TY JOUR TI INFLUENCE OF NUTRITION BACKGROUND AND SURFACE IMPROVEMENT METHODS ON PRODUCTIVITY OF FLOODPLAIN MEADOWS OF MIDDLE VOLGA STEPPE REGION KW combined subsurface-cultivators KW sod treatment KW nitric phosphoric and potash fertilizers KW productivity KW forage quality KW economic efficiency JO Vestnik of Kazan State Agrarian University AU Khismatullin, M.. AU Safiollin, F.N. AU Minnullin, G.. AU Khismatullin, M.M. PY 2017 IS 11 PB Kazan state agrarian University