Effect of Potato Digger Speed Ratios and Elevator Agitation on Harvesting Efficiency, Cost and Tuber Losses

Abstract

A field experiment was conducted at the Faculty of Agriculture Farm, University of Alfateh, Tripoli, Socialist People’s Libyan Arab Jamahiriya, during 1976. The objective was to study the theoretical field capacity, labor used and cost of harvesting by a mechanical potato digger at 4 elevator speed to forward speed ratios, with and without elevator agitation. The digger had 7.9 times more theoretical field capacity, required 12.8% labor and 38.4 % of the cost of the manual harvesting. The elevator agitation increased the capacity and reduced the labor and cost as compared to no agitation. The speed ratios of 0.57:1 and 0.85:1 seemed more effective to give increased capacity, and to reduce labor and cost.

The tuber damage with speed ratio of 1.55:1 was significantly higher than the manual method. The speed ratios of 1.04:1 and 0.85:1 without agitation, and 0.57:1 were not significantly different. The tuber damage was higher with agitation than without agitation of the elevator chain.

The skinning, total tuber damage and total damage excluding skinning were significantly increased by elevator agitation. The speed ratios had a significant effect on serious damage, total tuber damage and total damage excluding skinning. There was no effect of speed ratios and agitations on slight tuber damage and field leavings. The interaction between the speed ratios and the elevator agitations was not significant. The digger under study has poor manoeuvrability, cushionless elevator chain and instability of different components due to enormous vibrations at higher speeds. These drawbacks adversely affected its performance and require redesigning of the related components.