• Journal of Wetlands Research
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• v.22 no.4
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• pp.295-301
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• 2020

This research analyzed the relationship between environmental factors and the density of Sycios angulatus in the Miho Stream, Geum River water system in order to secure basic data for the control of the ecosystem-distrubing plant Sycios angulatus. As a result of the soil particle size analysis of Sycios angulatus habitat, it was found that the density of Sycios angulatus decreased as the silty and clay contents increased. Most of the Sycios angulatus habitats had high sandy and silt content, and low clay content of less than 2%. The increased flow rate reduced the density of Sicyos angulatus. This is because when the flow rate is increased, the Sicyos angulatus cannot grow due to the change in soil characteristics. Water quality plays a role in supplying nutrients when Sicyos angulatus are submerged. However, due to the change in soil characteristics during flooding, the density of Sicyos angulatus tended to decrease due to impaired growth. The Sicyos angulatus can be managed through artificial and natural techniques. The appropriate natural control technique is the creation of a natural waterway in the habitats to change the water contents.

• Korean Journal of Environmental Agriculture
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• v.23 no.1
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• pp.15-21
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• 2004

Objectives of this study were to monitor the distribution of heavy metals, to compare extractable heavy metal with total content and to investigate the relationships between soil physico-chemical properties and heavy metals in orchard soil. Sampling sites were 48 in Gyeonggi, 36 in Gangwon, 36 in Chungbuk, and 44 in Chungnam, Soils were collected farm form two depths, 0 to 20 and 20 to 40 cm (here after referred to as upper and lower layers) from March to May in 1998. Total contents of heavy metal in soils were analyzed by ICP-OES after acid digestion ($HNO_3$:HCl:$H_2O_2$) whereas extractable contents were measured after successive extraction of 0.1N-HCl, 0.05 M-EDTA, and 0.005 M-DTPA. Mercury was analysed by mercury atomizer. The average contents of Cd Cu, and Pb in the extractant with 0.1N-HCl at upper layer were 0.080, 4.23, and 3.42 mg/kg, respectively. As content in the extractant with 1N-HCl was 0.44 mg/kg, and total contents of Zn, Ni and Hg were 78.9, 16.1, and 0.052 mg/kg, respectively. The ratios of concentrations of heavy metals to threshold values (Cd 1.5, Cu 50, Pb 100, Zn 300, Ni 40, Hg 4 mg/ke in Soil Environmental Conservation Act in Korea (2001) were low in the range of $1/2.5{\sim}1/76.9$ in orchard soils. The ratios of extractable heavy metal to total content ranged $5.4{\sim}9.21%$ for Cd, $27.9{\sim}47.8%$ for Cu, $12.6{\sim}21.8$% for Pb, $15.8{\sim}20.3%$ for Zn, $5.3{\sim}6.3%$ for Ni, and $0.7{\sim}3.6%$ for Zn, respectively. Cu and Pb contents in 0.05 M-EDTA extractable solution were higher than those in the other extractable solution. Total contents of Cd, Ni and Ni in soils were negatively correlated with sand content but positively correlated with silt and clay contents. Ratios of extractable heavy metal to total content were negatively correlated with clay content but ai and Ni contents were positively correlated with soil pH, organic matter, and available phosphorous. Therefore, the orchard soil was safe because the heavy metal contents of orchard soil were very low as compared to its threshold value in the Soil Environmental Conservation Act. However, it need to consider the input of agricultural materials to the agricultural land for farming practices for assessment of heavy metals.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6C
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• pp.213-220
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• 2011

Fines such as silt or clay are usually mixed with granular particles in natural or reclaimed soils which are slightly cemented. Such fines contained within weakly cemented soils may influence permeability and also mechanical behavior of the soils. In this study, a series of unconfined compression tests on weakly cemented sands with fines are carried out in order to evaluate the effect of fines on unconfined compressive strength (UCS) of cemented soils. Two different cement ratios and fine types were used and fine contents varied by 5, 10, and 15%. Two types of specimens were prepared in this testing. One is the specimen with the same compaction energy applied. The other is the one with the same dry density by varying compaction energy. When the same amount of compaction energy was applied to a specimen, its density increased as a fine content increased. As a result, the UCS of cemented soils with fines increased up to 2.6 times that of one without fines as an amount of fines increased. However, when the specimen was prepared to have the same density, its UCS slightly decreased and then increased a little as a fine content increased. Under the same conditions, a UCS of the specimen with silt was stronger than the one with kaolin. As a cement ratio increased, a UCS increased regardless of fine type and content.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.3
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• pp.235-241
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• 2016

The soil does not only serve as a medium for plant growth but also for engineering construction purposes. It is very weak in tension, very strong in compression and fails only by shearing. The behaviour of the soil under any form of loading and the interactions of the earth materials during and after any engineering construction work has a major influence on the success, economy and the safety of the work. Soils and their management have therefore become a broad social concern. A limitless variety of soil materials are encountered in both agronomy and engineering problems, varying from hard, dense, large pieces of rock through gravel, sand, silt and clay to organic deposits of soft compressible peat. All these materials may occur over a range of physical properties, such as water contents, texture, bulk density and strength of soils. Therefore, to deal properly with soils and soil materials in any case requires knowledge and understanding of these physical properties. The desired value of bulk density varies with the degree of stability required in construction. Bulk density is also used as an indicator of problems of root penetration,soil aeration and also water infiltration. This property is also used in foundation engineering problems. While not conforming to standard test procedures, this work attempts to add to the basic information on such important soil parameters as water content, bulk density.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.5
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• pp.383-390
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• 2017

Heavy metal contamination of soil might be a cause of serious concern due to the potential health impacts of consuming contaminated products. In this study, the total content of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn, As, and Hg) in soils was analyzed, and the difference of heavy metal contents depending on crops, soil characteristics, and topography was compared in 169 greenhouse soils obtained from Gyeongnam Province. The concentrations of the heavy metals were $0.25mg\;kg^{-1}$ (ranged 0.01~0.44) for Cd, $28.94(0.53{\sim}72.63)mg\;kg^{-1}$ for Cr, $26.03(0.5{\sim}166.13)mg\;kg^{-1}$ for Cu, $14.91(1.27{\sim}33.22)mg\;kg^{-1}$ for Ni, $15.76(0.43{\sim}57.1)mg\;kg^{-1}$ for Pb, $119.72(6.33{\sim}239.39)mg\;kg^{-1}$ for Zn, $2.54(0.01{\sim}23.57)mg\;kg^{-1}$ for As, and $0.049(0.012{\sim}0.253)mg\;kg^{-1}$ for Hg in topsoils. The concentrations of Pb and As in topsoil were highest in green pepper and those of Cd, Cr, and Ni were highest in melon. In addition, the concentrations of Cr and Ni were highest in diluvial terrace compared with the other topographies. Higher concentrations of Cd, Cr, and Ni were found in silty clay loam and silt loam soils than sandy loam and loam soils.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.5
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• pp.599-608
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• 2009

This manuscript covers the results of field investigation and lab-scale experiments to design a double-layered biofilter system to control urban storm runoff. The biofilter system consisted of a coarse soil layer (CSL) for filtration and fine soil layer (FSL) for adsorption and biological degradation. The variations of flow rate and water quality of runoff from a local expressway were monitored for seven storm events. Laboratory column experiments were performed using seven kinds of soil and mulch to maximize pollutants removal. The site mean concentration (SMC) of storm runoff from the drainage area (runoff coefficient: 0.92) was measured to be 203 mg/L for SS, 307 mg/L for $TCOD_{Cr}$, 12.3 mg/L for TN, 7.3 mg/L for ${NH_4}^+-N$, and 0.79 mg/L for TP, respectively. This study employed a new design concept, to cover the maximum rainfall intensity with one month recurrence interval. Effective storms for last ten years (1998-2007) in seoul suggested the design rainfull intensity to be 8.8 mm/hr Single layer soil column showed the maximum removal rate of pollutants load when the uniformity coefficient of CSL was 1.58 and the silt/clay contents of FSL was virtually 7%. The removal efficiency during operation of double layer soil column was 98% for SS and turbidity, 75% for TCODCr, 56% for ${NH_4}^+-N$, 87% for TP, and 73-91% for heavy metals. The hydraulic conductivity of the soil column, 0.023 cm/sec, suggested that the surface area of the biofilter system should be about 1% of the drainage area to treat the rainfall intensity of one month recurrence interval.

• Journal of the Mineralogical Society of Korea
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• v.26 no.2
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• pp.65-80
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• 2013

Sediment transport mechanism and distribution of organic sediments are elucidated by the study of particle size, mineralogy, organic matters and microfossils of the surface samples collected from seafloor adjacent Dokdo island. Shallow marine sediments are dominated by coarse- grained sediments including gravel and sand, and their sedimentation has mainly been controlled by traction. While the samples collected from oceanic zone are characterized by high contents of fine- grained sediments such as silt and mud in bulk sediments, and the changes of mineral compositions including clay minerals and feldspar, and the fine sediments have been deposited mainly by suspension. The change of organic sedimentary communities is detected between neritic and oceanic zone. Although marine organic matter is predominant in neritic zone, terrestrial organic matter is monopolized according to increasing water depth. This trend is associated with grain size of sediments. The results also suggest that high pollen concentrations in whole organic matters may played an important role in excessive organic carbon in sediment.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.213-219
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• 1992

Geomorphological properties for the phylite-derived soil were examined to relate processes to four landscape positions, shoulder, backslope, footslope, and toeslope in Chungbuk. The distribution of Ogcheon-geology system was 216 thousand ha in South Korea. 2 orders, 3 suborders, 4 great groups, 5 subgroups, and 9 series were mapped. Soil color was interlocked by landscape. Soil color index values and $Fe_2O_3$ contents increased with soil-drainge class. Silt/clay and Ca/Mg ratios tended to narrow wish elevation and decreased with depth. Therefore, profile development or age on the landscape position was shoulder>backslope>footslope>toeslope. Color index(C2m) has a sighificant correlation with $Fe_2O_3$, in soil profile($r=0.777^{**}$). Pedologic type was continuity/discontinuity and soil property changes of depth<12cm would have a continous function.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.434-439
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• 2016

Anthropogenic soil in cropland is formed in the process of subsoil reversal and the refill of soil into cropland. However, there was little information on the chemical properties within soil profiles in anthropogenic soil under rice paddy near the river. In this study, we investigated the chemical properties within soil profiles in the anthropogenic soil located at 4 sites in Gumi, Kimhae, Chungju, and Euiseong to compare with the natural paddy soil near the river. Among particle sizes, the sand content decreased under soil profiles but the silt and clay contents increased compared to the natural paddy soil in soil profiles. Organic matter content in topsoil of anthropogenic soil was lower than in that of natural soil, which was shown the contrary tendency within soil profiles. Also, the soil pH, available $P_2O_5$, and exchangeable cations were higher in anthropogenic soil compared to natural paddy soil at topsoil, which was maintained these tendency into soil depth. Nutrients may be equally distributed in anthropogenic soil during the process of refill in paddy soil near the river. This results indicated that anthropogenic soil would contribute to carbon sequestration, the mitigation of compaction, and reduction of fertilizer application in paddy soil. Therefore, characteristics of anthropogenic soil can be used for the soil management in cropland.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.2
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• pp.79-85
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• 1991

This study reports on the physical and chemical properties of the whole soils (<2mm) derived from five major rocks of granite, granite-gneiss, limestone, shale, and basalt in Korea. The properties were considered from the kind and frequency distribution of rock-forming minerals in the parent rocks. In particle size distribution, sand fractions were high in the soils from granite-gneiss, silt fractions mainly, in the residual soils from limestone, shale, and basalt. And clay fractions were particularly high in the colluvial soil from limestone and the old alluvial soil from basalt. pH, extractable Ca and Mg, and cation exchange capacity of the soils derived from limestone might be considered to be high due to the presence of sand and/or silt-sized calcite and dolomite inherited from the parent rocks. However, the soils derived from granite and granite-gneiss, being abundant in feldspars, quartz, and micas, showed a tendency to the contrary. A soil from shale composing of high quartz tended to have pH. extractable Ca, base saturation, and low exchangeable Al. In total element analysis, the soils derived from parent rocks with high contents of (i) orthoclase and micas, (ii) biotite, primary chlorite, and augite, and (iii) carbonate minerals and plagioclase as a rock-forming mineral showed a tendency to decrease the contents of $K_2O$, $Fe_2O_3$ and MgO, and CaO in comparison with those of their parent rocks.