During the three years (1997 - 1999) an experiment was carried out to verify the technical and economical benefit of harvesting onion mechanically by using potato-digging machine (model ASA Lift) with an effective width of 1.4 meters which is mounted on a tractor. Seven treatments were tested, six of them by using the machine (three levels of speed 1.6 km/h, 1.75 km/h and 1.9 km/h and two digging depth of 12 cm and 15 cm). The seventh treatment was the traditional hand digging. Regarding the studied machine, it was able to harvest all onion bulbs in the field at 100% efficiency. The statistical analysis for the intact yield showed a significant difference between manual harvesting and three mechanical treatments (1.60 km/h + 12 cm depth, 1.90 km/h + 12 cm depth and 1.90 km/h + 15 cm depth). The intact yield in manual harvesting was 91.9%, while the lowest values were for the treatment (1.90 km/h + 12 cm depth), which gave 87.43%. Regarding the severe damage which was caused by mechanical reasons, the statistical analysis indicated significant differences between manual harvesting which was 3.71% and the other three mechanical harvesting methods. The treatment (1.90 km/h + 12 cm depth) showed the highest damage with 6.5%. Using the Potato Digger has reduced harvesting cost up to 76% since the total costs for using the machine was only YR 3144 in comparison to the manual harvesting which costs 13320 YR/h. The net benefit of using the mechanical harvesting was 7312 YR/ha when the values for mechanical damage were excluded.
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