• Title/Summary/Keyword: 작업여건

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Effective Geophysical Methods in Detecting Subsurface Caves: On the Case of Manjang Cave, Cheju Island (지하 동굴 탐지에 효율적인 지구물리탐사기법 연구: 제주도 만장굴을 대상으로)

  • Kwon, Byung-Doo;Lee, Heui-Soon;Lee, Gyu-Ho;Rim, Hyoung-Rea;Oh, Seok-Hoon
    • Journal of the Korean earth science society
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    • v.21 no.4
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    • pp.408-422
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    • 2000
  • Multiple geophysical methods were applied over the Manjang cave area in Cheju Island to compare and contrast the effectiveness of each method for exploration of underground cavities. The used methods are gravity, magnetic, electrical resistivity and GPR(Ground Pentrating Radar) survey, of which instruments are portable and operations are relatively economical. We have chosen seven survey lines and applied appropriate multiple surveys depending on the field conditions. In the case of magnetic method. two-dimensional grid-type surveys were carried out to cover the survey area. The geophysical survey results reveal the characteristic responses of each method relatively well. Among the applied methods, the electric resistivity methods appeared to be the most effective ones in detecting the Manjang Cave and surrounding miscellaneous cavities. Especially, on the inverted resistivity section obtained from the dipole-dipole array data, the two-dimensional distribution of high resistivity cavities are revealed well. The gravity and magnetic data are contaminated easily by various noises and do not show the definitive responses enough to locate and delineate the Manjang cave. But they provide useful information in verifying the dipole-dipole resistivity survey results. The grid-type 2-D magnetic survey data show the trend of cave development well, and it may be used as a reconnaissance regional survey for determining survey lines for further detailed explorations. The GPR data show very sensitive response to the various shallow volcanic structures such as thin spaces between lava flows and small cavities, so we cannot identify the response of the main cave. Although each geophysical method provides its own useful information, the integrated interpretation of multiple survey data is most effective for investigation of the underground caves.

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대구지역 대기환경용량평가에 관한 연구

  • Choe, Geun-Sik;Kim, Hae-Dong
    • 한국지구과학회:학술대회논문집
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    • 2010.04a
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    • pp.90-91
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    • 2010
  • 우리나라는 산업화와 도시화의 급속한 발전으로 인한 대기오염물질배출시설, 자동차 통행량, 에너지 사용량의 증가 등으로 대기오염물질배출원의 수와 규모가 증대되어 광역도시를 중심으로 대기질이 악화되고 있다. 특히 우리나라의 수도권대기질은 선진국의 주요 도시에 비해 대기오염 상태가 좋지 않은 것으로 평가됨에 따라 정부는 대기질을 OECD선진국 수준으로 개선한다는 목표를 세우고 있으나, 지역의 대기상태 및 그 동안의 대기질 개선을 위해 이행된 정책의 효율성 측면에서 볼 때 사후적인 규제위주의 농도규제 방식으로는 급증하는 대기오염배출시설의 배출량총량 관리가 어렵고, 지자체별로 개별적인 분산관리로는 광역적으로 이동되는 대기오염물질의 관리가 불가능하다. 또한 대기오염과 상관성이 큰 에너지정책, 산업정책, 도시계획 등 관련 정책과의 통합적 접근이 어렵기 때문에 사전에 이를 예방하는 총량관리가 요구되어 진다. 총량규제란 특정지역의 기상, 지형조건 등을 이용하여 대기환경용량을 산출하고 이를 기초로 지역별 배출허용총량을 할당하여 궁극적으로는 오염원별로 대상오염물질의 삭감량을 정하는 제도로 선진국에서는 대기환경용량을 바탕으로 1970년대부터 사업장을 중심으로 배출농도 규제와 함께 총량규제를 병행 실시하고 있으며, 최근에는 자동차에도 실시하고 있다. 우리나라에서도 대기환경보전법 제9조에서 환경기준을 초과하여 사람의 건강이나 재산, 동식물의 생육에 중대한 위해를 가져올 우려가 있다고 인정되는 경우에는 동 지역 또는 특별대책지역 중 사업장이 밀집되어 있는 구역에 대하여 배출되는 오염물질을 총량으로 규제할 수 있도록 규정하고 있다. 또한, 환경부는 2003년도에 서울, 인천, 경기도내 19개시 지역을 대상으로 대기오염물질의 배출총량을 관리하는 대기오염총량제 실시를 포함한 '수도권대기질개선에관한특별법'을 제정하였고, 현재는 사업장에게 연도별 배출허용총량을 할당하고, 할당량 이내로 오염물질을 배출하도록 관리하는 사업장 대기오염물질총량관리 제도로 시행 중에 있다. 그러나 수도권대기질개선특별대책을 수립하면서 총량관리의 본격 이행 및 배출권 거래제도 도입에 대한 특별법안이 제정되고 부분적으로 시행되고 있으나, 우리나라에 총량관리를 본격 이행하는데 있어서의 필요한 준비여건은 아직 초기 단계이고, 관련 연구의 수행실적 또한 수도권에 제한되어 적은 편이다. 따라서 현재는 총량관리가 수도권에 국한하여 실시되고 있으나, 점차 타 도시까지 광역적으로 확대될 것으로 예상되는 바 이에 필요한 제반 사항들에 대한 조사 분석을 통하여 정책방향을 설정하는 더 많은 연구가 필요할 것이다. 이러한 배경에서 본 연구에서는 대구지역을 대상으로 대기오염농도 및 대기오염물질 배출량에 대한 현황조사를 실시하고, 이를 토대로 고농도가 자주 발생되거나 그러할 가능성이 높은 $NO_X$을 대상으로 대기오염기여도를 평가하고 대기확산모델을 통한 대기환경용량을 산정하였다. 대기오염농도 현황을 살펴본 결과, 대구지역의 대기오염은 $NO_2$, $SO_2$, CO는 전형적인 1차오염물질의 변화경향을 보였으며, $PM_{10}$는 봄철에 황사의 영향을 크게 받는 것으로 나타나 실제 대구지역에서 배출되는 양을 추정하기 힘든 것으로 판단된다. 또한 $NO_2$는 공업, 상업지역에서 $SO_2$$PM_{10}$는 공업지역, CO는 상업지역, $O_3$은 교외지역에서 높은 농도를 나타내는 것으로 파악되었다. 대구지역의 대기오염물질 배출량 현황은 CO가 47%, NOX가 43%로 전체 배출량의 90%를 차지하였고, 2005년 이후 $NO_X$는 감소하고 $SO_X$가 증가하는 추세이다. 또한 배출원대분류 중도로 및 비도로이동오염원에서 발생되는 선 오염원이 75%로 대구지역에서 가장 크게 기여하는 것으로 나타났다. ISCST3 대기확산모델을 이용하여 대기환경용량을 산정하기위하여, 먼저 대구지역의 대기환경용량평가는 가시적인 위해성이 높고 개선정책이 용이한 $NO_X$을 대상물질로 선정하였고, 배출량과 오염농도간의 상관도가 0.659로 높은 것으로 판단되어, 배출량을 삭감하였을 때 대기오염농도의 개선이 명확히 나타나는 것을 알 수 있었다. 다음으로, 단위격자 당 한계배출율을 알아내는 작업을 실시하여, 대구지역을 동일하게 장기환경기준 80%수준인 22.4ppb를 만족시키기 위한 한계배출율은 2.23g/s가 필요한 것으로 파악되었고, 산출한 한계배출율을 이용하여 장기환경기준치 80%수준 달성을 목표로 하는 경우의 대기환경용량을 산정하고 실제 배출량과 비교 분석하였다. 그 결과, 대구지역 전체의 환경용량은 약 3만 톤으로 실제 배출량 2만2천 톤에 약 8천 톤 이상의 여유가 있는 것으로 파악되었다. 그러나 구역별로 상이한 차이를 보였으며, 이에 따른 구역별 개선정책이 필요할 것으로 사료된다. 대기환경용량을 파악한 후 단위격자 당 한계배출율을 초과하는 대상 지역을 추출하여 삭감한 결과 초과배출량의 80%를 삭감해야 대구지역 전체에서 50ppb이하 농도가 되는 것을 알 수 있었는데, 실제로 초과배출량의 80%를 삭감하는 것은 어려움이 있다고 판단되어, 대구지역을 동일한 %율로 삭감한 결과 30% 삭감했을 때 50ppb수준을 달성하였고, 50%삭감했을때 2007년 환경기준인 30ppb수준을 달성하였다. 또한 배출원대분류 중 기여율이 높은 도로와 비도로오염원을 50%삭감한 결과 도로이동오염원의 삭감만으로도 상당한 고 배출지역의 농도저감에 효과가 있는 것으로 파악되고, 비도로오염원을 포함하여 삭감하였을 때는 대구지역 전체에서 50ppb이하로 내려가는 것을 볼 수 있었다. 따라서 향후 총량규제의 실시에 맞추어 대구지역의 실제적인 환경용량의 정확한 파악과 고배출지역에 대한 삭감방법에 관한 더 많은 연구가 필요하다고 사료된다. 이 연구 결과는 앞으로 시행될 지역총량규제에 대한 기초적인 방법론으로 활용될 수 있을 것이다.

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Environmental Condition for the Butt-Rot of Conifers by Cauliflower Mushroom (Sparassis crispa) and Wood Quality of Larix kaempferi Damaged by the Fungus (꽃송이버섯에 의한 침엽수 심재부후 발생환경 및 낙엽송 피해목의 재질 특성)

  • Park, Hyun;Oh, Deuk-Sil;Ka, Kang Hyeon;Ryu, Sung-Ryul;Park, Joo-Saeng;Hwang, Jaehong;Park, Jun-Mo
    • Journal of Korean Society of Forest Science
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    • v.98 no.1
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    • pp.16-25
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    • 2009
  • Cauliflower mushroom (Sparassis crispa) is recently recognized as a new edible and/or medicinal mushroom cultivated with conifers. By the way, the mushroom is notorious as a brown-rot fungus that causes a buttrot of larch. So, there should be a careful consideration to apply the mushroom cultivation in coniferous stand. This study was conducted to clarify the seriousness of heartwood decay on conifers such as larch by cauliflower mushroom with surveying the mushroom producing environment and to examine whether the cultivation of cauliflower mushroom produce any problem in conifer stands or not. The mushroom occurred in various coniferous stands such as Larix kaempferi, Pinus koraiensis, P. densiflora and Abies holophylla on fertile soils with adequate moisture. Soil texture of the mushroom producing site was comparatively fine compared to general forest soils; sandy loam, loam and silty loam. Soil pH ranged from 4.6 to 5.2, and organic matter contents were 4~11%, which showed relatively wide range. We could find S. crispa by a DNA technique from the wood that seemed to have no heartwood decay by naked eyes. The damaged wood showed 30% higher moisture contents than that of sound wood, while the compressive strength was 30% lowered down compared to that of sound wood. The fungus may invade conifers through the scars occurred on roots or stems, in this case spore dispersion of the mushroom takes a great role. Thus, we concluded that forest tending activities need to be applied with considering the invasion of S. crispa, and cultivation of cauliflower mushroom in forest should be attempted very carefully. By the way, we also infer that conifer stands can be nurtured without heartwood decay by S. crispa if the stand be managed in good aeration conditions by proper silvicultural practices such as sanitary thinning.

Key Methodologies to Effective Site-specific Accessment in Contaminated Soils : A Review (오염토양의 효과적 현장조사에 대한 주요 방법론의 검토)

  • Chung, Doug-Young
    • Korean Journal of Soil Science and Fertilizer
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    • v.32 no.4
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    • pp.383-397
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    • 1999
  • For sites to be investigated, the results of such an investigation can be used in determining foals for cleanup, quantifying risks, determining acceptable and unacceptable risk, and developing cleanup plans t hat do not cause unnecessary delays in the redevelopment and reuse of the property. To do this, it is essential that an appropriately detailed study of the site be performed to identify the cause, nature, and extent of contamination and the possible threats to the environment or to any people living or working nearby through the analysis of samples of soil and soil gas, groundwater, surface water, and sediment. The migration pathways of contaminants also are examined during this phase. Key aspects of cost-effective site assessment to help standardize and accelerate the evaluation of contaminated soils at sites are to provide a simple step-by-step methodology for environmental science/engineering professionals to calculate risk-based, site-specific soil levels for contaminants in soil. Its use may significantly reduce the time it takes to complete soil investigations and cleanup actions at some sites, as well as improve the consistency of these actions across the nation. To achieve the effective site assessment, it requires the criteria for choosing the type of standard and setting the magnitude of the standard come from different sources, depending on many factors including the nature of the contamination. A general scheme for site-specific assessment consists of sequential Phase I, II, and III, which is defined by workplan and soil screening levels. Phase I are conducted to identify and confirm a site's recognized environmental conditions resulting from past actions. If a Phase 1 identifies potential hazardous substances, a Phase II is usually conducted to confirm the absence, or presence and extent, of contamination. Phase II involve the collection and analysis of samples. And Phase III is to remediate the contaminated soils determined by Phase I and Phase II. However, important factors in determining whether a assessment standard is site-specific and suitable are (1) the spatial extent of the sampling and the size of the sample area; (2) the number of samples taken: (3) the strategy of taking samples: and (4) the way the data are analyzed. Although selected methods are recommended, application of quantitative methods is directed by users having prior training or experience for the dynamic site investigation process.

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Optimal Operation of Gas Engine for Biogas Plant in Sewage Treatment Plant (하수처리장 바이오가스 플랜트의 가스엔진 최적 운영 방안)

  • Kim, Gill Jung;Kim, Lae Hyun
    • Journal of Energy Engineering
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    • v.28 no.2
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    • pp.18-35
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    • 2019
  • The Korea District Heating Corporation operates a gas engine generator with a capacity of $4500m^3 /day$ of biogas generated from the sewage treatment plant of the Nanji Water Recycling Center and 1,500 kW. However, the actual operation experience of the biogas power plant is insufficient, and due to lack of accumulated technology and know-how, frequent breakdown and stoppage of the gas engine causes a lot of economic loss. Therefore, it is necessary to prepare technical fundamental measures for stable operation of the power plant In this study, a series of process problems of the gas engine plant using the biogas generated in the sewage treatment plant of the Nanji Water Recovery Center were identified and the optimization of the actual operation was made by minimizing the problems in each step. In order to purify the gas, which is the main cause of the failure stop, the conditions for establishing the quality standard of the adsorption capacity of the activated carbon were established through the analysis of the components and the adsorption test for the active carbon being used at present. In addition, the system was applied to actual operation by applying standards for replacement cycle of activated carbon to minimize impurities, strengthening measurement period of hydrogen sulfide, localization of activated carbon, and strengthening and improving the operation standards of the plant. As a result, the operating performance of gas engine # 1 was increased by 530% and the operation of the second engine was increased by 250%. In addition, improvement of vent line equipment has reduced work process and increased normal operation time and operation rate. In terms of economic efficiency, it also showed a sales increase of KRW 77,000 / year. By applying the strengthening and improvement measures of operating standards, it is possible to reduce the stoppage of the biogas plant, increase the utilization rate, It is judged to be an operational plan.

Introduction of the International Standardization of ISO in the Production and Quality of Herbal Medicines and a Review of Countermeasures (한약재 생산 및 품질부문의 ISO국제표준화 등재현황 소개 및 대응방안 고찰)

  • Kim, Yong Il;Kang, Young Min;Han, Sin-Hee;Hur, Mok;Kim, Young Guk;Chang, Jae Ki
    • Journal of the Korean Society of International Agriculture
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    • v.30 no.4
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    • pp.257-268
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    • 2018
  • Recently, the international standardization of ISO in the field of Oriental Herbal Medicine has been progressing rapidly under the direction of China's promotion. China's intention to promote international standardization is to extend its influence to the world and beyond the domestic market. The Oriental medicine system in East Asia has similar roots in academic terms, but the medicines that can be supplied and received in each country are different and have developed independently. The international standardization of medicinal herbs is expected to function in a direction that weakens such differentiation and independence. From a commercial point of view, international standardization is no different from creating evaluation criteria for oriental medicinal products, and it is expected that its potential impact on domestic and overseas markets and producers will be large. In particular, the international standardization centered on China can lead to favorable evaluation criteria for China, which may further negatively affect the market competitiveness of domestic raw materials, which have been pushed back by Chinese manufacturers. If the domestic production base is weakened, not only will the farmers suffer but the supply and demand of raw materials will also be manipulated, safety management control will be reduced, and the development of oriental herbal products using domestic raw materials will be hurt. Therefore, in the promotion of international standardization, it is necessary not only to reflect the value of Korean herbal medicine but also to provide strategic responses to protect the domestic production base. However, in the case of recent initiatives, there is no precedent in analyzing influence on the production partners and the related industries. In addition, there are few related papers and reports on the subject, so the publicity process has not been done sufficiently. In response to this, this study will examine the countermeasures against the international standardization of herbal medicines through reviewing its present status and evaluating the agenda of the Korean initiative.

Report on Extended Leak-Off Test Conducted During Drilling Large Diameter Borehole (국내 대구경 시추공 굴진 중 Extended Leak-Off Test 수행 사례 보고)

  • Jo, Yeonguk;Song, Yoonho;Park, Sehyeok;Kim, Myung Sun;Park, In-Hwa;Lee, Changhyun
    • Tunnel and Underground Space
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    • v.32 no.5
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    • pp.285-297
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    • 2022
  • We report results of Extended Leak-Off Test (XLOT) conducted in a large diameter borehole, which is drilled for installation of deep borehole geophysical monitoring system to monitor micro-earthquakes and fault behavior of major fault zones in the southeastern Korean Peninsula. The borehole was planned to secure a final diameter of 200 mm (or more) at a depth of ~1 km, with 12" diameter wellbore to intermediate depths, and 7-7/8" (~200 mm) to the bottom hole depth. We drilled first the 12" borehole to approximately 504 m deep and installed American Petroleum Institute standard 8-5/8" casing, then annulus between the casing and bedrock was fully cemented. XLOT was carried out for several purposes such as confirming casing and cementing integrity, measuring rock stress states. To that end, we drilled additional 4 m long open hole interval to directly inject water and pressurize into the rock mass using the upper API casings. During the XLOT, flow rates and interval pressures were recorded in real time. Based on the logs we tried to analyze hydraulic conductivity of the test interval.

A Study on Forestation for Landscaping around the Lakes in the Upper Watersheds of North Han River (북한강상류수계(北漢江上流水系)의 호수단지주변삼림(湖水団地周辺森林)의 풍경적시업(風景的施業)에 관(関)한 연구(硏究))

  • Ho, Ul Yeong
    • Journal of Korean Society of Forest Science
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    • v.54 no.1
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    • pp.1-24
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    • 1981
  • Kangweon-Do is rich in sightseeing resources. There are three sightseeing areas;first, mountain area including Seolak and Ohdae National Parks, and chiak Provincial Park; second eastern coastal area; third lake area including the watersheds of North Han River. In this paper, several methods of forestation were studied for landscaping the North Han River watersheds centering around Chounchon. In Chunchon lake complex, there are four lakes; Uiam, Chunchon, Soyang and Paro from down to upper stream. The total surface area of the above four lakes is $14.4km^2$ the total pondage of them 4,155 million $m^3$, the total generation of electric power of them 410 thousand Kw, and the total forest area bordering on them $1,208km^2$. The bordering forest consists of planned management forest ($745km^2$) and non-planned management forest ($463km^2$). The latter is divided into green belt zone, natural conservation area, and protection forest. The forest in green belt amounts to $177km^2$ and centers around the 10km radios from Chunchon. The forest in natural conservation area amounts to $165km^2$, which is established within 2km sight range from the Soyang-lake sides. Protection forest surrounding the lakes is $121km^2$ There are many scenic places, recreation gardens, cultural goods and ruins in this lake complex, which are the same good tourist resources as lakes and forest. The forest encirelng the lakes has the poor average growing stock of $15m^3/ha$, because 70% of the forest consists of the young plantation of 1 to 2 age class. The ration of the needle-leaved forest, the broad-leaved forest and the mixed forest in 35:37:28. From the standpoint of ownership, the forest consists of national forest (36%), provincial forest (14%), Gun forest (5%) and private forest(45%). The greater part of the forest soil, originated from granite and gneiss, is much liable to weathering. Because the surface soil is mostly sterile, the fertilization for improving the soil quality is strongly urged. Considering the above-mentioned, the forestation methods for improving landscape of the North Han River Watersheds are suggested as follows: 1) The mature-stage forest should be induced by means of fertilizing and tendering, as the forest in this area is the young plantation with poor soil. 2) The bare land should be afforested by planting the rapid growing species, such as rigida pine, alder, and etc. 3) The bare land in the canyon with moderate moist and comparatively rich soil should be planted with Korean-pine, larch, ro fir. 4) Japaness-pine stand should be changed into Korean-pine, fir, spruce or hemlock stand from ravine to top gradually, because the Japanese-pine has poor capacity of water conservation and great liability to pine gall midge. 5) Present hard-wood forest, consisting of miscellaneous trees comparatively less valuable from the point of wood quality and scenerity, should be change into oak, maple, fraxinus-rhynchophylla, birch or juglan stand which is comparatively more valuable. 6) In the mountain foot within the sight-range, stands should be established with such species as cherry, weeping willow, white poplar, machilus, maiden-hair tree, juniper, chestnut or apricot. 7) The regeneration of some broad-leaved forests should be induced to the middle forest type, leading to the harmonious arrangement of the two storied forest and the coppice. 8) For the preservation of scenery, the reproduction of the soft-wood forest should be done under the selection method or the shelter-wood system. 9) Mixed forest should be regenerated under the middle forest system with upper needle-leaved forest and lower broad-leaved forest. In brief, the nature's mysteriousness should be conserved by combining the womanly elegance of the lakes and the manly grandeur of the forest.

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Policy Direction for The Farmland Sizing Suitable to Regional Trait (지역특성을 반영한 영농규모화사업의 발전방향-충남지역을 중심으로-)

  • Shim, Jae-Sung
    • The Journal of Natural Sciences
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    • v.14 no.1
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    • pp.83-121
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    • 2004
  • This study was carried out to examine how solid the production foundation of rice in Chung-Nam Province is, and, if not, to probe alternative measures through the size of farms specializing in rice, of which direction would be a pivot of rice industry-oriented policy. The results obtained can be summarized as follows : 1. The amount of rice production in Chung-Nam Province is highest in Korea and the size of paddy field area is the second largest : This implying that the probability that rice production in Chung-Nam Province would be severely influenced by a global trend of market conditions. The number of farms specializing in rice becoming the core group of rice farming account for 7.7 percent of the total number of farm household in Korea. Average field area financial support which had been input to farm household by Government had a noticeable effect on the improvement of the policy of farm-size program. 2. Farm-size program in Chung-Nam Province established from 1980 to 2002 in creased the cultivation size of paddy field to 19,484 hectares, and this program enhanced the buying and selling of farmland and the number of farmland bargain reached 6,431 household and 16,517 hectares, respectively, in 1995-2002. Meanwhile, long-term letting and hiring of farmland appeared so active that the bargain acreage reached 6,970 hectares, and farm involved was 7,059 households, however, the farm-exchange-and-unity program did not satisfy our expectation, because the retirement farm operators reluctantly participated to sell their farms. Another reason that had delayed the bargain of farms rested on the general category of social complication attendant upon the exchange and unity operation for scattered farm. Such difficulties would work negative effects out to carry on the target of farm-size work in general. 3. The following measures were presented to propel the farm-size promotion program : a. Occupation shift project, followed by the social security program for retirement and elderly farm operators, should be promptly established and also a number of types of incentives for promoting the letting and hiring work and farm-exchange-and-unity program would also be set up. b. To establish the effective key system of rice production, all the farm operators should increase the unit area yield of rice and lower the production cost. To do so, a great deal of production teams of rice equipped with managerial techniques and capabilities need to be organized. And, also, there should be appropriate arrays of facilities including information system. This plan is desirable to be in line with a diversity of the structural implement of regional integration based on farm system building. c. To extend the size of farm and to improve farm management, we have to devise the enlargement of individual size of farm for maximized management and the utilization of farm-size grouping method. In conclusion, it can be said that the farm-size project in Chung-Nam Province which has continued since the 1980s was satisfactorily achieved. However, we still have a lot of problems to be solved to break down the barrier for attainment of the desirable farm-size operation work.. Farm-size project has fairly close relation with farm specialization in rice and, thus, the positive support for farm household including the integrated program for both retirement farmers and off-farm operators should be considered to pursue the progressive development of the farm-size program, which is key means to successful achievement of rice farming enforcement in Chung-Nam Province.

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