TY JOUR TI OPTIMIZATION OF PARAMETERS OF POWERED TILLAGE TOOL WITH SOIL SPIKERS KW soil KW processing KW tool KW disk KW optimization JO Bulletin Samara State Agricultural Academy AU Savelyev, Y.A. AU Kirov, Y.A. AU Ishkin, P.A. AU Petrov, M.A. PY 2021 IS 6 PB Samara State Agricultural Academy