• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.937-943
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• 2011

In order to develop constructed wetlands for treating hydroponic wastewater in greenhouses, removal efficiencies and decomposition velocities of pollutants in constructed wetland were investigated for treating hydroponic wastewater. Removal rates of BOD, COD, SS, T-N and T-P in effluent in constructed wetlands were 88%, 79%, 92%, 64% and 92%, respectively. The decomposition velocities (K; $day^{-1}$) of pollutants in $1^{st}$ HF bed of constructed wetlands were higher in the order of SS ($0.54day^{-1}$) > BOD ($0.39day^{-1}$) > COD ($0.27day^{-1}$) > T-P ($0.26day^{-1}$) > T-N ($0.06day^{-1}$). In $1^{st}$ HF bed of constructed wetlands, the decomposition velocity of SS was rapid than that for BOD, COD, T-N and T-P in constructed wetland for treating hydroponic wastewater. The decomposition velocity (K; $day^{-1}$) of pollutants in $2^{nd}$ HF bed of constructed wetland were higher in the order of T-P ($0.52day^{-1}$) > BOD ($0.28day^{-1}$) > COD ($0.15day^{-1}$) > T-N ($0.06day^{-1}$) > SS ($0.10day^{-1}$). In $2^{nd}$ HF bed of constructed wetlands, the decomposition velocity of T-P was rapid than that for BOD, COD, SS and T-N in constructed wetland for treating hydroponic wastewater.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.18-24
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• 2007

Paddy fields are apparently nonpoint source pollution and influence water environment. In order to improve water quality in rivers or lakes, to low nutrient load from paddy fields are required. To establish comprehensive plan to control agricultural non-point source pollution, it is imperative to get a quantitative evaluation on pollutants and pollution load from paddy fields. A field monitoring study was carried out to investigate the water balance and losses of nutrients from fields in Sumjin river basin. The size of paddy fields was 115 ha and the fields were irrigated from a pumping station. The observed total nitrogen loads from paddy fields were larger than those of the unit loads determined by Ministry of Environment data (MOE). It is because the nitrogen fertilization level at the studied field was higher than the recommended rate and the high irrigation and subsequent drainage amount. On the contrary, total phosphorus loads were less than those addressed by MOE since phosphorus fertilization level was lower than that of standard level. Therefore, it was found that fertilization, irrigation, and drainage management are key factors to determine nutrient losses from paddy fields. When the runoff losses of nutrients were compared to applied chemical fertilizer, it was found that 42 to 60% of nitrogen lost via runoff while runoff losses of phosphorus account for 1.3 to 7.6% of the total applied amount during the entire year.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.4
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• pp.347-355
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• 2021

During the earthquake, for multi-story structure, if the first floor is soft, the deformation will concentrate on that floor causing a serious damage to the column members which might leads to the collapse of the whole structure like Piloti structure during the Pohang earthquake in Korea. According to the 2016 National Disaster Management Research Institute's "Investigation of Seismic Reinforcement and Cost Analysis of Domestic Non-seismic Buildings", the rate of seismic resistance of private reinforced concrete buildings was 38.3 %. Among them, it was reported that the seismic-resistance ratio of the two to five-story structures was less than 50 %. Accordingly, the government is trying to improve the seismic rate through support projects, but the conventional seismic reinforcement methods are still expensive, and emergency construction is difficult. Therefore, in this study, the field applicability was evaluated by improving the reinforcement method using Velcro, which was developed through the research project of the Ministry of Land, Transport and Maritime Affairs in 2014. In order to improve the performance of the Velcro reinforcement method, introducing the initial tension of Velcro using high foaming rigid urethane filling between the Velcro and concrete of the columns was applied. Additionally, an experiment was conducted to evaluate the ductility of Velcro specimen from the concrete confinement effect. As a result, the ductility of the Velcro specimen was improved compare to Normal specimen. However, the energy dissipation capacity of VELCRO2 is better than VELCRO1, yet the maximum ductility of those two specimens did not show a significant difference. Therefore, the improvement of the internal filler material is still needed to have a better maximum ductility.

• Korean Journal of Breeding Science
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• v.42 no.6
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• pp.649-653
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• 2010

'Dacheong', a new japonica rice variety developed from a cross between Iksan450 having a good eating-quality and multi-disease resistance, and YR21258-GH3 having insect resistance, was developed by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2008. This variety has about 125 days growth duration from transplanting to harvesting in west-southern coast, Honam and Youngnam plain of Korea. It has 87 cm culm length and tolerance to lodging. In reaction to biotic and abiotic stresses, it shows resistance to blast, bacterial blight pathogen races from $K_1\;to\;K_3$, stripe virus and brown plant hopper. The milled rice of 'Dacheong' exhibits translucent, relatively clear non-glutinous endosperm and medium short grain. It has slightly lower amylose content of 18.8% and lower protein content of 5.7%, and good palatability of cooked rice compared with Nampyeongbyeo. The milled rice yield performance of this variety is about 5.91 MT/ha in local adaptability test for three years. 'Dacheong' would be adaptable to west-southern coast, Honam and Youngnam plain of Korea.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.443-446
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• 2008

'Gangbaek' is a japonica rice variety developed and registered by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2006. 'Gangbaek' was derived from a cross between 'Suweon345' with good grain quality and 'DV85' resistant to bacterial blight, $K_{3a}$. $F_1$ plants were grown in the greenhouse in winter of 1992/1993 and backcrossed with 'Suweon345' as the recurrent parent. Plants resistant to $K_{3a}$ race of bacterial blight (BB) were selected from $BC_1F_1$ to $BC_4F_1$ and used as parents in the backcrossing processes. This variety has about 120 days growth duration from transplanting to harvesting in west-southern coast and Honam plain of Korea. It is about 69 cm in culm length and tolerance to lodging. In reaction to biotic and abiotic stresses, it shows moderately resistance to blast, and resistance to bacterial blight pathogen, $K_1$, $K_2$, $K_3$ and $K_{3a}$, but susceptible to other major diseases and insect pests. The milled rice of 'Gangbaek' exhibits translucent, relatively clear non-glutinous endosperm and midium short grain. It has lower amylose content of 18.6% and protein content of 6.4% compared with 'Nampyeongbyeo'. The milled rice yield performance of this variety is about 5.28 MT/ha in local adaptability test for three years. This cultivar would be adaptable to the bacterial blight-prone area in the south-western coastal and Honam plain of Korea.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.503-506
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• 2008

'Saenuri' is a new japonica rice variety developed and registered by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2007. This variety was derived from a cross between Gyehwa17 with lodging tolerance and high yield potential, and HR14026-B-68-6-1-5 with resistance to diseases and good eating quality. This variety has about 124 days growth duration from transplanting to harvesting in west-southern coast, Honam and Youngnam plain of Korea. It is about 78 cm in culm length and tolerance to lodging. In reaction to biotic and abiotic stresses, it shows moderately resistance to blast, and resistance to bacterial blight pathogen races from K1 to $K_3$ and stripe virus, but susceptible to other major diseases and insect pests. The milled rice of "Saenuri" exhibits translucent, relatively clear non-glutinous endosperm and midium short grain. It has similar amylose content of 19.0% and lower protein content of 6.1%, and good palatability of cooked rice compared with Nampyeongbyeo. The milled rice yield performance of this variety is about 5.71MT/ha in local adaptability test for three years. "Saenuri" would be adaptable to west-southern coast, Honam and Youngnam plain of Korea.

• Korean Journal of Breeding Science
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• v.42 no.3
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• pp.252-256
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• 2010

'Honong' is a new japonica rice variety developed and registered by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2009. This variety was derived from mutagen MNU (N-methyl-N-nitrosourea) treatment on fertilized egg cells of Unbong31. This variety has about 126 days growth duration from transplanting to harvesting in west-southern coast, Honam and Youngnam plain of Korea. It has 79 cm in culm length and is tolerant to lodging. In reaction to biotic and abiotic stresses, it show resistance to blast, bacterial blight pathogen races from $K_1$ to $K_3$ and stripe virus, but susceptible to other major diseases and insect pests. The milled rice of 'Honong' exhibits translucent, relatively clear non-glutinous endosperm and medium short grain. It has higher amylose content (20.3%) and lower protein content (6.3%), and good palatability of cooked rice compared with Nampyeong. The milled rice yield performance of this variety is about 5.44MT/ha in local adaptability test for three years. 'Honong' would be adaptable to west-southern coast, Honam and Youngnam plain of Korea.

• Korean Journal of Breeding Science
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• v.40 no.2
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• pp.188-191
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• 2008

'Hwangkeumnuri' is a japonica rice variety developed and registered by the rice breeding team of Honam Agricultural Research Institute, NICS, RDA in 2006. This variety was derived from a cross between 'Milyang 165' (Junambyeo) with good quality and high yield and HR14732-B-67-2-3 with multi-disease resistance. This variety has about 125 days growth duration from transplanting to harvesting in west-southern coast, Honam and Youngnam plain of Korea. It is about 76 cm in culm length and tolerance to lodging. In reaction to biotic and abiotic stresses, it shows resistance to blast, bacterial blight pathogen from $K_1$ to $K_3$ and stripe virus, but susceptible to other major diseases and insect pests. The milled rice of 'Hwangkeumnuri' exhibits translucent, relatively clear non-glutinous endosperm and midium short grain. It has similar amylose content of 18.9% and lower protein content of 6.2%, and good palatability of cooked rice compared with 'Nampyeongbyeo'. The milled rice yield performance of this variety is about 5.74 MT/ha in local adaptability test for three years. 'Hwangkeumnuri' would be adaptable to west-southern coast, Honam and Yeongnam plain of Korea.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.533-536
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• 2008

Hopum is a new japonica rice cultivar developed from the cross between Milyang165 and F1 crossing Milyang165 and Iksan438 at Department of Rice and Winter Cereal Crop, NICS, RDA, in 2006. This cultivar has a short grain shape and about 141 days growth duration from direct seeding to harvesting in the southern plain including Chungcheong province. This cultivar has short culm and spikelet number per panicle is similar to that of Nampyeongbyeo, while filled grain rate is lower than standard variety. This cultivar has medium size of brown rice and shows moderate resistance to leaf blast, to bacterial blight pathogens of $K_1$, $K_2$ and $K_3$ and stripe virus disease but susceptible to major virus diseases and insect pests. The milled kernel of Hopum is translucent with non-glutinous endosperm. Protein and amylose content of Hopum is about 6.5% and 18.7%, respectively. This cultivar has better palatability of cooked rice than Chucheongbyeo harvested in Gyeongki province. Its milling recovery (76.8%) and percentage of perfect-shaped milled rice (94.7%) were higher than Nampyeongbyeo. The milled rice yield of Hopum was 5.83 MT/ha (15% higher than Juan) under wet-direct seeding, 5.66 MT/ha (8% higher than Juan) under dry-direct seeding, and 6.00 MT/ha (8% higher than Nampyeong) under ordinary transplanting cultivation. "Hopum" would be adaptable for ordinary transplanting and direct seeding in the southern plain including Chungcheong province.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.2
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• pp.105-113
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• 2019

A two-year study was conducted from 2017 to 2018 by the establishment of a test field at Chungju-si and Cheongyang-gun. Plant height, number of leaves, insects and diseases, and fresh and dry matter yields for corn hybrid('Kwangpyeongok') were investigated. Daily average, maximum, and minimum temperature, monthly average temperature, daily precipitation, and sunshine duration during the growing season were investigated. We selected climate-critical factors to corn productivity and conducted an evaluation of vulnerability to climate change from 1999 to 2018 for both regions. In 2018, the dry matter yield of forage corn was 6,475 and 7,511 kg/ha in Chungju and Cheongyang, respectively, which was half of that in 2017. The high temperature and drought phenomenon in the 2018 summer caused the corn yield to be low. As well as temperature, precipitation is an important climatic factor in corn production. As a result of climate impact vulnerability assessment, the vulnerability has increased recently compared to the past. It is anticipated that if the high temperature phenomenon and drought caused by climate change continues, a damage in corn production will occur.