Effect of Machine and Crop Parameters on Paddy (Oryza sativa) Threshing using Axial Flow Thresher

India is one of the largest rice producers in the world, contributing 20% to global rice production. In Central India, Madhya Pradesh recently started rice production after the failure of soybean. Paddy harvesting in Madhya Pradesh is mostly done by manual labour, and threshing is done by electric or tractor-operated threshers. To minimize threshing losses, proper combination operational parameter conditions for thresher are to be known. In this study, performance evaluation of tractor-operated axial flow paddy thresher was conducted at JNKVV Research farm Jabalpur at 3 feeding rates (1750, 1800, 1850 kg.h-1), 3 cylinder speeds (456, 536, 610 rev.min-1), and 3 paddy moisture contents [12, 14, 16% (d. b.)] for 3 different varieties (Kranti, JR-81, PS-5) of paddy. The thresher gave best results at 610 rev.min-1 cylinder speed, 1,850 kg.h-1 feed rate, and 12% grain moisture. Kranti variety had 98.54% threshing efficiency, 97.93% cleaning efficiency, and 0.13% broken grain. With JR-81 variety, the thresher could operate with 98.40% optimum threshing efficiency, 97.39% cleaning efficiency, and 0.67% broken grain. Similarly, the threshing performance of PS-5 variety was 98.0% threshing efficiency, 98.61% cleaning efficiency, and 0.4% broken grain percentage. Significant effect of different experimented varieties was not observed in threshing and cleaning efficiencies. However, lowest broken grain percentage in Kranti variety might be due to minimum grain length as compared to the other two varieties.