Application of Microbiological Preparations in the Cultivation of Promising Soybean Varieties in Oryol Oblast

This paper discusses the yield enhancement effect of microbiological preparations on different soybean varieties. The field studies were conducted in Oryol oblast in 2019–2023. The following soybean varieties were tested: Lider 1, Mezenka, Orleya, Osmon’, and Zusha. Presowing seed treatment and foliar treatments at the stage of one to three trifoliates and budding stage were performed using a number of preparations: Biostim Start, Rizoform Soya, Organit Р, Organit N, Pseudobacterin 3, and Biodux. In the Zusha variety, inoculation of seeds with Rizoform Soya in combination with Biostim Start ensures the highest (6.0%) increase in soybean yield compared to the control. In the presence of native rhizobacterial races in the soil, presowing seed treatment and foliar treatments with OrganitР, Organit N, Pseudobacterin 3, and Biodux contribute to the introduction of microorganisms contained in these preparations into the plant rhizospheric community and their subsequent participation in nitrogenous nutrition processes. On average for all tested varieties, in variants with presowing treatment and two foliar treatments, the number and weight of nodules increase by 57.6 and 65%, respectively, while nitrogenase activity increases by 67.3% compared to the control. A combination of Organit Р, Organit N, Pseudobacterin 3, and Biodux applied in the course of presowing seed treatment and one-time foliar treatment at the stage of one to three trifoliates increases yields to the greatest extent in the Lider 1 (0.29 t/ha), Zusha (0.35 t/ha), and Mezenka (0.40 t/ha) varieties. The maximum increase in protein content in grain was recorded in the Mezenka variety in the variant with presowing seed treatment and one or two foliar treatments: by 1.1 and 1.0%, respectively.