• Title/Summary/Keyword: Field slopes

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Development and Verification of Eco-hybrid Rolling Mat for Preventing Bank Erosion Based on Large-scale Experiments (실규모 하천 실험을 통한 하안침식 방지 Eco-hybrid 롤링매트 공법 개발 및 검증)

  • Ji, Un;Jang, Eun-Kyung;Ahn, Myeonghui;Kim, Won
    • Ecology and Resilient Infrastructure
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    • v.6 no.4
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    • pp.217-226
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    • 2019
  • Optimum engineering methods for bank protection were classified based on steepness of bank slope and an existence of waterfront facility in the floodplain, and a new concept of eco-hybrid rolling mat method which could be applicable for the unfitted cases with previously developed countermeasures was suggested in this study. The eco-hybrid rolling mat method can be constructed while maintaining the river environment and ecosystem that does not interfere with the ground and slopes, when bank erosion occurs, it is an economical and efficient construction method that can protect the revetment and the bank slope immediately. The developed eco-hybrid rolling mat method was verified for the designed structure, system, function and effect based on large-scale river experiments including field exposure and decomposition test. As a result, the normal operation and effect of the rolling mat ted under low and high velocity conditions were confirmed with respect to bank protection. The effect of bank erosion prevention was quantitatively validated by sediment concentration monitoring and analysis, and the product specification of the eco-hybrid rolling mat was presented based on the standardized mat applied in real-scale tests.

Environmental and Ecological Characteristics of Pulsatilla tongkangensis Habitats (동강할미꽃 자생지의 환경 및 생태적 특성)

  • Yoo, Ki-Oug;Cheon, Kyeong-Sik;Jang, Su-Kil
    • Korean Journal of Environment and Ecology
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    • v.23 no.5
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    • pp.439-446
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    • 2009
  • This is a study intended to investigate the environmental factors including vegetation and soil in order to better understand the environmental and ecological characteristics of four different habitats of Pulsatilla tongkangensis(Mt. Baekun, Maha-ri, Kyulam-ri and Mt. Deokhang). These habitats, according to investigations, are mostly located on the slopes of mountains facing northwest at an altitude of 220m to 772m above sea level with angles of inclination ranging from 41 degree to 85 degree. A total of 27 vascular plant taxa are identified in ten quadrates of the four habitats. The importance value of these plants is as follows: Pulsatilla tongkangensis is 9.65%; Carex humilis var. nana 28.93%; Potentilla dickinsii 16.55%; Mukdenia rossii 7.09%; Peucedanum terebinthaceum and Eragrostis ferruginea 4.55%; and Vicia venosa var. albiflora 3.90%. The importance value of these six species is high, so they are at affinity with P. tongkangensis m their habitats. The degree of their average species diversity is 0.75, and that of dominance and evenness 0.24 and 0.85, respectively. Their average field capacity of soil is 19.05%, organic matter 10.51%, and soil pH is 7.43, which are similar among their habitats.

A geographical study of the Korean Tobacoo forming region (韓國 煙草載培地域의 地理學的 硏究)

  • ;Kim, Kwang Ja
    • Journal of the Korean Geographical Society
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    • v.21
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    • pp.16-37
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    • 1980
  • The purpose of this study is to clarify how the Korean tobacco farming region has been geographically formed by natural and cultural environments, and to examine and cultural environments, and to examine whether it can be recognized as a major part of agricultultural regions. The questions asked in this study are associated with the spatial diffusion of tobacco cultivation, the patterns and processes of the farming region from 1900 to 1960, and the regional characteristics of the concentrated farming area since 1960. The study is inductively approached and most data used were collected from old records and field works. The delineation of the tobacco farming region was derived by applying the concept of the uniform region. Tobacco was introduced through Japan during the years of Kwang Hae Kun (1616-1622). According to the old records, three places, Waekwan, Dongrae, and Ulsan, were the first tobacco raising areas. In the 1700's the well-known tobacco farming regions were scattered all around the nation in places like Jinan, Samdeung, Seongcheon, Gangdong, Yeongweol and Yeongyang. This distributon pattern suggests that tobacco farming in Korea developed spatially along main traffic routes before the 1700's. Untill the 1920's the pattern of tobacco regions was relatively static. Since the 1920's, it has shown a pattern of concentration in the Choongbuk province, where the new highly productive yellow tobacco has been introduced. It was not until the 1960's that yellow tobacco instead of the native variety came to be cultivated all over the country. In the 1960's, the tobacco farming region tended to be concentrated and localized in north western Choongnam, northern Cheonbuk, Choongbuk, and Kyeongbuk including Cheongsong, Andong, and Yeongyang. Since 1970, tobacco production has declined in some of the former major areas of cultivation in terms of its density, while there have appeared highly concentrated areas in Cheongsong and Andong, centered around Yeongyand. There has also emerged a secondary major concentrated area along the coast including such places as Kochang, Yeongkwang and Mooan. The appearance of the Yeongyang tobacco area as the most important core region can be described as follows; at first this area has the disadvantage of being in competition with other places for selling cash crops besides tobacco, because it is located in a mountain zone and it is far from the major metropolises of Seoul and Pusan. Thus has been formed the farming mentality that agricultural management makes the most profit on farming tobacco because tobacco is stable in price and selling routes. As a result of this longstanding belief, these areas (Yeongyang, Cheongsong and Andong) have developed into tobacco concentrated regions. Finally, the tobacco concentrated regions of Korea have changed through time. The factors affecting this change have been the kind of tobacco grown, the monopoly system, agricultural techniques and the expansion of arable land through the clearing of slopes. In conclusion, the research indicates that the localized and concentrated patterns of tobacco cultivation are geographically typical. Thus, recognition of tobacco farming region is important to understanding the agricultural region of Korea as a whole.

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Analysis of the Propagation Characteristics of Blast Vibrations in Pasir Coal Mine (파시르 탄광에서의 발파진동의 전파특성 분석)

  • Choi, Byung-Hee;Ryu, Dong-Woo;SunWoo, Choon
    • Explosives and Blasting
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    • v.24 no.2
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    • pp.51-63
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    • 2006
  • The typical blasting method adopted in Pasir Coal Mine is a surface blasting technique with a single free face. It means that there is only one free face, which is usually the ground surface. This kind of blasting method is easy to use but inevitably causes enormous ground vibrations, which, in turn, can affect the stability of the slopes comprising the various boundaries of the open pit mine. In addition, the method also has the problem of lowering the overall blast efficiency compared to other methods such as bench blasting methods or ones with more than two free faces. In this respect, a project was launched to develop a new blasting method that is suitable for both controling the ground vibration and enhancing the blast efficiency. As a part of the project, we investigated the current blasting method of the mine, and have conducted field measurements of the ground vibrations from 12 biasts. This Paper presents the details of the typical blasting pattern and the Propagation characteristics of the ground vibration from the surface blasting in the mine. Especially, various predictive equations for peak Particle velocities that can be used to estimate the ground vibration level in the mine area were derived from the regression analyses using the measured ground vibration data.

The Stability and Characteristic Analysis of Cut Slope Behavior using Real-time Monitoring System (상시 계측시스템을 이용한 붕괴 절토사면 거동 특성 분석 및 안정성 해석)

  • Baek, Yong;Koo, Ho-Bon;Jang, Ki-Tae;Yoo, Byung-Sun;Bae, Gyu-Jin
    • The Journal of Engineering Geology
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    • v.14 no.1
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    • pp.71-80
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    • 2004
  • The failure of cut slopes frequently occurs particularly during the thawing season and the rain season in summer. This study interpreted data collected from site to which a real-monitoring system was applied in order to analyze the causes of ground behaviors and to forecast future slope failure. As for research methods, this study analyzed the size and mechanism of failure by integrating the results of field surveys and measurements. Furthermore, it analyzed data transmitted by the monitoring system installed in the a result, three times of ground displacement occurred as well as a number of partial tension cracks. The cut slope composed of sandstone and siltstone started its initial behavior as a result of torrential downpour and the loss of support of the substructure. For quantitative analysis of the characteristics of ground behavior, this study measured 5 lateral lines. According to the result of the measurement, displacement happened little in the section to which countermeasure had been applied, but displacement of maximum 400mm happened in the section to which countermeasure had not bee applied. The analysis of data on displacement and rainfall suggested a close relationship between ground behavior and rainfall. According to the result of stability interpretation along with the change of ground saturation, stability rate appeared to be less than 1.0 when ground saturation is over 55%. Although the current trend of ground behavior is at a stable stage falling within the range of tolerance, it is considered necessary to continue monitoring and data analysis because ground displacement is highly possible with the change of temperature during the winter.

Production of Gastrodia elata Tuber using Armillaria spp. (Armillaria 속균을 이용한 천마의 생산)

  • Sung, Jae-Mo;Jung, Bum-Shig;Yang, Keun-Joo;Lee, Hyun-Kyung;Harrington, T.C.
    • The Korean Journal of Mycology
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    • v.23 no.1 s.72
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    • pp.61-70
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    • 1995
  • The genus Armillaria is important because they produce Gastrodia tubers. Seventy two isolates of Armillaria were obtained from fruit bodies grown on decayed wood in Korea. Twenty four isolates from Pinus koraiensis were identified as A. ostoyae. Two isolates from G. elata growing in the field were identified as A. mellea. Seven isolates from Acer ginnala and Quercus spp. were identified as A. tabescens. Thirty nine isolates were identified as A. gallica. Armillaria gallica was isolated from Quercus spp., Ainus japonica, Vitis amurensis and Prunus sargentii. Armillaria spp. isolates were divided into four groups based on the cultural characteristics. Group II (A. gallica KNU-A110) was better than the other groups for mycelial growth and rhizomorph formation. Isolate KNU-A110 proved to be good for production of G. elata tubers. This fungus forms mycelial fan in the plant tissue and rhizomorphs in contact with G. elata tubers. Gastrodia spp. was found in thirteen sites in Kangweon province in Korea. The plants were divided into three different kinds based on stem color. Plants with stems of brownish orange and greyish yellow were identified as G. elata, and those with greyish green colored stems were identified as G. gracilis. Gastrodia was collected mainly from humus soils rich in leaf debris, and slopes facing south from mid-May to mid-July. Once the new tubers are formed from the ancestry tuber, the ancestry tuber begins to decay. The offspring tuber, apparently gaining nutrients through rhizomorphs, begins to grow in length and slowly to enlarge. It takes three years for the offspring tuber to become ancestry tuber.

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Environmental Characteristics and Vegetation of Hanabusaya asiatica Habitats (금강초롱꽃 자생지의 환경특성과 식생)

  • Jang, Su-Kil;Cheon, Kyeong-Sik;Jeong, Ji-Hee;Kim, Zin-Suh;Yoo, Ki-Oug
    • Horticultural Science & Technology
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    • v.28 no.3
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    • pp.497-506
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    • 2010
  • This study intended to investigate the environmental factors including soil and vegetation in order to better understand the environmental and ecological characteristics of ten different habitats of $Hanabusaya$ $asiatica$. These habitats, according to investigations, are mostly located on the slopes of mountains facing north at an altitude of 580 m to 1,396 m above sea level with angles of inclination ranging from 5 degrees to 80 degrees. A total of 146 vascular plant taxa are identified in 32 quadrates of the ten habitats. The importance value of $H.$ $asiatica$ is 8.87%, and 5 highly ranked species such as $Carex$ $siderosticta$ (8.67%), $Ainsliaea$ $acerifolia$ var. $subapoda$ (7.10%), $Calamagrostis$ $arundinacea$ (6.79%), $Athyrium$ $yokoscense$ (5.33%), $Astilbe$ $rubra$ (3.11%) are considered to be an affinity with $H.$ $asiatica$ in their habitats. Dominant species of woody plants in ten habitats are represented as $Quercus$ $mongolica$ in tree layer (T1), $Acer$ $pseudo$-$sieboldianum$ in subtree layer (T2), $Rhododendron$ $schlippenbachii$ and $Tripterygium$ $regelii$ in shrub layer (S). The degree of their average species diversity is 1.30, and that of dominance and evenness are 0.08 and 0.88, respectively. The type of soil is sandy loam, loam and loamy sand, and the average field capacity of soil is 23.95%. Their average organic matter is 12.28%, soil pH 5.79, and available phosphorus is 25.48%. Correlation coefficients analysis based on environmental factors, vegetation and soil analysis shows that the coverage of tree layers is correlated with richness, diversity, dominance, evenness and coverage of $H.$ $asiatica$.

Distribution of Megaleranthis saniculifolia Ohwi (Ranunculaceae) in Mt. Halla, Jeju Island (한라산 모데미풀(미나리아재비과) 자생지 분포 특성)

  • Han, Jong-Won;Lee, Ga-Hyung;Yang, Sun-Gyu;Kang, Shin-Ho
    • Korean Journal of Plant Resources
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    • v.23 no.2
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    • pp.179-186
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    • 2010
  • This study was conducted to provide basic information for conservation and restoration through investigation of vegetation and soil condition of Megaleranthis saniculifolia Ohwi, Korean endemic species, in Mt. Halla, Jeju Island. Very few individuals were discontinuously distributed and restricted at 1,075 m above sea level, very steep slope ($60-70^{\circ}C$), rocky area of north face of Eorimok Valley. For investigation of environmental condition, we established two $10\;{\times}\;10\;m$ quadrats in the habitats and one control quadrat. Twenty-four species were found at site 1 under 10-12 m Carpinus laxiflora tree layer (35%) and soil conditions are pH 5.9, moisture content (field capacity) 9.39%, organic carbon 8.22% and organic matter 14.17%, respectively. Site2, 15 taxa were found under 8-12 m Platycarya strobilacea tree layer (40%) and soil conditions are pH 5.07, moisture content 4.99%, organic carbon 5.34% and 9.21 percentage of organic matter. In the control quadrat, 14 taxa were found under 10 m Carpinus laxiflora tree layer (10%) and soil conditions are pH 5.27, moisture content 6.23%, organic carbon 4.74% and organic matter 8.17%, respectively. The principal causes of threat which were investigated in this study are competition among company, very steep slopes, artificial management of valley. For restoration and conservation of habitats, it is needed to suitable plans.

Calculation of Soil Moisture Control Section to determine Soil Moisture Regime of Medium Textured Soil Catena in Hilly Area (경사지(傾斜地) 중립질토양연접군(中粒質土壤連接群)에 대한 토양수분상(土壤水分相) 결정(決定)을 위한 부위(部位) 선정(選定))

  • Jung, Yeun-Tae;Kim, Jung-Kon;Son, Il-Soo;Yoon, El-Soo
    • Korean Journal of Soil Science and Fertilizer
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    • v.22 no.1
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    • pp.1-5
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    • 1989
  • This study was carried out by using laboratory data to calculate Soil Moisture Control Section (SMCS) for medium textured topo-sequential soils derived from porphyry in Milyang area. The soils studied were characterized by loam to silty clay loam, and the moisture content at -1/3 bar in the solum ranged around 21.06% to 32.42%. The moisture contents per centimeter of soil layer within a solum calculated at field capacity (FC) ranged from 0.11cm to 0.19cm. The upper boundaries of SMCS of the soils calculated on the basis of FC as the water content at -1/3 bar, ranged from 16.2cm to 21.2cm and the lower boundaries from 44.4cm to 63.8cm, and the depth of SMCS were from 27.7cm to 42.6cm in the soil profiles. The Bongsan soil on the summit had shallower in the boundaries and narrower in the depth of SMCS than the soils on side-slopes or on valley.

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Relationships between Soil Physico-chemical Properties and Topography in Jeonbuk Orchard Fields (지형에 따른 전북지역 과수원 토양의 물리화학적 특성)

  • Ahn, Byung-Koo;Lee, Jin-Ho;Ha, Sang-Keun
    • Korean Journal of Soil Science and Fertilizer
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    • v.44 no.5
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    • pp.859-865
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    • 2011
  • This study looked into 110 sites of orchard fields to investigate the relationships between the physical and chemical properties of soils, including heavy metal contents, and the topographic characteristics of the fields in Jeonbuk province. The topographic distribution of orchard fields in Jeonbuk province was local valley and fans, hilly and mountains, mountain foot slopes, alluvial plains, diluvium, and fluvio-marine deposits. Forty-six percent (46%) of total orchard fields were located in the hilly and mountains. Soil texture of the local valley and fans was mostly sandy clay loam, and the soil texture of other topographical sites were varied. Bulk density, porosity, and soil hardness were not different among the various topographic sites. The content of plant available water was the highest (19.5%) in the sites of diluvium. Soil pH, electrical conductivity (EC), and exchangeable $Mg^{2+}$ content were the highest in the sites of fluvio-marine deposits, whereas the contents of soil organic matter (SOM), available phosphorus, and exchangeable $Ca^{2+}$, $K^+$, and $Na^+$ were not significantly different among the topographic sites. Also, soil pH and SOM content were generally in optimal ranges for the fruit plants in the orchard fields, but other values were mostly higher than those in optimum. In addition, the contents of heavy metals were much lower than the levels of Soil Contamination Warning Standard.