TY JOUR TI THE INFLUENCE SILPHIUM PERFOLIATUM AS PREDECESSOR ON PRODUCTIVITY OF GRAIN-CROPS KW cup plant KW awnless brome KW prede- cessor KW green manure KW the term of ploughing up KW grain-crops KW productivity JO Bulletin of KSAU AU Chupina, M.P. AU Stepanov, A.F. AU Khristich, V.. PY 2017 IS PB Krasnoyarsk State Agrarian University