Evaluation of Agroecosystem Stability in Spring Wheat Cultivation Using ¹⁵N and Seed Inoculation with Biopreparations

The study was conducted to investigate the effect of different doses of nitrogen fertilizer and biopreparations on the functioning of the spring wheat agroecosystem on dark gray forest soil. The work was carried out in two layings of a microfield experiment in 2020–2021, the experimental design involved studying the following options: studying the following options: N₄₅P₄₅K₄₅ (background), background + Extrasol based on strain Ch-13 (standard), background + endophytic strain V167, background + endophytic strain 417, and N₉₆P₄₅K₄₅. Biopreparations based on the studied microorganisms were used by inoculating spring wheat seeds on the day of sowing. When N₄₅ and N₉₀ are applied against the background of PP (phosphorus–potassium fertilizer), plants used between 46 and 42% of the labeled fertilizer, respectively, to form a crop. The use of biopreparations against the background of N₄₅ increased the use of N fertilizer to 51–53%. The immobilised ¹⁵N in the soil of the applied dose was 33–36%, and when innoculated with biopreparations, the value of this indicator decreased to 30%; when inoculated with biopreparations, the value of this indicator decreases to 30%. With the application of ammonium nitrate, 33–36% of ¹⁵N is lost; the inoculation of seeds with biopreparations reduces losses to 16–18%. The use of biopreparations leads to the fact that, after harvesting spring wheat, 0.47–0.51 g/m² less mineral nitrogen remains in the soil, which indicates its better use by plants. According to the ratio of reimmobilized nitrogen to mobilized nitrogen (RI : M = 25–31%), the agrocenosis of spring wheat with the application of nitrogen fertilizer and inoculation of seeds with biopreparations functions in the resistance mode, and the impact level is characterized as maximum permissible. According to the standardization criterion, which is assessed by the ratio of net mineralized nitrogen to reimmobilized nitrogen (N-M : M = 2.24–2.98), the agrocenosis of spring wheat is in the stress or resistance mode. The use of an endophytic biopreparation based on the V 417 strain leads to the fact that the agrocenosis of spring wheat functions in the resistance mode at an acceptable impact level.