An investigation on the performance of rice threshing drums in the southwestern region of Bangladesh

This study evaluated the performance indices of the locally developed rice-threshing drum in the Khulna region of Bangladesh. Threshing efficiency, throughput capacity, output capacity, threshing capacity and grain to straw ratio were assessed and data were analyzed using ANOVA as a statistical tool. The study involved the thresher with different engine horsepower capacities (25hp, 20hp, and 16hp). The variables of paddy were two stages of moisture content (14% referred as dry condition and 23% referred as wet condition), four different cutting heights of paddy (25-30, 30-35, 35-40 and 40-45 cm). The values for threshing efficiency, threshing capacity, output capacity, throughput capacity and grain to straw ratio in dry conditions ranged from 97.83 – 98.83%, 1700-2373 kg/hr, 27.75 -36.46 kg/hr, 930 – 1436 kg/hr and 1.21-1.54 respectively and in wet condition ranged from 96.15 – 97.79%, 1168-2167 kg/hr, 41.64 -49.99 kg/hr, 622 – 1280 kg/hr and 1.14-1.45, respectively. It was observed that with the increase in moisture content, cutting height and decrease in engine horsepower, there was a significant decrease (p < 0.05) in output capacity, threshing capacity, threshing efficiency and grain to straw ratio and vice versa. Therefore, the thresher used would be more useful by maintaining a proper combination of machine-crop parameters such as a moisture content of 14-15 %, an engine horsepower of 25 hp and a cutting height of 25-30 cm. Insights from this study can guide the development and adoption of improved paddy-threshing technologies in the region.