TY JOUR TI Photosynthetic activity and agro-energy efficiency of growing perennial grasses under different modes of use of the grass stand KW hayfield and pasture use KW perennial grasses KW agrophytocenosis KW photosynthetic activity KW leaf surface KW productivity KW agro-energy efficiency. JO Agrarian Bulletin of the AU Grebennikov, V.G. AU Shipilov, I.A. AU Khonina, O.V. PY 2020 IS 198 PB Ural State Agrarian University