EFFECTS OF COMBINE OPERATING PARAMETERS ON HARVEST LOSS AND QUALITY IN RICE

Combine tests were conducted in commercial rice fields near Keiser, Ar kansas. Data was collected and analyzed for two long-grain rice variet ies, 'Newbonnet' and 'Lemont', over a period of two harvest seasons. T he test system used allowed for the collection of the clean grain auge r discharge, shoe discharge, and rotor discharge separately and simult aneously. Independent variables tested were field speed (feedrate), ma terial-other-than-grain to grain (MOG/G) ratio, moisture content, roto r speed, and concave clearance. Feedrate was the most important factor affecting combine harvest loss. Material-other-than-grain to grain ra tio was the second most important factor affecting loss rates. Moistur e content, by itself,was significant only in the 'Newbonnet' variety b ut affected loss rate in the 'Lemont' variety by influencing feedrate and MOG/G ratio. Rotor speed also influenced loss rates but affected e ach of the varieties differently. Concave setting was significant in b oth varieties but to a lesser degree in 'Newbonnet'. Head rice yields from combine-harvested samples and hand-harvested samples followed sim ilar trends. Less than two percentage points of reduction in head rice yield were found in the combine-harvested samples when compared to ha nd-harvested samples.