TY JOUR TI CHANGES IN THE COMPOSITION OF POLY-SPECIESSOWINGS OF FODDER CROPS BY YEARS AND THEIR PRODUCTIVE LONGEVITY UNDER THE UPPER VOLGA REGION KW forage crops KW legumes KW cereals KW mixed cultures KW composition KW density of herbs KW botanical composition KW longevity KW productivity KW nutrient content and their balance JO Adaptive Fodder Production AU Esedullaev, S.T. PY 2020 IS 2020 PB Federal Williams Research Center of Forage Production and Agroecology