Influence of bioactive products on nitrogen fixation and yield of soybean at different levels of mineral nutrition

Topicality. Today, in the context of environmental and economic crises in the world, attention to the use of the potential of agroecosystems and minimization of the pesticide and agrochemicals load has increased. For this purpose, the use of environmentally safe plant growth stimulants and the latest microfertilizers is one of the most promising methods in crop production. Scientific substantiation and adaptation to the soil and climatic conditions of a particular growing zone, as well as studying the impact of bioactive products on varietal characteristics of the crop are needed to improve the environmentally safe technology of soybean cultivation. Purpose. For increase of productivity by 15–20 % and biologization of crop cultivation , it is necessary to determine the best variants of combining mineral fertilization with foliar dressing, seed and crops treatment with bioactive products for soybean varieties. Methods. Field method, quantitative-weight, laboratory, mathematical and statistical methods was used. Results. We determined that the activity of nitrogen-fixing symbioses formation on soybean largely depends on the method of treatment with bioactive substances, in particular, stimulants of Vympel brand and Orakul microfertilizer. When processing soybeans with biologically active drugs, the mass of nodules increases much more intensively than their number. The increase in the mass of bubbles was up to 50.7 % in the Diadema Podillia variety and up to 60.8 % – in the Samorodok variety. The application of the investigated methods of seed treatment and foliar dressing ensured an increase in the soybean seed yield of the Diadema Podillia variety by 4.4–42.7 %, and of the Samorodok variety by 4.7–44.4 %, depending on the level of mineral nutrition. Conclusions. Growth stimulants of Vympel brand and Orakul microfertilizers are effective for increasing yields, enhancing nitrogen fixation soybean. The use of bioactive products can serve as an important element of economic and environmentally safe technologies for growing soybeans, which can reduce the impact of stress factors on plants, in particular, the lack of fertilizers. Key words: soybean, nitrogen-fixing activity, microfertilizers, growth stimulants, soybean yield