The main task of increasing the productivity of perennial grass-legumes grown on the slopes withdrawn from cultivation is to form optimal conditions for the growth and development of meadow grasses, which would ensure the highest yield of forage during the entire period of use of grass and the production of high-quality and cheap feed for public livestock. To successfully solve the problem of productivity of agrophytocenoses in scientific and practical applications, it is important to know exactly how the relationship of plants in the process of their joint growth and development, what changes occur in the chemical composition of feed when applying mineral fertilizers and growth promoters on eroded lands with steepness 6–7° under soil sedimentation of the research sites of the Rivne Institute of Agricultural Industry of NAAS of Ukraine. The results of research are presented, which showed that it is economically more effective on the slopes to grow cereals and legumes with a longer period of productive longevity, while using low rates of nitrogen fertilizers, which promotes the formation of phytocenosis, which is dominated by valuable species of cereals and perennial legumes. sowing). The introduction of mineral fertilizers and growth promoters had a positive effect on the biochemical composition of cereals. The results of studies have shown that for the creation of cereals and leguminous herbs hay use in a non-coating way, you must sow a grass mix, which includes the following herbs: alfalfa sowed (4.4 million pieces per hectare) + long beetroot horned (4.4 million pieces per hectare) + bromus inermis (3.4 million pieces per hectare) + lolium perenne (3.4 million pieces per hectare) of conditioned seeds that affect the productivity and chemical composition of the herb during the growing season. On the basis of the conducted researches it is established that the influence of different doses of mineral fertilizers and growth promoters (emistim C and fumar) significantly increases the yield of dry weight and biochemical composition of feed. The results of the research are presented, which showed that during the years of the formation of cereals and leguminous grass hay use, the highest yield of dry fodder (7.5 t/ha) was collected in the variant, where mineral fertilizers were calculated at the rate of N60P60K90 with the use of fumarant plant growth stimulator and high quality, the yield of feed units was 5.25 t/ha, and digestible protein 0.82 t/ha. Years of research have shown that it is advisable to use low rates of mineral fertilizers (N60P60K90) and growth stimulants emistim C and fumar to improve feed quality.