TY JOUR TI RATIONAL USE OF VERSATILE 2375 TRACTOR ON THE MAIN SOIL TILLAGE KW algorithm KW ballasting KW tillage KW productivity KW tractor KW specific gravity JO Bulletin of KSAU AU Selivanov, N.I. AU Sedakov, D.A. PY 2019 IS PB Krasnoyarsk State Agrarian University