Biological Inoculant Seed Treatment on Soybean Cultivated in Clay, Sandy and Clay-sandy Soil Conditions in Brazil

Microorganisms and biological products used as biofertilizers can play a crucial role in crops such as soybean, where fertilization management is essential for improving both productivity and the sustainability of agricultural practices. These technologies enhance plant development and crop yield by improving soil conditions in the root zone. This study aimed to evaluate the agronomic efficiency of a Bacillus-based seed inoculant on soybean growth and yield under different soil conditions. Four experiments were conducted, each including five treatments: a control, Biophosphoros® inoculant at 2 mL commercial product kg-1 of seed, and the Bacillus-based inoculant at 1,1.5, and 2mL commercial product kg-1 of seed. Evaluations included leaf concentrations of N, P, K, Mn, and Zn, yield components (grains per pod, pods per plant, thousand-grain weight), and overall grain yield. The results demonstrated that in sandy clay soil (Area 1) and sandy soil (Area 3), the Bacillus-based inoculant at 2 mL kg-1 was more effective than Biophosphoros® in increasing leaf P (Area 1) and K (Area 3) concentrations, the number of grains per pod, and soybean yield (3,851.02 and 3,122.08 kg ha-1, respectively). In contrast, in clay-textured soil (Area 4), the most efficient treatment was the biological soil conditioner at 3.5 L ton-1. Additionally, the use of the Bacillus-based inoculant significantly increased soybean yield compared to the uninoculated control in Area 2 (average yield of 3,489.39 kg ha-1) and Area 4 (3,306.07 kg ha-1).