• 농업과학연구
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• 제26권2호
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• pp.77-93
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• 1999

This study is aiming at identifying the foreward and backward lingkage effects of the farm land base development project. Korean Government has continuously carried out farmland base development projets including the integrated agricultural development projects. large and medium scale irrigation projects and the comprehensive development of the four big river basin including tidal land reclamation and estuary dam construction for the all weather farming since 1962. the starting year of the five year economic development plans. Consequently the irrigation rate of paddy fields in Korea reached to 75% in 1998 and to escalate the irrigation rate, the Government had procured heavy investment fund from IBRD. IMF and OECF etc. To cope with the agricultural problems like trade liberalization in accordance with WTO policy, the government has tried to solve such problems as new farmland base development policy, preservation of the farmland and expansion of farmland to meet self-sufficiency of foods in the future. Especially, farmland base development projects have been challanged to environmental and ecological problems in evaluating economic benefits and costs where the value of non-market goods have not been included in those. Up to data, in evaluating benefits and costs of the projects, farmland base development projects have been confined to direct incremental value of farm products and it's related costs. Therefore the projects'efficiency as a decision making criteria has shown the low level of economic efficiencies. In estimating economic efficiencies including Leontiefs input-output analysis of the projects could not be founded in Korea at present. Accordingly this study is aimed at achieving and identifying the following objectives. (1) To identify the problems related to the financial supports of the Government in implementing the proposed projects. (2) To estimated backward and foreward linkage effects of the proposed project from the view point of national economy as a whole. To achieve the objectives, Hwangrak benefited area with reservoir which is located in Seosan-haemi Disticts, Chungnam Province were selected as a case study. The main results of the study are summarized as follows : a. The present value of investment and O & M cost were amounted to 3,510million won and the present value of the value added in related industries was estimated at 5.913million won for the period of economic life of 70 years. b. The total discounted value of farm products in the concerned industries derived by the project was estimated at 10,495million won and the foreward and backward linkage effects of the project were amounted to 6,760 and 5,126million won respectively. c. The total number of employment opportunities derived from the related industries for the period of project life were 3,136 man/year. d. Farmland base development projects were showed that the backward linkage effects estimated by index of the sensitivity dispersion were larger than the forward linkage effect estimated by index of the power of dispersion. On the other hand, the forward linkage effect of rice production value during project life was larger than the backward linkage effect e. The rate of creation of new job opportunity by means of implementing civil engineering works were shown high in itself rather than any other fields. and the linkage effects of production of the project investment were mainly derived from the metal and non-metal fields. f. According to the industrial linkage effect analysis, farmland base development projects were identified economically feasible from the view point of national economy as a whole even though the economic efficiencies of the project was outstandingly decreased owing to delaying construction period and increasing project costs.

• 한국관개배수논문집
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• 제18권2호
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• pp.3-14
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• 2011

Increased impervious surfaces alter stream hydrology resulting in lower flows during droughts and higher peak flows during floods. Not only urban area but also rural area has been expanded impervious surfaces because of increasing of greenhouses. The main objective of this study was to evaluate the performance of the AnnAGNPS (Annualized Non-Point Source Pollution Model) on the surface runoff characteristics of the Daejeon-Stream watershed, and to predict the hydrological effects due to increasing of impervious surfaces. The model parameters were obtained from the geographical information system (GIS) databases, and additional parameters calibrated with the observed data. The model was calibrated by using 2004 of the runoff data and validated by using 2002 data obtained from WAMIS (Water Management Information System) to compare the simulated results for the study watershed. R2 values and efficiency index (EI) between observed and simulated runoff were 0.78 and 0.80, respectively at the calibration period. In this study, expanding of impervious surfaces such as greenhouses caused increasing of surface runoff, but caused decreasing of total nitrogen and total phosphorus loads.

• 한국농공학회논문집
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• 제50권4호
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• pp.17-24
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• 2008

Exposure risk assessment of pesticide molinate using the RICEWQ model in a rice paddy plot was performed to observe the effects of various water and pesticide management scenarios. Several scenarios were developed to represent the specific water and pesticide management practices of rice cultivation in Korea. The results of the scenario analysis using the RICEWQ model simulation from the previous studies were analysed. The molinate risk for aquatic organisms is evaluated by the ratio of the predicted environmental concentration(PEC) and the predicted no-effect concentration(PNEC). The results showed that the no-effect periods for aquatic organisms for the deep, shallow and very shallow irrigation conditions were 33.3, 28.9 and 25.6 DATs for the lable rate application and 36.4, 33.7 and 30.8 DATs for the double lable rate application, respectively. The higher application rate showed greater exposure risk to the aquatic organisms. Based on this study, the withholding period of molinate practiced in Korea, that is 3 to 4 DATs, must be much longer. The results of this study can be used for the non-point source pollution control and environmental policy making regarding pesticides.

• 한국물환경학회지
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• 제21권2호
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• pp.141-146
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• 2005

The aim of this study is to quantify and characterize the dissolved organic carbon (DOC) from paddy fields and crop fields in Tottori, Japan. DOC and ultraviolet (UV) absorption were measured in the filtrated water of each sample. The DOC concentration and the SUVA (specific UV absorption) of biodegradation analysis samples were determined around 50 days after their incubation. In the Fukui paddy fields, DOC concentration varied seasonally from 1.1 to $10.1mg\;Cl^{-1}$, becoming higher during heavy runoffs in April, a non-agriculture period. Variations in DOC concentration did not always correspond to rainfall, though. The Obadake paddy fields showed a DOC concentration pattern similar to that of the Fukui paddy fields. The daily DOC discharge per area in the Fukui (up), Fukui (down), Obadake (south) and Obadake (north) paddy fields influent from paddy fields were 0.02, 0.0161, 0.0135 and $0.0027kg\;a^{-1}day^{-1}$, respectively. These differences resulted from differences in agricultural types and customs of farmers according to paddy fields and other kinds of fields. Also, the SUVAs [which are indirect means to evaluate humic substances (hydrophobic fractions)] of the studied influent waters from paddy fields were generally lower than those of the influent waters from crop fields. Nonbiodegradable DOC accounted for 50.2 - 98% and 46.8 - 85.5% of the total DOC in the paddy fields and in the crop fields, respectively.

• 한국농공학회지
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• 제16권4호
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• pp.3555-3571
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• 1974

This experiment of which aim contribute to plan irrigation system so as to increase forage crop yields, was conducted to estimate evapotranspiration amount of forage crops and to find out system of consumed water in a pasture-ground. The results obtained by this study are as follows: 1. The general weather conditions which, were closely related to the evapotrannpiration of forage crops were nearly same as those of the average year with the exception that temperature of May and June were slightly low. 2. According to the investigation of potential evapotranspirations (P.E) or forage crops and its changes during growing periods, changes of tenday P.E. were high significant according to the harvesting period. P.E of Alfalfa of which yield was the largest was the biggest. Althrough the correlations between P.E. and meteorological factors were irregular oming to three-time harvesting, correlation between ten-day evapotraspiration amount and copper plated pan evaporation or solar radiation was high positive significant. 4. Predicting formulas of P.E. were led by weather factors, and also relatione between P.E. and weather factors were showed as figure. from the these formulas, P.E. may be calculated by weather factors. 5. Predicting formulas of P.E. were led by mean temperature and copper plated pan evaporation, and by mean temperature and solar radiation. As computed values and measured values showed in figure, these formulas were high signiflent. 6. In the total consumed soil water duration of 10 days which, was non-rain period from 12th to 21th of August, Alfalfa was the largest 48.1mm, second, Orchard grass 40.1mm and Fescue 37.6mm, and Ladino clover was the smallest 37.1mm, also, order of each forage crop yield amound. was same to the abov. Order of soil moisture extraction rate of soil layer of all the for forage crops dulation of ten-day was soil layer 1 which was largest, soil layer 2, 3, and 4 Reviewing the the first five-day and the second five day, in the first five-day, order of that of all the forage crops was same to the above, but in the second five-day, that of soil layer 2 or 3 was more than the of soil layer 1.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2017년도 학술발표회
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• pp.424-424
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• 2017

Several studies of the world have analyzed the regional rainfall trends in large data sets. However, it reported that the long-term behavior of rainfall was different on spatial and temporal scales. The objective of this study is to determine the local trends of rainfall indices in the Yom River Basin, Thailand. The rainfall indices consist of the annual total precipitation (PRCTPOP), number of heavy rainfall days ($R_{10}$), number of very heavy rainfall days ($R_{20}$), consecutive of dry days (CDD), consecutive of wet days (CWD), daily maximum rainfall ($R_{x1}$), five-days maximum rainfall ($R_{x5}$), and total of annual rainy day ($R_{annual}$). The rainfall data from twelve hydrological stations during the period 1965-2015 were used to analysis rainfall trend. The Mann-Kendall test, which is non-parametric test was adopted to detect trend at 95 percent confident level. The results of these data were found that there is only one station an increasing significantly trend in PRCTPOP index. CWD, which the index is expresses longest annual wet days, was exhibited significant negative trend in three locations. Meanwhile, the significant positive trend of CDD that represents longest annual dry spell was exhibited four locations. Three out of thirteen stations had significant decreasing trend in $R_{annual}$ index. In contrast, there is a station statistically significant increasing trend. The analysis of $R_{x1}$ was showed a station significant decreasing trend at located in the middle of basin, while the $R_{x5}$ of the most locations an insignificant decreasing trend. The heavy rainfall index indicated significant decreasing trend in two rainfall stations, whereas was not notice the increase or decrease trends in very heavy rainfall index. The results of this study suggest that the trend signal in the Yom River Basin in the half twentieth century showed the decreasing tendency in both of intensity and frequency of rainfall.

• 생물환경조절학회지
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• 제21권4호
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• pp.385-391
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• 2012

국내에서 육성된 딸기 품종인 '매향' 및 '설향'을 대상으로 비가림 포트 육묘 시 런너의 절단 시기에 따른 자묘의 생육과 정식 후 수량을 2작기(2009년 및 2010년)에 걸쳐 검토하였다. 자묘는 정식일(2009년 9월 11일 및 2010년 9월 10일)을 기준으로 30일, 20일, 10일 및 5일 전에 모주로부터 런너를 절단하였다. 런너의 절단 시기가 늦을수록 모주에서 양수분이 육묘 후기까지 자묘로 공급되어 지상부 생체중, 관부직경 및 엽록소 함량은 증가하는 경향을 보였다. 반면에 근중 등 지하부 생육은 런너의 절단 시기가 빨라서 모주로부터 자묘의 독립 기간이 길수록 증가하였다. 모주에서 런너를 절단한 경우의 관수 요구량이 런너를 절단하지 않은 처리구에 비하여 29.7% 증가하였다. 또한, 런너를 절단하였을 경우에 런너를 통하여 탄저병이 침입한 경우가 런너를 절단하지 않은 처리구에 비하여 37.6% 높게 나타났다. 정식 후 정화방의 출뢰 및 개화 개시기는 런너 절단 시기가 늦을 경우 2~3일까지 지연되었으나 런너 절단 시기에 따른 조기 수량의 차이가 없으므로 런너 절단 시기를 정식일의 5~10일 전인 8월 하순 이후로 늦추어 실시하는 것이 탄저병 발생 경감 측면에서는 유리한 것으로 생각된다.

• 한국유기농업학회지
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• 제6권1호
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• pp.133-149
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• 1997

Recently, the importance of management and cultivation of grasses has been increased in Korea. Among these cultural practices, the appropriate control of diseases is considered more important than other cultivation techniques such as fertilization and irrigation. The damages of brown patch and large patch caused by Rhizoctonia spp. and Pythium blight caused by Pythium spp. are serious in the major cultivation area of turfgrass in Korea. Since these diseases are difficult to control by agrochemicals, the damages are very serious if these are occured. The periodic spray of agrochemicals, to protect and control these diseases could make some problems of toxicity and environmental pollution as well as rising of non-target diseases. Therefore, the biological methods to control diseases have been required to decrease problems resulted from overuse of agrochemicals, to conserve natural ecosystem, and to control effectively diseases of grasses in the long period. The number of studies about biological control using antagonistic microorganisms have been increased for last half century. However, the application of biological control method has been very limited. In this study, thirteen isolates of R. cerealis, 8 isolates of R. solani and 3 isolates of Phthyn spp. have been isolated from diseased turfgrass in golf course and grass-culture area that have patch and wilting symptoms of zoysia grass and creeping bentgrass. Isolation frequency of R. cerealis and R. solani was high in especially zoysiagrass, while Pythym spp. was isolated from bent grass at low frequency but showed high pathogenicity. Totally, 205 isolates of soil microorganisms were isolated in this study as primary antagonistic microorganism by Herr's triple agar layer plate and dual culture method using rhizosphere of grasses, soil of crop field as the source of antagonistic microorganisms. Among the 205 isolates, 23 isolates were actinomycetes and 182 isolates were bacteria. All of the actinomycetes were isolated by Herr's method. Antagonistic effect of primary isolated microorganisms was tested for in vitro mycelial growth inhibition against pathogenic fungi isolated from grasses and for inhibition of disease occurrence in 24 well tissue culture plate and pot experiment. Then, four isolated of bacteria which are BG23, BG74, BG136 and BG171 were selected as antagonistic microorganisms against soil-born pathogenic fungi of bentgrass.

• 농업과학연구
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• 제32권2호
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• pp.107-126
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• 2005

The most limited production resource in Korea is land. During the period from 1995 to 2002, annual farm land area of 17,600ha have been converted to urban and industrial land. The self-sufficiency rate of rice, Korean staple food, is expected to be decreased from 97.5% in 2003 to 60-70% in 2020. Under such conditions, this study is aimed at first identifying multi-functional benefits of the reclamation projects such as agricultural production, industrial water supply, urban land supply, transportation effects, sightseeing effects and environmental values with and without the projects. To carry out the objectives, three existing tideland reclamation projects such as Daeho, Kumgang and Yongsangang irrigation project stage II were evaluated and Saemangeum tideland reclamation project which was jointly revaluated by environmental NGO and Govn't appointed specialists in 2000 was reviewed. According to this study results, tide land reclamation projects were showed financially and economically feasible and environmentally sustainable. The joint cost like estuary dam should be allocated based on the multi-functional benefits of the projects. To allocate the joint cost, legal and institutional improvement should adapt the joint cost allocation method as the specific cost-remaining benefit method. Korea has more than 402,000 ha of tidal flat of which 76,396ha have been reclaimed in 2003. To meet food security and to cope with shortage of land, phil-environmental reclamation projects should be continuously implemented and necessary tidal flats for protecting environmental ecosystem should be remained according to the detail survey results of reclaimable resources.

• 한국토양비료학회지
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• 제40권1호
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• pp.18-24
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• 2007

본 연구는 1999년 5월부터 2002년까지 광역 논에서 영농기간 동안 비점원오염의 유출부하량을 산정하기 위하여 수행되었다. 시험유역은 전북 남원시 금지면 금풍지구에 위치한 115 ha(논 면적 95 ha)의 양수장 관개 논에서 수문 및 수질 모니터링을 실시하였다. 시험유역의 물수지를 산정한 결과, 연도별 유입량은 1999년 2,410 mm, 2000년 2,486 mm, 2001년 2,938 mm, 2002년 2,880 mm로 4개년 평균 유입량은 2,680 mm로 조사되었으며, 유출량은 1999년 2,416 mm, 2000년 2,533 mm, 2001년 3,070 mm, 2002년 2,983 mm로 4개년 평균 유출량은 2,750 mm로 조사되었다. 물수지에 있어 유출량이 유입량보다 크게 나타났는데, 이는 양수장에서 관개를 실시하지 않을 경우 지하수 관개를 실시하는 논들이 있어 이들 지하수 관개량의 미측정에 의해 물수지의 차이가 있는 것으로 판단된다. T-N과 T-P를 대상으로 4개년동안 물질수지를 조사한 결과, 영농기간 영양물질의 평균 유입량은 화학비료에 의해 T-N $124.8kg\;ha^{-1}$, T-P $15.8kg\;ha^{-1}$, 강우에 의해 T-N $26.9kg\;ha^{-1}$, T-P $0.35kg\;ha^{-1}$, 관개수에 의해 T-N $50.4kg\;ha^{-1}$, T-P $0.48kg\;ha^{-1}$가 유입된 것으로 조사되었다. 영농기간 동안 유출수에 의한 영양물질의 유출량은 T-N의 경우 $53.4{\sim}68.3kg\;ha^{-1}$, T-P의 경우는 $1.38{\sim}2.20kg\;ha^{-1}$로 나타났다. 논에서 적절한 물관리를 통해 유출수를 최소화하면 영양물질 손실의 경감, 농업용수 사용의 경감을 통한 수자원 확보, 그리고 하천의 수질보전에 기여할 것으로 판단된다. 향후 비점원오염에 관한 연구는 다양한 영농조건에 대해 장기적이고 꾸준한 연구가 수행되어야 할 것으로 판단된다.