TY JOUR TI Two-cut use of perennial fodder agrocenoses in the conditions of the northern regions of Russia KW perennial grasses KW reed fescue KW red clover KW productivity KW crop structure KW protein yield KW nutritional value of green mass JO Agrarian Bulletin of the AU Shamanin, A.A. AU Popova, L.A. PY 2023 IS 23 PB Ural State Agrarian University