This research aimed to evaluate agronomic efficiency and phosphorus solubilization through Bradyrhizobium japonicum and product to be registered Pseudomonas fluorescens (BR 14810) in soybean, at seed and leaf-spray inoculation. Four experiments with soybean (2020/21 crop) were installed in the following locations in the State of Goiás: Experimental Area of the Goiano Federal Institute, in Rio Verde, Bela Vista Farm, in Indiara, Bauzinho Farm, in Rio Verde, and Cachoeira Farm, in Doverlândia. The B. japonicum was inoculated in the seed of all treatments. It was tested three phosphate fertilization doses: 0, 50, and 100% recommended P dose, with and without P. fluorescens, at seed treatment and leaf-spray inoculation. The use of inoculation with P. fluorescens and B. japonicum increases nitrogen (N) content in grains and total N. The P content in dry mass, grains and total are increased using P. fluorescens and B. japonicum, confirming the ability to solubilize phosphates. Inoculation with P. fluorescens and B. japonicum is efficient for increasing shoot dry mass and productivity, can be used as a sustainable soybean management technology. Leaf-spray was more efficient than inoculation in seed treatment and can be used as an alternative mode of application. The results demonstrated that the product under test (P. fluorescens-BR 14810) can be used associated with B. japonicum, in ST or leaf-spray, resulting in increases of agronomic parameters and soybean yield.