• Korean Journal of Environmental Agriculture
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• v.28 no.1
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• pp.32-37
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• 2009

This study was conducted to assess the impact of agricultural land use on the water quality in mountain village farmlands. Two soil types, paddy and upland soil were analysed for their chemical properties. Although, pH and organic matter contents were not significantly different to each other, concentrations of available P and exchangeable K and Ca were much higher in upland soil compared with those in paddy soil. The results of water quality analysis indicated that, in Goseong-cheon watershed, the nutrients contents were much higher in downstream area than in upstream area. Particularly, the elevation of $COD_{Mn}$ and T-P were significant during rainy season. When paddy fields coexist with upland fields, SS, T-N, and T-P concentrations in paddy fields were lower than those of upland fields. This may indicate that paddy fields possess an water-purifying ability by absorbing nutrients. This effect may reduce excessive nutrients discharged into the neighboring streams which may cause eutrophication problem. The difference between inflow and outflow of nitrogen and phosphorus during the cultivation period were measured as -98.9 kg $ha^{-1}$ and -29.7 kg $ha^{-1}$, which means that nutrient outflow was higher than inflow. This may suggest that much nutrient was discharged during the crop harvest period.

• Journal of agriculture & life science
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• v.46 no.4
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• pp.9-20
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• 2012

Eugenol is a volatile compound synthesized by eugenol synthase in various plants and belongs to phenylpropene compounds. However, characteristics of eugenol synthase in tomato has not been known. Therefore, we cloned a full length cDNA of a putative eugenol synthase from tomato 'Micro-Tom' using rapid amplification of cDNA ends (RACE) technique and named a clone SlEGS. Open reading frame of SlEGS was 921bp long and its deduced amino acid sequence was 307bp. The BLAST analysis indicated that SlEGS shared high similarity with PhEGS1 (67.1%) and CbEGS2 (69.4%). Amino acid composition of SlEGS was determined by CLC genomics workbench tool and 3D structure of SlEGS was constructed by homology modeling using Swiss-PDB viewer and validated using PROCHECK and ProSA-web tool. In addition, the physiochemical properties of SlEGS was evaluated using ExPASy's ProtParam tool. Molecular weight was 33.93kDa and isoelectric point was 5.85 showing acidic nature. Other properties such as extinction coefficient, instability index, aliphatic index, and grand average hydropathy was also analyzed.

• Journal of agriculture & life science
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• v.45 no.5
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• pp.17-23
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• 2011

Growth characteristics and adaptability of 10 poplar clones planted at a reclaimed tidal flat were evaluated. The contents of $Na^+$, $Ca^{2+}$ and $Mg^{2+}$ were 10.0, 3.4 and 1.5 times higher, respectively than those of control although the electrical conductivity(EC) in the soil at the test plantation was low as much as 0.51 dS/m. The contents of organic matter(OM) and total nitrogen(TN) in the soil were 22.9 and 23.0 times lower than those of control. Average survival rate of 10 poplar clones showed 88% at three years after planting. Clones Eco28(Populus euramericana), Dorskamp(Populus deltoides ${\times}$ P. nigra) and I-476(Populus euramericana) showed the best survival rate of 100%. However, clones 97-19(Populus deltoides(Lux) ${\times}$ P. deltoides(Harvard)) and Suwon (Populus koreana ${\times}$ P. nigra var. italica) were relatively lower than other clones. Average height and DBH of all clones were 4.8 m and 3.6 cm, respectively. Clone Dorskamp showed the greatest height and DBH, 5.9 m and 5.0 cm, respectively. Clones 97-19 and Dorskamp showed the least defoliation by stress and visible damage by insects and diseases, whereas clones Suwon and I-476 were the most sensitive at the reclaimed tidal flat. Clone Dorskamp showed the best adaptability at the reclaimed tidal flat, but clone Suwon showed the worst based on survival rate, growth, and visible damages.

• Korean Journal of Remote Sensing
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• v.22 no.6
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• pp.553-563
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• 2006

This study aims to produce land-cover maps of Korean peninsula using multi-temporal MODIS (Moderate Resolution Imaging Spectroradiometer) imagery. To solve the low spatial resolution of MODIS data and enhance classification accuracy, Linear Spectral Mixture Analysis (LSMA) was employed. LSMA allowed to determine the fraction of each surface type in a pixel and develop vegetation, soil and water fraction images. To eliminate clouds, MVC (Maximum Value Composite) was utilized for vegetation fraction and MinVC (Minimum Value Composite) for soil fraction image respectively. With these images, using ISODATA unsupervised classifier, southern part of Korean peninsula was classified to low and mid level land-cover classes. The results showed that vegetation and soil fraction images reflected phenological characteristics of Korean peninsula. Paddy fields and forest could be easily detected in spring and summer data of the entire peninsula and arable land in North Korea. Secondly, in low level land-cover classification, overall accuracy was 79.94% and Kappa value was 0.70. Classification accuracy of forest (88.12%) and paddy field (85.45%) was higher than that of barren land (60.71%) and grassland (57.14%). In midlevel classification, forest class was sub-divided into deciduous and conifers and field class was sub-divided into paddy and field classes. In mid level, overall accuracy was 82.02% and Kappa value was 0.6986. Classification accuracy of deciduous (86.96%) and paddy (85.38%) were higher than that of conifers (62.50%) and field (77.08%).

• Korean Journal of Food Science and Technology
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• v.51 no.3
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• pp.248-257
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• 2019

This study aimed to determine the chemical components of different cultivars (Gabjubaekmok, Sangjudungsi, and Godongsi) of persimmon (Diospyros kaki Thunb.) and the effects of maturity. The detected free sugars were fructose and glucose, and glucose levels tended to increase with maturity. Palmitic acid, oleic acid, linoleic acid and stearic acid, and potassium were major components. In the amino acid component analysis, the following were usually present in the following month: glutamic acid in Gabjubaekmok in July, lysine in Sangjudungsi in August, and threonine in Godongsi in October. Vitamin C tended to increase with aging, and fruit harvested in July had the highest total phenolic and flavonoid contents. In the metabolite analysis, there were significant differences among cultivars and with maturity. The major physiological compounds were analyzed using ultra performance liquid chromatography quadrupole time-of-flight tandem mass ($UPLC/Q-TOF/MS^2$) and were citric acid and gallic aicd. As maturity progressed, citric acid increased but gallic acid decreased.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.411-411
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• 2022

보는 수로나 하천의 수위를 조절하고 취수 등의 편의를 제공하기 위해 건설되는 하천 구조물이다. 일반적인 보(고정보)는 상시 담수 되어 농업용수, 생활용수, 공업용수 등의 취수원으로 활용되지만, 최근에 설치되는 보(가동보)들은 수문을 설치하여 필요에 따라 수위를 조절할 수 있게 되어 있다. 이와 같은 보의 운영은 보 상류의 유속, 수심, 흐름 특성, 하천 형상 등의 변화를 발생시킨다. 특히 하류 보는 운영현황에 따라 하천 흐름에 직접적인 영향을 주기 때문에 하천 흐름 특성에 핵심적인 요소로 볼 수 있다. 따라서 이에 대한 모니터링이 필요하며 이에 따른 수위-유량관계를 규명할 필요가 있다. 본 연구에서는 함평천 유역에 위치한 함평군(영수교)관측소를 대상으로 하류 약 1.3km에 위치한 개량형 공압식 가동보의 2021년 기립각도 변화에 대한 보 모니터링을 실시하여 수위-유량관계 변화를 분석하였다. 2021년에는 가동보의 기립각도 변화 및 취수조건에 따라 총 37회의 수위관측 및 유량측정을 하였으며 총 29회의 가동보의 기립각도를 계측하였다. 2021년 전반기에는 부분개방1, 부분개방2, 부분개방3, 완전개방, 취수조건으로 기간 분리되었고 후반기에는 완전개방, 부분개방3, 부분개방4, 부분개방5 조건으로 가동보의 기립각도에 따라 총 6개의 기간분리가 발생하였다. 결과적으로 본 연구에서는 하류 가동보 운영현황에 대한 보 모니터링과 흐름 특성이 변화하는 기간의 유량측정성과 확보를 통해 신뢰도 높은 수위-유량관계곡선식을 개발하였고 이를 통해 생산된 유량자료는 정확도가 매우 높은 것으로 분석되었다.

• Korean Journal of Organic Agriculture
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• v.14 no.1
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• pp.55-67
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• 2006

A survey of 31 organic farmers were conducted to investigate the actual conditions of organic matter application. The amounts of organic matter application in the fields were higher in order of fruit, vegetable and rice farm. The average was 50 ton/ha in vegetable farms. In the green vegetable farms saw dust and animal manure were mainly utilized to make compost. Rice straw, wood chip, and forest bushes were also used for composting. In the fruit vegetable farms materials relatively lower in nitrogen content such as rice straw and cattle manure were used in vegetative period and materials higher in nitrogen content such as oil cake and wild grass were used in reproductive phase. Nutrient balance investigated in the farm in Icheon region who produce lettuce, angelica, and kale continuously in one cropping year indicated surplus in three major nutrients. Nitrogen and phosphorous were in excess by 29 and 10 kg respectively in the organic rice farm in yang-pyoung region. While soil chemical properties in the organic farms are within the adequate range in open field, it is much higher than the limits in the greenhouse soils. Overall application of organic matter is in an oversupply state. This results suggested that the organic matter management should be based on the soil conditions for sustainable cultivation. Chemical composition of organic matters and soil test reports should be considered prior to the application of organic matter.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.2
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• pp.99-106
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• 1993

A two-dimensional numerical analysis is performed for the simulation of intertidal-flat and analysis of hydraulic characteristics during seadike construction in Sae-Man-Keum tidal basin. The shallow water equations are selected as a mathematical model and the Leendertse's ADI scheme is used as the corresponding numerical model. The simulated results of tide and current by the present model agree welt with the experimenta1 results by the hydraulic Lab. or ADC (1989). In the application of the model, the possibility of rapidly varied flow analysis and the introduction of turbulence model required for more accurate hydraulic calculation at closing gap are described. The successive simulation of flooding/drying effects by a modification of the method by Stelling et al. (1986) can easily be used for the intertidal-flat analysis during tidal reclamation.

• The Korean Journal of Mycology
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• v.49 no.1
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• pp.81-86
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• 2021

We isolated endophytic fungi from Smilax china and Cryptomeria japonica. These fungal strains were identified based on their morphological characteristics and phylogenetic analyses of their internal transcribed spacer, large subunit rDNA, and translation elongation factor 1-α DNA. Among them, we discovered two fungi belonging to the genus Phyllosticta, which have not been previously recorded in Korea. We have described these two fungal strains, Phyllosticta ericarum 19E458 and Phyllosticta philoprina 19E012 in this study.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.72-72
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• 2021

가뭄은 수개월, 수년 이상에 걸쳐 서서히 발생 및 지속되며, 식생에 대한 피해가 발생할 때까지 확실한 인식이 어렵다. 최근에는 기후변화로 인하여 가뭄의 발생빈도가 증가하고 있으며, 기상 이상에 따른 다양한 형태의 가뭄이 발생하고 있다. 미국에서 정의한 'Flash Drought'는 비교적 짧은 기간 동안 표면온도의 상승과 비정상적으로 낮고 빠르게 감소하는 토양수분으로 인하여 식생에 대한 극심한 스트레스를 유발하면서 광범위한 작물 손실 및 용수공급 감소 등에 대한 피해를 야기하는 가뭄이다. 국내에서는 Flash Drought에 대한 모니터링이 활성화되지 않았기 때문에 본 연구에서는 '돌발가뭄'이라는 새로운 정의를 제시하면서 토양수분, 증발산량, 강수량, 기온 등의 가뭄 관련 주요인자를 활용하여 국내에서 발생한 돌발가뭄 (Flash Drought)를 감지하고 분석하고자 하였다. 돌발가뭄을 분석하기 위하여 선행연구에서 제시한 가뭄 관련 주요인자 기준 유형, 증발산량 기반 가뭄지수를 활용한 유형 등을 활용하였으며, 지상관측자료로는 국내 76개 종관기상관측 자료를 활용하였다. 또한, 토양수분 자료는 GRACE (Gravity Recovery and Climate Experiment) 위성영상 자료를 취득한 후 5 km 공간해상도 자료로 활용하였다. 가뭄지수의 경우 증발산 기반 가뭄지수 중 표준강수증발산지수 SPEI (Standardized Precipitation Evapotranspiration), 증발스트레스지수 ESI (Evaporative Stress Index) 등을 활용하여 국내 돌발가뭄 유형에 대한 분석에 적용하였다. 본 연구를 통하여 아직 명확하게 정의되지 않은 돌발가뭄에 대한 유형별 분석 및 국내 돌발가뭄의 수문기상학적 특성을 분석하고자 한다.