TY JOUR TI OPTIMAL METHODS OF FORAGE CROPS OF CROPS ON THE CALCULATED BACKGROUND OF MINERAL NUTRITION IN THE SOIL-CLIMATIC CONDITIONS OF FOREST-STEPPE OF THE MIDDLE VOLGA KW sunflower KW vetch KW oat KW NPK KW botanical composition KW quality of feed. JO Vestnik of Kazan State Agrarian University AU Safin, R.I. AU Amirov, M.F. AU Suleymanov , S.. AU Gilyazov, M.. PY 2018 IS 13 PB Kazan state agrarian University