Field Performance Evaluation of Different Rice Threshing Methods

Abstract

Threshing operation is one of the important and effective factors on quality and quantity of paddy. In this study, effects of four threshing methods namely power tiller-operated (T1), axial-flow thresher (T2), tractor-type thresher (T3) and combine harvester as a thresher (T4) on unthreshed grain, shattering loss, damaged grain and broken rice at milling stage were investigated. The results showed that there was a significant difference between means of unthreshed grains and shattering losses in different threshing methods. The highest value of unthreshed grain of 0.56% was in T4 and it was lowest in T1 with the average of 0.46%. The highest shattering loss was obtained in T2 with an average of 0.59%. The amounts of broken and hulled paddy in T1, T2, T3, and T4 were 0.9, 1.59, 2.46 and 2.98%, respectively. The percentage of broken rice after milling of paddy obtained using T1 was lowest with mean of 17.15% and that of T4 was maximum value of 25.05%. The percentage of broken white rice using T2 and T3 was 19% and 22.28%, respectively. It can be concluded that the quality losses in different threshing methods were more determinant than quantity losses.