Influence of Microbiological Preparations and Microelements on Indicators of Photosynthetic and Symbiotic Activity of Soybean Crops

The article presents the results of studies on the effect of the combined use of microbiological fertilizers and microelements on the formation of the photosynthetic and symbiotic apparatus, the size and structure of the yield, the chemical composition and quality of soybean seeds, carried out on leached chernozems in the Kabardino-Balkarian Republic foothills zone. The use of microbiological fertilizers and microelements as preparations for pre-sowing treatment of soybean seeds increases the weight of active nodules by 46.7–61.0 kg / ha, the active symbiotic potential – 2.4–2.8 thousand units, the amount of fixed atmospheric nitrogen by the symbiotic soybean system – 36.1–40.1 kg / ha. In 2022, the maximum number of nodules, including active ones, was formed in the Fon + Ultrastim® variant, the smallest – in the control. In 2023 which was less moisture-rich for nodule formation, the maximum number of nodules was in the Background + ATUVA® variant. Creating optimal conditions for biological nitrogen fixation (Background + ATUVA®) increases the area of soybean leaves by 14.1 thousand m²/ha, photosynthetic potential is 72.7 thousand units, dry matter accumulation is 1.84 t/ha, seed yield – 1.33 t/ha. The microbiological fertilizers and microelements application (Background + ATUVA®) increases the nitrogen content in the vegetative and generative organs of soybeans throughout the growing season, increases the nitrogen accumulation by seeds by 36.1–40.1 kg/ha, the share of atmospheric nitrogen in plant nutrition – 42–50%; the protein content in seeds is 1.1%, while the collection of protein with soybean seeds increases by 479 kg.