• 한국농공학회지
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• 제21권3호
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• pp.83-91
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• 1979

This study was conducted in order to find out the performance of rice transplanters in accordance with the change of the trans-planting days after pudding and the water depth flooding the paddy field at the time of transplanting : and thus to select the optimum paddy field preparation procedures for an efficient utilization of rice transplanters. The performance factors of the two different types of rice transplanters were measured during the first 6 consecutive days after puddling and with 3 different levels of water depth flooding the paddy fields. The results of this study were analysed and summarized as follows : 1. Wheel sinkage decreased very rapidly from 0 to 2 days after puddling and slowly from 3 to 5 days after puddling. 2. The depth of the test cone penetration decreased rapidly during the first few days after puddling. It was 17.8cm just after puddling, and decreased to 13.4cm one day after puddling. After 2 days, the rate of decrease was dampened, and after 5 days it kept constant value of 9.2cm. 3. Two days after puddling, the hill interval was 15.8cm (98.75% of the preset value) for broadcasted seedling rice transplanter with 3cm flooding depth : This value was the closest to the pre-adjusted value of 16cm. The general performance of broadcasted-seedling type rice transplanter was better than that of strip-seedling type rice transplanter. 4. Usually the working performance of a rice transplanter is evaluated with uniformity and adjustability of the hill intervals. The hill interval was the most uniform and closest to the pre-set value of 16cm when planted two days after puddling with 3cm of water depth. When it was inavoidable to plant 4 days after puddling with stripseedling type rice transplanter, it is advisable to let the water flooded somewhat deeper. 5. The percentage of missing hills including floating and burried seedlings was the highest just after puddling and ie decreased substancially until 3 days after puddling and then it increased again. Hence, the optimal time transplanting is to be between 2 and 3 days after puddling. 6. Better postures of planted seedlings were found when planter 2 days after puddling than 3 days after puddling. Six cm of flooding water depth always gave the best results with respect to the postures of planted seedlings. Broadcasted-seedling rice transplanter, in general, showed better posture of planted seedlings than did strip-seedling type rice transplanter. 7. Judging from the above results, the optimal conditions will be 3cm of flooding depth and transplanting between 2 and 3 days after puddling.

• 한국습지학회지
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• 제10권3호
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• pp.37-45
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• 2008

The Philippine government enacted the National Water Crisis Act in 1995, as a response to the burgeoning situation of water supply systems in the country. This act led to the privatization of Metropolitan Waterworks and Sewerage System (MWSS), sector having jurisdiction and control over all waterworks and sewerage systems in a service area including Metro Manila. Nowadays, the region's supply of water is still facing a lot of difficulties, both in quality and quantity. The unabated migration of people to the metro which increases its population, tapping from the aged pipelines, lack of water facilities and infrastructure, excessive groundwater withdrawal, environmental degradation, and surface and groundwater pollution are some of the issues that Metro Manila have to deal with. These situations lead to two primary water supply issues suffered by Metro Manila: water shortage and flooding. The purpose of this paper was to present water supply in Metro Manila with respect to the problems in its distribution, environmental implications and quality. In this paper, several technical reports, published literature, and news articles were consulted and became the major basis for identifying gaps and suggesting remedial measures.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.126-126
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• 2021

Stormwater reduction plays an important role in the safety and resilience to flooding in urban areas. Due to rapid climate change, the world is experiencing abnormal climate phenomena, and sudden floods and concentrated torrential rains are frequently occurring in urban basins and the amount of outflow due to stormwater increases. In addition, the damage caused by urban flooding and inundation due to extreme rainfall exceeding the events that occurred in the past increases. To solve this problem, water supply, drainage, and water supply for sustainable urban development, the water management paradigm is shifting from sewage maintenance to water circulation and water-sensitive cities. So, in this study, The purpose of this study is to examine measures to increase the resilience of urban ecosystem systems for urban excellence reduction by analyzing the effects of green infra structures and LID techniques and evaluating changes in resilience. In this study, for simulating and analysis of runoff for various stormwater patterns and LID applications, Storm Water Management Model (SWMM) was used.

• 농업과학연구
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• 제49권4호
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• pp.871-879
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• 2022

An increasing global population requires a greater food supply, and accordingly there is demand for enhanced production of rice, as a major crop plant that covers half of the world's population. Rice production in arid area is extremely difficult due to poor soil fertility, salinity, deficit of irrigation water, and weather conditions. The aim of the present study was to determine whether various fertilization recipes could provide a countermeasure to allow rice production while also providing soil amendment such as soil pH adjustment. The study was conducted at an experimental field of the United Arab-Emirates (UAE) from January to April, 2022. Rice seedlings (cv. Asemi, alkaline-resistant) were transplanted in plastic containers, and different types of water and nutrient managements were employed as follows: water management (flooding and aerobic for NPKs treatment group) and nutrient management (NPKs, slow release fertilizers [SRFs] and SRFs + NPK-1 treatment groups with flooding). Water and nutrient management did not show any effect on soil pH adjustment. Rice growth was significantly enhanced in the flooding compared to the aerobic condition, whereas the effect of nutrient management clearly differed among the treatment groups, with SRFs + NPK-1 showing the best results followed by SRFs and NPKs. Most of the fertilization groups markedly accumulated soluble sugars in the shoots and grains of rice plants, but concomitantly a decrease in the roots. Overall, the level of starch showed a tendency of relatively slight perturbation by fertilization. Taken together, the results indicate that soil physical structure should be preferentially amended to find the key for suitable rice production.

• 한국토양비료학회지
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• 제49권1호
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• pp.36-43
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• 2016

With transient flooding followed by poor or slow drainage plant roots may become reduction conditions because the root zone was fully filled with water. This study was examined the effects of calcium treatment in the early growth stage on biochemical changes in leaves and roots of melon (Cucumis melo L.) seedlings kept under flooding condition for 72 h. The activities of lactate dehydrogenase more gradually enhanced in the roots than those of leaves of melon seedlings treated with calcium. The activities of alcohol dehydrogenase associated with alcohol fermentation under low oxygen conditions continuously increased in the leaves and roots of seedlings untreated with calcium under flooding at least 72 h but those was constant within at least 12 h in treated with calcium. These results showed that calcium supplying in the early growth stage mitigated alcohol fermentation of melon seedlings kept under flooding condition for 72 h. Activities of nitrate reductase and acid phosphatase in the leaves and roots of seedlings in treated with calcium somewhat higher than those of non-treated with calcium. The activities of sucrose phosphate synthase and fructose-1,6-bisphosphatase of leaves of seedlings in treated with calcium more higher than those of non-treated with calcium. These results indicated that calcium nutrition mitigate the reduction of activities of some enzymes of melon seedling kept under flooding condition for 72 h.

• 한국물환경학회지
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• 제22권5호
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• pp.887-894
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• 2006

Water quality in the Daecheong reservoir has been deteriorated by algal bloom every year. Algal bloom is propagated from eutrophicated tributary into the main body of the reservoir during the wet season. Nutrients from diffuse sources trigger the propagation of the algal bloom. This study is aimed to analyze relationship between the water current by the simulation and algae transport from the main body in the Daecheong reservoir including tributary where algal bloom has occurred seriously every year. Water quality model CE-QUAL-W2 was applied to analyze water movement in draught season (2001) and flooding season (2003). The result of simulation corresponded with the observed water elevation level, 63~80 m and showed stratification of the Daecheong reservoir. In the draught season, as velocity and direction off low in the reservoir was estimated to affect algae transport including nutrient supply from small tributary, algal blooms occurred in the stagnate zone of middle stream of the reservoir. On the other hand, in the flooding season, it was resulted in nutrient transport from upstream of main reservoir and nutrients were delivered up to downstream by fast water velocity. In result, algal blooms occurred in stagnate zone of reservoir downstream as the current of downstream was retarded according to dam outflow control.

• 한국지리정보학회지
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• 제23권1호
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• pp.51-64
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• 2020

본 연구의 목적은 위성강우와 글로벌 지형자료를 이용하여 미계측 지역에 있는 홍수터에서의 홍수를 정량적으로 분석하기 위한 방법을 제시하는 것이다. 이를 위해서 두만강의 도문/남양 지역 홍수터에 대한 범람을 모의하고 대상 지역의 침수 상황을 정량적으로 분석하였다. 강우는 위성영상으로부터 유도된 강우 자료인 IMERG 자료를 이용하였다. 유출모의는 GRM 모델을 적용하였으며, 도문/남양 지역의 범람해석은 G2D 모델을 이용하였다. 홍수사상은 2016년 8월 태풍 라이언록으로 인해 발생된 홍수를 대상으로 하였다. 유출모의 결과의 검증은 도문/남양 지역의 첨두유량 기록을 사용하였으며, 범람해석 결과의 검증은 현지답사를 통해 수집된 홍수상황과 홍수 전후의 위성영상 자료를 이용하였다. 연구결과 유출모의 첨두유량은 7,639㎥/s로 기록된 첨두유량 7,630㎥/s와 약 0.1%의 상대오차를 나타내었다. 범람모의에서는 홍수발생 당시에 대한 상황 조사 자료 및 위성영상에서 확인된 침수 범위와 유사한 결과를 얻을 수 있었다. 또한 도문/남양 지역의 홍수터에서 침수심의 변화와 침수시간을 평가할 수 있었다. 본 연구에서 적용한 방법과 연구결과는 향후 미계측 지역에서의 홍수를 정량적으로 평가할 때 유용하게 활용될 수 있을 것이다.

• 한국수자원학회논문집
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• 제47권11호
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• pp.1051-1060
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• 2014

본 연구에서는 분산 메모리환경 병렬프로그래밍 모델의 표준인 MPI (Message Passing Interface) 기법과 침수해석 모형인 DHM(Diffusion Hydrodynamic Model) 모형을 연계하여 침수모형을 병렬화하고 기존의 기법으로 복잡하고 장시간의 계산시간을 요구하였던 계산에 대해 향상된 계산 성능을 구현하고자 하였다. 개발된 모형을 다양한 침수 시나리오를 바탕으로 가상유역과 실제유역에 대하여 코어 개수별로 모의함으로써 제내지 침수에 따른 침수범위 및 침수위의 추정, 및 계산시간 단축 효과를 입증 하고 병렬기법에 대한 홍수해석 분야의 적용성을 입증하고자 하였다. 본 연구에서 개발된 모형의 검증을 위하여 2차원 가상 제내지 및 실제 침수 사례에 대하여 적용하였고, 적용결과 동일한 정확도를 기준으로 계산시간 면에서 단일 코어와 비교하여 멀티코어를 사용한 경우 약 41~48%의 개선효과가 나타나는 것을 확인하였다. 본 연구에서 개발된 병렬해석 기법을 이용한 침수해석 모형은 멀티코어를 적용하여 짧은 계산시간으로 침수심, 침수구역, 홍수파 전달속도 등이 계산 가능하여, 실제 홍수 발생 시 침수지역에서의 신속한 예측 및 대처, 홍수위험지도 구축 등에 유용하게 이용될 수 있을 것으로 기대된다.

• Weed & Turfgrass Science
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• 제7권3호
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• pp.171-179
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• 2018

국내에서 수집되어 농업유전자원센터에 기탁된 잡초성벼 유전자원 중 100점을 이용하여 토양 매몰 깊이, 담수 처리 깊이 및 기간, 생육 온도에 따른 출현율을 분석하고 출현하지 못하고 토양 속에 존재하는 종자를 회수하여 종자 상태를 분석하였다. 토양 매몰 깊이가 1 cm로 얕을 시 담수 깊이 5 cm 및 10 cm 처리에서 출현율이 각각 54, 57% 감소하였으며, 토양 매몰 깊이가 5 cm 깊어지면서 담수 처리에 따른 출현율 감소는 담수 5 cm, 10 cm에서 66, 84%로 크게 증가하였다. 잡초성벼 유전자원 별 담수 처리에 따른 출현율 변화를 분석한 결과, 토양매몰깊이 1 cm 및 담수 깊이 5 cm에서는 대부분의 유전자원이 60% 이하의 출현율을 보였으며, 토양매몰깊이 5 cm 및 담수 깊이 5 cm에서는 출현율은 크게 감소하여 94%의 유전자원이 10%이하의 출현율을 나타내었다. 출현이 완료된 뒤 출현하지 않고 토양 속에 남아있는 종자를 회수하여 종자 상태를 분석한 결과, 토양 매몰 깊이가 5 cm 일 시, 담수 처리에 의해 발아는 하였지만 출현하지 못하는 비율이 증가한 반면 죽거나 소멸된 종자의 비율은 감소하였다. 생육 온도를 달리하여 담수 처리 기간 동안의 유효 적산 온도에 따른 종자의 변화를 분석한 결과, 출현율은 유효 적산 온도와 유의한 상관관계를 보이지 않았으나 종자 사멸율 및 발아/미출현율은 유효 적산온도에 따라 증가, 감소하는 경향이었다. 담수 처리에 따른 출현율 변화는 담수 처리 온도 보다는 담수 처리 기간에 따른 차이가 컸으며 담수 처리 기간이 21일 이상일 시 출현율이 크게 감소하였다.

• 한국농공학회지
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• 제44권3호
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• pp.146-156
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• 2002

The objective of this study was to develop a modified CREAMS model for paddy field conditions. The model simulates daily balance of water and nutrient from irrigated paddies using meteorological, irrigation, and agricultural management data. The model simulates daily evapotranspiration of paddy using Penman equation and determines daily flooding depth changes. Total nitrogen and phosphorus concentrations within flooding water, surface runoff, and leaching water from a paddy field also can be simulated. Parameters of the model were calibrated using observed data of the Agricultural Experiment Station of the Seoul National University in Suwon Korea. The model was applied for the irrigation period of paddy field in Gicheon area when 1,234 mm annual rainfall was occurred. The simulated losses of the total nitrogen and total phosphorous were 11.27 kg/ha and 0.98 kg/ha, respectively. There was a good agreement between observed and simulated data. It was found that CREAMS-PADDY model was capable of predicting runoff and nutrient losses from irrigated paddy fields.