• Journal of Korean Society of Forest Science
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• v.109 no.4
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• pp.390-399
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• 2020

We investigated the effect of seedling age and planting density on early growth performance of Zelkova serrata trees. Containerized Z. serrata seedlings, 1-year-old and 2-year-old, were planted according to two different planting densities (3,000 and 5,000 trees ha-1) at the end of March, 2017. Three plots were established for each treatment (2 seedling ages × 2 planting densities). We calculated the survival rate (%) of out-planted seedlings as well as the stem volume based on the root collar diameter (RCD) and height (H) in September of each year, from 2017 to 2019. Seedling age and planting density did not affect survival rate of the out-planted trees. Planting density did not affect height of the trees, whereas the treatment significantly affected RCD and the H/D ratio for 2-year-old seedlings in 2019. The stem volume per tree was highest in the plot of 2-year-old seedlings at 5,000 trees ha-1 and lowest in the 1-year-old seedlings at 3,000 trees ha-1. In addition, the tree height in both 1-year-old and 2-year-old Z. serrata trees was greater in the 5,000 trees ha-1 plot than in the 3,000 trees ha-1 plot. There was no interactive effect between seedling age and planting density on stem volume; however, as seedling age and planting density increased, stem volume of Z. serrata trees increased. The values for stem volume per hectare are 85%, 68%, and 300% higher in 1-year-old 5,000 trees ha-1, 2-year-old 3,000 trees ha-1, and 2-year-old 5,000 trees ha-1 plots, respectively, compared to the values in 1-year-old 3,000 trees ha-1. This result shows that high planting density (close planting) affects tree growth differently based on seedling age, and suggests that the planting density of 5,000 trees ha-1 is suitable for 2-year-old seedlings to improve early growth field performance.

• Journal of the Korean Society of Tobacco Science
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• v.19 no.1
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• pp.18-23
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• 1997

The study was carried out to clarify reasonable production of healthy seedling, optimal Pot depth, and appropriate transplanting time, which can be deduced from understanding of seedling quality. Seedling quality results from growth of root and shoot, morphology and distribution of root system under influence of Pot depth during seedling growing period. Stem height, shoot dry weight, leaf area and leaf number were increased in proportion to depth of pots. Growth of shoot and root during seedling growing period showed the most dramatic development between 20th and 25th day after temporary planting. Root number increased as pot depth decrease and total root length and dry weight increased as pot depth increase. In 5cm pot, relative multiplication rate was higher and mean extension rate was lower than other depth of Pot. The limitation of pot volume in which rhizosphere was located enhance the development of roots of second and third order. At 20th days after temporary Planting root distribution was relatively uniform in length and development of adventitious root on stem base was poor as Pot depth decreased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.4
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• pp.286-291
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• 2002

Seedling establishment of soybean [Glycine max (L.) Merr.] is a critical factor in production system and cultural practices. The objective of this study was to identify the components of soybean seedling developments encompassing planting dates and cultivars that respond to emergence, early growth stage and dry matter accumulation. Three soybean cultivars, Hwangkeumkong, Shinpaldalkong 2, and Pungsannamulkong, were planted at Baegsan silty loam soil. Planting date was May 13, June 3, and June 24 in 2001. Sprinkler irrigation was accompanied with 30mm after seeding for three planting dates. Soybean seedlings were sampled at the growth stages from VE to V5. Days to emergence of soybean seedlings were taken 8 at May 13 and 5 at June 24 plantings. Emergence percentage was over 90 at three planting dates. May 13 planting took 33 days and June 24 planting was 25 days for reaching V5 growth stage. Cotyledon number was decreased after V2. Significant cultivar difference was found in cotyledon dry weight until V2 which differed in seed dry weights at the planting times. Leaf and total dry weights of soybean seedlings were not differed from V1 to V3 among planting dates and cultivars. Leaf water contents were generally ranged 78 to 85%. Branch was appeared from V4. Leaf/stem ratio among cultivars was similar at five growth stages and gradually increased from 2.1 at V1 to 2.8 at V5. The results based on this experiment indicated that seedling establishment of soybean was continued from VE to V3 growth stages affecting mainly by planting date and soil moisture.

• Korean Journal of Organic Agriculture
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• v.10 no.2
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• pp.111-120
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• 2002

This study was conducted to investigate the effect of foliar application of Chitosan and seedling types on increasing the production of fall-growing potatoes(Solanum tuberosum) at the height of 250m from the sea in Jeju Island. The experiment main-plots consisted of four Chitosan applications, and subplots had three seedling types as cutting plug seedlings, mine-tuber plug seedling planting plot and seed potatoes planting plot. The foliar application of Chitosan of 2000ppm was carried out 0, 1, 3, 5 times at intervals of ten days after ten days of transplanting. Plant height and top dry weight were significantly more vigorous as three to five application of Chitosan. In the small tubers(under 80g), the number of tubers and tuber yield were relatively increased in the seed potatoes planting plot and mine-tuber plug seedling plot, but the large tubers(over 80g) was higher in the cutting plug seedling planting plot. T-N content in leaves was increased as the number of application of Chitosan was increased. A similar tendency was shown in K, P Ca, Mg and Na. The growth and tuber yield in cutting plug seedlings, mine-tuber plug seedling planting plot and seed potatoes planting plot were effectively increased as three to five foliar applications of Chitosan was increased.

• Journal of Drive and Control
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• v.21 no.2
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• pp.30-35
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• 2024

Domestic rice is more expensive than imported products, so it is necessary to reduce production costs to secure competitiveness. Low-density planting developed in Japan is a cultivation technology that reduces labor and production costs without yield loss. The area of low-density cultivation is continuously increasing. However, research on how rice transplanters adapt to low-density planting has not been conducted. Therefore, this study was carried out to determine the optimal working conditions of a rice transplanter for low-density planting. Three types of rice transplanters were used and treated based on 3 conveying distance levels. The number of picked seedlings, pick missing rate, the number of planted seedlings, and the mis-planted rate were investigated to evaluate planting accuracy according to the transfer distance to the seedling tray. The results showed that the number of planted seedlings was 4.31~4.95 EA with an L1 seedling tray transfer distance (horizontal 9 mm, vertical 8 mm), but the mis-planted rate was higher than in other conditions. At L2 (horizontal 9 mm, vertical 10 mm) and L3 (horizontal 11 mm, vertical 8 mm) transfer distance conditions, the number of planted seedlings were 4.89-5.68 EA and 4.69-5.66 EA, respectively, with a low mis-planted rate of less than 3%. The results showed that if the transfer distance is adjusted properly, a rice transplanter can be used for low-density planting with high planting accuracy.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.2
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• pp.72-79
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• 2010

This research was initiated to investigate the revegetation characteristics under seedling types of native woody plants on a disturbed slope. 4 different seedling types of woody plants (control, unit seedling plot, nature seedling plot, pot seedling plot) with the same woody plants (Rhus chinensis Mill, Albizzia julibrissin Duraz., Quercus acutissima Carr., Pinus densiflora S. et Z.) were treated with 3 replications on the experimental disturbed slope. Data such as the died number of native woody plants, growth height and visual quality were analyzed. The died number of plants were high in unit seedling plot when compared to the rest plots of seedling types. From the standpoint of died plant species, the died number were high in Rhus chinensis and Albizzia julibrissin whereas the died number were low in Quercus acutissima and Pinus densiflora. That's because we used 1-year old seedlings of Rhus chinensis and Albizzia julibrissin and 3-year old seedling Quercus acutissima and Pinus densiflora. This result indicated that the died reason of native woody seedling was not species but seedling age. Both growth height and visual quality were ranked first in the pot seedling plot, second in the nature seedling plot, third in the unit seedling plot, and last in the control plot, respectively. However, the difference of both growth height and visual quality in each seedling plot was not observed on the 11 months after planting. Especially, the main reason of low rooting and growth value in the unit seedling plot was due to wooven fabric outer crust of pot that obstruct seedling rooting into the soil. We concluded that pot seedling of native woody plants was effective in the viewpoint of the ecological disturbed slope revegetation.

• 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.3
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• pp.260-264
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• 2009

Sufficient seedling establishment of Chinese milk vetch (CMV) is the most important factor in the CMV cultivation. In order to obtain sufficient seedling stand, CMV seed should be planted at right seed planting date. An optimum CMV seed planting time for stable seedling establishment was determined based on the final water drainage time for rice harvest in fall. Five planting times from 10 days before water drainage (DBWD) to 15 days after water drainage (DAWD) at five day interval were evaluated during the period of 2006-2007 and 2007-2008 and the optimum CMV seed planting time was determined based on seedling stand, winter survival rate, and dry matter production. CMV seedling stand before winter was high with $575{\sim}1,050\;plants/m^2$ regardless of seed planting times but after overwintering, it was greater in seed planting date between 5 DBWD to 5 DAWD than that of 10 to 15 DAWD treatments. Winter survival rate, dry matter production and seed production yield also showed similar trend to the seedling establishment. On the other hand, when CMV seeds were sowed early at 10 DBWD, seedling stand and winter survival rate were lower than that of 5 DBWD to 5 DAWD. This result indicates that an optimum CMV seed planting time based on the final water drainage could be between 5 DBWD (September 20) to 5 DAWD (September 30).

• Journal of Biosystems Engineering
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• v.28 no.5
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• pp.395-402
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• 2003

Standard ginseng seedling, selected after one year's rearing in the seedling bed has been conventionally transplanted in Korea. Recently, the direct seeding areas have been increasing to product high quality ginsengs for red-ginseng processing. Reciprocating push-rod brush, holed-roller and vacuum suction seeders, planting with 30 ${\times}$ 30mm spacings and adjustable to the folds were designed and theirs performances were evaluated. The developed three types of seeders reliably performed at the success rate over 95% with less than 10% in slip rate, and could be used a seeder for the greater spacings by adjusting metering parts. The research concluded that the vacuum suction seeder was the most feasible and practical with the greatest metering success and the least slip among three type seeders of the reciprocating push-rod brush, holed-roller and vacuum suction seeders. The vacuum suction seeder holds a seed with each needle nozzle using the negative pressure created by a vacuum pump. The capacity was 24.5 times greater than a man power at the speed of 5 m/min.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.6
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• pp.77-86
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• 2016

Due to aging of the rural and mountain populations the labor force is reduced. However work intensity continues to increase, thus, there is a need to improve the current effectiveness of forest operations. This study compared and analyzed the Operation productivity and efficiency of planting containerized seedlings using a battery-powered planting auger and a mattock. Growth was also investigated by looking into the initial growth increments in the planted seedlings. Tasks were investigated by analyzing the process and operation time needed to plant 1 containerized seedling using a planting auger and a mattock. The time spent on the various elements of the planting process was measured with a stopwatch but observations were done continuously. Result of the study shows that with the use of a lightweight planting auger the average time spent to plant a containerized seedling is 18.61 seconds while with the use of a mattock it took an average of 26.96 seconds which clearly demonstrates that the planting auger is more efficient in terms of working hours. Working intensity was also analyzed with the use of a portable heart rate monitor (Polar V800). The average increase in heart rate and work intensity index were analyzed for one planting cycle. It was observed that when using the lightweight planting auger, there was a 46.51% increase in the average heart rate while a 74.67% increase in heart rate when the mattock was used which shows that there is a significant increase in heart rate when mattock is used. In addition, work intensity index was observed to be 29.95% and 47.83% when the planting auger and mattock were used respectively. With the continuous use, work intensity index is significantly higher with the use of the mattock as compared to that of the lightweight planting auger. There were no significant differences on the growth increment of seedlings planted using the different tools until a year after planting, however differences in growth increment were observed after a year. A difference of 15.1 cm in height and 3.41 mm in diameter was observed which shows that the use of lightweight planting auger is excellent for planting containerized seedlings.