This article presents the results of scientific research conducted from 2022 to 2025. The research method involved a field experiment comprising seven treatments with three replications, carried out on drained, soddy-podzolic, medium loamy arable land. The study was conducted at the experimental field of VolRC RAS, located in the Vologda Region. The grass mixture consisted of double-cut clover (Trifolium pratense), hybrid alfalfa (Medicago varia), tall fescue (Festuca arundinacea), and timothy (Phleum pratense). Fertilizer rates were applied according to a developed methodology. The aim of the research is to study the effect of different nitrogen rates (against a background of phosphorus and potassium) on the yield and forage value of a clover-alfalfa-grass mixture harvested three times per season. The scientific novelty lies in the fact that for the first time, the effects of different nitrogen application rates and timing of nitrogen top-dressing on the productive performance of a clover-alfalfa-grass mixture under three cuts are being studied. The results obtained revealed that nitrogen fertilizer application did not significantly affect the yield of the grass stand in the first year of use. In the second year of use, the application of mineral nitrogen had a significant effect on yield. In terms of dry matter yield, treatments 2–3 and 5–6 provided an increase over the control (treatment 1) of 0.6–1.3 t/ha of dry matter, or 9.6–17.8%. In the third year of use, grass mixtures receiving nitrogen application provided a substantial increase over the control of 13–16%. The nutritive value of the green mass in the first year of use was high and unrelated to nitrogen application. In the second year of use, the protein content in the control was reduced (to 15.9%) and increased with nitrogen application (to 16.1–17.8%). The protein level of the grass mixture in the third year of use in treatment 1 (without nitrogen) was 14.8%, while in treatments 2–7 (with nitrogen application) it ranged from 15.0–16.6%. Under the influence of mineral nitrogen, the height of grasses increased, while the proportion of legume species decreased. This research is intended for the conditions of the European North of Russia
Keywords
Grass mixture, alfalfa, clover, tall fescue, timothy, three cuts, mineral nitrogen, yield, protein