Effect of Groundfix and Ecostern biological preparations on soil microbiota under soybean (Glycine max L.) cultivation
Authors: Bolokhovskyi V. , Borodai V. , Kosovska N. , Bolokhovska V. , Nagorna O. , Yakovenko D. , Kuzmych V. 
Published: October 2024

In recent years, the system of farming using biologisation elements has become increasingly popular as an effective tool in agricultural production. By introducing agronomically useful microbiota into the soil, whose living cells are part of biological products (including biodestructors and biofertilisers), many valuable processes are triggered: restorative changes in the soil ecosystem by expanding microbial cenosis, improving its phytosanitary condition, protecting future crops of crop rotation from the allopathic effects of predecessors, increasing the availability of nutrients in the soil and improving its structure, as well as increasing yields and improving the quality of agricultural products. The aim of the research was to determine the effect of biological products based on bacteria of the genera: Bacillus, Paenibacillus, Azotobacter, Enterobacter, Enterococcus, Agrobacterium and fungi of the genus Trichoderma on the main ecological and trophic groups of soil microorganisms during the cultivation of soybean plants. The study was conducted using laboratory and vegetation methods of research in the conditions of the Institute of Applied Biotechnology LLC. Soybean seeds of Kent variety (SAATBAULINZ, Austria) were treated with biological products produced by BTU: biofertiliser Groundfix® (Bacillus subtilis, B. megaterium var. phosphaticum, Azotobacter chroococcum, Enterobacter sp, cell titer 0.5–1.5·109 CFU/cm3), biodestructor Ecostern® Classic (Bacillus, Paenibacillus, Azotobacter, Enterobacter, Enterococcus, Agrobacterium and fungi of the genus Trichoderma — cell titer not less than 2.5– 5.0·109 CFU/cm3) according to the recommended doses. The effectiveness of biological products Groundfix and Ecostern Classic in the formation of ecological and trophic groups of soil rhizosphere microorganisms for the cultivation of soybean plants of Kent variety is highlighted. DSTU 7847:2015 was used to determine soil microorganisms and their associations. The coefficients of soil mineralisation, oligotrophicity and pedotrophicity were calculated by the ratio of the corresponding ecological and trophic groups. It was found that under the action of biological products Ecostern Classic and Groundfix in the rhizosphere of soybean plants, the number of ammonifiers increased by 1.8–2.1 times, oligonitrophilic bacteria (including bacteria of the genus Azotobacter) — by 14.3–33.3%, oligotrophs — by 54–57% compared to the control variant. The number of pedotrophs in soybean plants grown with the addition of Ecostern Classic biological product was 1.6·105 CFU/g soil, which is 1.5 times lower than in the control. The highest values of pedotrophs were determined for the soil in the variant with Kent soybean grown under the influence of the biological product Groundfix, which is 4% higher compared to the control. Under the influence of biological products Ecostern Classic and Groundfix, the number of microorganisms that use mineral forms of nitrogen decreased by 2.3–8 times, respectively, compared to the control. According to the values of the coefficients of oligotrophicity, nitrogen mineralisation and immobilisation, and pedotrophicity, the direction of soil biological processes was characterised. The coefficient of oligotrophicity in the studied soil samples under the influence of biological products was 0.28–0.35, which indicates a high supply of nutrients to the soil microbiome. Soil variants, when growing soybean plants in the presence of biological products, had a lower pedotro­phicity coefficient. Thus, when soybean plants were grown under the influence of the biological product Groundfix (0.54), the value of the pedotrophicity coefficient was 2 times lower compared to the control (1.09), while under the influence of Ecostern (0.4) it was 2.7 times lower compared to the control. This indicates the accumulation of stable organic compounds and humus formation. The soil under the influence of the studied biological products is characterized by a sufficient amount of available nitrogen, high supply of soil microbiome with nutrients, accumulation of stable organic compounds and stable humus formation. The use of biological products Groundfix and Ecostern Classic improves microbial biodiversity and soil microbiota activity during soybean cultivation, increases the number of specific microbial taxa involved in the suppression of phytopathogenic microorganisms in the soil, promotes nutrient cycling and soil structure formation.