TY JOUR TI VARIABILITY OF CHEMICAL COMPOSITION OF HARVEST AND NORMATIVE REMOVAL OF NUTRITIONAL SUBSTANCES OF WINTER RHY UNDER THE IMPACT OF AGROCHEMICALS KW gray forest soil KW winter rye KW Extrasol biopreparation KW mineral fertilizers KW economic and normative removal of nutrients. JO Vestnik of Kazan State Agrarian University AU Gilyazov, M.. AU Yunusov, B.R. PY 2018 IS 12 PB Kazan state agrarian University