• Journal of the Korean Society of Tobacco Science
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• v.22 no.2
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• pp.123-132
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• 2000

Evaluation method of soil fertility by combination of soil color characteristics and survey data from soil map as well as chemical properties was investigated on total 35 field and pot experiments. Total 35 tobacco fields including 11 fields located at Cheonweon county in Chungnam Province, 9 fields located at Goesan county in Chungbuk Province, and 15 fields located at Youngcheon county in Kyongbuk Province were selected in 1984 to cover the wide range of distribution in landscape and soil attributes. Yields of tobacco grown on the plots of both the pot and field experiment which were not applied with any fertilizer were considered as basic fertility of the soil (BFS). The BFS was estimated by 32 independent variables including 15 chemical properties, 3 color characteristics, and 14 soil survey data from soil map. Twenty-four independent variables containing 16 quantitative variables selected from 24 quantitative variables by collinearity diagnostics and 8 qualitative variables, were classified and analyzed by multiple linear regression (MLR) of REG and GLM models of SAS. Tobacco yield of field experiment showed high variations by eight times in difference between minimum and maximum yield indicating the diverse soil fertility among the experimental fields. Evaluation for the BFS by the MLR including quantitative variables was still more confidential than that by a single index and that showed more improvement of coefficient of determination ($R^2$) in pot experiment than in field experiment. Evaluation for the BFS by MLR in field experiment was still improved by adding qualitative variables as well as quantitative variables. The variability in the BFS of field experiment was explained 43.2% by quantitative variables and 67.95% by adding both the quantitative and qualitative variables compared with 21.7% by simple regression with NO$_3$-N content in soil. The regression evaluation for the best evaluation of the BFS of field experiment by MLR included NO$_3$-N content, L value, and a value of soil color as quantitative variables and available soil depth and topography as qualitative variables. Consequently, it is assumed that this approach by the MLR including both the quantitative and qualitative variables was available as an evaluation model of soil fertility for tobacco field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.3
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• pp.257-265
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• 2015

This experiment was carried out to determine the optimum planting density for rice pot seedling cultivation in wheat-rice double cropping system in Honam plain area. A mid-late maturing rice variety 'Chinnong' was raised in pot seedling tray and conventional tray for 30 days, and then transplanted on June 25 in 2012 and 2013. Four different planting densities (15.2, 18.9, 21.6, and 25.3 hills per $m^2$) in pot seedlings were applied as treatment. Conventional tray seedling was implicated as control at a single planting density of 27.8 hills per $m^2$. In this experiment, the number of effective tillers was increased as planting density increasing, but stem diameter was decreased. Pot seedling showed higher stem diameter and effective tillers than the control. Heading dates of pot seedling plots were not significantly different between the planting densities but 2 days faster than the control. Culm length, number of panicles, panicle length, and ripening grain ratio were higher in pot seedling compared to the control, but 1000-grain weight showed no significant difference. Milled rice yields in pot seedlings ranged from 5.19 to $5.43\;t\;ha^{-1}$, and the highest yield was observed in 21.6 hills per $m^2$. Head rice ratios in pot seedlings and the controls were not significantly different. Above results on planting density of rice pot seedling cultivation would be applicable to wheat-rice double cropping and also to late transplanting cultivation of rice single cropping.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.5
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• pp.1258-1265
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• 2016

The aim of this study was to evaluate the impact on the fishery resources and marine ecosystems by derelict fishing gears as part of the R & E (Research and Education) program that supervised by the busan metropolitan city office of education. In this study, we verified the ghost fishing effects caused by derelict fishing gears through the process which fish were caught to be attracted to bait for gillnet and trap in tank. In results, the dead fish to be gilled in gillnet and to enter in pot have been shown to attract other fish to the bait role. The result showed that the ghost fishing was caused by abandoned, lost or discarded fishing gears continuously. In particular, as a result of pot experiment, if the lost pot has a escape device, the entered fish could escape from the pot and the fisheries resources could protect from derelict fishing gears. In addition, the high school students are capable of raising the problem solving skills through carrying out the research project and expect to contribute to raising awareness about the protection of the marine environment.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.6
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• pp.71-85
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• 2011

In Okdong coal mine abandoned area, every year large amount of mine wastes have been swept away due to heavy rains in summer. Because pH of coal-mine waste is in the early 4, plant naturally does not grow there due to unfavorable condition for growing plant. This study had an experiment to grow plant for 6 months using Mycorrhizae which can be adapted well in acid soil. As a result of Experiment, In the infected experiment pot, 90% of the plants survived but in case of uninfected experiment pot, only 25% were alive. From Growth Experiment, it appeared that average stem length increase (cm/month), average fresh weight increase ($g^{fw}/month$), average dry weight increase ($g^{dw}/month$) were increased by 60%, 21%, 31% respectively. Especially, Mycorrhizae plays an important role in providing nutrients and water when seeding are established. Mycorrhizae prevents death caused by lack of nutrients and water and helps growth and development of plant when seeding are established in the early stage. This study proved that Mycorrhizae is comparatively effective in plant growth and prevention of erosion in coal-mine abandoned area.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.1
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• pp.50-57
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• 2008

Winter season cultivation of rye as green manure for soybean have been a favorite with farmer because it could remove a risk of injury by continuous cropping and increase N uptake and yield of soybean. Effects of rye green manure on soybean N uptake, $N_2$ fixation and yield were investigated with $^{15}N$ as pot experiment in greenhouse in 2004 and field in 2005, respectively. The N derived from N fertilizer ($^{15}N$) in rye green manure increased with increasing of N fertilizer rate compared to N derived from soil. N uptake and DM yield of soybean at the pot with paddy soil was higher than those at the pot with upland soil mainly due to the increase of N uptake from paddy soil. Total $^{15}N$ recovery in soil was higher at rye green manure than no green manure because $^{15}N$ applied to rye plant was remained highly as soil organic N compared to chemical N fertilizer. $^{15}N$ recovery in soybean plant increased in proportion to amounts of N fertilizer applied to rye. The N fractions from $N_2$ fixation of soybean plant at the pot experiment in 2004 ranged from 92% to 95%, on the other hand those in field experiment in 2005 ranged from 82% to 84%. Estimation of amount of $N_2$ fixation was not different between Difference method and $^{15}N$ method in 2004 and 2005.

• Journal of the Korean Society of Tobacco Science
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• v.9 no.2
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• pp.3-9
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• 1987

This study was been conducted to determine chemical characteristics of soils in the major districts cultivating flue-cured tobacco plant. Also native soil productivities were measured by means of bioassay planting tobacco plant without fertilizer at 87 selected lolls through pot and field experiments. Inorganic nutrient in soils affecting the dry weight of tobacco leaves cultivated in the field were investigated. The results obtained are summarized as follows; 1. Among soil chemical characteristics, pH, $NO_3$-N, $NH_4$-N , $P_2O_5$, and Mg Influenced significantly the dry weight of tobacco loaves In pot experiment, whole In the field experiments, pH, $NO_3$-N, $NO_3$-N+$NH_4$-N, and Ca had influence. 2. Correlation coefficients between soil chemical characteristics and dry weight of tobacco leaves were higher in pot experiment than field. The results revealed that soil morphological characteristics might more close influence on dry weight of tobacco leaves than chemical characteristics. 3. For prediction of dry weight (Productivity) of tobacco leaves without fertilizer multiple regression analysis were introduced using troll chemical characteristics. A combination of pH, $NO_3$-N, and Ca was very reliable for prediction of productivity as equation. y=5.02+18.07$x_1$ +2.61$x_2$ +5.36$x_3$ R=0.444** Where $x_1$ : pH, $x_2$ : $NO_3$-N, $x_3$:Ca

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.3
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• pp.193-198
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• 2022

In this study, for the purpose of reducing the catch of small giant octopus in a net pot, an escape experiment of octopus was performed on five types of escape rings of different sizes. As a result of the experiment, the smallest giant octopus with a weight of 406 g was found to escape from an escape ring with a diameter of 30 mm or larger, and 592 g octopus, a weight similar to the octopus of the current minimum landing weight (600 g), escaped from an escape ring with a diameter of larger than 40 mm. An individual weight with 406 g becomes 39 mm when converted from a diameter of 25 mm circular escape vent; that is, the circumference to the inner diameter of the mesh. It can be inferred that the converted mesh size of 39 mm cannot escape. Logistic regression analysis was performed using a generalized linear model (GLM) to investigate the correlation between the ratio of escape ring size/Mantle diameter (R/MD) and the escape rate. As a result, it was found that there was a significant correlation between the R/MD ratio and the escape rate and that the higher the R/MD ratio, the greater the escape rate. As a result of logistic regression analysis, the R/MD value was denoted 0.520 with the 50% escape rate. In addition, it can be estimated to be about 50 mm when converted to the mesh size. Therefore, in this study, the diameter of the escape ring and the size of the escape possible of the octopus were experimentally considered. It was found that there was a significant correlation.

• Korean Journal of Medicinal Crop Science
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• v.7 no.4
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• pp.282-287
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• 1999

This study was conducted to investigate the effects of different soil texture in agronomic characteristics, root yield and quality of baloon flower (Platycodon grandiflorum A. DC.). Three kinds of soil texture, sandy loam, silt loam and clay loam, were tested for two years. Baloon flowers were seeded with 20cm row space and cultivated in the one square meter pot with 0. 6m depth. Fifty plants per pot were remained. In growth characteristics of one-year-old plants, shooting date was not significantly different according to the changes of soil texture. The ratio of stem growth was highest between July and August. In two-years-old plants, it was showed between May and June. Plants grown on clay loam showed the highest growing characteristics than those of other soil textures. Dry root weight cultivated on clay loam was 274kg/10a in one-year-old and 934kg/10a in two-years-old plants. The content of ethanol extracts from root was highest at those of sandy loam as 47.1 % in one-year-old root. The crude saponin content was not different significantly among the three kinds of soil texture.

• Journal of the Korean Society of Tobacco Science
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• v.4 no.1
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• pp.79-81
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• 1982

Cytoplasmic male- sterile Hyangchio, derived from male- sterile Burley 21 containing N. megalosiphon cycloplasm, and male- fertile Hyangchio (Korean local aromatic variety) were evaluated in replicated pot trials in green-house. Male- sterile Hyangchio was comparable to the male- fertile Hyangchio for six agronomic traits and total alkaloids content. The only significant difference was that the male- sterile Hyangchio flowered 2.3 days later than the male- fertile Hyangchio. M ale- sterile Hyangchio has increased the yield than the male- fertile Hyangchio significantly in case of non- topped.

• Korean Journal of Plant Resources
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• v.10 no.2
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• pp.145-150
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• 1997

To find out the optimum fertilizer level for onion, early maturing cultivar Fechongjoseng, experiment with four fertilizer levels was conducted of the field of the paddy and upland in Muan and Changyeong from Sep.1993 to Feb.1995. The yield character of onion was higher and rate of the rottenness was lowest under the treatment of $N-P_2O_5-K_2O$=28-9.5-23Kg/10a in the soil of paddy and upland field of Muan area. But the onion yield was excellent and rate of the rottenness was lowest under the treatments, $N-P_2O_5-K_2O$=21-19-17.3Kg/10a, in the soil of paddy field and $N-P_2O_5-K_2O$=28-9.5-23Kg/10a, in the soil of upland field of Changyeong area.