INFLUENCE OF SOYBEAN SEEDS BACTERIZATION WITH RIZOTORFIN VR 835 ON THE MICROBIOLOGICAL ACTIVITY OF THE RHIZOSPHERE AND CULTURE PRODUCTIVITY

The purpose of the study is to determine the effect of pre-sowing inoculation on the microbiological activity of the rhizosphere, the productivity of new soybean varieties Cheremshanka and Sibiryachka, and their resistance to stressful conditions in the southern forest-steppe of Western Siberia. The study was carried out in the southern forest-steppe zone of Western Siberia (Omsk Region) in 2020–2021. The objects of the study were soybean varieties selected by the Federal State Budgetary Scientific Institution "Omsk ANC" Sibiryachka and Cheremshanka, as well as their rhizosphere. Experiment options: Sibiryachka K (control), Sibiryachka Rizotorfin VR 835, Cheremshanka K (control), Cheremshanka Rizotorfin VR 835. The use of the biological product Rizotorfin VR 835 had an impact on the intensity of the transformation processes of organic substances occurring in the rhizosphere of the crop. In 2020, saprotrophic bacteria were most active, due to which the immobilization process predominated. In 2021, nitrogen fixation in microbial cells occurred more abundantly compared to the previous year. A positive effect was also exerted on the number of microorganisms in the rhizosphere of the culture, stimulating their growth relative to the control. At the same time, the number of ammonifiers on MPA (meat peptone agar) increased by 53 %, amylolytic microorganisms by 24–41 %, oligonitrophils by 50 %, and phosphate-mobilizing bacteria by 2 times. The number of soil fungi as sources of phytopathogenic infection in the Cheremshanka variety in 2021 decreased by 4 times compared to the control. On average, over the two years of the study, the total number of microorganisms in the rhizosphere of soybean varieties under the influence of inoculation increased by 1.4–1.6 times relative to the control, and to a slightly greater extent in the Sibiryachka variety. An increase in the number of rhizosphere microorganisms when using Rizotorfin BP 835 contributed to an increase in soybean yield by 0.2 t/ha in both varieties compared to the control, which was confirmed by the calculated coefficient of determination r2 = 0.43.