This study was carried out in spring season 2011 in Tal Al-Hawa region in Rabeea which is located 95 Km. north east Mosul city/Iraq that is charac- terized by its clayey soil and carried out on potato crop type Draga in order to study the effect of three lifting dates 29/6, 6/7, 26/7 which is after 116, 123, 143 days of planting date. The effect of two kinds of lifting machines was used, one of them is chain lifter (Turkish Type) with shaking separating apparatus in two stages, and the second one is Japanese lifter (type Duck foot) in order to measure the ratio of undamaged tubers, big-scratched tubers, and simple-scratched tubers, also to measure quantitative and qualitative losses and lifted potato and ratio of damaged tuber for potato.
The experiment data were analyzed statistically by using randomized complete block design in split experiment using three replycates, also the regression equations were used to estimate values of studied properties and to determine the best time to lift the tubers, and the results showed that the second date showed significant difference which showed the highest ratio of undamaged tubers 77.74%, and lifted tubers 94.76% and less ratio of quantitative loss 5.24% and less ratio of qualitative loss 17.01% and the ratio of damaged tuber 79.22%, while the third date showed significant difference which showed less ratio of simple scratched tubers 12.54%.
In concern to the effect of the lifter type in the studied properties, the results showed that the Japanese lifter showed significant difference which showed the highest ratio of the undamaged tubers 71.33%, less ratio for the simple scratched tubers13.61%, qualitative loss 17.47%, and ratio of damaged tuber 94.94%, while the chain lifter showed a significant difference which showed less ratio of quantitative loss 6.96%, highest ratio for the lifted tubers 93.04%, while the use of the Japanese lifter at the third date had lowered the ratio of simple scratched tubers to 4.66% and lowered the ratio of qualitative loss to 11.99%, and raised the ratio of quantitative loss to 15.02% and the ratio of damaged tuber to 131.73% at the first date.