• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.653-662
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• 2017

Copper(II) acetate spectrophotometry method (CASM) was used for the rapid and convenient determination of cation exchange capacity (CEC) in soils. This method is composed of a single-step exchange reaction that adsorbs copper and is measured through spectrophotometry. The CEC of 16 Korean soils were measured using 1M ammonium acetate method (AAM) and the CASM. The CEC values determined by CASM and AAM were not significantly different, and were highly correlated ($r=0.966^{**}$). Due to the convenience, cost effectiveness, and time saving analysis of CASM, this method is recommended for most soil laboratories to measure CEC in Korean soils. However, CASM may not be applicable for soils that have a much higher CEC (greater than $20cmol_c\;kg^{-1}$).

• Proceedings of the Ginseng society Conference
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• 2008.05a
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• pp.74-75
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• 2008

This study is for geochemical relationships between ginsengs and soils from three representative soil types from Keumsan, shale, phyllite and granite. For these study, ginsengs, with the field and weathered soils were collected from the three regions, and are analysed for the major and trace elements. In the weathered soils(avg.), the granite and phyllite areas are high in the most of elements while the shale area is low. In the correlation coefficients, negative correlations are shown in the $Al_2O_3$-MgO pair while positive correlations, are shown in the Ba-Sr, Zr, Sr-Zr and Cs-Ge pairs. In the field soils(avg.), the granite and phyllite areas are, generally, high in the most of elements while the shale area is low. In the shale area, the major elements are high in the 4 year soils, but low in the 2 year soils. The LFS(Ba, Sr, Cs) and transitional elements are high in the 2 year soils, but low in the 4 year soils. The HFS(Y, Zr) is high in the 4 year soils. In the correlation coefficients, most of the elements from the 4 year show positive relationships. Positive correlations are shown in the $Al_2O_3$-CaO, MnO-MgO, V-Tl, and Ba-Sr pairs in all localities. In the ginseng contents, clear chemical differences with the ages are shown in the shale and granite ares, but not clear in the phyllite area. In the shale area Mn, Mg, Ba, Sr, and Y contents, increase with ages but decrease in Al, Cs, Be and Cd. In the correlation coefficients, degrees of the correlations for the major elements become low with the ages. Positive correlations are shown in the Al-Mn, Ti, Mn-Ti, Mg-Ca, Ca-K, Ba-Cs, Y and Cs-Y pairs. Comparisons with ginsengs of the same ages from the different areas suggest that generally, the 2 years in the shale and 3 and 4 years in the granite area are distinctive. Relative ratios(granite/ shale area) of the ginsengs are below 1 in the major elements except Mn in the 2 year ginsengs and above 1 in the other elements except Mg and Na in the 4 year. Relative ratios(granite/ phyllite area) of the ginsengs are high in the 3 year from the phyllite area. In the relative ratios(weathered/field soils) of the soils, numbers of the elements showing the ratios of above 1 increase from the shale, to phyllite and granite in the case of the major elements, but decrease in the case of the trace elements. These results suggest that major elements are high in the granite while trace elements are high in the shale area. In the relative ratios between field soils and ginsengs(field soils/ginseng), the shale area, regardless of the ages, show differences of several hundred times in the $Al_2O_3$, $TiO_2$, Y and Tl, of several ten times in the MnO, MgO and Ba and of several times in the CaO contents. These results suggest that ginseng contents are significantly different from the field soils in the $Al_2O_3$, $TiO_2$, Y and Tl, but similar in the CaO contents. The phyllite area, regardless of the ages, show differences of several hundred times in the $Al_2O_3$, $TiO_2$, Y, Tl and Be, of several ten times in the MnO, MgO, $Na_2O$ and Ba, and of several times to ten times in the CaO, $K_2O$ and Sr contents. These results suggest that ginseng contents are significantly different from those of the field soils in the $Al_2O_3$, $TiO_2$, Y, Tl and Be, but similar in the CaO, $K_2O$ and Sr contents. The granite area, regardless of the ages, show differences of several hundred times in the $Al_2O_3$, $TiO_2$, Tl and Be, of several ten times in the Ba, and of several times to ten times in the MgO and CaO contents. Of the other elements, differences of several times to ten times are shown in the MnO, $K_2O$ and Sr contents. These results suggest that ginseng contents are significantly different from those of the field soils in the $Al_2O_3$, $TiO_2$, Tl and Be, but similar in the $K_2O$ and Sr contents. Comparisons among the different ages from the same area suggest that, in the case of shale area, differences of several hundred times in the $Al_2O_3$ and $TiO_2$, of the several ten times in the MnO, MgO and Ba and several times in the CaO and $K_2O$ are shown in the 2 year ginsengs. Differences of several hundred times in the $Al_2O_3$, $TiO_2$, Cs, Y, Tl and Be, of above several ten times in the MnO, MgO, $K_2O$ and Ba, and of several times in the CaO and Sr are shown in the 3 year ginsengs. Differences of several hundred to thousand times in the $Al_2O_3$, of above several hundred times in the $TiO_2$, Cs and Y, and of several ten times in the MnO, MgO, $K_2O$ and Ba, and of several times in the $Na_2O$ are shown in the 4 year ginsengs. These relationships suggest that, regardless of the localities in the shale area, $Al_2O_3$ contents of the soils show big differences from those of the ginsengs. Regardless of the ages of ginsengs, comparisons with the overall average contents of each area show differences of several hundred times in the $Al_2O_3$, $TiO_2$, Cs and Tl and of several ten times in the MnO. These overall relationships suggest that the $Al_2O_3$, $TiO_2$, Cs and Tl contents of the soils are higher than those of the ginsengs, show big differences between two and low different contents are found in the MnO. In detail, differences of several hundred times in the Y, and ten times in the MgO and Sr, and of several times in the CaO, $Na_2O$, $K_2O$ in the case of shale area, are shown. These results suggest that the soils are higher than the ginsengs in the Y and significantly differences in Y, and moderately differences in the MgO and Sr, and low differences in the CaO, $Na_2O$ and $K_2O$ are shown between soils and ginsengs.

• Journal of Forest and Environmental Science
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• v.36 no.2
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• pp.133-142
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• 2020

Soil physical and chemical properties at three layers such as top (0-10 cm), middle (10-20 cm) and bottom (20-30 cm) layers under three different vegetation types were studied. Soil samples were collected from Acacia forest, vegetable and fallow lands of Chittagong university campus, Chittagong, Bangladesh. Results showed that sand was the dominant soil particle followed by clay and silt fractions in all soil depths under different vegetation types. Soils of fallow land showed the highest values of bulk density while forest soils had the lowest values at three depths. Acacia forest soil having lowest values of dispersion ratio (DR) is less vulnerable while fallow soil with highest DR values is more vulnerable to soil erosion. The lower pH value at all soil layers in three ecosystems represented that soils under study are acidic in nature. Contents of organic matter, total nitrogen, exchangeable cations (Ca²⁺, Mg²⁺, K⁺ and Na⁺) and cation exchange capacity (CEC) were observed higher in Acacia forest soils compared to vegetable and fallow soils. Only soils of vegetable land had higher level of available phosphorus in three layers than that of other two land covers. The study also revealed that different soil properties were observed in three different vegetation types might be due to variation in vegetation and agronomic practices.

• The Journal of Engineering Geology
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• v.19 no.3
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• pp.409-415
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• 2009

Kozeny-Carman equation has been generally applied to prediction of permeability for soil. The Kozeny-Carman equation has indicated fairly good results in prediction of sandy soils, but it is known that the equation is not appropriate for fine-grained soils such as cohesive soils. Therefore, a theoretical equation based on Kozeny-Carman equation is proposed to predict of permeability for cohesive soils in this paper. To develop the theoretical equation, soil properties of cohesive soil existed in the coastal areas and compacted cohesive soil used for the core of a dam were investigated and analyzed. As the results of this limited study, the most related factors between soil properties and permeability were #200 passing percentage for compacted cohesive soil, and clay content for cohesive soil at the coast areas.

• Journal of Soil and Groundwater Environment
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• v.15 no.4
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• pp.13-20
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• 2010

The purpose of this study was to develope the remediation method of contaminated soils with metals and petroleum. The diesel degrading strain was isolated and identified from the soil contaminated by petroleum at industrial sites. Diesel biodegradation experiment was performed by diesel degrading bacteria in both solution and soil slurry. Contaminated soils by Zn or As and diesel were treated consecutively by steam-vapor extraction, biodegradation, and acid washing. The strain was identified as Pseudomonas aeruginosa, and named as Pseudomonas aeruginosa TPH1. The optimal culture conditions of TPH1 were $20^{\circ}C$ and pH 7.0, 3% of diesel concentration. Biodegradation of diesel was performed using the separated strain in liquid medium, and 63% of diesel was degraded in 72 hours. And 52% of diesel was removed in the tested soils. In the treatment of contaminated soils with diesel and Zn or As, 29% ~ 44% of diesel was reduced by steamvapor extraction, 60% ~ 71% of diesel was removed after biodegradation. 47% of Zn and 96% of As were removed after acid(mixture of sulfuric and oxalic acids) washing. It is recommended that consecutive treatment method of steam-vapor extraction, biodegradation and acid washing is effective for remediation of complex contaminated soils with metals and petroleum.

• Korean Journal of Environmental Agriculture
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• v.14 no.2
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• pp.179-185
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• 1995

Three aminothio derivatives of carbofuran including carbosulfan, furathiocarb and benfuracarb were subjected to the degradation study in soils to investigate how fast and efficiently carbofuran would be evolved from them. Carbofuran was rapidly released from the derivatives in soils as the carbamoyl nitrogen-sulfur bond cleaved. Their degradation rates in soils, with half-lives of $23{\sim}68$ hours, were largely affected by structures of aminothio moieties and soil moisture conditions. Conversion rates into carbofuran ranged from 64 to 84% in soils on the basis of parent compounds 5 days after treatment. Application of aminothio derivatives led to less drastic increase in the carbofuran level in soils than when carbofuran was applied as such, and hence this might result in lower side effects in situ.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.4
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• pp.89-98
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• 1996

This study was conducted to evaluate the relationships between the geotechnical properties and the CBR values of the subgrade materials used in the rural roal construction. A total of 77 Soil samples was investigated and tested from 45 agricultural and industrial sites in Kyungpook Province. The results obtained are as follows : 1. The maximum dry densities of the coarse grained soils are larger than those of the fine grained soils. The optimum moisture contents of the coarse grained soils are smaller than those of the fine grained scils. 2. The mean values of the medified CBR values of the soils classified by the USCS, are decreased in the order of GP-GM, SW-SM, GM, SC, SP-SM, ML, CL-ML. And, those classified by the AASHTO are decreased in the order of A-i-a, A-i-b, A-2-4, A-3, A-4, A-6, A-7-6. 3. As passing percentage of No.200 sieve is increased, the CBR Value of soils is decreased gradually. 4. As the optimum moisture contents of the soil is increased, the CBR values is decresed the maximum dry density of the soils increased, the CBR values increased. 5. The CBR values are decreased as Group-lndex(GI) are increased. And Activity(A) is showed no relation with the CBR values. 6. The relation ships between the modified CBR value and standand proctor compaction CBR value at 95% compaction ratio can he expressed as the following equation : Y(CERmod)= 2.3638 + 0.8922X(CBR25).

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.69-78
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• 2003

In order to investigate the dynamic behavior of weathered granite soils before and after freezing-thawing, cyclic triaxial tests were conducted for the specimens not only with the variation of silt contents within 20% but with plasticity index within 20%. As the results, the dynamic shear modulus of weathered granite soils decreased with increasing silt contents. However, the change in damping ratio was negligible. The influence of freezing-thawing on shear modulus and damping ratio was minimal for the granite soils with variation of silt contents. For the case of the weathered soils with variation of plasticity index, the shear modulus increased with plasticity index within 20%, while the modulus decreased remarkably after freezing-thawing.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1140-1147
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• 2005

The objective of this study was to identify the effect of the degree of saturation on the resilient modulus of cohesive soils as subgrade. Six representative cohesive soils representing A-4, A-6, and A-7-6 soil types collected from road construction sites across Ohio, were tested in the laboratory to determine their basic engineering properties. Resilient modulus tests were conducted on unsaturated cohesive soils at optimum moisture content, and samples compacted to optimum conditions but allowed to fully saturate. The subgrade compacted at optimum moisture content may be fully saturated due to seasonal change. Laboratory tests on fully saturated cohesive soils showed that the resilient modulus of saturated soils decreased to less than half that of soil specimens tested at optimum moisture content. The reduction of resilient modulus would possibly be caused by the buildup of pore water pressure. In resilient modulus testing performed in this study on saturated samples, pore water pressure increases were observed. Pore water pressure and residual pore water pressure gradually increased with an increase in deviator stress.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.253-260
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• 2004

Many scholars and researchers has been studied for many kinds of soil characteristics, but a lot of part are still unsolved. Cyclic load-induced decreasing characteristics of strength and stiffness of soils are also well not known among them. To know that, the characteristics of five kinds of soils; clay, plastic and non-plastic silt, sand, and a weathered soil are compared with dividing two types as plastic or non-plastic soils through direct simple shear(DSS) test. From the results of DSS test, it is known that decreasing characteristics of strength and stiffness are different according to soil types. The strength of plastic and non-plastic soils increases with increment of plasticity index and decrement of volume decrease potential, respectively. And the decreasing stiffness of plastic and non-plastic soils increases with decrement of plasticity index and increment of volume decrease potential, respectively.