Performance Evaluation of a Tractor Mounted Yam Dioscorea spp. Harvester fitted with aCollection Unit

摘要

The performance of a tractor mounted yam (Dioscorea spp.) harvester fitted with a trailer for collection of harvested tubers was evaluated. The harvester was operated at the forward speeds of 1.6 kmh~(-1), 2.4 kmh~(-1) and 3.2 kmh~(-1); lift angles of20°, 22.5° and 25° and depths of cut of 46 cm, 48 cm and 50 cm in a split-split-plot design. The harvester was evaluated by determining the number of tubers lifted from the mounds, number of tubers exposed, number of damaged tubers and number of tubers conveyed into the collection unit. The results were analyzed using ANOVA at p < 0.05. The number of lifted, exposed, damaged and conveyed tubers were determined by visual inspection, counted and analysed as simple percentage. Lower tuber damage occurred at the speed of 3.2 km/h at all the lift angles and depths of cut investigated. The lift angle had significant effect on tuber lifted from the mounds. Speed and depth of cut had no significant effect on tuber lifted, exposed, damaged and conveyed intothe collection unit. However, the lift angle had significant effect on the tuber exposed and damaged. The speed and lift angle influenced the damage of tubers. The harvester operated at a speed of 3.2 kmh~(-1), depth of 46 cm and lift angles of 20° and22.5° offered the least tuber damage of 19 %. The highest tuber conveyance of 41 % occurred at a speed of 3.2 kmh~(-1), depth 46 cm and lift angle 22.5°.