COMBINE LOSS AND GRAIN CLEANLINESS IN KANSAS HARD WINTER-WHEAT

A survey designed to explore combine processing loss and grain cleanli ness during the 1994 and 1995 Kansas wheat harvests was performed in a n attempt to provide new information for the debate over the economic feasibility of cleaning wheat. Average combine processing losses for 1 994 and 1995 were 4.2 and 4.4%, respectively. The dockage contents wer e 0.6 and 4.8% for 1994 and 1995, respectively. Grain lost from the co mbine was significantly smaller in diameter, lighter weight, and more variable compared with wheat collected by the combine. Regression anal ysis indicated that the harvest rate (bushel of wheat processed per ho ur), material other than grain, and cylinder speed best described the amount of variability in dockage among wheat samples collected in the combine after processing. Harvest rate, harvest rate squared, and the interaction between harvest rate and sieve opening best described the variation in combine loss during processing.