Full explanation
Primary function: efficient grain-ear separation with minimal grain damage. Too-large gap → under-threshing (up to 5–10% of grain left in straw); too small → cracked/damaged grain. Adjusted from cab (modern combines) or mechanically by handle (older models). Automated systems: JD Advanced PowerCast Tailboard + Auto HarvestSmart, Claas CEMOS Auto, Case AFS Harvest Command — adjust clearance and other parameters from flow sensors, rotor load, grain-in-straw indicators. Typical setting procedure: (1) starting values per operator manual; (2) 50–100 m initial pass; (3) assess losses behind the combine and grain cracking; (4) correct clearance by 2 mm at a time to optimum. Trade-off: automated systems (CEMOS, AFS Harvest) save 2–5% of losses and 0.5–1.0% of cracked grain → UAH 100–300/ha extra.