The studies were carried out in a field experiment in the north of the Arkhangelsk region. Under study were twocomponent grass stands of the first and second year of life, composed of cereal (meadow fescue, reed fescue) and legume grasses (meadow clover and blue alfalfa ). It has been established that in the climatic conditions of the Northern region the studied perennial grasses do not go through the full life cycle during the first year of life: meadow clover develops up to the root rosette phase, blue alfalfa – up to the branching phase, cereals ‒ to the tillering phase. In the first year, the yield is formed due to the legume component, especially meadow clover, which occupies 73 % of the structure. In the second year of life, cereal grasses increase their influence on the yield formation up to 93 %. The most productive variant in the second year was the “reed fescue + meadow clover” variant. With a higher ratio of the cereal component (67 %) in total for two mowings in comparison with the control variant "meadow fescue + meadow clover", the increase in dry matter yield was 2.81 t/ha (LSD05 = 1.46 t/ha), the output of exchange energy was 30.56 GJ/ha higher, crude protein yield increased by 0.22 t /ha. Agrophytocenoses of reed fescue and meadow clover in the first year of intensive use make it possible to obtain green fodder with the protein content in 1 kg of dry matter at the level of 114.28 g ‒ 153.33 g and sugars 133.54 g ‒ 154.65 g depending on the mowing. High loss of blue alfalfa in the grass stand is due to its weak winter hardiness and the effect of low spring temperatures during the period of the beginning of regrowth. Thus, in the conditions of the European North of Russia among legume-cereal grass stands during the first two years of life the grass mixture of meadow clover and reed fescue has been identified as perspective. There has been noted a potential for regulation the feed nutritional value (protein, sugars and fiber content) by means of grass mixture components selection.