Abstract
Factors to improve the mechanical transplanting accuracy of lettuce plug seedlings were examined for transplanting accuracy and yield under different ridge conditions after rice cropping.
1) A ridger with small radius blades attached in the middle improve pulverization of soil and rice stubble at the ridge surface. However, care was necessary to ensure that submerged rice stubble was raised up to the surface layer at some PTO speeds.
2) Lettuce globe shape differed according to planting depth and angle differences.
3) Missing plants were increased by rice straw which was shredded and sprinkled during combine harvesting. Therefore, it was better to carry the straw off of the field.
4) Picking misses of the fully-automatic transplanter were increased by insufficient seedling root spread because of its pincette style picking mechanism.
5) The compact seedling shape was effective to improve transplanting accuracy of the transplanter with the openertype planting finger.
