• Journal of Ecology and Environment
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• 제39권1호
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• pp.31-42
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• 2016

The object of this study was to determine long-term temporal and spatial patterns of nutrients (nitrogen and phosphorus), suspended solids, and chlorophyll (Chl) in Chungju Reservoir, based on the dataset of 1992 - 2013, and then to develop the empirical models of nutrient-Chl for predicting the eutrophication of the reservoir. Concentrations of total nitrogen (TN) and total phosphorus (TP) were largely affected by an intensity of Asian monsoon and the longitudinal structure of riverine (Rz), transition (Tz), and lacustrine zone (Lz). This system was nitrogen-rich system and phosphorus contents in the water were relatively low, implying a P-limiting system. Regression analysis for empirical model, however, showed that Chl had a weak linear relation with TP or TN, and this was mainly associated with turbid, and nutrient-rich inflows in the system. The weak relation was associated with non-algal light attenuation coefficients (Kna), which is inversely related water residence time. Thus, values of Chl had negative functional relation (R² = 0.25, p < 0.001) with nonalgal light attenuation. Thus, the low chlorophyll at a given TP indicated a light-limiting for phytoplankton growth and total suspended solids (TSS) was highly correlated (R² = 0.94, p < 0.001) with non-algal light attenuation. The relations of Trophic State Index (TSI) indicated that phosphorus limitation was weak [TSI (Chl) - TSI (TP) < 0; TSI (SD) - TSI (Chl) > 0] and the effects of zooplankton grazing were also minor [TSI (Chl) - TSI (TP) > 0; TSI (SD) - TSI (Chl) > 0].

• Journal of Forest and Environmental Science
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• 제30권1호
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• pp.120-125
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• 2014

Halophytes are plants of saline habitats that grow under conditions that may vary in extremes of temperatures (freezing to very hot), water availability (drought to water logging) and salinity (mild to almost saturation). Halophytes may also face sudden micro-environmental variations within their habitats. In this study, we examine some of the factors that determine the ability of seeds of Artemisia fukudo to germinate when conditions are optimal for seedling growth and survival. Germination percentage was the highest at 77.5% when treated in 0% seawater and seedling growth was best in 0% seawater plug cell tray. Physiological quality (chlorophyll contents) and mean germination time were best in the condition in which seeds were treated with 0% seawater (control). Germination performance index in the control group showed the highest value to 3.8. Seedling growth, seedling vigor index in the length of seedling growth andthe relative growth rate were the highest values of 0.76 cm, 1.43, 0.0099, respectively.

• 한국토양비료학회지
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• 제51권2호
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• pp.79-89
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• 2018

Subsurface drip irrigation (SDI) system is considered one of the most effective methods for water application. A 2-year field study was conducted to investigate the effect of SDI systems with various dripline spacing (0.7 or 1.4 m) and position (under furrow or ridge) on soybean (Glycine max L.) production at a sandy-loam soil in Miryang, South Korea. For 2016-2017, average grain yield in SDI irrigated plots, $3.16Mg\;ha^{-1}$, was statistically greater than rainfed irrigated plot ($2.63Mg\;ha^{-1}$). Soybean grain yield averaged $3.25Mg\;ha^{-1}$ for the 0.7 m dripline spacing and $3.07Mg\;ha^{-1}$ for the 1.4 m spacing for the two-year period compared to a rainfed irrigated average of $2.63Mg\;ha^{-1}$ for the same period. Soybean treated with SDI system had significantly greater values of normalized difference vegetation index and stomatal conductance, indicating that soybean plants in SDI plots had greater photosynthetic and stomatal activity due to the higher water availability in soil. Irrigation water use efficiency (IWUE) was greatest in the plot of 0.7 m spacing installed under ridge position than any other plot across growing season. Average soil water content in plots with 0.7 m dripline spacing was $0.21m^3\;m^{-3}$ at 5 cm depth layer, which was 45% greater compared to the plots with 1.4 m spacing, even though the gross irrigation amounts were greater in 1.4 m spacing plots. It is concluded that wide dripline spacing (1.4 m) is probably the more economical installation design for SDI system compared to 0.7 m spacing in this study soil because the initial cost for dripline may be reduced with wide spacing design, even though the IWUE is greater in the plot of 0.7 m dripline spacing.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.145-145
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• 2022

Availability of abundant water resources data in developing countries is a great concern that has hindered the adoption of deep learning techniques (DL) for disaster prevention and mitigation. On the contrary, over the last two decades, a sizeable amount of DL publication in disaster management emanated from developed countries with efficient data management systems. To understand the current state of DL adoption for solving water-related disaster management in developing countries, an extensive bibliometric review coupled with a theory-based analysis of related research documents is conducted from 2003 - 2022 using Web of Science, Scopus, VOSviewer software and PRISMA model. Results show that four major disasters - pluvial / fluvial flooding, land subsidence, drought and snow avalanche are the most prevalent. Also, recurrent flash floods and landslides caused by irregular rainfall pattern, abundant freshwater and mountainous terrains made India the only developing country with an impressive DL adoption rate of 50% publication count, thereby setting the pace for other developing countries. Further analysis indicates that economically-disadvantaged countries will experience a delay in DL implementation based on their Human Development Index (HDI) because DL implementation is capital-intensive. COVID-19 among other factors is identified as a driver of DL. Although, the Long Short Term Model (LSTM) model is the most frequently used, but optimal model performance is not limited to a certain model. Each DL model performs based on defined modelling objectives. Furthermore, effect of input data size shows no clear relationship with model performance while final model deployment in solving disaster problems in real-life scenarios is lacking. Therefore, data augmentation and transfer learning are recommended to solve data management problems. Intensive research, training, innovation, deployment using cheap web-based servers, APIs and nature-based solutions are encouraged to enhance disaster preparedness.

• 농촌계획
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• 제29권1호
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• pp.37-49
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• 2023

Active attention and effort are needed to develop an integrated water management system in response to climate change. In this study, it proposed models for cross-use of agricultural water and river maintenance water using sewage treatment water as an integrated water management system for the Yeongsan River. The impact of the integrated water management models was assessed by applying the concept of Nexus, which is being presented worldwide for sustainable resource management. The target year was set for 2030 and quantitatively analyzed water, energy, land use and carbon emissions and resource availability index by integrated water management models was calculated by applying maximum usable amount by resource. An integrated water management system evaluation model using the Nexus concept developed in this study can play a role that can be viewed in a variety of ways: security and environmental impact assessment of other resources. The results of this research will be used as a foundation for the field of in the establishment of a policy decision support system to evaluate various security policies, as we analyzed changes in other factors according to changes in individual components, taking into account the associations between water, energy, food, and carbon resources. In future studies, additional sub-models need to be built that can be applied flexibly to changes in the future timing of the inter-resource relationship components.

• 한국농공학회지
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• 제18권3호
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• pp.4195-4205
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• 1976

The purpose of this study is to evaluate the existing methods for calculating or estimating the consumptive use (Evaportranspiration) of any agricutural development project area. In determing the consumptive use water in the project area, there will require the best way for estimating irrigation requirement. Many methods for computing the evaportranspiration have been used, each of them with its merits and demerits at home and abroad. Some of these methods are listed as follows: 1.The Penman's formula 2.The B1aney-Criddle method 3.The Munson P.E. Index method 4.The Atmometer method 5.The Texas Water Rights Commission (TWRC) method 6.The Jensen-Haise method 7.The Christiasen method Therefore, the authors will introduce the more widely used method for calculating Consumptive Use by G.H. Hargreaves. The formula is expressed in the form Ep= K·d·T (1.0-0.01·Hn) Hn=1.0+0.4H+0.005H2. This method was adopted for the first time to determine the Irrigation requirements of Ogseo Comprehensive Agricultual Development project (Benefited area:100,500ha) in Korea. This method is presented in somewhat greater detail than the others. Formula is given for the computation of evaportranspiration (with various levels of data availability) Sampel computation of irrigation requirements for Ogseo irrigation project is included. The results and applied materials are summarized as follows. 1. In calculating the Hargreaves formula, the mean temperature relative, humidity, length of day, and percentage of sunshine from three stations of Iri, Jeonju, and Gunsan were used. 2. Monthly evaporation values were calculated by using the formula. 3. Meteological data from the three stations records for the ten years (1963∼1972) were used. 4. The annual irrigation requirements is 1,186mm per hectare, but the case to consider effective rainfall amount takes the annual irrigation demand being 700mm per hectare.

• 한국환경농학회지
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• 제25권4호
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• pp.323-330
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• 2006

공업단지 인근 중금속 복합오염 농경지에서 중금속 오염 특성과 재배작물인 미나리중에 흡수 축적된 중금속과의 관계를 구명하기 위해 토양내 중금속의 상대적인 오염평가지수, 미나리의 중금속 축적양상 및 식물흡수도 등을 분석 검토하였다. 토양의 화학성분은 일반 논토양보다 대체로 높았으며, 특히 토양 pH및 치환성 Ca 함량이 매우 높았다. 토양의 중금속 중 Cd 및 Cu 농도가 우리나라 토양환경기준을 초과하였고, 년차별 0.1N-HCl 추출 가용성함량은 감소하는 경향을 보였다. 토양의 중금속 오염지수(PI) 및 그 편차는 재배토양 보다 농수로 퇴적토양에서 높았고, 중금속별 지화학적농축계수(Igeo)는 Cu>Cd>Ni>Zn>Pb 순이었다. 토양의 전함량에 대한 0.1N-HCl 침출성 함량 비율은 Cd>Cu>Zn>Ni>Pb 순이었고, 그 관계에서 Cd 및 Ni 성분은 고도의 정의 상관을 나타내었다. 미나리 부위별 중금속은 대부분이 뿌리에 축적되었으며, 지상부로의 이행지수(TF)는 Zn 및 Cu가 높은 경향이었다. 식물 흡수도는 비나리 부위 및 성분별로 큰 차이를 보였고, 토양 및 부위별 농도간에는 Cd, Cu 및 Ni 성분이 상관성이 높게 나타났다. 이상의 결과에서 토양의 중금속 오염도는 매우 높았으나 재배작물인 미나리중의 중금속은 대부분 뿌리에서 축적되고, 가식부위인 지상부로의 이행성은 매우 낮은 것을 알 수 있었다.

• 생태와환경
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• 제39권3호통권117호
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• pp.296-309
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• 2006

조사 시기 동안 (2000~2004년) 주암호와 동복호에서는 겨울을 제외한 시기에 표층과 저층의 수온차이로 인해성층화가 발생하였지만 영산호에서는 나타나지 않았다. 투명도는 주암호>동복호>영산호 순으로 영산호에서 낮은 투명도를 보였으며 주암호와 동복호에서는 식물플랑크톤의 생물량이 높게 나타나는 가을 저층에는 저산소상태로 수질 악화를 나타내었다. 암모니아, 질산염, 인산염 TN, TP는 주암호와 동복호에 비해 영산호에서 높게 나타났으나 클로로필 a는 평균적으로 동복호에서 높았으며 영산호에서 낮았다. 3개호소의 여름, 가을 연평균 영양상태는 평균적으로 영산호>동복호>주암호 순으로 영산호에서 높았다. 주암호와 동복호에서는 TSI (CHL)>TSI (SD)>TSI (TP) 순으로 나타나 조류성장에 있어 인산염이 제한영양염으로 작용할 가능성을 나타내었으며 영산호에서는 TSI (TP)>TSI (SD)>TSI (CHL) 순으로 나타났다. 영산호에서는 인산염에 의한 제한보다는 탁도 즉 광량에 의한 제한이 식물플랑크톤의 성장에 영향을 미치는 것으로 판단된다. 주암호는 빈, 중영양을 보였으며, 동복호에서는 중, 부영양을 영산호에서는 부, 과영양을 보였다.

• 한국습지학회지
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• 제20권2호
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• pp.173-180
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• 2018

상수용, 농업용 등으로 사용되고 있는 낙동강수계의 30개소 호소를 대상으로 새로운 환경기준인 TOC(총유기탄소, Total organic carbon)의 활용성을 평가하였다. 적극적인 수자원의 이용은 양호한 수질을 확보하는 것으로 시작된다. 이는 사람과 자연에게 질적 안정성을 유지할 수 있게 하므로 양호한 수질 확보를 위해 수질기준은 보다 엄격하게 강화되고 있다. 생활환경 중 호소의 유기물질 오염수준을 개선하는 데에는 적절한 유기물질 지표의 활용성이 중요하다. 대상호소에서는 새로 도입된 TOC와 기존에 사용하던 COD(화학적산소요구량, Chemical oxygen demand)간의 상호성이 양의 관계로 나타났는데 이는 TOC의 COD 대체가능성을 의미한다. 그러나 TOC를 활용한 환경기준의 등급이 COD를 활용한 환경기준의 등급보다 더 양호한 것으로 나타나 TOC를 유기물질인자로 이용한 수질등급 수준이 완화된 것과 동일한 효과를 지니게 된다. 이것은 호소의 유기물질 지표를 활용하여 질적 수준을 판단하거나 개선하고자 할 때에 기존의 COD에 직접적으로 대체하기에 TOC의 한계를 나타내는 것이다. 따라서 호소의 질적 안전성을 확보하기 위해서는 수질등급 면에서 TOC의 환경기준 강화가 요구된다. 또 호소의 이용특성에 따라 TOC와 COD간의 상관성에도 큰 차이를 나타내고 있다. 이에 대한 명확한 과학적 규명이 필요하며, 이를 위해 호소의 유기물질 지표의 축적에 기존에 사용하던 COD의 지속적인 모니터링이 요구된다.

• 생물환경조절학회지
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• 제29권1호
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• pp.20-27
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• 2020

본 연구는 적외선 열 영상 장치를 이용하여 2년생 '유미' 복숭아나무의 토양수분 수준에 따른 엽온 및 CWSI를 분석하여 수분스트레스 측정 가능성을 검토하였다. 엽온은 대기온도와 유사한 일변화를 보이며 낮 시간대에는 대기온도보다 높은 양상을 보였다. 엽온은 전일(24시간) 기준으로 대기온도(r² =0.95), 일사량(r² =0.74), 상대습도(r² =-0.88)와 모두 높은 상관계수를 나타났다. 또한 토양수분장력은 낮 시간대(11~16시)에 엽온(r² =-0.57), 엽-대기온도차(r² =-0.71), CWSI(r² =-0.72)와 높은 부의상관을 나타냈다. CWSI와 엽온, 엽-대기온도차의 상관계수는 24시간 기준으로 매우 높았고(r² =0.90, r² =0.92), CWSI와 토양수분장력의 상관분석에서 24시간 기준으로는 상관관계가 낮았으나(r² =-0.27), 낮 시간대(11~16시)에는 상관관계가 매우 높았다(r² =-0.72). CWSI (y)와 토양수분장력(x)의 상관관계 결정계수(r² )는 11~12시간대에 가장 높았으며(r² =0.68), 이때 회귀식은 y = -0.0087x + 0.14로 조사되었다. 일반적인 토양수분스트레스 시점인 -50 kPa에 해당되는 CWSI는 0.575로 계산된다. 따라서 적외선 열 영상 장치를 이용한 엽온 및 CWSI는 토양수분장력에 대해 높은 상관계수를 나타낸 것으로 보아 복숭아나무의 수분스트레스 진단에 유용하게 활용할 수 있을 것으로 예상된다.