• The Korean Journal of Ecology
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• v.23 no.5
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• pp.369-375
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• 2000

Although urban soils must be well understood in order to ensure their conservation and optimum use, these intensively managed and disturbed soils have not been extensively investigated up to now. Urban soils from forest, lawn, streetside, and bare ground and under pavement in Inchon had high bulk density as a result of widespread trampling-induced soil compaction. The various urban soils including forests showed lower water content and higher temperature as compared with rural forest soil. Chemically, soils from urban areas had an unusual neutral pH and low organic matter content. Total bacterial numbers in urban soils was only 5∼50% of that in the rural forest soil. An analysis of stepwise multiple regression revealed that soil organic matter was the most important predictor variable on total bacterial number. The dehydrogenase activity of most urban soils was not significantly different from that of rural forest soil, whereas the microbial activity of soils under pavement was lower. Our investigations show that inadequate organic matter of highly compacted soils has adversely affected the abundance of microorganisms involving nutrient cycling in urban soils.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.1
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• pp.39-53
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• 1999

This study quantified carbon uptake and emissions in urban landscape, and the role of urban greenspace in atmospheric carbon reduction for several cities of Chuncheon and Kangleung in Kangwon province. Mean carbon storage by trees and shrubs was 26.0 t (mertric tons)/ha in Chuncheon and 46.7 t/ha in Kangleung for natural lands, and ranged from 4.7 to 6.3 t/ha for urban lands (all land use types except natural and agricultural lands) in both cities. Mean annual carbon uptake by trees and shrubs ranged from 1.60 to 1.71 t/ha/yr for natural lands, and from 0.56 to 0.71 t/ha/yr for urban lands. There was no significant difference (95% confidence level) between the two cities in the carbon storage and annual carbon uptake per ha, except the carbon storage for natural lands. Organic carbon storage in soils (to a depth of 60 cm) of Chuncheon average 24.8 t/ha for urban lands and 31.6 t/ha for natural lands, 1.3 times greater than for urban lands. Annual carbon accumulation in soils was 1.3 t/hr/yr for natural lands of the study cities. Annual per capita carbon emissions from fossil fuel consumption were 1.3 t/yr in Chunceon and 1.8 t/yr in Kangleung. The principal carbon release in urban landscapes was from transport and industry. Total carbon storage by urban greenspace (trees, shrubs, and soils) equaled 66% of total carbon emissions in Chuncheon and 101% in Kangleung. Carbon uptake by urban greenspace annually offset total carbon emissions by approximately 4% in the study cities. Thus, urban greenspace played a partial important role in reducing atmospheric $CO_2$ concentrations. To increase $CO_2$ uptake and storage by urban greenspace, suggested are conservation of natural lands, minimization of hard surfaces and more plantings, selection of tree species with high growth rate, and proper management for longer healthy tree growth.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1048-1051
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• 2011

This study was carried out to find out properties and total and phytoavailable contents of heavy metals (Cd, Pb, Cu, Zn) in 21 urban agricultural soils in Seoul. The investigated urban soils showed $pH_{(1:5)}$ 6.89, $EC_{(1:5)}$ $0.14dS\;m^{-1}$, organic mater 2.22%, available $P_2O_5$ $139mg\;kg^{-1}$, cation exchange capacity (CEC) $11.36cmol_c\;kg^{-1}$, total nitrogen 0.15% and exchangeable Ca, Mg, K and Na were 6.71, 1.44, 1.06 and $0.30cmol^+\;kg^{-1}$, respectively. Total heavy metal concentrations in urban agricultural soils were lower than those of the warning levels in the area 1 according to the Soil Environmental Conservation Act of Korea. Phytoavailable-Cu, -Pb, and -Zn concentrations of the samples showed 0.02-0.28, N.D-0.09, $0.01-0.43mg\;kg^{-1}$, respectively.

• Journal of Forest and Environmental Science
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• v.15 no.1
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• pp.71-76
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• 1999

This study compared soil characteristics and carbon storage between urban and natural lands in Chunchon. Soil pH was lower in natural lands (5.0) than in urban lands (6.6), and therefore exchangeable cation was a little lower in natural lands. Organic matter and cation exchange capacity were respectively, 1.4 and 1.7 times higher in natural lands than in urban lands, while available $P_2O_5$ was about 3.2 times higher in urban lands. Organic carbon storage in soils averaged $24.8{\pm}1.6$ (standard error) t/ha in urban lands and $31.6{\pm}1.6t/ha$ in natural lands, 1.3 times greater than in urban lands. Annual carbon accumulation in soils of natural lands was 1.3 t/ha/yr (litterfall minus decomposition). The carbon storage in Chunchon' s soils equaled about 31% of annual carbon emission (245,590 t/yr).

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.129-136
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• 2004

Anisotropic characteristics of deformation are important to understand the particular behavior in the pre-failure state of soils. Recent experiments shows that cross-anisotropic moduli of granular soils can be expressed by functions of normal stresses in the corresponding directions, which is closely linked to micromechanical characteristics of particles. Granular soils are composed of a number of particles so that the force-displacement relationship at each contact point governs the macroscopic stress-strain relationship. Therefore, the micromechanical approach in which the deformation of granular soils is regarded as a mutual interaction between particle contacts is one of the best ways to investigate the anisotropic deformation of soils. In this study, a numerical program based on the theory of micromechanics is developed. Modified Hertz-Mindlin model is adopted to represent the force-displacement relationship in each contact point for the realistic prediction of anisotropic moduli. To evaluate the model parameters, a set of analytical solutions of anisotropic moduli is derived in the isotropic stress condition. By comparing the analytical solutions with exact values, we confirm that the analytical solutions can be utilized to evaluate model parameters within the acceptable range of error of 10%.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.3
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• pp.106-115
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• 2009

Knowledge about how to stabilize soil structure is essential to conserve soil systems and maintain various biogeochemical processes through soil. In urban area, soil structural systems are degraded with inappropriate management and land use and become vulnerable to erosion. We analyzed the structural changes of surface soils with different land uses, i.e., forests, parks, roadside green area, riparian area, and farmlands (soybean fields), in the Anyang Stream Watershed in order to find the factors influencing the stability of soil structure and the implication for better management of surface soil. Soil organic matter contents of other land use soils were only 18~52% of that in forest soils. Soil organic matter increased the stability of soil aggregates in the order of soybean fields < roadsides < riparian < parks < forests and also reduced soil bulk density (increased porosity). The lowest stability of soybean field soils was attributed to the often disturbance like tillage and it was considered that higher stability of park soils comparing to other land use soils except forests was owing to the covering of soil surface with grass. These results suggest that supply of soil organic matter and protection of soil surface with covering materials are very important to increase porosity and stability of soil structure.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.529-531
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• 2003

In order to investigate the level of heavy metal contamination and the seasonal variation of metal concentrations in soils and sediments influenced by past mining activities, tailings, soil and sediment samples were collected from the Hwacheon mine in Korea. The main pollution sources in this mine site are suggested as tailings and mine waste rocks. Elevated levels of Cd, Pb and Zn were found in soils and sediments. In a study of seasonal variation on the heavy metals in soils and sediments, heavy metals were higher enriched collected from before rainy season ($2^{nd}$ sampling) than after rainy season ($1^{st}$ sampling). Also, in order to estimate the microbial effects on Cd speciation in sediments, bacteria which can adsorb Cd was isolated and Cd adsorption characteristics of isolated bacteria in Cd solution was evaluated. The Cd bioremoval efficiency in Cd solution (5 ppm) by bacteria was more than $90\%$. Bioremoval efficiency in single metal solution was higher than that in mixed metal solution of Pb and Zn.

• 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.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.572-576
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• 2016

Soil quality assessment is an important tool for environmental management in an agricultural field. It can be used to evaluate the health of the soils and to establish the basis for sustainable urban agriculture and soil management. For this study, the chemical properties of the soils used for urban agriculture were examined. Results of the soil analysis for chemical properties were applied to soil quality assessment system, which is composed of principal component analysis, application to scoring function and derivation of soil quality index (SQI). Soil pH, electrical conductivity (EC), organic matter (OM), total nitrogen (T-N) were determined for minimum data set (MDS) according to principal component analysis. Based on the results of scoring for four indicators (pH, EC, OM, T-N), soil pH was the indicator that needs the most urgent management. Results of SQI derivation showed that many of the urban farms appeared to be insufficient score in comprehensive soil quality assessment. In conclusion, soil management practices based on scores derived from soil chemical indicators need to be carried out to maintain sustainable urban agricultural soil environment and to provide easy-to-understand information to urban farmers.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1206-1211
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• 2010

Soil-cement, a hardened mixture of Portland cement, soil, and water that contain sufficient durability, has been widely utilised in Seoul urban construction sites to retain lateral earth pressures or reinforce grounds. However, little information has been reported about the strength characteristics of soil-cement constructed in Seoul urban area. In this study, we performed a number of unconfined test to the soil-cements mixed from soils sampled in 3 sites in Seoul urban area. Results indicate that unconfined strengths and optimum cement amounts of soil-cements are highly dependent on the proportion of coarse-grain particles of mixed soils. Furthermore, changes of unconfined strengths with curing time are diverse with respect to mixing conditions.