Abstract

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The objective of this study was to evaluate the performance of a mechanical yam harvester. The harvester was operated at average soil depth of 0.30 - 0.33 m and tuber spread values of 0.18 - 0.22 cm. The tuber length varied from 0.33 to 0.38 cm and tuber depth of penetration also varied from 0.29 to 0.37 cm irrespective of yam variety. The tractor harvesting speed and field capacity values were 1.04 to 1.31 m/s and 0.30 to 0.38 ha/h respectively. Fuel consumption and wheel slippage ranged from 9.07 to 9.75 l/ha and 2.93 to 3.79 % for mound and ridged landforms respectively. Tuber damage values were 1.96% and 3.45% for ridge and mound harvesting respectively. Mechanical harvesting reduced harvesting cost by 50%. The cost of US$ 1500.00 for the yam harvester gave a breakeven point of about 180 h of use (~ 64 ha of harvested land area) when used for custom services at a cost of US$ 5.00 per h.

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