Evaluation of Tractor Mounted Axial Flow Combine Harvester for Mung Bean (Vigna radiata L.)

Abstract

A cost-effective, tractor mounted axial flow combine harvester designed to minimize harvesting losses was evaluated. Performance evaluation of the machine was done on summer mung bean (Vigna radiata L. Wilczek) under various operational conditions: three forward speeds (FS): 2.1, 3.0, and 4.8 km h-1, three-cylinder peripheral speeds (PS): 11.08, 13.16, and 14.79 m s-1, and days after irrigation (DAI): 2, 4, and 6 days after last irrigation. Threshing efficiency, cleaning efficiency, broken percentage, shattering losses, and non-collectable losses were estimated. Cost of operation of the combine harvester was compared with manual harvesting and subsequent threshing using a spike tooth type thresher. The results show that the threshing efficiency and grain breakage increased by 1.1% and 1.01%, respectively, with an increase in DAI and PS, however, both these parameters decreased with an increase in FS. The non-collectable loss increased by 0.9% with an increase in FS and DAI; however, PS did not affect the non-collectable losses. The cleaning efficiency increased with an increase in FS, but it decreased with an increase in PS and DAI. The shattering loss increased with an increase in FS and DAI, although PS had no impact. The best combination of operational variables for threshing operation was found for treatment combination of 6 days after last irrigation, with a cylinder peripheral speed of 14.79 m s-1 and a forward speed of 3.0 km h-1. At this combination, threshing efficiency, non-collectable losses, grain breakage, and cleaning efficiency were 99.28%, 4.53%, 2.96%, and 95.89%, respectively. This combine-harvester saved 91.75% in labor costs and 53.71% in harvesting costs compared to the combination of manual harvesting and subsequent threshing using a spike tooth type thresher.