• Journal of the Korean Geographical Society
• /
• v.36 no.3
• /
• pp.233-246
• /
• 2001

Topography and soil characteristics of earth hummocks are examined in the summit crater of Mt. Halla in order to evaluate their morphoclimatic significance as an indicator of a periglacial environment. The hummocks are generally oval in outline, and they have a diameter of 42 to 200 cm and a height of 9 to 27 cm Seventeen hummocks are distributed In a 5$\times$5 m quadrat at an interval of 20 to 40 cm Excavation reveals the cryoturbated soil profiles which consist of upper dark brown layer and lower brown layer. The dark brown layer has 61.8% total clay and silt content, implying Its high frost susceptibility Earth hummocks have the dry density of 0.761 to 1.009 g/㎤ the void ratio of 1420 to 2.008, and the moisture content of 24.2 to 68.8% by weight, respectively. The hummocky soils become compacted and desiccated downward. Earth hummocks are frozen as a hard solid mass during winter and early spring, and freezing fronts reach about 45 cm below their apices. The layer with high lute content appears in the upper horizon of dark brown soil. but Ice lenses are not so much segregated The moisture content of hummocky soils generally increases up to 73.9 to 118.80% for dark brown layer and 49.9 to 82.8% for brown layer during thins period Because the cohesive soil of earth hummocks indicates 72.8% of the moisture content as a liquid limit, the dark brown layer is highly fluid and consequently subject to cryoturbation processes.

• Journal of Korean Society of Environmental Engineers
• /
• v.36 no.7
• /
• pp.469-475
• /
• 2014

The study investigated the physicochemical characteristics and the ecological risk of the Northport sediment in B city and the releasing properties of heavy metals into seawater during the resuspension also studied. The major components of the sediment are fine silt and clay which contains high organic matter and AVS (Acid volatile sulfide) and the ecological risk of the heavy metals in sediment also very high. The release rate of heavy metals into seawater was in order of Pb>>Cu>Cr>>Zn>Cd during the resuspension in a batch experiment, and the heavy metal release mainly attributed to the oxidation of metal sulfides. Heavy metals which came from easily oxidisable metal sulfides rapidly contaminated seawater within about 1.0 h of the sediment resuspension. The sulfide oxidation during the resuspension increased the residual fraction of heavy metals in the sediment, decreased the organic bound fraction, and changed the other fractions of heavy metals in the sediment. The release of heavy metals from the sediment during resuspension was affected by the resuspension time, the oxidation rate of metal sulfides and resuspended concentration of the sediment particle.

• Journal of Korean Society on Water Environment
• /
• v.33 no.4
• /
• pp.460-473
• /
• 2017

In order to certificate the contamination assessment of heavy metals in surface sediments from the Nakdong river. Surface sediments were collected of 24 sampling sites (main 14st., tributary 10st.) and analyzed for grain size heavy metals contents. Study area mainly composed of sand (avg. 94.1%) and mean grain size was $1.46{\Phi}$ on average. Heavy metals contents (avg. Al: 12.5%, Zn; 74.4, Cr: 45.3, Li: 26.0, Pb: 17.1, Ni: 10.5, Cu: 7.8, Cd: 0.22 mg/kg) were relatively high contents in the composed of fine sediments. In addition, the results of pearson's correlation coefficient showed that most heavy metals and grain size (silt and clay) were highly correlated. The contents of Zn (6st.) and Ni (1st.) evaluated as moderately polluted, Zn (6st.) evaluated as LEL when compared with sediment quality standard of USEPA and Ontario sediment quality guidelines. Most heavy metals contents were I levels that dose not affected the benthos when compared with sediment pollution evaluation standard of NIER. The results of EX, EF, Igeo and CF showed the contents of Zn, Pb and Cd exceed the background contents and distributing of anthropogenic pollution and evaluated as moderately polluted level. And Nm-08 were relatively high level of contamination in the study area. However as results of PLI (less than 1), all sampling sites were evaluated unpolluted level.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.12 no.2
• /
• pp.169-175
• /
• 1992

The Maximum Dry Density (${\gamma}_{dmax}$) and the Optimum Moisture Content (${\omega}_{opt}$) of the soil samples are determined from the compaction curve plotted with the laboratory compaction test results. But in this study three reported tests, and tests on the silty clay and the sandy silt samples are reviewed through the interpolation methods using an equation of the Moisture-Density relations induced from Lagrange's Interpolation Formula without drawing the compaction curves. As the results of the study ${\gamma}_{dmax}$ and ${\omega}_{opt}$, were calculated rapidly and simply using the equation and approached to the results from the compaction curves, and also due to the differences of the ${\gamma}_{dmax}$ and ${\omega}_{opt}$, calculated from the equation between the compaction curves were within $0.01g/cm^3$(0.5%) and 0.4% respectively the method in this study be recommended as a simple method determining ${\gamma}_{dmax}$ and ${\omega}_{opt}$, during the laboratory compaction tests.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.2 no.2
• /
• pp.155-160
• /
• 1969

The soil textures and chemical compositions of Tapes Philippinarum beds were investigated in order to estimate the grade of the habitat soil of T. Philippinarum for the improvement of natural tidal flats. The coefficients of correlation between tile percentages of debris, coarse sand, fine sand, silt, and clay of the habitat soil, and the population density of T. Philippinarum were 0.78, 0.73, -0.42, -0.68, and -0.51 respectively. And the optimum levels of same were above $13.5\%,\;above\;23.0\%\;below\;41.5\%,\;below\;10.0\%$, and below $6.8\%$ respectively The $SiO_2\;Al_2O_3+Fe_2O_3$ ratio of the soil of T. Philippinarum beds showed the range of 5.09 to 5.60. The levels of soil pH, water holding capacity, organic matter, total nitrogen, available phosphorus, exchangeable magnesium were 6.15-6.60, $4.26-6.86\%$, $0.40-1.10\%$ 14.0-27.0 ppm, $0.041-0.394\%,\;and\;0.009-0.132\%$ respectively.

• Journal of the Korean Geosynthetics Society
• /
• v.12 no.3
• /
• pp.31-41
• /
• 2013

In this study, the properties of mudstone weathered soils related to landslides were analyzed at the area of landslide induced by heavy rainfall in Pohang. The soil tests were carried out to the soils obtained from landslide and non landslide sites, and the soil properties were investigated. The correlation between soil properties and landslides were analyzed using statistical technique, and then the soil factors were extracted from the correlation analysis. The correlation equation which can calculate the coefficient of permeability influenced on landslides was proposed using the soil factors. As the result of analysis, the porosity and unit weight of soils from the landslide area is smaller than those of soils from the non landslide area. The soils with poor grain size distribution and loose unit weight are prone to landslides because the soils have a large void ratio and a low unit weight. The permeability of soils from the landslide area is larger than that of soils from the non landslide area. According to the result of correlation analysis, the effective grain size, the saturated unit weight and silt and clay contents are evaluated as the influence factors. These factors were considered to estimate the coefficient of permeability of mudstone weathered soils.

• Journal of Korean Society of Forest Science
• /
• v.111 no.3
• /
• pp.428-434
• /
• 2022

This study was conducted to derive the site index of forest productivity of Robinia pseudoacacia (honey plant) to characterize suitable planting sites and to investigate the effect of the site environmental factors on the site index using the quantification theory I method. The data used in the analysis were growth factors (stand age, dominant height, etc.) of the 6th national forest resources survey and various site environmental factors of a forest soil map (1:5,000). The average site index value of the R. pseudoacacia stand in Korea was 14 (range, 8 to 18). The environmental factors affecting the site index were parent rock, climatic zone, soil texture, local topography, and altitude. The accuracy of the estimation model using quantification theory I was only 33%. However, the correlation between the site index and the site environmental factors was statistically significant at the 1% level. Results of quantification analysis between site index and site environmental factors revealed that metamorphic and igneous rocks received high grades as parent rocks, climate zones received higher grades than central temperate zone, clay loam and silt loam received high grades in soil texture, and hillside received a high grade in local topography. Analysis of the partial correlation between site topographical factors and forest productivity (site index) found that soil class and altitude were partially correlated to x by 0.4129 and 0.4023, respectively, indicating that these factors are the most influential variables.

• Korean Journal of Environment and Ecology
• /
• v.36 no.4
• /
• pp.422-432
• /
• 2022

Soil and micro-climatic environmental monitoring was conducted to evaluate the factors causing tree growth impediments at the Baekdudaegan ecological axis restoration project site. As a result, it was found that the nutrient supply was insufficient in the restoration project site due to the lack of organic matter, total nitrogen and cation exchange capacity of the soil compared to the surrounding forest. After the completion of the restoration, the soil moisture in the autumn decreased more than 7 times faster than that of the surrounding forest, and it was evaluated that the soil moisture was significantly low due to the lack of silt and clay content. In the case of the restoration site, the annual potential evapotranspiration was analyzed to be 975mm, which is approximately two times higher than that of the surrounding forest. The soil moisture of the restoration site in the summer decreased rapidly during the daytime when the amount of insolation increased and this was found to be strongly influenced by the increase in potential evapotranspiration. In order to improve the above factors affecting the tree growth at the Baekdudaegan ecological axis restoration project site, it is necessary to induce the smooth supply of nutrients and water to plants by improving physical proprieties and cation exchange capacity, i.e., using litterfall, humus soil, soil conditioner and organic fertilizer. The results of this study are expected to serve as basic data for the design, construction, and management of ecological axis restoration projects in the future.

• Journal of Korean Society of Forest Science
• /
• v.113 no.1
• /
• pp.14-30
• /
• 2024

This study characterized areas at risk of land creep by focusing on a site that has undergone this phenomenon in Ulju-gun, South Korea. Land creep in the area of interest was catalyzed by road expansion work conducted in 2022. The site was examined on the basis of its geological features, topography, effective soil depth, soil hardness, electrical resistivity, and subsurface profile. It consists of a slope covered with sparse vegetation and a concave top that retains rainwater during rainfall. Compositionally, land creep affected the shale, sandstone, and conglomerate formations on the site, which had little silt and more sand and clay compared with areas that were unaffected by land creep. An electrical resistivity survey enabled us to detect a groundwater zone at the site, which explains the softness of the soil. Finally, the effective soil depth at the land creep-affected area was 30.4 cm on average, indicating deep colluvial deposits. In contrast, unaffected sites had an effective soil depth of 24.7 cm on average. These results should facilitate the creation of systems for monitoring and preemptively responding to land creep, significantly mitigating the socioeconomic losses associated with this phenomenon.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.3
• /
• pp.399-403
• /
• 2012

The management of heavy metals in soil is important for environmental-friendly agriculture and keeping an ecosystem healthy. In this study, we examined the concentrations of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn, and As) in 260 paddy soils sampled from Gyeongnam Province. The concentrations of the heavy metals were 0.143 mg $kg^{-1}$ (ranged 0.003-0.537) for Cd, 0.322 (0.002-0.986) mg $kg^{-1}$ for Cr, 25.41 (6.03-76.19) mg $kg^{-1}$ for Cu, 16.36 (2.63-32.94) mg $kg^{-1}$ for Ni, 18.67 (4.16-87.02) mg $kg^{-1}$ for Pb, 71.76 (22.99-153.58) mg $kg^{-1}$ for Zn, and 3.516 (0.002-19.481) mg $kg^{-1}$ for As, respectively. In addition, the concentration of Cd was highest in mountain foot-slope, Ni and As were highest in diluvial terrace, and Zn was highest in marine plains. Higher concentrations of Cd, Cu, and Zn were found in silty clay loam soils compared to silt loam, sandy loam, and loam soils.