ASSESSMENT OF THE BIOLOGICAL ACTIVITY OF THE SOIL UNDER SORGHUM X DRUMMONDII (STEUD.) MILLSP. & CHASE WHEN APPLYING MINERAL FERTILIZERS

In this study (2020-2022), the effect of mineral fertilizers on the activity of the microbial pool and the enzymatic activity of meadow-chernozem soil under the sowing of sorghum-sudank hybrid (Sorghum х drummondii (Steud.) Millsp. & Chase), as well as the productivity of the culture. The experiment was carried out in a long-term stationary experiment of the laboratory of field feed production of the Omsk Agrarian Scientific Center. The highest population of microorganisms was observed with complex fertilization, an increase in relation to the non-maneuverable variant was 39%. The number of saprotrophic bacteria increased to 39,1 × 106 CFU/g of soil (30,0 × 106 CFU/g at the control), amylolytic microorganisms, including actinomycetes – up to 30,4 × 106 CFU/g (19,8 × 106 CFU/g at the control), cellulose–destroying - up to 97,0 × 103 CFU/g (66,6 × 103 CFU/g under control). It was found that microbiological processes in the soil proceeded more intensively on a fertilized (N60P60) background, the increase in the Pm coefficient was 15% compared to the control. The determination of the enzymatic activity of meadow-chernozem soil, depending on the application of the studied agricultural method, revealed an increase in the enzymatic processes of invertase and urease formation (up to 6%), inhibition of catalase (decrease to 34%) as a result of acidification of the soil by anions of mineral fertilizers. The improvement of the nutrient regime of the soil due to the integrated use of mineral fertilizers ensured the collection of 22,67 t/ha of green mass, 6,32 t/ha of feed units, 0,75 t/ha of digestible protein, 69,87 gj/ha of metabolic energy. Sponsorship information. The work was carried out within the framework of the state research program FNUN-2022-0015.