Recently, there has been growing interest worldwide in the use of biological multifunctional preparations for plant nutrition (biopreparations), which have a direct and indirect impact on soil fertility and play an active role in regulating the stability and productivity of grain crops in the context of climate change. During 2021-2022, under the conditions of the Khmelnytskyi State Agricultural Research Station of the Institute of Soil Science and Plant Cultivation of the National Academy of Agrarian Sciences (Western Forest-Steppe of Ukraine), the effectiveness of applying Azotohelp® and Groundfix® biopreparations (biotechnology company BTU, Ukraine) before sowing cultivation on the dynamics of microbial communities in the rhizosphere of winter wheat was studied. A significant influence of Groundfix and Azotohelp on the structure of ecological-trophic groups and the functional orientation of the microbial community in the winter wheat rhizosphere, and subsequently on crop productivity, was established. Under unfavorable conditions of crop vegetation in 2020-2021, the use of biopreparations contributed to the balance of processes and a stable level of available nutrients. Thus, the ratio of nitrifiers and ammonifiers during the flowering phase in the variants with Groundfix (3l/t) and Azotohelp (3 l/t) variants was 0.58 and 0.92, respectively, compared to the control (0.49). The combined application of Groundfix® 1.5 l/ha +Azotohelp® 1.5 l/ha in 2022 during the flowering phase stimulated the development of microorganisms that use mineral forms of nitrogen and heterotrophic microorganisms that use organic nitrogen, their number was 3.8 and 5.8 times higher, respectively, compared to the control variant. Also, the content of bacteria of the genus Azotobacter increased 3 times compared to the control (16.6 vs. 5.4 CFU/g of dry soil, respectively). At the same time, during the grain ripening phase, the number of these groups was at the control level, indicating a balance between mineralization and humification processes, microbiome development in the absence of excessive activation of destructive processes. The average yield increase over two years compared to the control was 0.58–0.94 t/ha. A prolonged positive effect was observed when using Groundfix® 1.5 l/ha + Azotohelp® 1.5 l/ha in the BBCH 87–89 phase. Despite a decrease in root exudate formation during this period, a stable number of nitrogen fixers, pedotrophs, microorganisms that use organic nitrogen compounds, and spore-forming bacteria were observed, which leads to a slowdown in biological depletion of the soil after harvesting, the formation of an organo-mineral balance, and creates the conditions for better soil structure and effective destruction of post-harvest residues.

Key words: Triticum aestivum L., ecologicaltrophic groups of microorganisms, plant rhizosphere, multifunctional biopreparations.