• Journal of Biosystems Engineering
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• v.41 no.1
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• pp.21-33
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• 2016

Purpose: In order to ensure that vegetable seedlings (with a soil block around their roots) are planted in an upright orientation after metering in a vegetable transplanter, they need to be dropped freely from a certain height. The walk-behind hand-tractor-powered machines do not have sufficient space to drop the seedlings from that height. In the present work, a hopper-type planting device was developed for the walk-behind hand-tractor-powered vegetable transplanter to ensure that the soil block seedlings are planted in an upright orientation. Methods: Various dimensionless terms were developed based on the dimensional analysis approach, and their effect on the planting of soil block seedlings in an upright orientation (planting efficiency) was studied. The optimum design dimensions of the hopper-type planting device were identified by the Taguchi method of optimization. Results: The ratio of the height of free fall to the sliding distance of the seedling on the surface of the hopper had the highest influence on planting efficiency. The planting efficiency was highest for plants with a height $15{\pm}2cm$. The plant handling Froude number, in interaction with the design of the hopper-type planting device, also significantly affected the planting efficiency. Of the hopper design factors, the length of the slide of the seedlings on the surface of the hopper was most important, and induced sufficient velocity and rotation to cause the seedling to fall in an upright orientation. An evaluation of the performance of the planting device under actual field conditions revealed that the planting efficiency of the developed planting device was more than 97.5%. Conclusions: As the seedlings were fed to the metering device manually, an increase in planting rate increased missed plantings. The planting device can be adopted for any vegetable transplanter in which the seedlings are allowed to drop freely from the metering device.

• Journal of Bio-Environment Control
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• v.6 no.3
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• pp.159-167
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• 1997

To cope with the mass-production and supply of plug seedling, the supply of transplanters is necessary. In the study, a transplanting test was carried out to find the optimum working condition in the mechanizd transplantation and to acquire the basic data for the improvement of transplanters by the research and analysis of working capacity of the local manual transplanters. The size of hopper affected transplanting stand and rate. Re-irrigation was required for the transplanted seedlings because they wilt 1 day after the transplanting if soil compaction is incomplete. Consequently, back-forth-left-right compaction method was good for soil covering and compaction. It may be thought to increase the amount of irrigation water at the time of transplanting by double-irrigation mechanism, but it needs to increase the larger water tank which makes the operation uneasy. So, assuming the working model by 1 or 2 operators with the machine size as small as possible, it seemed that eliminating of automatic irrigation method was desirable in view of efficiency. Though semiautomatic transplanter needs some structural improvements, it seemed still suitable for transplanting of plug seedlings such as 45-day red pepper seedlings in 128-hole tray and 25-day Chinese cabbage seedling in 128-hole tray. If traveling speed of the transplanter is limited to less than 14 m/min, with the transplanting depth of 2~3cm and transplanting space of 30cm.