Influence of the dynamics of stocks of mobile forms of nitrogen in gray forest soil and the use of fertilizers on the yield of oats under various weather conditions

In a long-term field experiment on the gray forest soils of the Vladimir opole, the influence of mineral fertilizers and the aftereffect of cattle manure, their interaction on the yield of oats going 2nd crop after the occupied steam, and the dynamics of mobile nitrogen forms under various weather conditions were studied. The determining role of ammonium nitrate nitrogen in the composition of NPK and the aftereffect of cattle manure in increasing the yield of oats has been established. The results of the study indicated that the culture was fed mainly with the nitrate form of nitrogen. A high degree of correlation was revealed between the reserves of N-NO₃ in the soil layer of 0–40 cm, formed as a result of the transformation of soil nitrogen and fertilizers to oat seedlings, and its yield (0.981 > R² > 0.787). The influence of fertilizers and weather conditions on the formation of nitrate nitrogen reserves in the phases of growth and development of oats and their dynamics, ensuring the achievement of high grain yield and quality, are determined. Depending on weather conditions and fertilizer systems, the coefficients of using N-NO₃ formed during the growing season of oats for nitrogen removal by grain (40.7–66.6%), grain and straw (58.3–75.0%), grain, straw and crop-root residues (71.2–88.6%) are calculated. In nitrogen-fertilized variants, on average, at 4 levels of manure aftereffect (0, 40, 60 and 80 t/ha), they were highest when using a single dose of N40P40K40, when using a double dose of N80P80K80, they significantly decreased. On average, at 4 levels of mineral fertilizer application (0, P40K40, N40P40K40 and N80P80K80), the utilization coefficients of N-NO₃ formed during the growing season with the aftereffect of manure of 60 t/ha were maximum. When N80P80K80 is combined with the aftereffect of organic fertilizers of 80 t/ha, the highest losses of N-NO₃ due to denitrification and leaching are possible.