• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.629-636
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• 1995

This study was carried out to clarify the proper nitrogen application methods under the different seedling density in puddled-soil drill seeding of rice. Seedling density was adjusted as 30, 60, 90, 120 and 150ea/$m^2$ just after emergence and nitrogen was applied with five methods including conventional respectively. The maximum tillering stage was shorten as the seedling density was increase but decreased the percentage of productive tillers. Lodging was occurred serverely as the seedling was more than 120ea/$m^2$, when nitrogen was applied at panicle initiation stage. Grain yield wasn't significantly different among seedling densities when it was more than 60ea/$m^2$, but the density of 30ea/$m^2$ was decreased. It wasn't significantly different among the nitrogen application methods when it was more than 90ea/m, but was higher at early application of tillering fertilizer (T$_2$) than conventional method when the seedling density was less than 60ea/$m^2$. Supposing that the yield of reseeding is the same as optimum seedling density, minimum seedling density needs for reseeding would be less than 55 ea/$m^2$ as the aspect of income allowed for managing expense.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.6
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• pp.448-452
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• 2002

The purpose of this study was to determine the optimum sowing amount for raising rice seedlings in automatic facility. four levels of seeding amount, 200, 220, 250 and 300 tray were applied to compare the seedling characteristics according to seeding density. Sowing dates were fixed at May 10 for single cropping and June 10 for double cropping. The seedling height was taller as the increase of sowing amount from 200g to 300g/tray, however the seedling quality was decreased with increasing of seed density. At 40-50 days after transplanting, there was no significant difference in the plant height and tiller number among the rice seedling raised under different seeding densities. Grain yield of 15-day old seedlings transplanted at May 25 was not significantly different among four different levels of seeding amount. However, the yield of 10day old seedling transplanted at June 20 was significantly higher in seeding density of 250g/tray than that of 300g/tray.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.2
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• pp.57-63
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• 1979

This study has been carried out to find out the optimum plant density and number of seedling per hill in the late season culture of rice at Chung Buk. P.O.R.D. Up to the level of 33 hills per m2 and 6 number of seedling per hill, rice yield was increased as the number of seedling per hill and plant density per unit areas increased. However it is recommendable to have a plant density of 28~33 hills per m$^2$ with 4~6 number of seedling per hill for the late season culture.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.2
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• pp.77-86
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• 2019

To determine none top soil covering in rice seedling nursery method for the sparse machine transplanting, four different sowing methods were tested. Shoot and root length, fresh weight, leaf number and color using leaf color chart(LCC) and SPAD were collected as the data comparison of methods. The seedling height showed the highest growth according to the conventional (230g seed rate of pre-emerged seeds and top-soil covering) > high sowing density 1 (290g seed rate of pre-emerged seeds and top-soil covering) ≥ high sowing density 2(290g seed rate of pre-emerged seeds and none top-soil covering) > high sowing density 3(290g seed rate of iron-coated seeds and none top-soil covering). There was any statistical difference between groups in root length, leaf number, LCC, and SPAD values. Thus, a high sowing density of 290g for rice nursery seedling box was recommended to the sparse machine transplanting in rice cultivation with the none top-soil covering method, enabling convenient handling in transportation and machine transplanting work.

• Korean Journal of Plant Resources
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• v.11 no.3
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• pp.315-318
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• 1998

This study was carried out to investigate the effect of seedling growth with different seedling rate for machine transplanting with turf. Chosun Zoysia was sown on May 17 with three levels seedling rates. The plant charactersitics were greater in 500g/box plots than the other seedling rates on the seedling box. It ws shown that the 30-40day old seedlings of 1.000 and 2,000g/box seedling plots appeared to be proper methods for Sprigging as the high seedling density. The 70 day old seedling plant with 500g/box were shown to be propoer methods for Sprigging. The seedling periods need to be 60 days for 500g/box plots and 40 days for 1,000 and 2,000g/box plots as forming the mats.

• Journal of Korean Society of Forest Science
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• v.103 no.4
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• pp.556-563
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• 2014

The purpose of this study was to evaluate the effects of container types on seedling growth of Chamaecyparis obtusa (2-year-old) in the container nursery culture. We used three container types [20 cavities (400 mL/cavity, $150seedlings/m^2$), 24 cavities (320 mL/cavity, $200seedlings/m^2$), and 35 cavities (240 mL/cavity, $260seedlings/m^2$)] and measured root collar diameter (RCD), height, biomass, root density and seedling quality index (SQI). The RCD, height, biomass, root density and SQI were the highest at 20 cavities/tray because this container has the largest volume and lowest seedling density. However, H/D and T/R ratio at all container types were not significantly different. The total biomass per unit area ($m^2$) were the lowest at 35 cavities/tray and those at both 20 and 24 cavities/tray were not significantly different. Container volume was positively correlated with RCD, height, biomass, root density and SQI except for H/D and T/R ratio, while seedling density negatively affected on them. Based on these results, 20 cavities/tray are optimal for container seedling production of C. obtusa. Usage of optimal container will make us get better quality seedlings and reduction of production costs in the container nursery as well as good field performances with higher survival rate in plantation.

• Journal of Korean Society of Forest Science
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• v.95 no.4
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• pp.501-506
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• 2006

To study the regeneration process of tree species after clear cutting, we investigated the density of seedling occurred after 1 year in the coniferous forest of Sikotuko Hokkaido, northern Japan that was clearcut after windthrow damage due to typhoon. As the results, 25 species of tree seedlings were growing and the density of seedlings and sprouts was $9.8trees/m^2$ ($1.25tres/m^2{\sim}54.44trees/m^2$) in the area of clear cutting. The 87% ($8.6/m^2$) of all seedlings was current seedlings and non-animal dispersal seedlings (average density $7.2tree/m^2$) were about 5 times more than animal-dispersal seedlings ($1.4tree/m^2$). The seedling density was beyond $6tree/m^2$ within 10m and $2{\sim}9tree/m^2$ in 150~250m from a natural forest. Number of non-animal dispersal seedlings were decreased along the distance from a natural forest but there was not such a tendency in animal dispersal seedlings. The variation in seedling density was higher in non-animal dispersal seedling than in animal dispersal seedling. In natural regeneration of tree species after clear-cutting, the possibility that pioneer species like Betula spp. etc. will be composed of the major species is high. Therefore, in order to maintain the species diversity, the nurture work for reducing competition among the individuals is necessary.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.6
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• pp.418-421
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• 2002

This study was carried out to clarify the effect of sowing method in four planting densities on growth and root yield of Cynanchum wilfordii. vine diameter, number of branches, number of branched roots, and root length, were greater in seedling transplanting than in direct sowing. In planting densities, main vine length, number of branches, and number of tillers were increased at higher planting density, but vine diameter, leaf length, leaf width, root length, and root diameter were increased at lower planting density. fresh root yield was greater in seedling transplanting than in direct sowing. In seedling transplanting, it was 53% higher in 27 plants per unit area than 1,680 kg/10a in 17 plants per unit area. Therefore, seedling transplanting in 27 plants per unit area showed most effective for increasing root yield of Cynanchum wilfordii.

• Korean Journal of Agricultural Science
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• v.5 no.2
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• pp.49-55
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• 1978

In order to get healthy seedling of rice suitable for rice transplanter, the growing characteristics of the seedling grown under different growing days and sowing densities were invesigated and the results obtained were summarized as follows; In the 20 days old seedling, the difference of growing state of seed ling and its characteristics between the two types of nursery bed was not found, but for the 30 days old seedling, both of the crop growth rate and the relative growth rate on the band-type nursery bed appeared higher than those on the mat-type nursery bed. And also, "the dry weight, the content of cardohydrate and the ratio of dry weight to plant height of the seedling grown on the band-type nursery bed were much higher than those on the mat-type nursery bed, however the amount of difference of seedling characteristics between two types of nursery bed was decreased for 40 days old seedling and leaf number was not increased. The amount of the seedling growth was increased with less density of sowing and for the difference between the higher and the less density, the difference getting bigger with the longer nursery days. The maximum density of sowing was approximately 200cc per nursery case on the band-type nursery bed and 250cc per nursery case on the mat-type nursery bed. It was seemed that the growing uniformity of the seedling grown on the mat-type nursery bed was better than that on the band- type nursery bed, As the coefficient of variation of the plant height and the leaf numbers of the seedling grown on the band- type nursery bed was higher than that on the mat-type nursery bed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.1
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• pp.62-67
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• 1996

High density (HD) grains is associated with seedling vigor. Studies were conducted on the relationship of different grain densities and vascular bundle(VB) development and seedling growth. IR58 (indica type) and Unbong 7 (japonica type) were used in this experiment. HD grains had more and bigger VB in the leaf blade and sheath than poor density grain at seedling stage. IR58 had more large VB at the leaf compared with Unbong 7. Higher development of VB in seedling of HD grains can increase transport of assimilate and growth rate. Plant height, leaf number, root growth and dry weight increased with increasing grain density from poor to high. The total area of large VB in the leaf blade and sheath was highly correlated with the dry weight. Higher number and larger area of VB and dry weight can be obtained by using HD grains and these initial advantages can contribute to high yield potential.