ASSESSMENT AND ADAPTATION OF A NAERC PEDAL MILLET THRESHER FOR THRESHING SORGHUM (Junelo) IN NEPAL
Traditional threshing (pounding, animal trampling, beating the harvested heads with sticks on bare ground or in bags), a most common manual threshing practice for majority of the farm households is a slow, tedious, drudgerious and labor intensive practices in Nepal. Therefore, there is need of threshing mechanization option suitable for smallholder farmers to replace the manual threshing of sorghum. As most of the farmers have small land holding, poor economy and insufficient electric power supply, a pedal operated millet thresher was playing important role especially for threshing millet in Nepal. Hence, a study was conducted to evaluate the performance of a NAERC pedal millet thresher for threshing sorghum. Thresher was evaluated in terms of different performance parameters such as threshing capacity, threshing efficiency, grain loss, and associated threshing labour and cost. In addition, the physical and engineering properties of sorghum grain namely, moisture content, linear dimensions, 1000 grain weight, particle and bulk density, arithmetic mean diameter, geometric mean diameter, equivalent diameter, shape index, sphericity, aspect ratio, porosity, repose angle and friction properties behavior on different surfaces were studied. The average threshing capacity of the pedal thresher (machine threshing) for sorghum was obtained as 28.20±3.07 kg/hr with a threshing efficiency of 93.36% at an average moisture content of 11.44%, and concave clearance of 6 mm, respectively while that of stick beating (manual method) was 12.2±0.2 kg/hr. The average broken grain losses of 5.00±1.19% and 6.8±0.9% were found in machine threshing and manual threshing, however, unthreshed grain was higher in thresher (6.6±0.91%) than stick beating (4.1±1.2%). Considering economic perspectives, a labour saving of 46.41% was achieved by the use of pedal thresher (47.85 man-hr/mt) compared to manual threshing (103.9 man-hr/mt). Manual threshing needs almost 2.15 hours to thresh equal mass as that by thresher in one hour. Similarly, cost saving of 24.24 % was occurred in custom hired machine threshing (NRs 7000/mt) with respect to manual method (NRs 9239.7/mt). Conclusively, this technology is widely accepted by farmers for threshing finger millet, thus this study on sorghum threshing explored its multi-use benefit in maximizing thresher use per year and increase profitability.
Sorghum, pedal millet thresher, physical properties, manual threshing, efficiency