TY JOUR TI FORMATION OF HIGHLY PRODUCTIVE AGROCENOSES OF PERENNIAL LEGUMINOUS GRASSES IN THE CONDITIONS OF THE NON-CHERNOZEM ZONE OF THE WEST SIBERIAN REGION KW perennial leguminous grasses KW yield KW green mass KW productivity KW nitrogen fixation JO Vestnik of Omsk SAU AU STEPANOV, A.F. AU KHRAMOV, S.Y. PY 2023 IS 50 PB FSBEI HE Omsk SAU