• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.251-255
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• 2008

This study was carried out in 2002 to determine the usefulness of Jeju scoria for a component of a growth medium and optimum planting density of 'Dejima' seed potatoes (Solanum tuberosum L.) grown in a wick hydroponic system. The minitubers ($7.0{\pm}0.2\;g$) produced in an aeroponics system were planted at five planting densities (3 to 15 tubers/box; 19 to $95\;tubers/m^2$) in polystyrene boxes (51 cm long $\times$ 31 cm wide $\times$ 20 cm high) containing two media (perlite + peatmoss and Jeju scoria + peatmoss 1:2, v/v mixtures). There were no significant interactions between medium and planting density for the growth and tuber yield traits. Shoot growth and the number of tubers per plant were not significantly affected by the media. However, tuber yield was higher in the perlite + peatmoss mixture than in the Jeju scoria + peatmoss mixture. The percentage of underdeveloped plants ranged from 8.3 to 14.7% at four lower planting densities (3 to 12 tubers/ box), and was 25.8% at the highest planting density (15 tubers/box). As planting density was increased from 3 to 15 tubers per box, seed potato (${\geq}5\;g$ tuber) number increased from 101 to 269 and yield from 6.3 to $11.6\;kg/m^2$. These results indicate that the perlite + peatmoss mixture might be more suitable for seed potato production in the wick hydroponic system, and considering the percentage of underdeveloped plants and tuber yield, optimum planting density would be 56 to $76\;tubers/m^2$ in the system depending on availability of seed potatoes.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.3
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• pp.21-36
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• 2023

As a solution to environmental issues, such as climate change response, the carbon neutrality strategy, urban heat islands, fine dust, and biodiversity enhancement, the value of urban green spaces and trees are becoming important, and various studies dealing with the effects of trees for environmental improvement are being conducted. This study comprehensively considers the preceding studies on planting tree species, planting structure, planting density, and planting base to propose a direction for the planting renewal of green areas in urban parks and applies the findings to a renewal plan to improve the urban environment through landscaping trees. A field survey was conducted on the planting status of Seoul Children's Grand Park, a large-scale neighborhood park in Seoul, and based on the survey data, a planting function evaluation was conducted, and areas needing improvement in planting function were identified. The planting function evaluation was carried out considering the park function setting, planting concept according to spatial function, and planting status. As a result of the study, the direction of planting renewal according to functional change was derived for each stage of planting function evaluation. Increasing the green area ratio is a priority in setting up park functions, but user convenience should also be considered. As a concept of planting, visual landscape planting involves planting species with beautiful tree shapes, high carbon absorption, and fine dust reduction effects. Ecological landscape planting should create a multi-layered planting site on a slope. Buffer planting should be created as multi-layered forests to improve carbon absorption and fine dust reduction effects. Green planting should consist of broad-leaved trees and herbaceous layers and aim for the natural planting of herbaceous species. For plant species, species with high urban environment improvement effects, local native species, and wild bird preferred species should be selected. As for the planting structure, landscape planting sites and green planting sites should be composed of trees, shrubs, and trees and herbaceous layers that emphasize ecology or require multi-layered buffer functions. A higher standard is applied based on the planting interval for planting density. Installing a rainwater recycling facility and using soil loam for the planting base improves performance. The results of this study are meaningful in that they can be applied to derive areas needing functional improvement by performing planting function evaluation when planning planting renewal of aging urban parks and can suggest renewal directions that reflect the paradigm of functional change of created green areas.

• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.1
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• pp.1-9
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• 1990

Tillering of orchardgrass during establishment year was considered as an important factor for ground cover and forage yield. Field experiment was conducted to examine seasonal fluctuation of tiller number in three cultivars of orchardgrass; Potomac, Hall-mark, and Sumas, after transplanting with five planting density. Also, effects of plant density and nitrogen application in cultivar, Potomac were studied on tillering, forage yield and various growth characteristics in pot experiment Tillers per plant decreased with increased density and showed seasonal variations. It increased up to July, decreased during summer months, and increased again from October. Sumas had less tillers than other cultivars, especially at high density. Tillers per unit area kept high during spring. After then, there was stady decrease through summer and remained constant without affecting by planting density. Nitrogen application increased tillers per unit area in Potomac up to 20kg/10a, but decreased its tiller production at 40kg/lOa. Maximum number of tiller was obtained in the combinations of 20kg application of nitrogen with higher density than 324 plant per square meter. Forage yield increased as nitrogen application increased, while it did not respond to plant density. Forage yield had high linear correlation between LAI, leaf number with a peak at 2800 culrns. For high forage yielding, it was suggested to obtain optimum number of tillers per unit area in early season as possible, applying of adequate amount of nitrogen with relative high density depend on cultural condition.

• Proceedings of the Korean Society of Crop Science Conference
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• 1989.02a
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• pp.114-115
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• 1989

• Korean Journal of Medicinal Crop Science
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• v.1 no.1
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• pp.70-73
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• 1993

This experiment was carried out to investigate the effect of planting density on thegrowth and yield of Rehmannia glutinosa. A local variety was planted on the 100cm row, with different planting density of 20, 30 and 40 plants per $m^2$. Nitrogen, phosporus and potassium fertilizers were applied as 12, 12, and 16 kg /10a, respectively with compost of 1,000kg /10a. Plant height became shorter with increase in the planting density from 20 to 40 $plants\;/\;m^2$. But emergence date, leaf length and width were not significantly changed with planting density. As the planting density was increased, tuber diameter got slender and tuber number was decreased, but tuber length was not affected. The tuber yield was 793kg /10a at the planting density of 20 $plants\;/\;m^2$ and it increased 40% at 30 $plants\;/\;m^2$ and 45% at 40 $plants\;/\;m^2$ Regarding on the farmer's income, optimum planting density was estimated 30 $plants\;/\;m^2$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.2
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• pp.177-184
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• 1991

Soybean cultivars for bean sprouting, and for cooking with rice are related closely with Korean dietary tradition, but their yields have been kept in low level. The yielding responses of Danyup, a cultivar for bean sprouting and Gumjung, a cultivar for cooking with rice were compared with Paldal as standard cultivar in planting density within 10 to 80 plants per ㎡. Yield of Paldal increased as planting density increased from 10 plants up to 80 plant/㎡. But, Danyup reached at threshold as planting density reached up to 40 plants/㎡. Gumjung did not have significant difference in yield within planting density. Danyup had the highest yield, 445 kg/l0a at 80 plants/㎡. The highest yield of Paldal was 406kg/10a at 40 plants /㎡ while Gumjung had 373kg/ l0a at 40 plants. The yield responses of cultivars were influenced by canopy structure and light utilization. Paldal had short and straight canopy with determinate growth habit responded well at the heavy density, and had 6.2 in critical LA!. But Gumjung, tall and dense canopy with indeterminate growth habit had limited utilization of light within canopy with 5.4 in critical LAI and high rate of lodging. Gumjung was concluded as a low yielding cultivar, since it did not have good response to increasing source size and sink number.

• Korean Journal of Environmental Agriculture
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• v.42 no.3
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• pp.239-252
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• 2023

Most apple trees in South Korea are grafted on M.9 and M.26 rootstocks; however, these rootstocks are susceptible to fire blight. Although M.7 rootstocks are moderately resistant to fire blight, they tend to exhibit excessive vigor, which is unsuitable for high-density planting, unless weak cultivars are used. This study investigated the vegetative growth, yield, and fruit quality of apple trees grafted onto M.7, M.9, or M.26 rootstocks to assess the feasibility of establishing high-density apple orchards domestically using the M.7 rootstock a period of seven years (1-7 years after planting). Rootstocks were tested using three cultivars with contrasting induced vigor and harvesting times: vigorous and late-maturing 'Fuji,' moderate vigor and middle-maturing 'Hongro,' and low vigor and early-maturing 'Sansa.' The planting density was maintained constant, with 190 trees per 10 a. Primary thinning (leaving only the king fruit on clusters) was performed, whereas secondary thinning (controlling crop load) was not. Vegetative growth, accumulated yield per 10 a, and yield efficiency varied depending on cultivars and rootstocks; however, the cultivars had a more notable effect on fruit quality than the rootstocks. Biennial bearing often occurred in the M.26 rootstock. 'Fuji'/M.7 was overly vigorous for high-density planting. The fruit quality and accumulated yield per 10 a of M.7 were similar to those of M.9 with the 'Hongro' and 'Sansa' cultivars. In particular, 'Hongro'/M.7 did not show tree vigor reduction due to heavy crop load, and the degree of biennial bearing in 'Sansa'/M.7 was not particularly high. These results indicated that high-density apple planting using the M.7 rootstock was achievable using the 'Hongro' and 'Sansa' cultivars.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.91-91
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• 2022

Popcorn grains are consumed around 10,000 tons per year, in South Korea. It is consumed in amusement parks, movie theaters and snacks. The size of the popcorn processed market in Korea is estimated to be 3.6 billon won per year. So, the popcorn grain market has good prospects. On the other hand, domestic grain is at the level of 1 %, which is less domestic production than the size of the market. Maize Research Institute has developed domestic varieties in order to increase the use of domestically produced grains. The Oyrunpopcorn variety which was commonly distributed is a preferred cultivar because it has a good popping rate compared to imported grains. In addition, 'G-Popcom', 'Oyrun #2' and 'Kichan Popcorn' were developed, which diversified the choice of the farmers. Yield per unit area is important to improve farmers' income. At present, domestic grain production is traded at 5,000 won/kg, so if the yield improves, a high farmer^ income is expected. Therefore, this study compared the growth characteristics and yield according to the appropriate sowing time and plant density to improve the yield of domestically grown popcorn. We used 'Oryunpopcorn', for this research. Agronomic characteristics were compared by sowing times April 23, May 22 and June 22. The 100 seeds weight were 15.9g, 17.7g and 15.0g, respectively. Kernel weight planted in May 22 is the highest value. Yield per 10a were 414kg, 434kg and 296kg, respectively. It shows the yield planted in May 22 was higher than other trials. Therefore, the sowing time to increase the kernel weight and yield is appropriate for planting in mid-May. The number of plants in planting density trial was 5,700 plants, 4,700 plants and 4,000 plants in 10a area. Plant height at each trial were 221 cm, 214cm and 218cm, respectively. It was the highest height in 5,700 plants trials. The 100 kernel weight were 14.8g, 15.9g and 16.5g, respectively. Low planting density trial indicated high kernel weight. Yield per 10a was 415kg, 357kg and 314kg, respectively. It was higher at high density trial than other experimental plots. Therefore, appropriate sowing time was in mid-May and planting density was 5,700 plants/10a in order to increase the yield of popcorn in South Korea. This study will be useful for farmer's income to use the domestic cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.4
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• pp.311-318
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• 2002

Planting date of soybeans [Glycine max (L.) Merr.] is one of production components in cultural systems. The objective of the current study was to identify the components of soybean production and cultural practices encompassing planting dates and cultivars that respond to dry matter accumulation, harvest index and yield components. Three determinate soybean cultivars were planted on May 13 (early), June 3 (mid), and June 24 (late). Planting density was 60$\times$15cm with 2 seeds (222,000 plants per ha). Soybean plants were sampled every 10 days interval from the growth stages of V5 to R8 and separated into leaves including petioles, stems, pods, and seeds. Dry matter accumulations, harvest indices, and yield components were measured. Early planting had taken 55 days from VE to R2 and late planting taken 39 days indicating reduced vegetative growth. Early planting showed higher leaf, stem, pod and seed dry weights than late planting. However, late planting appeared to be higher harvest index and harvesting rate. Vegetative mass including leaf and stem increased to a maximum around R4/R5 and total dry weight increased to a maximum around R5/R6 and then declined slightly at R8. The highest seed yield was obtained with mid planting and no difference was found between early and late plantings. Cultivar differences were found among planting dates on growth characteristics and yield components. The results of this experiment indicated that soybean yield in relation to planting dates examined was mainly associated with harvest index and harvesting rate, and planting date of cultivars would be considered soybean plants to reach the growth stage of R4/R5 after mid August for adequate seed yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.214-220
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• 1999

Rice production in Korea has markedly increased during the last two decades due to newly developed high yielding varieties and improved production technology. This experiment was conducted to determine the potential of tropical japonica germplasm in enhancing the yield of temperate japonica. The yield performance of two tropical japonicas (IR 65597-29-3-2 and IR66154-52-1-2) and one temperate japonica (Dongjinbyeo) was compared at different plant densities and nitrogen levels under Korean environmental conditions. Although tropical japonicas showed low tillering habit and large panicles, they had similar leaf area index and dry weight at heading stage to Dongjinbyeo of the high tillering type indicating that there was not much difference between tropical and temperate japonica in terms of biomass production. The highest milled rice yield of 6.15 t/ha was obtained from Dongjinbyeo at a high nitrogen level with less planting density (220 kg N/ha and 30 $\times$ 15 cm). However, those of the two tropical japonicas were 5.36 t/ha at the condition of 165 kg N/ha and 30 x 10 cm planting density and 5.06 t/ha at the condition of 165kgN/ha and 15 x 15 cm planting density, respectively. Ripened grain of tropical japonicas ranged from 65 to 87%, while that Dongjinbyeo ranged from 82 to 97% under Korean conditions.