The results of application of biological product Rizobakt SP on soybean in the southern forest steppe the Western Siberia

The goal of the research carried out in 2014 and 2015 in the fields of the Siberian Research Institute of Agriculture (SibRIA) was to tentatively evaluate the effect of Rizobakt SP biological product (manufactured by the OOO “Peterburgskie Biotekhnologii”, St. Petersburg, Pushkin) on the development, yield and quality of soybean seeds under the conditions of the southern forest-steppe of the Omsk Region. The field trials involved 8 soybean varieties: 7 varieties developed at SibRIA and the variety SibNIIK 315 developed at the Siberian Research Institute of Forages (Novosibirsk). Winter rye for grain was the forecrop. The soil of the trial plot was leached, medium-thick, heavily loamy chernozem with humus content about 6%, salt extract pH about 7; the availability of mobile phosphorus and exchange potassium was high; the content of nitrate nitrogen in the soil layer of 0-40cm corresponded to the medium value. The varieties were drill seeded at the end of the second ten-day of May by the SSFK-7.0 seeder in plots of 15 sq. m in four replications. The seeding rate was determined taking into account the laboratory germination, thousand-seed weight, and the seed sowing rate of 800 thousand of germinable seeds per hectare. The maximum height of bottom pod attachment in the trial was found in the varieties Eldorado and Cheremshanka (12.6 cm), and Zolotistaya (12.9 cm). The varieties Eldorado and SibNIIK 315 under comparatively favorable weather conditions for soybean growing in 2014 and 2015 had the greatest increase as compared to the control (without Rizobakt SP application) regarding the main elements of the yield formula: the number of productive branches and nodes, pods and seeds on a plant, and seed weight; the increase was from 22% to 44%. In general, in the studied varieties, it was soybean plant branching that increased most significantly (+ 34.3%).The application of Rizobakt SP did not affect positively on field emergence, plant survival, growing season length, bottom pod attachment height, seed yield and seed biochemical indices of the varieties involved in the trial. The most productive varieties were Cheremshanka (3.19 t ha) and Zolotistaya (2.95 t ha) in the control variant in 2015. As two-year average, the variants with Rizobakt SP application for the varieties Cheremshanka, SibNIIK 315 and Sibiryachka were significantly lower in seed yield than the control.