Influence of nitrogen fertilizers and predecessors on the productivity of winter wheat

Topicality. Global warming requires the search for effective predecessors and doses of nitrogen fertilizers to obtain stable yields of high quality winter wheat grain. Purpose. To study the influence of the grain legume predecessor (peas) on the yield of winter wheat (Triticum aestivum L.), and establish the optimal dose of nitrogen fertilizers for the biologization of its cultivation. Methods. Long-term field and analytical. Results. The data of researches on the influence of legume predecessor (peas) and doses of nitrogen fertilizers on the productivity of winter wheat are given. It was found that the legume predecessor (peas) and nitrogen fertilizers significantly increased the yield and quality of winter wheat grain. It was defined that increasing the dose of nitrogen fertilizers for winter wheat from 40 to 80 kg/ha on both predecessors was effective. Conclusions. The application of N80P60K60 for winter wheat in the crop rotation link with peas provided the highest grain yield – 5.42 t/ha with an excess to the control without fertilizers by 1.02 t/ha. Under the predecessor (meadow fescue), the application of N80P60K60 decreased grain yield by 1.03 t/ha. It was found that an increase in the nitrogen fertilizer dose from 40 to 80 kg/ha for winter wheat was more effective in the peas link – grain yield increased by 0.56 t/ha, while in the meadow fescue link – by 0.38 t/ha. A clear correlation between dose of nitrogen fertilizers and winter wheat grain yield was established: with the coefficient of determination in the meadow fescue link – 0.9999, the peas link – 0.9966. The plowing of pea straw under winter wheat against the background of the dose of mineral fertilizers N60P60K60 was determined to be effective; the grain yield increased by 0.23 t/ha compared to the application of mineral fertilizers alone, with an absolute indicator of 5.36 t/ha. The application of mineral fertilizers in both links increased the growth of stem mass, ensuring the straw yield in the peas link by 0.4–0.7 t/ha higher than in the meadow fescue link. Under peas as a predecessor, the quality of winter wheat grain has significantly improved. In the control without fertilizers, the protein content in wheat grain after peas was 11.4 %, after meadow fescue – 11.0 %; for the application of a dose of N40P60K60 fertilizers – 11.8 % and 11.4 %, respectively; N60P60K60 – 12.0 % and 11.5 %, N90P60K60 – 12.1 % and 11.7 %. Due to the legume predecessor (peas), the protein content in the grain increased by 0.4–0.5 % compared to the meadow fescue as a predecessor. Key words: nitrogen, predecessor, peas, productivity, winter wheat