TY JOUR TI MAIN DEVELOPMENT TRENDS AND DIRECTIONS FOR GRAIN SUBCOMPLEX REGULATION IN SOUTHERN FEDERAL DISTRICT KW grain subcomplex KW grain market KW digital transformation KW Southern Federal District JO Vestnik of Kazan State Agrarian University AU KHoruzhiy, L.I. AU Bykov, A.A. AU Sergeev, D.G. PY 2025 IS 20 PB Kazan state agrarian University