The article reveals the results of researching the nitrogen-fixing capacity of soybean varieties depending on seed inoculation and foliar fertilization with biopreparations. Nowadays the biologization of agriculture and biological crop production are quite urgent issues due to the high load of pesticides and mineral fertilizers which pollute the environment of agricultural systems. Furthermore, one of the main ways to optimize the agroecosystem in the conditions of organic production of this crop is the use of biopreparations based on nitrogen-fixing and phosphate-mobilizing bacteria. The widespread use of biopreparations to intensify agriculture is not only of ecological, but also in most cases of economic importance. The research outcomes confirmed the maximum formation of the symbiotic apparatus indicators: the number and weight of soybean nodules and their intensive functioning with the formation of the highest indicators of the total and active symbiotic potential and the amount of biologically fixed nitrogen, it is necessary to jointly inoculate seeds with Rizoline and double application of chelated microfertilizers at microstage BBCH 12-13: Organic balance + Azotophyte + Help-growth Soybean + Liposam and at microstage BBCH 51-69: Organic Balance + Azotophyte + Helprost Boron + Liposam. At the same time, the total number of soybean nodules was formed in the Samorodok variety − 50.3, of which 36.0 pcs./plant were active, in the Amadeus variety – 55.6 and 40.0 pcs./plant. The total and active weight of soybean nodules in the Samorodok variety made up 515 and 399 mg/plant, and in the Amadeus variety – 586 and 454 mg/plant. Indicators of total and active symbiotic potential were 31.2 and 21.6 thousand kg/day per ha in the Samorodok variety, as for the Amadeus variety – 36.5 and 25.5 thousand hectares. kg/day per ha and biologically fixed nitrogen in the Samorodok variety – 119.0 kg/ha, in the Amadeus variety – 140.1 kg.