The paper presents the materials of multi-year research on studying the soybeans inoculation with nitrogen-fixing and phosphorus-mobilizing preparations as well as on foliar fertilizing with a complex preparation on a chelate basis (EDTA) Nanovit-super alongside with calcined kieserite with mineral fertilizers application and without it at a rate of N60P60K60 kg/ha. It has been proved that pre-sowing soybean seed treatment with nitrogen-fixing preparation Optimize-200 as well as with phosphorobacterin contributes to the formation of Glycine maxbranyrhizobiumjaponieum system with the application of highly efficient nitrogen-fixing microorganisms and phosphorobacterin. The bacteria and root system symbiosis results in atmospheric nitrogen fixation – 82.3 kg/ha without mineral fertilizers application, but with their application at a rate of N60P60K60 the fixation of atmospheric nitrogen increases by 46.1 kg/ha. It has been determined that plants’ foliar fertilizing with a complex preparation on chelate basis alongside with calcined kieserite within the period of pod formation and grain filling, when the plants have used nearly 70% of nitrogen fertilizers and when the development of nodule bacteria stops, result in the re-establishing of a modulating process and in the introducing of a biologically active atmospheric nitrogen as much as 95.5 kg/ha, and after the application of mineral fertilizers the introduction of nitrogen increases by 27.0 kg/ha. The application of mineral fertilizers, seed inoculation and plants’ foliar fertilizing contribute to a soy yield increase (corresponding to the variants of the investigation) by 0.42-0.36-0.36-0.73-0.72 t/ha as compared to the variants without the application of mineral fertilizers

Keywords: soybeans, nitrogen fixation, phosphorus mobilization, complex fertilizers, biological nitrogen, yield rate