• Journal of Plant Biology
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• 제7권2호
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• pp.1-8
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• 1964

Cha, Jong Whan (Dept. of Biology, Graduate School, Dong Kuk Univ.) The changes of chemical properties of forest soils in dry and wet seasons. Kor. Jour. Bot. VII(2): 1-8, 1964. Soil selected for the present investigation was collected from a mountain of the Forestry Experiment Station of the vicinity of Seoul. The forest communities studied were three forest and a unplanted soils. The soil samples were obtained from each forest type during dry and wet seasons. And these samples were collected from four horizons of all communities respectively. It was showed that exchangeable hydrogen was increased by rainfall, and total exchangeable base decreased in the same way. The content of nitrogen is washed away by rainfall, especially ammonium nitrogen was highly significant between dry and wet season. On the contrary, organic matter and available phosphorus were of no significant difference between dry and wet seasons. The values of pH appeared a different response in dry and wet seasons according to the plant communities. The needle-leaved forest soils showed more acidity than the broad-leaved forest soils, and the least acidity in open places. All nutrients in soil studied gradually decreased down the profiles. According to statistical analyses of the soil components among all soil horizons, total exchangeable bases in wet season indicated only significant at 1%. Exchangeable hydrogen and organic matter of the soil in dry season was particularly very low with increased depth in the profile. The fertility level of most forested soils selected for the present investigation is low according to chemical tests for available nutrient elements.

• 한국지반공학회논문집
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• 제33권8호
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• pp.29-40
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• 2017

본 연구에서는 ${\bigcirc}{\bigcirc}$시 비위생매립장 정비사업 시행시 발생하는 특수한 선별토사를 부지 복원토로 활용하기 위한 다짐방안으로 현장상황과 선별토사의 토질조사 자료, 다짐시험 특성을 분석하여 동다짐공법을 적용하였다. 동다짐 전 후에 수행한 표준관입시험(SPT)에서 N치는 12~18 범위로 동다짐 전보다 평균 89% 증가하였으며, 평판재하시험(PBT)의 허용지지력은 $150{\sim}227kN/m^2$ 범위로 다짐 전에 비해 최소 80%이상 증가하였다. 이러한 결과로 기존의 준설 및 폐기물 매립지에 적용된 동다짐 효과와 비슷한 경향을 나타내고 있음을 알 수 있었다.

• Journal of Forest and Environmental Science
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• 제39권3호
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• pp.180-194
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• 2023

This study characterize, classify and evaluates the function of topography on spatial variability of some selected soil properties to assist in designing land management that support uniform agricultural production. The study site, an agricultural land, was part of the derived savanna zone in southwest Nigeria. Four soil profile pits each were established along two delineated toposequence and described following the FAO/UNESCO guidelines. Samples were collected from the identified genetic horizons. Properties of four soil series developed on different positions of the two delineated Toposequence viz upper, middle, lower slopes and valley bottom positions respectively were studied. The soil samples were analysed for selected physical and chemical properties and data generated were subjected to descriptive and inferential statistics. The results showed that soil colour, depth and texture varied in response to changes in slope position and drainage condition. The sand content ranged from 61 to 90% while the bulk density ranged between 1.06 g cm^-3 to 1.68 g cm^-3. The soils were neutral to very strongly acid with low total exchangeable bases. Available phosphorus value were low while the extractable micronutrient concentration varied from low to medium. Soils of Asejire and Iwo series mapped in the study area were classified as Typic isohyperthermic paleustult, Apomu series as Plinthic isohyperthermic paleustult and Jago series as Aquic psamment (USDA Soil Taxonomy). These soils were correlated as Lixisol, Plinthic Lixisol and Fluvisol (World Reference Based), respectively. Major agronomic constraints of the soils associations mapped in the study area were nutrient availability, nutrient retention, slope, drainage, texture, high bulk density and shallow depth. The study concluded that the soils were not homogenous, shows moderate spatial variation across the slope, had varying potentials for sustainable agricultural practices, and thus, the agronomic constraints should be carefully addressed and managed for precision agriculture.

• 생약학회지
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• 제22권1호
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• pp.33-35
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• 1991

Heavy metals may cause trouble(s) in human body. For consideration of the safety of crude drugs cultivated in Korea, we selected some medicinal plants and soils from cultivated site and estimated their heavy metal contents by inductively coupled argon plasma spectrometry (ICAP). Among heavy metals tested, the highest level of Cu and Zn were shown in plants cultivated in Kyung Ki; the highest level of Fe in those in Youngnam and the highest level of Mg and Mn in those in Youngdong. The heavy metal content s were as low as to be permeasible at least for the medicinal plants we selected. There were no significant correlations between heavy metal contents of soils and cultivated medicinal plants.

• 한국토양비료학회지
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• 제46권6호
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• pp.536-541
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• 2013

In Soil Taxonomy system, anthropogenic soils are still classified as Entisols since the International Classification Committee for Anthropogenic Soils is in the process of classifying anthropogenic soils as new orders. In reality, it is difficult to characterize anthropogenic soils because Soil Taxonomy (ST) system does not distinguish between natural and anthropogenic Entisols. On the other hand, World Reference Base for soil resources (WRB) considers human impacts on soils and contains an independent category of anthropogenic soils, which makes easier to understand anthropogenic soil characteristics than Soil Taxonomy system. A remodeled paddy field (Gasan) was selected to classify by ST and WRB. Soil samples were taken to analyze chemical and physical properties. Based on the results of the analyses, the ST system classified Gasan as coarse loamy, mixed, mesic, Aquic Udorthents while the WRB did as Stagnic Urbic Technosols (Oxyaquic, Arenic). As a conclusion, the WRB classification information of the anthropogenic provides more detail characteristics of the anthropogenic soils.

• 한국지반환경공학회 논문집
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• 제4권1호
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• pp.29-39
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• 2003

본 연구의 목적은 폐기물 매립장 선별토사를 도로성토재료로 재활용하기 위해 매립장 주변의 오염되지 않은 토사A 및 토사B와 혼합비를 달리하였을 때 다짐, 전단, CBR 시험 등을 실시하여 도로성토재료로서 재활용하기 위한 기초자료를 제공하는 것이다. 다짐시험결과 일반토사의 혼합비가 증가할수록 최대건조밀도는 증가하고 최적함수비는 감소하였으며, 직접전단시험 결과 토사A를 혼합하였을 경우에는 점착력의 변화가 크게 나타났고 토사B를 혼합한 경우에는 내부마찰각의 변화가 크게 나타났다. 또한, CBR 시험을 실시한 결과 토사A의 경우 혼합비가 50%이상일 때에는 상부노상재료로 활용가능한 것으로 나타났고, 토사B의 경우 혼합비가 30%이상일 때 상부노상재료로 활용가능한 것으로 나타났다.

• Geomechanics and Engineering
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• 제16권5호
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• pp.547-558
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• 2018

Studies of soil dynamic properties in Malaysia are still very limited. This study aims to investigate the dynamic properties of two selected tropical residual soils (i.e., Sandy Clay and Sandy Silt) and a sand mining trail (Silty Sand) in Peninsular Malaysia using 1g shaking table test. The use of 1g shaking table test for soil dynamic testing is often constrained to large strain level and small confining pressure only. Three new experimental setups, namely large laminar shear box test (LLSBT), small chamber test with positive air pressure (SCT), and small sample test with suction (SSTS) are attempted with the aims of these experimental setups are capable of evaluating the dynamic properties of soils covering a wider range of shear strain and confining pressure. The details of each experimental setup are described explicitly in this paper. Experimental results show that the combined use of the LLSBT and SCT is capable of rendering soil dynamic properties covering a strain range of 0.017%-1.48% under confining pressures of 5-100 kPa. The studied tropical residual soils in Malaysia behaved neither as pure sand nor clay, but show a relatively good agreement with the dynamic properties of residual soils in Singapore. Effects of confining pressure and plasticity index on the studied tropical residual soils are found to be insignificant in this particular study.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.200-202
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• 2002

This study was for comparisons of transitional element concentrations from the two different soil, serpentinite(SP) and granite area(GR), Kwangcheon and Hongseong area. Soils were collected by soil depths (10, 20 and 30cm) from the sites selected In the plant species(coniferous and deciduous species). In the soils, the SP was high in the Cr, Mn, Fe, Co, Ni and Zn concentrations, while the GR was high in the Cu, As, Sc and V. With the soil depths, the elements had high solubility, such as Cr, Co and Ni concentrations, were high in the SP, while the other elements were not clear. For the both species, the SP was high in the root and bolebark, while in the GR, not clear. Coniferous species in the same soil types, was higher than the deciduous In most elements. The more with increasing ages, the more with element accumulation in most plant parts except leaves. Comparisons between the soils and plant species, in the case of the element contents within the soils, the plant species in the same sites was similar trend. especially, clear in the SP

• Geomechanics and Engineering
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• 제4권2호
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• pp.135-150
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• 2012

This paper presents the study of the effect of microorganism Bacillus pasteurii on the properties such as Atterbergs' limit and unconfined compressive strength of cohesive soils. The results of this study reveal that the liquid limit and plasticity index for all clay soils decreased and the unconfined compressive strength increased. Decrease in plasticity index is very high for Kuttanad clay followed by bentonite and laterite. The unconfined compressive strength increased for all the soils. The increase was high for Kuttanad soil and low for laterite soil. After 24 h of treatment the improvement in the soil properties is comparatively less. Besides the specific bacteria selected Bacillus pasteurii, other microorganisms may also be taking part in calcite precipitation thereby causing soil cementation. But the naturally present microorganisms alone cannot work on the calcite precipitation.

• 한국수자원학회논문집
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• 제33권1호
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• pp.133-142
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• 2000

본 연구에서는 불포화 투수계수를 측정하기 위하여 Klute(1965a)에 의하여 제안된 정적측정방법의 원리에 axis-translation의 기법을 적용하여 새로운 실험장치를 개발하였다. 이 실험장치는 모관흡수력(matric suction)의 증가에 따른 함수특성과 투수계수의 변화를 동시에 측정할 수 있도록 설계되었다. 실험에는 불포화 투수특성과 No.200체 통과 세립분의 상호관계를 규명하기 위하여 각각 세립함유량이 7.3%(인주), 19.6%(성환), 35.9%(구리)인 시료를 인주, 성환, 구리지역에서 채취하여 사용하였다. 실험결과에 의하면 불포화토의 투수계수와 체적함수는 시료의 밀도가 증가하는 경우 전체적으로 감소하였으며 모관흡수력이 증가함에 따라 점차 비선형적으로 감소하는 거동을 보였다. 또한 불포화토의 투구계수와 체적함수비는 상호 비선형거동을 보였다. 체적함수비와 투구계수를 직접 비교하는 방법으로 경험상수 A,B를 No.200체 통과 세립분의 함유량에 따라 결정하였으며, 경험상수 A, B를 이용하면 직접 흙의 함수특성곡선으로부터 불포화 투수계수를 추정할 수 있다.