Optimization of productivity of old-seeded grass stands on drained lands of the Upper Volga region

A field experiment on methods for improving the quality of the obtained feed of legume-cereal agrophytocenoses and increasing their productive longevity was conducted at the VNIIMZ agrostationary from 2023 to 2025 on grass stands sown in 2018. Methods for optimizing the functioning of old-seeded agrocenoses with bentgrass, bluegrass and red fescue consisted of mineral fertilizing (N60P45K75) and overseeding the existing undisturbed grass stand of Lotus corniculatus Solnyshko. The component composition of the studied grass stands included: creeping clover, variable alfalfa, Lotus corniculatus (legumes) and reed fescue, perennial ryegrass and timothy grass (cereals). It was found that overseeding of Lotus corniculatus in old-growth grass stands increased the proportion of leguminous grasses in agrophytocenoses by 0.4–1.9% compared to the variant without overseeding. In variants with mineral fertilization, bluegrass grass stands provided a green mass yield of 15.5, fescue grasses – 18.0, red fescue grasses – 18.8 t/ha and 3.87, 4.41 and 4.14 t/ha of dry biomass, respectively. At the same time, the dry mass yield of all studied agrophytocenoses, compared to the control variant, increased by an average of 0.67–1.07 t/ha or by 20.9–34%. Overseeding of Lotus corniculatus into undisturbed grass stand had an insignificant effect on the yield of green mass, the increase was 7.8-18.2%, but improved their botanical composition. Greater accumulation of root mass was noted under grass stands with giant bentgrass. Against the background of fertilizers, more nitrogen accumulated in the root mass of grass stands, on average 222.6-288.0 kg/ha, and with overseeding of Lotus corniculatus - more phosphorus and potassium, on average 102.5-127.2 and 62.2-82.7 kg/ha, respectively. No significant differences in the quality of the resulting forage under the influence of the studied methods were revealed.