• Horticultural Science & Technology
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• v.16 no.3
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• pp.344-346
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• 1998

Early emergence of watermelon seeds was markedly enhanced by SMP treatment though the final emergence percentage was not significantly influenced. Mixing ratios of 10:1:5 and 10:1:6 (seed : Micro-Cel E : water by weight) were found to be most effective in promoting the early emergence of watermelon seeds primed for 72 hrs at $25^{\circ}C$. Even though the hypocotyl elongation was slightly promoted by SMP treatment, the hypocotyl diameter remained uninfluenced. Among the cultivars tested, 'House-Ilpum' and 'Surowang' showed the best response to the SMP treatment.

• Journal of Biosystems Engineering
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• v.29 no.3
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• pp.251-260
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• 2004

As a basic experiment for robot hand for transplanting plug seedling, the experimental robot hand system which moves up and downward vertically, and allows hand blade to open and close was made. The system was constructed with the robot hand mechanism, the tray, the plug seedling, and the measuring equipments. The penetrating force and holding efficiency were analyzed according to the soil moisture and the variation of hand blade angle. The highest holding efficiency could be obtained at the penetrating angle of approximately from 0 to 0.36 degree and at the moisture content of soil from 71% to 75%. The external force acted on the robot hand should maximum force when the robot hand was penetrated to soil, minimum of approximately 30.4 N when the penetrating angle was 0$^{\circ}$ and moisture content was 66-70%. It was increased with increasing or decreasing the Penetrating angle from 0 degree and also with increasing or decreasing the moisture content of soil from 66-70%. For optimal design of the robot hand and manipulator, the external force acted on robot hand had to be based on the returning force of soil, when the robot hand was penetrated to the soil. In consideration of safety ratio, the appropriate external force seemed to be 39-49 N.

• Journal of Biosystems Engineering
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• v.26 no.5
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• pp.415-422
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• 2001

A seedling pick-up device for vegetable transplanters was developed and its work performance was evaluated at the laboratory. The pick-up device extracts seedlings from a 200-cell tray of seedlings and transfers them to the place where they are to be transplanted into the soil. The device consists of a path generator, pick-up pins and a pin driver. The path generator is a five-bar mechanism comprised of a fixed link, a driving link, a driven link, a connecting link and a slider. The slider is constrained to move along the driven link and a fixed slot of combined straight-line and circular paths. The connecting link joins the driving link and the slider. When the slider moves along the straight-line path of the slot it takes seedlings out from the cell and transfers them to the transplanting hopper when moving along the circular path. A proto-type of the pick-up device was built and tested under the various operational conditions such as age of seedling, approach direction and penetration depth of pins to the cell, holding method of seedling and extracting velocity. The device extracted 30 seedlings per minute with the maximum success ratio of 97% using the seedlings of 23 days old. Some design details were also discussed and suggested to enhance the performance of the device.

• Horticultural Science & Technology
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• v.19 no.3
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• pp.334-337
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• 2001

This study was conducted to investigate the effect of highland (Daekwallyung, altitude of 800m above sea level) production of cucumber (Cucumis sativus L.) seedlings for retarding culture in lowland (Kangnung, altitude of 20m above sea level). Cucumbers (cv. Jangilbanbaek, Jeongsunyeoreum and Ginseollok) were raised during 25 days from 31st July to 25th August, and then planted under the rain-shelter at Kangnung 25th August. Mean and minimum temperature during raising seedlings at Daekwallyung, $20.9^{\circ}C$ and $16.1^{\circ}C$ were $3.7^{\circ}C$ and $5.3^{\circ}C$ lower than those of Kangnung, respectively. T/R ratio of the seedlings produced at Daekwallyung was lower than that of Kangnung, but chlorophyll contents were higher. Daekwallyung seedlings were higher female/male ratio compared with seedlings from Kangnung. Marketable yield from cucumber seedlings (cv. Jeongsunyeoreum) produced at Daekwallyung was 32% higher than that of Kangnung. These results showed that cucumber seedling raising place was Daekwallyung for the retarding culture during summer season, particularly, and the best cultivars was Baekchim (cv. Jeongsunyeoreum).

• Journal of Bio-Environment Control
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• v.12 no.4
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• pp.190-194
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• 2003

This study was carried out to investigate the effect of several subtrates on the growth of cucumber and tomato seedlings. Cucumber and tomato seeds were sown in plug trays that were filled with eight differenct kinds of substrates. One of them was filled with recycled rockwool by 100%. The other six were mixed with used rockwool media:several ratios of recycled rockwool+peatmoss (1:1, 1:2, 1:3, v/v) and recycled rockwool+chestnut wood ships (1:1, 1:2, 1:3, v/v), and the last was 100% chestnut wood chips. The growth of cucumber and tomato seedlingsin 72 plug tray was better in recycled rockwool+peatmoss (1:2, v/v) substrates that the others tested. CEC 9cation exchange capacity) and EC was a little higher in mixed substrates that blended with organic media. But 100% chestnut wood chips and mixed ones with recycled rockwool inhibited severely the growth of seedlings, especially in tomatos. Therefore, it is suggested that the recycled rockwool be capable of utilization to raise seedlings of cucumber and tomato.

• Journal of Bio-Environment Control
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• v.12 no.3
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• pp.139-146
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• 2003

This study was conducted to investigate the effects on the over-growth inhibition of fruit vegetables (tomato, cucumber, and hot pepper) seedling by the treatment of triazole-typechemicals and to select the most effective chemicals for the over-growth inhibition, and to investigate suitabla concentration treatment and times of the newly selected chemical. The triazole-type chemicals inhibited stem height more, the more the concentration is increased in any crops. The diniconazole showed the highest dwarfing ration, and the tebuconazole and hexaconazole are also good for dwarfing ratio. The diniconazole decreased the plant height of cucumber, tomato, and hot pepper as the concentration is increased. In cucumber, thc dwarfing ratio was 30% in the 5 mg${\cdot}L^{-1}$ treatment, and was 60% in thc l00 mg${\cdot}L^{-1}$ treatment. In tomato and hot pepper, the dwarfing ratio was 30% in the 25 mg${\cdot}L^{-1}$ treatment in any times. In diniconazole treatment, the cucumber and tomato should have 5 mg${\cdot}L^{-1}$ at the lst growth stage and the hot pepper should have 5 mg${\cdot}L^{-1}$ at the 2nd growth stage to obtain good seedlings.

• Horticultural Science & Technology
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• v.34 no.3
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• pp.414-423
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• 2016

Growers in plug seedling production think that root media in which rockwool is a component has given rise to several environmental problems. Therefore, the demand for new materials as a substitute for rockwool has been increased. This study examined the possibility of cultivation of tomato plug seedlings using a newly developed growing medium with phenolic foam. Plug seeds of tomato cultivar 'Madison' were sown in four pellet-type growing media: Grodan rockwool (GRW), UR rockwool (URW), phenolic foam LC (LC) or phenolic foam LC-lite (LC-lite). Then, the seedlings were transplanted to the four cube-type growing media 19 days after sowing. Seeds were germinated in a growth chamber ($25{\pm}2^{\circ}C$, 80% relative humidity, and dark) for 4 days and then the seedlings were grown with a nutrient solution supplied by an overhead irrigation system in a greenhouse. Plant height, number of leaves, leaf area, and fresh or dry weight of tomato seedlings were the greatest for the seedlings transplanted to URW cube media after being grown on LC-lite pellets. Root grade was the greatest for the seedlings transplanted on LC or LC-lite cube media after being grown on LC pellets. Chemical properties of all media tested for tomato growth were maintained within a stable range, while physical properties of URW showed high values in container capacity, air space, and total porosity. These results demonstrated that the phenolic foam media were effective for seedling growth and can substitute for rockwool as a root medium.

• Journal of Bio-Environment Control
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• v.27 no.1
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• pp.71-79
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• 2018

This study was conducted to compare the physicochemical properties of newly developed artificial medium and conventional plug medium and to investigate the proper irrigation interval to produce the high quality tomato seedlings. The five existing artificial media (organic medium coir, mixed medium Tosilee and Q plug, and inorganic medium LC and rockwool) and four newly developed artificial medium (mixed medium TP-S1 and inorganic medium PU 14-S1, PU-7B, and PU 15-S1) were used to grow tomato 'Yegwang' with irrigation interval of one-day (14 times), two-day (7 times), and three-day (5 times) for 14 days. The pH was the significantly highest in the PU 15-S1. All growing medium measured were in the range of pH 5.17-6.90. EC was the highest in the Q plug. The initial germination rate was the highest in the PU 15-S1. The final germination rate and mean daily germination were not significantly different in all growing medium except for the PU 14-S1. Growth of tomato seedlings at 15 days after sowing was the greatest in the Q plug. At 29 days after sowing, seedlings were also the greatest in the Q plug, followed by rockwool and PU-7B. Also, growth was better in the one-day interval treatment. As a result, we confirmed the applicability of the artificial medium to tomato plug seedlings in this experiment, and seedlings were the greatest in the Q plug. Therefor, it is considered that adding nutrients to the artificial medium of the newly developed medium PU-7B, and applying the irrigation one-day interval can produces high quality tomato seedlings similar to using Q plug.

• Journal of Bio-Environment Control
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• v.15 no.3
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• pp.217-224
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• 2006

Objective of this research was to determine the effect of application rate of dolomite in root media containing micronutrient mixes on growth of marigold 'Orange boy' in plug trays. To achieve this, three granular micronutrient mixes such as HF 1, MF 2, and MF 3 were produced and incorporated into three root media, peatmoss+composted pine bark (1:1, v/v, PB), peatmoss+composted rice-hull (1:1, v/v, PR), and peatmoss+composted saw-dust (1:1, v/v, PS), with a rate of $0.3g{\cdot}L^{-1}$. Elevated application rate of dolomite in PB medium containing MF 1 decreased crop growth at 35 days after sowing with the highest fresh and dry weight in the control treatment of dolomite. The treatments of 3.0 and $6.0g{\cdot}L^{-1}$ of dolomite in PB medium containing MF 2 produced 0.133g of dry weight and 0.686g of fresh weight, respectively, which were the highest among treatments of dolomite. But the treatments of 3.0 and $6.0g{\cdot}L^{-1}$ of dolomite in PB medium containing MF 3 produced the highest fresh and dry weight, respectively. Elevated application rate of dolomite in PR medium containing MF 1, 2, and 3 resulted in decrease of fresh an dry weight. The relative growth suppression induced by elevated application rate of dolomite was more severe when MF 3 were incorporated than MF 1 and 2. The treatments of 3.0 and $6.0g{\cdot}L^{-1}$ of dolomite in PS medium containing MF 1 and 3 showed good growth, but elevated application rate of dolomite in PS medium containing MF 2 and control resulted in increase of dry and fresh weight. These results indicated that the application rate of dolomite should be adjusted by kinds of root media and micronutrient mixes.

• Journal of Bio-Environment Control
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• v.26 no.3
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• pp.201-207
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• 2017

Objective of this research was to investigate the influence of pre-plant nitrogen levels in root media on plug seedling growth of radish cv. Soksungbommu. To achieve the research purpose, a root medium, the mixture of perlite, coir dust, and peatmoss (volume percentage of 30:35:35) was formulated and the N levels incorporated during mixing were controlled to 0, 100, 250, 500, 750, 1,000, and $1,500mg{\cdot}L^{-1}$. Then, the seeds were sown into 72-cell plug trays in which the root medium was packed. The measurements of growth and analysis of tissue and root media were conducted 2 and 4 weeks after sowing. Elevation of pre-plant N levels raised EC and turned down pH of root media. But, as seedling grew, the pH rose and EC get lowered in all treatments. The EC as well as $NH_4-N$ and $NO_3-N$ concentrations of root media declined gradually until week 2, but those declined sharply between weeks 2 to 4. The seedling growth 2 weeks after sowing showed quadratic response to pre-plant N levels with the highest growth in $250mg{\cdot}L^{-1}$ treatment and lagging growth in the treatments of lower or higher N levels than $250mg{\cdot}L^{-1}$. The seedling growth 4 weeks after sowing showed also quadratic response with the highest growth in $500mg{\cdot}L^{-1}$ treatment. The tissue N contents were get higher and those of K, Ca, and Mg were get lower as pre-plant N levels were elevated. Above results suggest that lower than $250mg{\cdot}L^{-1}$ in pre-plant N levels is optimistic for growth of plug seedling and avoidance of toxic injury in very young stage.