• Journal of Ginseng Research
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• 제13권1호
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• pp.105-113
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• 1989

This study was conducted to determine the cause of the occurence of marginal leaf chlorosis in ginseng plants (Panax ginseng C.A. Meyer), and to determine its emersion in fields (practically) and in pots (experimentally). The following results were obtained. In the Present investigation, ginseng plants raised in acidic soil containing a high a moue t of Mn showed marginal leaf chlorosis. Henre it Ivas suggested that the shoot growth and root weights became grad gractually lower. The leaves having marginal leaf chlorosis contained low amounts of N, P,. Ca, Mg, and Na and the Fe/Mn ratios were low. There was a corresponding increase in Mn uptake. It was founrl that in soils where marginal leaf chlorisis occured the pH urar brlolv 4.2 to 4.9 and the Ca, Mg and Na content was decreased thus effectively increasing the available manganese in the soil. The Mn/Fe ratios in the yellow leaf margins of ginseng Plants affected by the Mn toxicity was over 2.0 compared to the general Mn/Fe ratio of 0.50 for healthily leaves, stems and roots. Typically when ginseng plants grow fields having soil with a pH below about 5.0, there tenor to be an uptake of excess Mn. When ginseng plants are grown in a nutrient sand culture solution It with an increased Mn concentration, they accumulate large amounts of Mn in the roots and in the shoots. In both casts marginal leaf chlorosis appeared in the emersions. In the Present investigation, ginseng plants raised in acidic soil and containing a high amount of Mn showed marginal leaf chlorosis.

• 한국환경복원기술학회지
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• 제19권1호
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• pp.73-83
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• 2016

Forest degradation reduces ecosystem services provided by forest and could lead to change in composition of species. In North Korea, there has been significant forest degradation due to conversion of forest into terrace fields for food production and cut-down of forest for fuel woods. This study analyzed the phenological changes in North Korea, in terms of vegetation and moisture in soil and vegetation, from March to Octorber 2013, using MODIS (MODerate resolution Imaging Spectroradiometer) images and indexes including NDVI (Normalized Difference Vegetation Index), NDSI (Normalized Difference Soil Index), and NDWI (Normalized Difference Water Index). In addition, marginal farmland was derived using elevation data. Lastly, degraded terrace fields of 16 degree was analyzed using NDVI, NDSI, and NDWI indexes, and marginal farmland characteristics with slope variable. The accuracy value of land cover classification, which shows the difference between the observation and analyzed value, was 84.9% and Kappa value was 0.82. The highest accuracy value was from agricultural (paddy, field) and forest area. Terrace fields were easily identified using slope data form agricultural field. Use of NDVI, NDSI, and NDWI is more effective in distinguishing deforested terrace field from agricultural area. NDVI only shows vegetation difference whereas NDSI classifies soil moisture values and NDWI classifies abandoned agricultural fields based on moisture values. The method used in this study allowed more effective identification of deforested terrace fields, which visually illustrates forest degradation problem in North Korea.

• 복식
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• 제60권9호
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• pp.95-105
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• 2010

The purpose of this study is in allowing thinking about the design development process which is more towards the visual and perceptional aspects related to the form structure by more diverse methods by typology of idea generation. To accomplish such goal, researches in the psychology, pedagogy, engineering, and consilient studies as well as related precedent researches and reference data in architecture, promotion, industrial design, and other art fields and fashion designs are collected and analyzed to see the study trend. In addition, in the content analysis method based on such, the idea generation was classified into types in consideration of relevancy, usefulness, and suitability with fashion. First, a concentrated thinking of a limited space is a method of leading an optimal design by focusing on solving the cause of a problem within a space which generates the problem. Second, plan thinking per section of structure decomposition is a method of dismantling the design problems per organization, thinking type, factor, and characteristic into sub-modules to re-interpret and re-organize the problems in various aspects. Third, an associated thinking through interpreting relationships among vocabularies is a method of selecting the marginal languages that allow a person to come up with concrete forms and the key words related to fashion to import the characteristics and attributes of the marginal languages and thematic relationship between the two terms to search the relevancy. Lastly, the free integrated thinking of language extension is a method of groping integration between other fields and fashion by free integration among the extended terms by extending the vocabularies through inferring metaphorical expressions founded upon individual's memories or knowledge concepts regarding theme words that do not allow concrete forms to come up.

• 한국작물학회지
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• 제61권2호
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• pp.104-112
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• 2016

A double-cropping system with soybean (Glycine max) following the cultivation of potato, garlic, and onion is widely adopted in the southern region of Korea. For this system, marginal dates for planting must be determined for profitable soybean yields, because the decision to plant soybean as a second crop is occasionally delayed by harvest of the first crop and weather conditions. In order to investigate the effect of planting date on soybean yield, three cultivars (early and late maturity) were planted on seven different dates from May 1 to July 30 in both paddy and upland fields across 2012 and 2013. Soybean yields were significantly different among the planting dates and the cultivars; however, the interaction between cultivar and planting date was not significant. Based on linear regression, the maximum yield of soybean was reached with a June 10 planting date, with a sharp decline in yield for crops planted after this date. The results of this study were consistent with those of a previous one that recommends early and mid-June as the optimum planting period. Regardless of soybean ecotype, a reduction in yield of greater than 20% occurred when soybean was planted after mid-July. Frost during soybean growth can reduce yields, and the late maturity cultivars planted on July 30 were damaged by frost before completing maturation and harvest; however, early maturity cultivars were safely harvested. For sufficient time to develop and reach profitable yields, the planting of soybean before mid-July is recommended.

• 농업과학연구
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• 제31권1호
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• pp.53-75
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• 2004

This study is aimed at identifying the national economic value of the irrigation facilities by reviewing the existing papers on economic values of the irrigation facilities and presenting current status of dual O & M problems of the irrigation facilities. This study suggested the unified O & M system rather than continuing the existing dual O & M system of irrigation facilities based on the surveyed results of the activities of irrigation fraternities in Chungnam Province. The findings and proposals for the successful unified and mono O & M system of the irrigation facilities are as follows: (1) Total number of irrigation facilities in the nation accounts for 67,582, while the total length of irrigation and drainage canals amounted to about 174,259km. On account of the total length of structural canals was estimated at 31%, much losses of water and much O & M costs have been inevitable for the full irrigation rice culture. In spite of the past heavy investment for irrigation facilities, the ratio of rain-fed and partially irrigated paddy fields accounts for 23% in 2003. Both Korea Agricultural and Rural Infrastructure Corporation (KARICO) and the city and Gun Governments have managed the irrigation facilities separately by irrigation fraternities. The KARICO have commanded 59% of irrigation paddy area with 18% of the total irrigation facilities, while the city and Gun governments covered 41% of irrigation paddy area with 82% of the existing number of irrigation facilities representing small and medium scale. (2) The 1999 demand prices of irrigation water per ton expressed in 2000 constant market price was estimated at 388 won, the supply price was amounted to 184 won per ton. Considering the supply and demand curve of the irrigation water, the existing irrigation facilities could not satisfy the demand of irrigation water. (3) In 1999, total present added value of the irrigation facilities during the economic life accounted for 48 trillion won, while total supply cost was 44.7 trillion won. The marginal benefit and cost ratio of irrigation water was 1.08. (4) The total O & M cost per year amounting to 681.1 billion won have been required to maintain and repair the existing irrigation facilities in Korea. For the successful unified O & M of irrigation facilities covering whole irrigated paddy field in Korea, 950 billion won of O & M costs are required to keep up the marginal benefit of irrigation water as 2,800 billion won per year. The total O & M cost as 950 billion won should be allocated 40%, 380 billion won for O & M costs of irrigation facilities and 60%, 570 billion won for improvement of irrigation facilities. (5) The study investigated and reviewed the present O & M status of the irrigation facilities by small and medium irrigation fraternities. Most of the farmers belong to the irrigation fraternities preferred not only unified O & M but also KARICO take-over of the whole O & M activities of the irrigation facilities. The prevailing O & M cost per 10a expended by the Corporation was amounted to 104,890 won, while that of city and Gun governments was only amounted to 4,600 won per 10a. regarding the small amount of O & M cost expended by city and Gun governments, it is evident that the existing irrigation system have been managed ineffectively and deteriorated the facilities comparing that of KARICO. In conclusion, the Government could not satisfied the demand of irrigation water by suppling water with existing irrigation facilities. Therefore new additional investment and financial support for irrigation water development should be made to convert rain-fed and partially irrigated paddy fields into fully irrigated ones. The operation and maintenance cost should be supported to keep the marginal values of rice production of existing irrigation facilities in the national economy and to modernize the obsolete irrigation facilities. By unifying the existing dual O & M systems, all the farmers belong to the irrigated paddy fields have to be equally benefited and could be increased their farm income and be stabilized their rural lives.

• 한국지반공학회논문집
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• 제27권10호
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• pp.93-104
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• 2011

본 연구에서는 댐이나 보와 같은 수리구조물이 설치된 포화 기초지반에서의 구속흐름(confined flow)에 대하여 확률론적 침투해석을 수행하였다. 침투해석은 유한요소법을 이용하였으며 투수계수의 수평방향과 연직방향의 공간적 상관성이 상이한 비등방성을 고려하였다. 지정된 입력 확률분포함수와 자기상관함수(autocorrelation function)를 따르는 2차원의 랜덤필드를 생성하기 위하여 Karhunen-Lo$\grave{e}$ve 전개법을 사용하였으며 생성된 랜덤필드를 이용하여 확률론적 응답을 얻기 위해 Monte Carlo 시뮬레이션을 수행하였다. 이로부터 투수계수의 불확실성과 공간적 변동성이 수리구조물과 기초의 침투로 인한 안정성과 관련된 기초를 통한 유량, 구조물 하부에 작용하는 양압력, 하류 유출면에서의 유출동수경사에 미치는 영향을 연구하였다. 해석결과로부터 투수계수의 확률분포와 자기상관 구조를 만족하는 랜덤필드로 고려하여 공간적 변동을 고려하는 방법은 결정론적 해석이나 투수계수를 하나의 랜덤변수로 고려하는 경우에 나타나지 않는 다양한 지반의 침투거동을 효과적으로 고려할 수 있음을 보여준다.

• 한국지반공학회논문집
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• 제28권12호
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• pp.65-76
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• 2012

본 연구에서는 수리구조물이 설치된 2층으로 이루어진 포화 기초지반에서의 구속흐름(confined flow)에 대하여 확률론적 침투해석을 수행하였다. 투수계수는 지반의 층상구조에 따라 명확한 변동성을 보일 뿐 아니라 각각의 층 내에서도 공간적인 변동성을 보인다. 따라서 기존의 결정론적 침투해석기법을 층상지반에서의 투수계수의 불확실성과 공간적 변동성을 고려할 수 있도록 확률론적 해석으로 확장하였다. 각 층에 지정된 입력 확률분포함수와 자기상관함수(autocorrelation function)를 따르는 2차원의 랜덤필드를 생성하기 위하여 Karhunen-Lo$\grave{e}$ve 전개법을 사용하였다. 제안된 절차의 적용성을 검토하고 수리구조물 하부의 2층 지반을 통한 흐름에 공간적 불균질성이 미치는 영향을 연구하기 위해 생성된 랜덤필드를 이용하여 Monte Carlo 시뮬레이션을 수행하였다. 해석결과는 층상지반에서의 침투거동 평가에서 지반의 층상구조와 지층내에서의 투수계수의 공간적 변동성에 의한 지반에서의 다양한 침투패턴을 확률론적 해석기법을 통하여 효율적으로 고려할 수 있음을 보여주었다.

• 한국지반공학회논문집
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• 제25권12호
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• pp.13-25
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• 2009

본 연구에서는 확률론적 해석에 지반의 공간적 변동성을 고려하기 위한 해석 절차를 제시하였다. 제안된 방법은 한계평형법을 이용하는 결정론적 해석방법을 지반정수의 불확실성과 공간적 변동성을 고려할 수 있도록 확률론적 사면안정 해석으로 확장한다. 개발된 방법은 랜덤유한요소해석법과 같이 미리 임계파괴면을 가정하지 않으면서도 계산시간을 단축할 수 있다는 장점이 있다. 지정된 입력 확률분포함수와 자기상관함수를 따르는 2차원의 랜덤필드를 생성하기 위하여 Karhunen-Lo$\grave{e}$ve 전개법을 사용하였으며, 생성된 랜덤필드를 이용하여 확률론적 응답을 얻기 위해 Monte Carlo 시뮬레이션을 수행하였다. 개발된 해석기법의 적용성을 검토하고 지반정수의 공간적 변화가 확률론적 안정해석에 미치는 영향을 검토하기 위해 예제해석을 수행하였으며, 해석결과는 제안된 방법이 지반물성의 공간적 변동성에 따른 다양한 사면파괴 형태를 확률론적 사면안정 해석에 효과적으로 고려할 수 있음을 보여준다.

• 한국지반공학회논문집
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• 제24권8호
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• pp.111-123
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• 2008

지반공학 문제는 많은 불확실한 요인을 내포한다. 이러한 불확실성 중 일부는 해석 수행과정에 필요한 지반 물성의 변동성과 관련이 있다. 본 연구에서는 지반물성의 공간적 변동성을 고려한 확률론적 해석을 수행할 수 있는 절차를 제시하였다. 제시된 방법은 유한차분 해석기법과 랜덤필드 이론을 확률론적 해석기법에 통합하게 된다. 지정된 입력 확률분포함수와 자기상관함수를 따르는 non-Gaussian 랜덤필드를 생성하기 위하여 Karhunen-$Lo{\grave{e}}ve$ 전개법을 사용하였다. 생성된 랜덤필드를 이용하여 확률론적 응답을 얻기 위해 Monte Carlo 시뮬레이션을 수행하였다. 지반의 공간적인 변동성에 기인하는 불확실성의 효과를 연구하기 위하여 대상 기초의 침하량과 지지력에 대한 일련의 해석을 수행하였다. 해석결과는 지반공학 문제에서 불확실성을 고려할 수 있는 관점을 제시하며 확률론적 평가의 결과에 미치는 지반물성의 공간적 변동성의 중요성을 보여준다.

• 한국산림과학회지
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• 제97권5호
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• pp.492-500
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• 2008

Since vegetation significantly influences on soil carbon and nutrient storage, vegetation change has been focused on terrestrial carbon and nutrient cycling studies. In this study we investigated soil carbon and major nutrient capitals at the abandoned fields, which had different vegetation composition: a three year abandoned field ($AGR_3$), two ten years abandoned fields ($PD_{10}$ dominant with Pinus densiflora and Fraxinus rhynchophylla and $PM_{10}$ dominant with Populus maximowiczii), and an over sixty years forest ($FOR_{60}$). which were located at Hongcheon-gun, Kangwon-do, South Korea. Both main effects for organic matter (%) were significant: shallow soil > deep soil and $FOR_{60}=PM_{10}$ > $AGR_3=PD_{10}$. Nitrogen concentrations at $PM_{10}$ were the highest, while the lowest at $PD_{10}$. Available phosphorus concentrations were the highest at $PD_{10}$, which were over 10 times of site $FOR_{60}$ and $AGR_3$ at 0-10 cm soil depth. The average organic matter ($173Mg\;ha^{-1}$) and nitrogen contents ($10Mg\;ha^{-1}$) of $PM_{10}$ and $FOR_{60}$ were higher than those of $AGR_3$ and $PD_{10}$ by 57% and 42%, respectively. The available phosphorus contents above 30 cm mineral soil at $PD_{10}$ ($3.8Mg\;ha^{-1}$) and $PM_{10}$ ($1.3Mg\;ha^{-1}$) were over 120 times and 40 times more than at $FOR_{60}$. Calcium ($3.7Mg\;ha^{-1}$) and magnesium contents ($2.8Mg\;ha^{-1}$) at $FOR_{60}$ were twice or three times higher than at other sites. Organic matter amounts in 0-10 cm and 10-30 em soil had significant positive relationships with nitrogen, calcium, and magnesium contents, but not available phosphorus and potassium contents. This study could not identify the effect of chronological factor and vegetation composition on soil carbon and nutrient capital owing to diverse topography as well as limited study sites. However, this study suggests the accuracy of investigation for regional carbon and nutrient sequestration can be achieved by considering the period of abandoned time on the fields and the land use types. These results may suggest the benefits of forest restoration for soil carbon and nutrient accumulation in marginal agricultural lands in South Korea.