• Title/Summary/Keyword: Soil Geography

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Carbon Isotope Analysis for the Climatic Environment Change in South Korea During the Holocene: a Case Study in Yengjong Islands of Yellow Sea (탄소동위원소분석을 이용한 한국 홀로세의 기후환경변화: 서해 영종도지역을 사례로)

  • Jung, Hea-Kyung;Park, Ji-Hoon;Kim, Cheong-Bin
    • Journal of the Korean earth science society
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    • v.31 no.4
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    • pp.313-321
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    • 2010
  • The landform of the study area is defined as a small-scale alluvial plain in the valley bottom adjacent to the coast. By the aggradation of alluvial materials, this valley bottom plain was formed in dissected parts of low hills. For the purpose of reconstructing the palaeo climate environment in this study, $\delta^{13}C$ analysis and soil organic carbon analysis are therefore employed. Main results of this study are as follows: Section I: the period of $6,600{\pm}60yr$ B.P.$-5,350{\pm}60yr$B.P. was mostly in warm and humid climate environment. A little changes of the humid environment are detected as subdry (or sub-humid)${\rightarrow}$humid in terms of the dryness and wetness. Section II: the period of $5,350{\pm}60yr$ B.P.-2,200 yr B.P. was in warm and humid climate environment, which is similar to the present. However, The sediments between $4,720{\pm}60yr$ B.P. and $4,210{\pm}50 yr$ B.P. experienced the most humid climate environment of all studied sedimentary layers. After $4,210{\pm}50 yr$ B.P., the environment started to change from the humid to the sub-humid (or sub-dry) climate. Section III: the period of 2,200 yr B.P.$-210{\pm}60 yr$ B.P. was distinguish from previous two sections as the environmental changes to sub-humid (or sub-dry) climate was apparent.

Mineralogical Changes in the Weathering Profiles of Carnin Gneiss in the Yoogoo Area, Korea (유구지역 화강암질 편마암의 풍화작용에 의한 광물 조성의 변화)

  • 이석훈;김수진
    • Journal of the Mineralogical Society of Korea
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    • v.13 no.3
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    • pp.121-137
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    • 2000
  • Weathering profiles which were developed under a temperate, humid environment and relatively steep geography, show a thick saprolite and soil horiaon in the Precambrian granitic gneiss of the Yoogoo area. In the weathering profiles, secondary minerals such as interstratified biotite/vermiculite, tri- or di-octahedral vermiculite, halloysite, kaolinite, illite, smectite, gibsite and geothite were observed. Kaolinization of biotite is the most prevalent mechanism but vermiculitization is a minor from all ofweathering profiles. Biotite altered to B/V mixed layer-vermiculite, to illite and to halloysite, kaolinite and gibbsite. Halloysite is the most frequently observed weathering product of biotite in these profiles. Goethite is observed at the around or opened fissures of altered biotite. Tubular halloysite aggregates was fDrmed from dissolution-precipitation of plagioclase. The occurrence of halloysite aggregates is divided into a preferentially oriented type and a wrinkled one which were resulted from the dissolved type of plagioclase. Fe-bearing minerals have also been subjected to dissolution leaving the precipitation of geothite along dissolution voids. The profile of granitic gneiss is a typical weathering pattern showing a clay minerals increase toward the surface. Weathering of minerals were controlled by locally acidic and good-drainage environment, and formed a various and complicated secondary minerals in this study area.

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Actor's Role and Networks in the Environmentally Friendly Farming in Busan Metropolitan Agricultural Region (부산 김해평야 농업지역 친환경농업의 행위자-연결망 연구)

  • Kim, Ki-Hyuk
    • Journal of the Korean association of regional geographers
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    • v.9 no.3
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    • pp.276-296
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    • 2003
  • This study is to analyze the adoption of environmentally friendly fanning(EFF) by Actor-Network Theory(ANT). ANT declares that the world is full of hybrid entities containing both human and non-human elements and maintains that adoption of an innovation comes as a consequence of the action of everyone in the chain of actors who has anything to do with it. In this study, adoption of EFF will be analysed through the role of actors and networks. And this paper try to identify the intermediaries and obligatory passage point(OPP) in each networks. In study area, 5 actors, -nature, governmental institute, food processors, consumers and farmers-, have each roles in their networks, But only 18 farmers adopted EFF. This study revealed that three OPPs were not overcome in each network. The one is nature, such as water and soil pollution. Another is shortage of reliability between farmers and governmental institute. The other is shortage of information about agricultural commodity trade. And through this application of ANT to the EFF, we contend that ANT can be useful for studies of diffusion of EFF and sustainability of rural systems in situations where interactions of the social, technological and political are regarded as particularly important.

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Evaluation of a Hydro-ecologic Model, RHESSys (Regional Hydro-Ecologic Simulation System): Parameterization and Application at two Complex Terrain Watersheds (수문생태모형 RHESSys의 평가: 두 복잡지형 유역에서의 모수화와 적용)

  • Lee, Bo-Ra;Kang, Sin-Kyu;Kim, Eun-Sook;Hwang, Tae-Hee;Lim, Jong-Hwan;Kim, Joon
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.9 no.4
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    • pp.247-259
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    • 2007
  • In this study, we examined the flux of carbon and water using an eco-hydrological model, Regional Hydro-Ecologic Simulation System (RHESSys). Our purposes were to develop a set of parameters optimized for a well-designed experimental watershed (Gwangneung Research Watershed, GN) and then, to test suitability of the parameters for predicting carbon and water fluxes of other watershed with different regimes of climate, topography, and vegetation structure (i.e Gangseonry Watershed in Mt. Jumbong, GS). Field datasets of stream flow, soil water content (SWC), and wood biomass product (WBP) were utilized for model parameterization and validation. After laborious parameterization processes, RHESSys was validated with the field observations from the GN watershed. The parameter set identified at the GN watershed was then applied to the GS watershed in Mt. Jumbong, which resulted in good agreement for SWC but poor predictability for WBP. Our study showed that RHESSys simulated reliable SWC at the GS by adjusting site-specific porosity only. In contrast, vegetation productivity would require more rigorous site-specific parameterization and hence, further study is necessary to identify primary field ecophysiological variables for enhancing model parameterization and application to multiple watersheds.

Regional Differential Development as an Alternative Regional Development Theory (대안적 지역발전론으로서 지역차이발전론)

  • Lee, Jae-Ha
    • Journal of the Korean Geographical Society
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    • v.47 no.1
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    • pp.140-157
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    • 2012
  • Most of global citizens in the globalization era want to live peacefully in the symbiotic relationship among each region or locality with its identity. From this perspective, the new regionalist models of development such as new industrial districts, industrial clusters, regional innovation systems, and global city-regions isn't helpful to most of regions because they were developed to increase the global competitiveness of industrial region from a few advanced industrial areas. This study attempts to develop 'regional differential development' as an alternative regional development theory. This theory puts emphasis on the truth that the difference or differential industry between regions in the real world connotes two essential values of development like the symbiosis of global citizens and the regional identity. Regional differential development seeks the development of regional differential industry on the basis of geographical elements with differential advantage, and hence it reviews significantly geographical elements including location, natural environment(landform, soil, climate, etc.), natural resources, population, transportation, culture, and landscape which appear substantially differently among regions. And to realize regional differential development successfully, it is crucial that actors(government, company, related institutions, and regional residents) actively participate and play each complementary role in the relationship of cooperation and conflict. Further study needs to secure the universal validity of this theory through many empirical studies.

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Factors Influencing Farmers' Barriers to Adopting Climate Smart Agriculture Practices in the Coastal Area of Bangladesh (방글라데시 해안 지역 농업에서 기후에 대응한 스마트 농업 적용에 대한 농업인의 장애 영향요인)

  • Avijit Biswas;Prome Debnath;Dae Koo Kang
    • Journal of Agricultural Extension & Community Development
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    • v.31 no.3
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    • pp.153-175
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    • 2024
  • This study aims to identify the factors influencing farmers' barriers to adopting climate-smart agriculture (CSA) practices in the coastal area of Bangladesh. We have used a semi-structured, pre-tested questionnaire to collect quantitative and qualitative data from 160 coastal farmers who had at least 10 years of farming experience. We found that internal consistency (Cronbach's alpha) values for the items of agricultural vulnerability, adopted CSA practices, and perceived barriers to adopting CSA practices were 0.72, 0.74, and 0.79, respectively. The Agricultural Vulnerability Index (AGVI) found increased soil salinity in the dry season, reduced freshwater resources, poor seed germination, and more pests and diseases as vulnerabilities in agriculture. The Adoption Index (ADI) identified most adopted CSA practices as including growing HYVs of vegetables on high land, short-duration HYVs of rice, using compost, proper fertilizer management, and sarjon cultivation methods. The Barrier Index (BI) showed that high initial investment costs, poor embankment infrastructure, low crop prices, a lack of solar-powered irrigation systems, and insufficient technical assistance from local extension organizations are the main barriers to the adoption of CSA practices. Farmers' age, education, training experience, job satisfaction, and use of information sources have influenced barriers to adopting CSA practices. The study suggested policies on coastal farmer competency development, ensuring crop insurance, providing interest-free credit policies, and a fair pricing system for crops.

Geomorphic Features of Bing-gye Valley Area(Kyongbuk Province, South Korea) -Mainly about Talus- (의성 빙계계곡 일대의 지형적 특성 -테일러스를 중심으로-)

  • Jeon, Young-Gweon
    • Journal of the Korean association of regional geographers
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    • v.4 no.2
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    • pp.49-64
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    • 1998
  • Bing-gye valley(Kyongbuk Province, South Korea) is well known as a tourist attraction because of its meteorologic characteristics that show subzero temperature during midsummer. Also, there are some interesting geomorphic features in the valley area. Therefore, the valley is worth researching in geomorphology field. The aim of this paper is to achieve two purposes. These are to clarify geomorphic features on talus within Bing-gye valley area, and to infer the origin of Bing-gye valley. The main results are summarized as follows. 1) The formation of Bing-gye valley It would be possible to infer the following two ideas regarding the formation of Bing-gye valley. One is that the valley was formed by differential erosion of stream along fault line, and the other is that the rate of upheaval comparatively exceeded the rate of stream erosion. Especially, the latter may be associated with the fact that the width of the valley is much narrow. Judging that the fact the width of the valley is much narrow, compared with one of its upper or lower valley, it is inferred that Bing-gye valley is transverse valley. 2) The geomorphic features of talus (1) Pattern It seems to be true that the removal of matrix(finer materials) by the running water beneath the surface can result in partly collapse hollows. Taluses are tongue-shaped or cone-shaped in appearance. They are $120{\sim}200m$ in length, $30{\sim}40m$ in maximum width. and $32{\sim}33^{\circ}$ in mean slope gradient. The component blocks are mostly homogeneous in size and shape(angular), which reflect highly jointed free face produced by frost action under periglacial environment. (2) Origin On the basis of previous studies, the type of the talus is classified into rock fall talus. When considered in conjunction with the degrees of both weathering of blocks and hardness of blocks, it can be explained that the talus was formed under periglacial environment in pleistocene time. (3) The inner structure of block accumulation I recognize a three-layered structure in the talus as follows: (a) superficial layer; debris with openwork texture at the surface, 1.3m thick. (b) intermediate layer: small debris(about 5cm in diameter) with fine matrix(including humic soil), 70cm thick. (c) basal layer: over 2m beneath surface, almost pure soil horizon without debris (4) The stage of landform development Most of the blocks are now covered with lichen, and/or a mantle of weathering. It is believed that downslope movement by talus creep well explains the formation of concave slope of the talus. There is no evidence of present motion in the deposit. Judging from above-mentioned facts, the talus of this study area appears to be inactive and fossil landform.

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Rates and Factors of Path Widening in Seongpanak Hiking Trail of Mount Halla, Jeju Island (한라산 성판악 등산로 노폭의 확대 속도와 요인)

  • Kim, Tae-Ho
    • Journal of the Korean Geographical Society
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    • v.43 no.3
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    • pp.296-311
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    • 2008
  • In order to examine the rates and factors of path widening in Mount Halla, the retreat of path sidewalls was monitored at 32 sites of Seongpanak Hiking Trail located between 875 m and 1,400 m in elevation. The mean rate of sidewall retreat for the period 2002-2008 is 50.6 mm, equivalent to 10.0 mm/yr. The retreat rate of frozen period is 19.3 mm/yr, while the rate of unfrozen period is 4.3 mm/yr. The latter is divided into the rainy and dry periods that exhibit the retreat rates of 5.9 mm/yr and 2.9 mm/yr, respectively. The retreat rate of sidewalls is also varied with seasons; winter shows the maximum rate of 42.2 mm/yr, while summer exhibits the minimum rate of 1.3 mm/yr. Spring and fall show the intermediate rates of 13.9 mm/yr and 6.4 mm/yr, respectively. Soil hardness and elevation are not closely related to the retreat rate of sidewalls, even though the retreat rate is larger at the north-faced sidewalls than the south-faced sidewalls during the frozen period. Pipkrake is likely to be the most important factor contributing to the path widening in that the retreat of winter months accounts for 76.7% of the total retreat. The hiking trail is placed under the climatic conditions which develop pipkrake in 85 days annually. In addition, it is usual to observe the path sidewall covered with pipkrake in the freezing month of December and the thawing months of March and April. On the other hand, deflation and rainsplash erosion are not important due to the weak wind speed and the forested trail. Rainwash is also insignificant in that the path has been almost paved to mitigate trampling effects. Although biological activity is not dominant, hikers cause a large retreat of sidewalls in the thawing months since they would walk on the sidewalls to avoid snow-melting pools on the path.

Importance of Microtextural and Geochemical Characterizations of Soils on Landslide Sites (산사태지역 토층의 미세조직과 지화학적 특성의 중요성)

  • Kim Kyeong-Su;Choo Chang-Oh;Booh Seong-An;Jeong Gyo-Cheol
    • The Journal of Engineering Geology
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    • v.15 no.4 s.42
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    • pp.447-462
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    • 2005
  • The purposes of this study are to evaluate and discuss the importance of geochemical properties of soil materials that play an important role in the occurrence of the landslide, using analyses of microtexture, particle size distribution, XRC, and FE-SEM equipped with energy dispersive spectrum on soils collected from landslide slopes of gneiss, granite and sedimentary rock areas. Soils from gneiss and granite areas where landslides took place have much clay content relative to those from non landslide areas, particularly pronounced in the granite area. Therefore the clay content is considered a sensitive factor on landslide. Clay minerals contained in soils are illite, chlorite, kaolinite and montmorillonite. Especially the content of clay minerals in soils from the Tertiary sedimentary rocks is highest, with abundant montmorillonite as expandable species. It is believed that this area was much vulnerable to landslide comparable to other areas because of its high content of monoorillonite, even though there might be weak precipitation. Since no conspicuous differentiation in mineralogy between the landslide area and non landslide area can be made, the occurrence of landslide may be influenced not by mineralogy, but by local geography and mechanical properties of soils. Geochemical information on weathering properties, mineralogy, and microtexture of soils is helpful to better understand the causes and patterns of landslide, together with engineering geological analyses.

Case study on the lake-land combined seismic survey for underground LPG storage construction (LPG 지하저장기지 건설을 위한 수륙혼합 탄성파탐사 사례)

  • Cha Seong-Soo;Park Keun-Pil;Lee Ho-Young;Lee Hee-Il;Kim Ho-Young
    • 한국지구물리탐사학회:학술대회논문집
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    • 2002.09a
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    • pp.101-125
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    • 2002
  • A lake seismic survey was carried out to investigate possible geohazards for construction of the underground LPG storage at Namyang Lake. The proposed survey site has a land-lake combined geography and furthermore water depth of the lake is shallow. Therefore, various seismic methods such as marine single channel high resolution seismic reflection survey, sonobuoy refraction survey, land refraction survey and land-lake combined refraction survey were applied. Total survey amounts are 34 line-km of high resolution lake seismic survey, 14 lines of sonobuoy refraction survey, 890 m of land refraction survey and 8 lines of land-lake combined refraction survey. During the reflection survey, there were severe water reverberations from the lake bottom obscured subsurface profiling. These strong multiple events appeared in most of the survey area except the northern and southern area near the embankment where seems to be accumulated mainly mud dominated depositions. The sonobuoy refraction profiles also showed the same Phenomena as those of reflection survey. Meanwhile the results of the land-lake combined refraction survey showed relatively better qualities. However, the land refraction survey did not so due to low velocity soil layer and electrical noise. Summarized results from the lake seismic survey are that acoustic basement with relatively flat pattern appeared 30m below water level and showed three types of bedrock such as fresh, moderately weathered and weathered type. According to the results of the combined refraction survey, a velocity distribution pattern of the lake bottom shows three types of seismic velocity zone such as >4.5 km/s, 4.5-4.0km/s and <4.0km/s. The major fault lineament in the area showed NW-SE trend which was different from the Landsat image interpretation. A drilling was confirmed estimated faults by seismic survey.

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