• 한국농공학회지
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• 제28권3호
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• pp.79-88
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• 1986

Drought occurs most frequently and severely around transplanting season of the rice plants in Korea. Shortage of water due to drought for the paddy fields often delays transplanting, and less often the rice plants are subjected to water stress after delayed transplanting. The present study aimed at quantification of the rice crop loss due to delayed transplanting, different inten3ity of water stress, and the combined effect of delay in transplanting followed by water stress for better use of limited water for irrigation under drought. The rice variety Chucheong, a japonica, and Nampung, an indica x japonica, were grown, transplanted to 1/200 a plastic pots, and subjected to different timing of transplanting and degree of water stress under a rainfall autosersing, sliding clear plastic roof facility with completely randomized arrangement of 5 replications. The results obtained are summarized as follows: 1.Twelve days or 22 days delay in transplanting without water stress reduced rice yield by 25% and 43% in the japonica variety, and by 15% and 60% in the indica x japonica variety. 2.The 10 days or 20 days water stress developed without irrigation after drainage in the rice plants transplanted at proper time lowered the water potential at the paddy soil 10cm deep to -4 bar, and -12 bar and caused rice yield reduction by 14%, and 45% in the japonica variety and by 8%, and 50% in the indica X japonica variety. 3.The 12 days delay in transplanting and 10 days or 20 days water stress reduced rice yield by 39% and 59% in the japonica variety, and by 38% and 52% in the indica x japonica variety. The 22 days delay in transplanting plus 10 days water stress caused yield reduction by 76%, i.e. meaningless yield, in both varieties. 4.The intermittent irrigation just to wet the soil body for 10 days after 10 days water stress without irrigation increased rece yield by 12 to 16% compared to the rice plants water stessed without irrigation continuously for 20 days in both varieties respectively. 5.The above results suggest strongly 1) to transplant the rice plants at proper .time even with some water stress rather than delay for sufficient water from later rainfall, and 2) to distribute insufficient irrigation water to broader area of transplanted rice with limited irrigation for better use of limited irrigation water. A greater sensitivity of japonica variety to a moderate water stress than the indica X japonica variety during initial rooting and tillering stage was noticed. To cope with frequent drought in rice culture, firstly the lasting time of transplanting without yield reduction should be clarified by region and variety, and secondly a scheme of rational distribution of limited water should be developed by region with better knowledge on the varietal distribution of limited water should be developed by region with better knowledge on the varietal responses to varying intensity of water stress.

• 한국수자원학회논문집
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• 제55권2호
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• pp.121-133
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• 2022

기상학적으로 예년 대비 부족한 강우량으로 인해 발생하는 가뭄재해는 피해범위가 광범위하고, 그 발생과 소멸을 쉽게 파악하기 어려운 특징을 가지고 있다. 그렇기 때문에 가뭄 발생예상 지역과 그 물부족량을 신뢰성 있고, 신속하게 예측하는 것은 가뭄 대응체계 구축에서 중요한 요소이다. 하지만, 현재는 과거 약 50여년의 기상관측자료로 그 경우의 수가 제한된다는 문제점이 있다. 그렇기 때문에 과거에 발생한 가뭄과 양상이 다른 경우 가뭄으로 인한 물부족량을 예측하기 어려운 한계점이 있다. 이러한 문제 해결을 위해 본 연구에서는 4개 RCP 시나리오 자료를 물수지 분석 모형에 적용하여 360개년의 연간 물부족량을 산출하였다. 다음으로 다층신경망 모형의 입력값으로 RCP 시나리오로부터 산출된 SPEI 값을 그리고, 출력값으로 연간 물부족량을 적용하여 학습을 진행했다. 학습된 모형을 통해 과거 수 개월 동안의 SPEI값과 미래 예측되는 가뭄 상황을 입력함으로써 쉽고 신뢰성 있게 중권역별 예상 물부족량을 산정할 수 있다. 이는 의사결정자들이 가뭄 발생 이전에 효율적인 가뭄 대응책 수립에 도움이 될 것으로 판단된다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.311-317
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• 1998

Recently irrigation reservoir has been developed to perform multipurpose function. To get a maximum effect it requires to establish optimal management system for irrigation reservoir in drought and flood season. Especially we dealt with optimal flood control system for irrigation reservoir in this study. This system consists of real-time rainfall data via online system, real-time flood forecasted by SCS method in hourly basis, storage volume by water balance equation, optimal releasing discharge from the gate, the water level in right downstream, and calculation of innundated area, depth, and time using GIS, and amount of flood damages. If we consider the relation of these sub module reasonably, we can reach the optimal flood control to minimize flood damage

• 한국환경과학회지
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• 제24권9호
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• pp.1211-1220
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• 2015

Soil is the most important factor in natural environment for bio-diversity. Urbanization and development of city devastate urban soil by the fraternization of green network and run off pollution. In these facts, preservation of soil is the main issue in maintain of quality urban environment. In order to handle this issue, the gold network that link fragment soil patches is considered in maintain quality soil. This study researched the infiltration Treebox design technique based on the Low Impact Development. This technique suggest reduction of impervious area of the soil due to urbanization. The main concept of this study is encourage more permeable surfaces in urban area by using a infiltration planter. The function of the planter is hold run off as much as possible from intensive rainfall, and utilizes it in drought season. Also, this planter provides fertile soil for organism habitat by keeping appropriate moisture supplying.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1232-1237
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• 2009

Recently, we often encounter water shortage problem due to drought during dry season. Although we have built dams and expanded our tap water system greatly to meet the increasing demand of water, this approach has its inherent limitation including environmental destruction in the course of the dam construction. Therefore, this paper is aimed to analyze the water recycling models developed in other countries and modify them to fit into our system. Also the water recycling system in Busan municipal area was analyzed to propose an alternative method for reusing the recycled water from wastewater treatment area.

• Asian-Australasian Journal of Animal Sciences
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• 제9권2호
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• pp.215-221
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• 1996

In the marginal upland areas of East Java, Indonesia, ruminants provide farming households with tradable assets in addition to manure and draught power. Households are interested in acquiring ruminants at an early stage of household development. This paper discusses farmers' access to cattle via sharing arrangements. In these arrangements owners lend animals to other farmers in retum for a share of the offspring or the profits. Livestock owners only entrust cattle to households with prior experience in livestock keeping and sufficient labour. Details of the sharing contracts differ between villages. Changes in cattle numbers and ownership over time are attributed to patterns of the development of village agriculture and the economic development of farming households. Feed shortages in the dry season bring about short-term changes; cattle numbers decline and the proportion of households rearing shared cattle increases. The institution of sharing plays a major role in replenishing herds after periods of severe drought.

• 한국농공학회지
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• 제27권1호
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• pp.71-76
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• 1985

The objectives of this field experiment was to determine and recommend the water requirement for harrow considering the factors of soil class and soil moisture status. Experiment was conducted at the -paddy field of the Office of Rural Development in Chungnam Province. The results of experiment were summarized as follows: 1. Continuous drought day of 10-yr return period in transplanting season was about 25 days and the water content ratios at that point were approximately 20% in clayey-loam soil and 12% in sandy-loam soil irrelevantly to the soil-depth. 2. It was recommended that harrow-water requirement for standard design were approximately 9Omm in clayey-loam soil, 110mm in loamy soil and l3Omm in sandy-loam soil.

• Water Engineering Research
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• 제1권3호
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• pp.243-256
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• 2000

This physically-based hydrologic model is developed to calculate the soil-moisture balance on paddy fields. This model consists of three modules; the first is the unsaturated module, the second is the rice evapotranspiration module with SPAC(soil-plant-atmospheric-continuum), and the third is the groundwater and open channel flows based upon the interrehtionship module. The model simulates the hydrlogical processes of infiltration, soil water storage, deep perocolation or echarge to the shallow water table, transpiration and evaporation from the soil surface and also the interrelationship of the groundwater and river flow exchange. To verify the applicability of the developed model, it was applied to the Kimjae Plains, located in the center of the Dongjin river basin in Korea, during the most serious drought season of 1994. The result shows that the estimated water net requirement was 757mm and the water deficit was about 5.9% in this area in 1994. This model can easily evaluate the irrigated water quantity and visualize the common crop demands and soil moisture conditions.

• 한국농공학회지
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• 제34권1호
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• pp.33-40
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• 1992

Up to now, monthly water balance analysis has been dominantly used for the water resources planning. But, it is more reasonable to explain the variation of spatial and temporal distribution of water by the daily water balance model with daily streamflow data. Since we are recently facing the problems of regional unbalance of water quantity, and of multiuse of irrigation water, and of deterioration of water quality, it is urgently needed to develop the daily water balance model to solve those problems and establish the rational plannings of agricultural water resources. In the circumstances, Daily water Balance(DAWABA) model for irrigation reservoirs was developed and the operation rule of irrigation resorvoir during drought season was established.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2004년도 GIS/RS 공동 춘계학술대회 논문집
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• pp.203-208
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• 2004

NDVI (Normalized Difference Vegetation Index)는 식생의 건강상태 및 농작물 생산량 추정등에 효과적인 식생지수로, 20년 이상 축적된 MOAA NDVI data의 경우, 식생의 시기적, 계절적 변화탐지가 가능해져 이를 바탕으로 한 가뭄지수들이 개발되어 가뭄 모니터링에 사용되어지고 있다 지난 2001년, 한반도는 기상관측 이래 90년만의 강수량 최저치를 기록하여 전국적인 대 가뭄의 피해를 입었으며, 특히 북한은 유엔이 선정한 가뭄에 가장 취약한 국가로 그로 인한 식량난이 더욱 악화되고 있어 가뭄에 대한 정보는 필수적이라 할 수 있다. 이에 본 연구에서는 1994～2002년의 식물 생장기(growing season : 3～10월)동안 NDVI 10일 최대값 합성영상 (10-day maximum composite data)을 사용하여 남북한으로 나누어진 한반도를 대상으로 각각의 식생현황을 파악 및 비교하고, 산림, 농지, 도시지역별로 NDVI와 가뭄의 주원인인 강수량과의 상관관계로 그 효용성을 분석하였다. 그 결과, NDVI는 1～2개월 전 강수량의 영향이 가장 컸으며, 특히 농지지역에서의 상관계수가 높게 나타났다.