TY JOUR TI FUNCTIONAL DIAGRAM OF THE SOWING UNIT BASED ON A PNEUMATICCALLY OPERATED SEEDER KW seeder KW pneumatic system KW distributor KW apparatus KW unit JO Bulletin Samara State Agricultural Academy AU Kravtsov, A.V. AU Konovalov, V.V. AU Kuchmasov, K.Z. AU Zaitsev, V.Y. PY 2020 IS 5 PB Samara State Agrarian University