INFLUENCE OF VARIOUS MINERAL NUTRITION CONDITIONS ON BIOLOGICAL ACTIVITY OF MEADOW-CHERNOZEM SOILS AND PRODUCTIVITY OF AGRICULTURAL CROP
The study was conducted to assess the influence of various forms of mineral fertilizers on soil enzymatic activity, cellulose decomposition rate and crop yields, with the aim of improving fertilization systems. The study was conducted from 2022 to 2024 in Omsk region in a long-term stationary field experiment, which included the following treatments: no fertilizer (control), N60, P60 and N60P60. The experimental plot soil was a medium-humus, heavy loamy meadow-chernozem soil. Enzymatic activity was determined in air-dried samples. Meteorological conditions during the observation period and crops grown influenced the soil’s enzymatic activity. Catalase demonstrated its highest activity under perennial grass crops towards the end of growing season, in August, reaching 2.03 O2 cm3/min. No significant effects of nitrogen and phosphorus fertilizers on invertase and urease activity were observed. The highest rate of cellulose decomposition in the soil was observed in oil flax crops, where this indicator varied from 0.82 to 0.95% per day, compared to 0.60 to 0.71% per day under perennial grasses and 0.69 to 0.85% per day under the sorghum-sudanic hybrid. Under the current conditions, the use of N60P60 in flaxseed, orchardgrass mixed with sainfoin and sorghum-sudanic hybrid crops was most effective, yielding 1.54 t/ha of oilseeds and 4.21 and 5.23 t/ha of aboveground plant dry matter, respectively.