The results of the research of festulolium and alfalfa in a joint herbage with different methods of sowing and doses of mineral nitrogen conducted in the forest-steppe of Western Siberia in the period from 2020–2023 are presented. The growth and development of crops in the initial period of life, winter hardiness, productivity and economic feasibility of cultivation were taken into account both in favorable 2019–2021 (HTC = 1.0...1.29) and in unfavorable 2022–2023 (HTC = 0.6...0.99). A high response of perennial grasses was achieved in sowing festulolium one row + alfalfa three rows — 38.13 t/ha of green mass, which corresponds to a single-species alfalfa crop. Sowing with a mixture of seeds is 21% less productive. A positive effect was obtained from optimizing the level of cenosis and foliage of alfalfa by 56%, which was confirmed by an average correlation (r = 0.58). The energy efficiency coefficient (CEE) had maximum values of 9.8–11.7 and was characterized as high, the profitability of cultivating mixtures was 407–465%. A positive effect was obtained when N30 was introduced into the sowing of festulolium one row + alfalfa three rows — 21–36% to 37.41 t/ha of green mass. In comparison with the unfavorable background, the share of festulolium in the yield of mixtures increased to 58–71%, alfalfa decreased to 29–42%. CEE = 4.9–5.6 (the value is from medium to high), the profitability of cultivating mixtures is 325–378%. The application of mineral nitrogen N60 to joint crops of festulolium and alfalfa increases the collection of green mass compared with single-species sowing of festulolium by 10–20%, to 34.74–37.93 t/ha of green mass due to the maximum proportion of cereals in mixtures — 62–80% with its responsiveness to fertilization. CEE = 4.5–4.9 (average value), the profitability of cultivating mixtures is 323–365%.