TY JOUR TI THEORETICAL UNDERPINNING OF FIELDS MAPPING AUTOMATION FOR IMPROVEMENT OF THE WAY OF SOIL SAMPLIN KW robot sampler KW test KW soil KW automation KW mapping JO Bulletin Samara State Agricultural Academy AU Vasilev, S.I. AU Mashkov, S.V. AU Kruychin, P.V. PY 2019 IS 4 PB Samara State Agrarian University