• 한국농공학회논문집
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• 제57권1호
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• pp.59-67
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• 2015

Because reservoirs that supply irrigation water play an important role in water resource management, it is necessary to evaluate the vulnerability of this particular water supply resource. The purpose of this study is to provide water supply risk maps of agricultural reservoirs in South Korea using irrigation vulnerability model and cluster analysis. To quantify water supply risk, irrigation vulnerability indices are estimated to evaluate the performance of the water supply on the agricultural reservoir system using a probability theory and reliability analysis. First, the irrigation vulnerability probabilities of 1,346 reservoirs managed by Korea Rural Community Corporation (KRC) were analyzed using meteorological data on 54 meteorological stations over the past 30 years (1981-2010). Second, using the K-mean method of non-hierarchical cluster analysis and pre-simulation approach, cluster analysis was applied to classify into three groups for characterizing irrigation vulnerability in reservoirs. The morphology index, watershed area, irrigated area, and ratio between watershed and irrigated area are selected as the clustering analysis parameters. It is suggested that the water supply risk map be utilized as a basis for the establishment of risk management measures, and could provide effective information for a reasonable decision making on drought risk mitigation.

• 한국농공학회논문집
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• 제63권3호
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• pp.47-57
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• 2021

Drought monitoring over paddy field area is an important role as the frequency and intensity of drought due to climate change increases. This study analyzed the applicability of drought monitoring on paddy crops using MODIS-based field surveys. As a satellite-based drought index using evapotranspiration for quantitative drought determination, ESI (Evaporative Stress Index), was applied and calculated through the ratio of MODIS- based actual and potential evapotranspiration. For the irrigated areas of Idong, Gosam, Geumgwang, and Madun reservoirs the availability of irrigation water supply, ponding depth, precipitation, paddy growth were investigated for the paddy field within one grid of MODIS. In addition, the percentile-based ESI drought severity was calculated to compare the growth process of paddy and changes in the drought category of ESI. The Idong area was irrigated about a week later than other reservoirs for the period of water supply, transplanting, and water drainage and the ESI drought category tended to be different. The Gosam, Geumgwang, and Madun area expressed moderate drought prior to the farming season, and indicated normal as the water was supplied. During the water drainage, the drought category intensified, indicating that the water available on land was decreasing. These results demonstrated that the MODIS-based ESI could be an effective tool for agricultural drought monitoring over paddy field area.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.107-114
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• 1999

The large-scale distribution of crops Is usually determined by climate. We present the results of a climate-crop prediction based on spatial bio-physical process model approach, implemented in a GIS (Geographic Information System) environment using several regional and global agriculture-environmental databases. The model utilizes daily climate data like temperature, rainfall, solar radiation being generated stocastically by in-built model weather generator to determine the daily biomass and finally the crop yield. Crops are characterized by their specific growing period requirements, photosynthesis, respiration properties and harvesting index properties. Temperature and radiation during the growing period controls the development of each crop. The model simulates geographic/spatial distribution of climate by which a crop-growing belt can also be determined. The model takes both irrigated and non-irrigated area crop productivity into account and the potential increase in productivity by the technical means like mechanization is not considered. All the management input given at the base year 1995 was kept same for the next twenty-year changes until 2015. The simulated distributions of crops under current climatic conditions coincide largely with the current agricultural or specific crop growing regions. Simulation with assumed weather generated derived climate change scenario illustrate changes in the agricultural potential. There are large regional differences in the response across the country. The north-south and east-west regions responded differently with projected climate changes with increased and decreased productivity depending upon the crops and scenarios separately. When water was limiting or facilitating as non-irrigated and irrigated area crop-production effects of temperature rise and higher $CO_2$ levels were different depending on the crops and accordingly their production. Rise in temperature led to yield reduction in case of maize and rice whereas a gain was observed for wheat crop, doubled $CO_2$ concentration enhanced yield for all crops and their several combinations behaved differently with increase or decrease in yields. Finally, with this spatial modeling approach we succeeded in quantifying the crop productivity which may bring regional disparities under the different climatic scenarios where one region may become better off and the other may go worse off.

• 한국토양비료학회지
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• 제30권4호
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• pp.314-327
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• 1997

점적 관개시 근권에서의 토양 수분 이동 현상을 2차원 원통 좌표를 이용하여 모델링 하였다. 엽면 증산, 다양한 형태의 지면 증발, 관개율의 증가로 인한 지면에서의 물 고임 현상등을 고려하였다. 모델은 유한 차분법을 이용한 수치해로 풀었다. 여러가지 비교의 결과로부터 본 연구에서 개발된 모델은 근권에서의 토양 수분 이동 현상을 잘 묘사한다고 볼 수 있었다. 모델의 민감도 분석을 통해서 몇가지 유익한 사실을 발견하였다. 토양 수분이 연직 방향으로 이동하는 속도가 더 큰 것으로 보아 자동 관개용 토양 수분 측정 센서를 설치할 경우, 관개점의 연직하방이 좋은 측점임을 알 수 있었다. 습윤대의 형태가 단지(pot) 모양으로 되는 것은 지면 증발로 인한것임을 알 수 있었다. 또한, 토양의 포화 수리 전도도가 습윤대의 확산에 큰 영향을 주는 것을 알 수 있었고, 관개 중단 후에도 연직 방향의 확산은 계속됨을 알 수 있었다.

• International Journal of Industrial Entomology and Biomaterials
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• 제18권2호
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• pp.97-103
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• 2009

Sericulturists in the vicinity of Bangalore city irrigate their mulberry gardens with Vrishabhavathy stream water, which is polluted with domestic and industrial wastes from the city. To investigate the effect of pollutants on silkworm crops, a detailed field survey was conducted to study the cocoon yield pattern of the crops raised on mulberry irrigated with wastewater as against irrigation by bore/open wells. The villages along the stream were grouped into five test batches at about a distance of $5{\sim}8$ km from each other. The seasonal yield data with relevant information were collected through questionnaires from 117 rearers using stream water and 35 rearers using bore/open wells, the latter serving as control group. The average yield for 100 layings was 46 to 57 kg in the control group whereas in test groups, it ranged between 34 to 51 kg in the first test group and 22 to 38 kg in the rest. The difference in yield was $9{\sim}19$ kg depending on the season between control and test batches. In summer, this difference was higher, with high co-efficient of variation in test groups ($33{\sim}52$%). Further, water, soil and leaf samples were collected from selected rearers and were analyzed for zinc, copper, iron, lead and nickel. Results indicated significantly higher contents of these metals in samples from gardens using wastewater when compared control samples. Significantly (p<0.05 & p<0.01)) higher levels of zinc ($24{\sim}122$ ppm) and iron ($208{\sim}683$ ppm) were noticed in mulberry leaves during summer followed by winter and rainy season. The significance of high content of heavy metals in mulberry leaves and cocoon yield pattern of this area in relation to the quality of irrigation water is discussed.

• 한국토양비료학회지
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• 제48권5호
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• pp.499-504
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• 2015

Decision making by farmers regarding irrigation is critical for crop production. Therefore, the precision irrigation technique is very important to improve crop quality and yield. Recently, much attention has been given to remote sensing of crop canopy temperature as a crop water-stress indicator, because it is a scientifically based and easily applicable method even at field scales. This study monitored a series of time-variant canopy temperature of cucumber under three different irrigation treatments: under-irrigation (control), optimal-irrigation, and over-irrigation. The difference between canopy temperature ($T_c$) and air temperature ($T_a$), $T_c-T_a$, was calculated as an indicator of cucumber water stress. Vapor pressure deficit (VPD) was evaluated to define water stress on the basis of the temperature difference between leaf and air. The values of $T_c-T_a$ was negatively related to VPD; further, cucumber growth in the under- and over-irrigated fields showed water stress, in contrast to that grown in the optimally irrigated field. Thus, thermal infrared measurements could be useful for evaluating crop water status and play an important role in irrigation scheduling of agricultural crops.

• 한국환경농학회지
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• 제1권2호
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• pp.116-122
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• 1982

1981년(年) 황구지천(黃口池川)의 수질(水質)을 조사(調査)하고 아울러 황구지천 유역(黃口池川 流域)의 오수 유입답(汚水 流入畓)에서 주구(主區)로 실소수준(室素水準)을 달리하고 세구(細區)로 토양개량제(土壤改良劑)의 종류(種類)를 달리하여 수양반응(收量反應)을 검토(檢討)한 결과(結果)를 요약(要約)하면 다음과 같다. 1) 황구지천(黃口池川)의 수질(水質)은 중류(中流)인 안영리(安寧里)에서 파종기(播種期)에 COD 54ppm, $NH_4-N$는 6.5ppm이고 이앙기(移秧期)는 COD 52ppm, $NH_4-N$ 5.2ppm으로 기준치(基準値)를 상회(上廻)하였다. 수질오염(水質汚染)은 주(主)로 유기성 폐기물(有機性 廢棄物)의 유입(流入)에 의(依)한 것으로 생각된다. 2) 질소적량(窒素適量)은 NPK 3요소(要素)인 표준구(標準區) 7.2㎏/10a에 비(比)하여 가리배양(加里倍量)+규회석(珪灰石)+석회(石灰)+생고(生藁) 500 ㎏/10a인 종합개량구(綜合改良區)는 7.3㎏/10a, 석회구(石灰區)는 7.5㎏/10a, 규회석구(珪灰石區)에서는 8.2㎏/10a로 증가 경향(增加 傾向)이며 황구지천변(黃口池川邊)에서 수도재배시 질소량(水稻栽培時 窒素量)은 $7{\sim}8Kg/10a$가 적양(適量)이었다. 3) 질소적정 사용시(室素適正 施用時)의 수량(收量)은 NPK 3요소(要素)인 표준구(標準區) 569㎏/10a에 비(比)하여 3요소(要素)+석회(石灰)+규회석(珪灰石)+가리배양(加里倍量)+생고(生藁) 500㎏/10a인 종합개량구(綜合改良區) 8%, 석회구(石灰區) 5%, 가리배양구(加里倍量區)에서 4% 증수(增收)하였다.

• 한국농공학회논문집
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• 제61권5호
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• pp.23-31
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• 2019

Crop response to weather and internal water pressure changes is more sensitive to crop water stress than soil water content. Recently, its implementation to optimal irrigation scheduling has been receiving much attention. This study was conducted to determine and compare the theoretical crop water stress index (CWSI) using meterological data and canopy temperature collected from three different irrigation treatments, which were Tr-1 plot (rainfed), Tr-2 plot (50% of daily evapotranspiration (ET) irrigated) and Tr-3 plot (75% of daily evapotranspiration (ET) irrigated). The readings of canopy temperature and CWSI were significantly different among irrigation treatment schemes. The average canopy temperatures and CWSIs of Tr-1 and Tr-3 plots were $34.6^{\circ}C$ and $32.6^{\circ}C$, 0.79 and 0.64, respectively. Solar radiation had the biggest correlation with CWSI (R=0.68) which was followed by wind speed, relative humidity and air temperature. Overall, the findings of this study indicated that canopy temperatures and CWSIs could be further used for irrigation scheduling for crop growth.

• 한국토양비료학회지
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• 제25권1호
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• pp.8-15
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• 1992

토양수분(土壤水分)의 상태(狀態)가 콩의 지하부(地上部) 및 뿌리의 생육(生育)과 P, K흡수(吸收)에 미치는 영향(影響)을 알아보기 위하여 강수(降水)가 차단(遮斷)된 비닐하우스 내(內)에서 지하수위(地下水位)를 20cm, 40cm 그리고 60cm로 조절(調節)된 상태(狀態)의 mini-rhyzotron에서 팔달콩을 재배(栽培)하였다. 이와 비교(比較)하기 위하여 1/2000a Wagner 포트에서 단장용수량(團場容水量)으로 유지(維持)된 적습상태(適濕狀態)와 유효수분(有效水分)의 80%가 소모(消耗)되어 토양수분(土壤水分)이 부족(不足)한 상태(狀態)를 비교(比較)하였다. 각 포트에 발아(發芽)된 콩을 심어 세 개씩의 개체(個體)를 재배(栽培)하여 재배(栽培) 37일(日) 째와 수확기(收穫期)에 식물체(植物體)의 지상부(地上部) 및 뿌리를 채취(採取)하여 분석(分析)하였다. 지상부(地上部) 및 뿌리의 생육(生育)은 토양수분(土壤水分)이 부족(不足)한 처리(處理)와 지하수위(地下水位)가 20cm로 높아 과습상태(過濕狀態)가 유지(維持)된 처리(處理)에서 제한(制限)되었다. 적습유지(適濕維持) 처리(處理)와 지하수위(地下水位) 및 60cm 유지(維持) 처리(處理) 간(間)에는 큰 차이(差異)가 없었다. 생육초기(生育初期)에 식물체(植物體) 지상부(地上部)의 P 및 K의 함량(含量)은 토양수분(土壤水分)이 부족(不足)한 처리(處理)에서 적습유지(適濕維持) 처리(處理)에서보다 높았으며, 후기(後期)에는 적습유지(適濕維持) 처리(處理)에서 높았다. 전체(全體) 흡수량(吸水量)은 건물중(乾物重)이 많은 적습유지(適濕維持) 처리(處理)에서 많았다. 뿌리의 건물중(乾物重)과 길이는 지상부(地上部)보다 더 크게 영향(影響)을 받았다. 토양수분(土壤水分)의 상태(狀態)의 차이(差異)에 의하여 뿌리의 형태해부학적(形態解副學的) 차이(差異)가 있음이 관찰(觀察)되었다. 적습유지(適濕維持) 처리(處理)에서는 정상적(正常的)인 치밀(緻密)한 cortex조직(組織)이 발달(發達)되었으나, 지하수위(地下水位)가 높아 토양수분(土壤水分)이 과다(過多)한 상태(狀態)에서 생육(生育)한 뿌리에서는 비정상적(非正常的)인 cortex조직(組織)에 aerenchyma가 형성(形成)되었다. Aerenchma는 내초(內梢)의 분열조직(分裂組織) 부근을 중심(中心)으로 형성(形成)되었다. 이 시험조건(試驗條件)에서 발견(發見)된 콩의 뿌리에서 aerenchyuma의 형성(形成)은 과다(過多)한 토양수분(土壤水分) 조건(條件)에 대한 콩 식물체(植物體)의 적응성(適應性)의 하나로 판단(判斷)되며, 우리나라에서 논뚝과 같이 토양수분(土壤水分)이 과다(過多)한 조건(條件)에서 콩의 재배(栽培)가 가능(可能)한 이유(理由) 중(中)의 하나로 보아진다.

• 농촌계획
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• 제8권1호
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• pp.15-25
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• 2002

The study was carried out to investigate the water balance and losses of nutrients from paddy fields during cropping period. The size of paddy fields was 95 ha and the fields were irrigated from a pumping station. The runoff loading was the highest in June because of the high concentrations of nutrients due to applied fertilizer, When the runoff Bosses of nutrients were compared to applied chemical fertilizer, it was found that 39.1 % to 42.5 % of nitrogen lost via runoff while runoff losses of phosphorus account for 14.5 % to 17 % of the total applied amount during cropping period. When the ratio was calculated between nutrients losses by infiltration and the applied of chemical fertilizer, two year results showed 9.1% to 10.8% for nitrogen and 0.5% for phosphorus, respectively.