• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.341-346
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• 2016

This study was conducted to analyze soil physico-chemical properties of agricultural land composed from the river-bed sediments. We investigated the changes of soil physico-chemical properties at 30 different sampling sites containing paddy, upland and plastic film house from 2012 to 2015. pH, exchangeable calcium and magnesium decreased gradually in paddy soils during the four years, whereas the available $P_2O_5$, exchangeable Ca, Mg and EC increased in upland and plastic film house soil. For the soil physical properties, bulk density and hardness of topsoil were $1.47g\;cm^{-3}$ and 21.5 mm and those of subsoil were $1.71g\;cm^{-3}$ and 25.7 mm in paddy soils. In upland soils, bulk density and hardness of topsoil were $1.48g\;cm^{-3}$ and 15.9 mm and those of subsoil were $1.55g\;cm^{-3}$ and 16.9 mm. In plastic film house soils, bulk density and hardness of topsoil were $1.42g\;cm^{-3}$ and 14.4 mm and those of subsoil were $1.40g\;cm^{-3}$ and 18.5 mm, respectively. The penetration hardness was higher than 3 MPa below soil depth 20 cm, and it is impossible to measure below soil depth 50 cm. As these results, in agricultural anthropogenic soils dredged from river basins, the pH, amount of organic matter and exchangeable cations decreased and soil physical properties also deteriorated with time. Therefore, it is needed to apply more organic matters and suitable amount of fertilizer and improve the soil physical properties by cultivating green manure crops, deep tillage, and reversal of deep soils.

• The Journal of Natural Sciences
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• v.19 no.1
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• pp.65-75
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• 2008

This research was conducted to determine heavy metal contents of soil and tree in pear orchard located near national road with heavy traffics. Topsoil (0-15 cm depth) and subsoil (15-30 cm) samples in pear orchard located within 40 m from national road had higher Pb, Cu, and Zn contents than background orchard (BG) and these heavy metal contents decreased with distance from road. Topsoil samples taken at 10 m from national road had 4 times higher level in Pb, 3 times in Cu, and 2.5 times in Zn compare to BG. The Cd contents of topsoil in orchard were higher than those of BG but were not in subsoil. Highest heavy metal contents of pear leaves in roadside orchard were 20.08 in Pb, 7.02 in Cu, 30.83 in Zn, and $1.68\;mm.kg^{-1}$ in Cd and these heavy metal contents in roadside orchard were higher than BG. Cd contents of fruit and Pb contents of fruit stalk in roadside orchard were higher than BG and these heavy metal contents decreased with distance up to 40 m from the road.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.1 no.1
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• pp.141-150
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• 1998

This study was conducted to find out the possibility of seeding of Zoysia japonica and woody plants for the revegetation of rock-exposed-cutslopes by Natural Topsoil Restoration Methods (NTRM). The 5cm thick layer of artificial soil was attached at rock-exposed cutslopes for the growth of Zoysia japonica and native woody plants by NTRM. The main results were summarized as follows. 1. Artificial soil attached at rock-exposed-slopes by NTRM was not eroded until recovered by Zoysia japonica and native woody plants. It shows extremely low soil erodibility. 2. One year later after seeding, woody plants show 100% ground coverage. But, in early stage, they grew more quickly at northwest slopes than at southeast slopes. 3. In seeding of Zoysia japonica, it grew more quickly at southeast slopes than at northwest slopes. Also, it grew better at lower part of the slopes than at middle part of the slopes. 4. After one year from seeding, the height of Lespedeza cyrtobotrya and Indigo/era pseudo-tinctoria were longer than any other plants. The next were Albizzia julibrissin, Lespedeza cuneata and wild flowers. The tree height of Rhus chinensis shows 28cm length, so it has enough possibility to be used for roadside revegetation works. 5. Lespedeza cyrtobotrya and Indigo/era pseudo-tinctoria show different importance values according to slope aspect. But, they show tendency to outweigh the other plants at all slope-aspects. 6. Most of the plants seeded by NTRM were germinated well and they covered rock-exposed-slopes so quickly and effectively. Thus it leads to conclusion that the revegetation methods used in this experiment was a very effective methods to recover rock-exposed-slopes by seeding of zoysia japonica and native woody plants.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.2
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• pp.105-110
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• 1994

Field experiment was carried out to obtain the basic information on the soil improvement with different improved methods on job's tears yield and soil properties in the newly-reclaimed land from 1985 to 1988. Job's tears yield, soil properties and annual changes of soil were investigated and analyzed. Soil bulk density and hardness of topsoil decreased from 1st year to 3rd year, but those increased in 4th year. Soil pH of topsoil had no differences in different soil depths and cultivated years. Average yield of job's tears in the integrated improvement plot was 2.16ton/ha. That was increased by 49% than the control plot. Crop yield was greatest in order of integrated improvement>subsoiling>phosphate>lime>compost>control plot. Correlation coefficients of job's tears yield with soil pH and organic matter content were higher significantly. Also those of subsoil were higher than topsoil. Ratios of annual changes of soil bulk density and hardness showed significant highly with job's tears yield. Also that soil pH was significant at 5 % level in the topsoil.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.351-360
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• 2015

Human influence on soil formation has dramatically increased with human civilization and industry development. Increase of anthropogenic soils induced researches on the anthropogenic soils; classification, chemical and physical characteristics of anthropogenic soils and plant growth from anthropogenic soils. However there have been no comprehensive analyses on soil pore or physical properties of anthropogenic soils from 3 dimensional images in Korea. The objectives of this study were to characterize physical properties of anthropogenic paddy field soils by depth and to find differences between natural and anthropogenic paddy field soils. Soil samples were taken from two anthropogenic and natural paddy field soils; anthropogenic (A_c) and natural (N_c) paddy soils with topsoil of coarse texture and anthropogenic (A_f) and natural (N_f) paddy soils with topsoil of fine texture. The anthropogenic paddy fields were reestablished during the Arable Land Remodeling Project from 2011 to 2012 and continued rice farming after the project. Natural paddy fields had no artificial changes or disturbance in soil layers up to 1m depth. Samples were taken at three different depths and analyzed for routine physical properties (texture, bulk density, etc.) and pore properties with computer tomography (CT) scans. The CT scan provided 3 dimensional images at resolution of 0.01 mm to calculate pore radius size, length, and tortuosity of soil pores. Fractal and configuration entropy analyses were applied to quantify pore structure and analyze spatial distribution of pores within soil images. The results of measured physical properties showed no clear trend or significant differences across depths or sites from all samples, except the properties from topsoils. The results of pore morphology and spatial distribution analyses provided detailed information of pores affected by human influences. Pore length and size showed significant decrease in anthropogenic soils. Especially, pores of A_c had great decrease in length compared to N_c. Fractal and entropy analyses showed clear changes of pore distributions across sites. The topsoil layer of A_c showed more degradation of pore structure than that of N_c, while pores of A_f topsoil did not show significant degradation compared with those of N_f. These results concluded that anthropogenic soils with coarse texture may have more effects on pore properties than ones with fine texture. The reestablished paddy fields may need more fundamental remediation to improve physical conditions.

• The Journal of Engineering Geology
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• v.33 no.1
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• pp.69-83
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• 2023

Forest fires increase the risk of subsequent soil erosion and mass movement in burned areas, even under rainfall conditions below landslide alert thresholds, by destroying plants and vegetation and causing changes to soil properties. These effects of forest fires can alter runoff in burned areas by altering soil composition, component minerals, soil water repellency, soil mass stability, and soil fabric. Heat from forest fires not only burns shallow organic matter and plants but also spreads below the surface, affecting soil constituents including minerals. This study analyzed X-ray diffraction and physical properties of topsoil and subsoil obtained from both burned and non-burned areas to identify the composition and distribution of clay minerals in the soil. Small amounts of mullite, analcite, and hematite were identified in burned soils. Vermiculite and mixed-layer illite/vermiculite (I/V) were found in topsoil samples from burned areas but not in those from non-burned areas. These findings show changes in soil mineral composition caused by forest fires. Expansive clay minerals increase the volume of soil during rainfall, degrading the structural stability of slopes. Clay minerals generated in soil in burned areas are therefore likely to affect the long-term stability of slopes in mountainous areas.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2010.10a
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• pp.208-212
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• 2010

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.4
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• pp.55-66
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• 2011

The objective of this study was to investigate the possibility of seeding methods for quarry rehabilitation. To achieve the objective, the experiment was designed for rehabilitation of quarry with seed mixing types (woody type and herbaceous type) and forest topsoil. Seeds and seeding materials were applied to the quarry slope using hydroseeding measures. The study was conducted in limestone quarry (Lafarge Halla Cement Inc.) near Baekdu Daegan Mountain System at Okke, Kanwon-do. The experimental seedbed was set in 2007 and field investigation was carried out from 2007 to 2010. As the result of experiment, it was found that the early-phase pattern for surveyed species to establish was affected by the soil mixture types. The mixture type of herbaceous seeds resulted in the higher plant coverage than the woody seeds. The application of forest topsoil showed a potential increase the plant diversity, but it was affected by mixing seeds. Naturally-emerged species as Alnus hirsuta, Quercus mongolica will be useful for rehabilitation at the quarry and damaged slopes.

• Geomechanics and Engineering
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• v.32 no.1
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• pp.85-96
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• 2023

Microbially induced carbonate precipitation (MICP) is extensively discussed as a promising topic for ground stabilization. The practical effect of stabilizing the expansive soil is presented in this paper with a logical process from the bacterial activity to the treatment technology. Temperature, pH, shaking frequency, and inoculation amount are discussed to evaluate the bacterial activity. The physic-mechanic properties are also evaluated to discuss the effect of the MICP process on expansive soil. Results indicate that the MICP method achieves the mitigation of expansion. The treated soil has a low proportion of fine particles (< 5 ㎛), the plasticity index significantly decreases, and strength values improve much. MICP process has a significant cementation effect on the soil matrix. Moreover, the infiltration model test presents the coating effect on the topsoil. According to the relation between the CaCO₃ content and the treatment effect, the topsoil has better treatment than the deeper soil.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.159-159
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• 2022

Soil represents a substantial component within the global carbon cycle and small changes in the SOC stock may result in large changes of atmospheric CO₂ particularly over tens to hundreds of years. In this study, we aim to (i) evaluate the SOC stock in the topsoil 0 - 15 cm from soil physical and chemical characteristics and (ii) find the correlation of SOC and soil organic matter (SOM) for national-scale in South Korea. First of all, based on the characteristics of the soil to calculate the soil hydraulic properties, SOC stock is the SOC mass per unit area for a given depth. It depends on bulk density (BD-g/cm³), SOC content (%), the depth of topsoil (cm), and gravel content (%). Due to insufficient data on BD observation, we establish a correlation between BD and SOC content, sand content, clay content parameter. Next, we present linear and non-linear regression models of BD and the interrelationship between SOC and SOM using a linear regression model and determine the conversion factor for them, comparing with Van Bemmelen 1890's factor value for the country scale. The results obtained, helps managers come up with suitable solutions to conserve land resources.