Optimization of operational parameters for mechanised harvesting of pigeon-pea (Cajanus cajan) with combine harvester

Pigeon-pea is very thick and woody stem crop, therefore the harvesting and threshing of this crop is a drudgery and time consuming.  At present in India pigeon-pea is harvested manually with sickle and after that the crop is left in the field in the form of heaps for 7-10 days for sun drying. After sun drying the crop is threshed with suitable thresher or beating with stick etc. Lack of mechanization of harvesting and threshing operation is one of the limitations to the increase production and productivity of pigeon-pea. Therefore, the present study was aimed at optimizing operational and crop parameters influencing the mechanized harvesting and threshing of pigeon-pea crop with combine harvester. PAU-881, AL-1856, AL-1817 and AL-1811 of extra-short duration pigeon-pea were selected for the study. The moisture content of crop and grain varied from 38 to 48% and 22 to 25% on wet basis respectively for crop varieties AL-1817 and AL-1811 and it was 48 to 53% and 24 to 27% on wet basis respectively for crop varieties PAU-881 and AL-1856. Concave clearance was kept as 16 mm at front side and 7 mm from rear side. Threshing efficiency was more than 98% at cylinder peripheral speed of 26.61 m/s and 34.85 m/s in all varieties except PAU-881. The percent grain breakage was higher for higher cylinder peripheral speed and lower for higher forward speed. The grain damage was below 1% for 23.85m/s, 26.61 m/s and 34.85 m/s cylinder peripheral speed in all crop varieties except AL-1811.  The optimum values of peripheral velocity and forward speed of combine harvester harvesting pigeon-pea were 26.61 m/s and 2.0 km/h for all selected varieties.