• Economic and Environmental Geology
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• v.38 no.3 s.172
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• pp.207-219
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• 2005

The physical and chemical characteristics of soils in a small watershed were investigated and the effect of geology and land use on soil quality were examined by using multivariate statistical methods, principal components analysis and discriminant analysis. The soil developed from andesite had finer texture and higher contents of water extractable inorganic components, clay, and mafic minerals than the soil developed from granite. It is considered that the accumulation of salts in the farmland soils indicated by electrical conductivity, contents of cations and anions and pH was caused by fertilizer input during cultivation. The low contents of organic matter in the farmland soils was due to the enhanced oxidation of organic matter by tillage and by the harvest of crops. The contents of inorganic components are increased as following order: upland > orchard > paddy field > forest. The high contents of water soluble $SO_4\;^{2-}$ of paddy soils is due to the oxidation of sulfides mineral formed during the flooding period during the air-dry and extraction. The results of principal components analysis show the difference of soil quality was controlled by geology and land use. PCI indicate the input of fertilizer, mineral weathering and ion exchange reaction by application of nitrogenous fertilizers. The results of two discriminant analyses using water extractable inorganic components and their ratios by land use were also clearly classified by discriminant function 1 and 2. In discriminant analysis by components, discriminant function 1 indicated the effect of fertilizer application and increased as following order: upland > orchard > paddy field > forest soil. The investigated and predicted data for land use from discriminant analysis showed similar results. The discriminant analysis can be used as a useful method certifying the change of land use.

• Journal of Soil and Groundwater Environment
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• v.12 no.1
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• pp.73-86
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• 2007

Risk-based remediation strategy (RBRS) is a consistent decision-making process for the assessment and response to chemical release based on protecting human health and the environment. The decision-making process described integrates exposure and risk assessment practices with site assessment activities and remedial action selection to ensure that the chosen actions are protective of human health and the environment. The general sequences of events in Tier 1 is as follows: initial site assessment, development of conceptual site model with all exposure pathways, data collection on pollutants and receptors, and identification of risk-based screening level (RBSL). If site conditions do not meet RBSL, it needs further site-specific tier evaluation, Tier 2. In most cases, only limited number of exposure pathways, exposure scenarios, and chemicals of concern are considered the Tier 2 evaluation since many are eliminated from consideration during the Tier 1 evaluation. In spite of uncertainties due to the conservatism applied to risk calculations, limitation in site-specific data collections, and variables affecting the selection of target risk levels and exposure factors, RBRS provides us time- and cost-effectiveness of the remedial action. To ensure reliance of the results, the development team should consider land and resource use, cumulative risks, and additive effects. In addition, it is necessary to develop appropriate site assessment guideline and reliable toxicity assessment method, and to study on site-specific parameters and exposure parameters in Korea.

• The Korean Journal of Pesticide Science
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• v.3 no.2
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• pp.29-36
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• 1999

The leaching behaviour of $^{14}C$-paraquat in soil was investigated using soil columns (5 cm I.D. ${\times}$ 30 cm H.) parked with two soils of different physicochemical properties. $^{14}C$-Activities leached from the soil A (loam) columns with and without rice plants for 117 days were 0.42 and 0.54% of the originally applied, whereas those from the soil B (sandy loam) were 0.21 and 0.31%, respectively. $^{14}C$-Activities absorbed by rice plants from soil A and B were 3.87 and 2.79%, respectively, most of which remained in the root. Irrespective of soil types, more than 96% of the total $^{14}C$ resided in soil, mostly in the depth of $0{\sim}5$ cm. The water-extractable $^{14}C$ in soil was in the range of $6.10{\sim}9.01%$ of the total $^{14}C$ applied. The rest of $^{14}C$, which corresponds to non-extractable soil residues of [$^{14}C$]paraquat, was distributed in humic substances in the decreasing order of humin>humic acid>fulvic acid. The soil pH of the columns without rice plants increased after the leaching experiment due to the flooded anaerobic condition resulting in the reduction of the $H^{+}$ concentration, whereas that of the columns with rice plants did not increase by the offsetting effect of the acidic exudates from the roots. Low mobility of paraquat in soil strongly indicates that no contamination of ground water would be caused by paraquat residues in paddy soils under normal precipitation.

• Horticultural Science & Technology
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• v.18 no.4
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• pp.529-535
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• 2000

Organic materials such as composted rice-hull, saw dust, and pine bark, and inorganic materials such as vermiculite, perlite, and recycled rockwool were commonly employed as container media in domestic greenhouse industry. The objective of this research was to get informations in soil physico chemical properties of those materials. Composted dry-peeling bark and wet-peeling bark had 72.1% and 69.1%, respectively, in particles larger than 1.0 mm, which were much higher than 34.7% of composted rice-hull and 33.7% of composted saw dust. Imported vermiculite had 89.9%, but domestic vermiculite had 25.7% in particles larger than 1 mm. In soil physical properties, Russian peat had the highest container capacity of 79.3%, and wet-peeling bark had the lowest container capacity of 58.2%. However, Russian peat and composted saw-dust had 4.1% in air space indicating that possible problems could occur in soil aeration when those are employed for container grown crops. Saw dust had $2.3mS{\cdot}cm^{-1}$ in electrical conductivity, while other composted organic materials had less than $0.25mS{\cdot}cm^{-1}$. Imported vermiculite had 64.0 meq/100 g in cation exchange capacity, which was 2.4 times higher than those of domestic vermiculite, 27.2 meq/100 g. Domestic vermiculite had higher Ca and Mg and less Na contents than those of imported vermiculite.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.5
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• pp.365-372
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• 2001

The objective of this study was to determine the effects of various kinds of composts on the change of soil physical properties and microorganism in upland soils. Field experiments were conducted in the loam and sandy loam soils, while the clay loam and sandy loam soils were used for laboratory experiments. Various kinds of composts such as poultry manure compost(PMC). cow manure compost(CMC). human excrement sludge(HES), and food industrial sludge compost(FISE) were applied annually at rates of 0, 40, and $80Mg\;ha^{-1}$ to soils grown with soybean and maize plants for 4 years during 1994 to 1997. The results of this study were as follows : Bulk density of loam soil decreased with compost application to $1.07{\sim}1.32Mg\;m^{-3}$ compared with $1.49Mg\;m^{-3}$ of control plot, while in sandy loam soil it decreased to $1.00{\sim}1.20Mg\;m^{-3}$ compared with $1.25Mg\;m^{-3}$ of control plot. Bulk density of soil was decreased according to maize cultivation compared with bare control, but soybean cultivation was similar. Population of organic material decomposing microorganisms was increased rapidly at the initial incubation stage at $25^{\circ}C$, and increased more sensitively at the loam soil than sandy loam soil. In the case of the change of microorganisms associated with nitrogen circulation, ammonia oxidizing bacteria was more at the initial incubation stage, and denitrifying bacteria was more at the initial incubation stage, and denitrifying bacteria increased until 1~4 weeks after incubation and increased more at the loam soil than sandy loam soil.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.2
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• pp.235-243
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• 2019

Radioactive materials are released into the air and deposited on the surface soil after a nuclear accident. Radionuclides deposited in soil are transported by precipitation to nearby environments and contaminate the surface water system. Basic data on surface watershed and soil erosion models have been collected and analyzed to evaluate the behavior of radionuclides deposited on surface soil after a nuclear accident. Data acquisition and analysis in aquatic environment were performed to investigate the physical characteristics and variation of biota in rivers and lakes of the Nakdong river area near the Wolsong nuclear power plant. For these purposes, a digital map, and hydrological, water quality and biota data were gathered and a systematic database (DB) was constructed in connection with them. Constructed aquatic DB will be supplied and used in surface watershed and soil erosion models for investigation of long-term movement of radionuclides in adsorptive form in surface soil. Finally, basic data and established models will be utilized for general radiological impact assessment in aquatic environment.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.1
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• pp.73-79
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• 2009

The hydraulic conductivity of porous media is the most important property in soil characteristics. The hydraulic conductivity is determined by outdoor and indoor methods. Indoor methods normally use soil columns for flow test. Assumption of the column test is that fluid one-dimensionally flows through the column. However, fluids may flow toward the wall of the column, resulting in "boundary flow". This study investigated the effect of boundary flow on the hydraulic conductivity by using a permeameter excluding boundary flow. The results showed that the hydraulic conductivity excluding boundary flow was much smaller than the hydraulic conductivity employing the conventional determination method. This study also investigated the effects of particle size and surfactant on the hydraulic conductivity. As the particle size increased, the hydraulic conductivity was increased. The hydraulic conductivity was reduced by increasing surfactant concentration. The result showed that the viscosity of fluid significantly affected the determination of hydraulic conductivity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.26-41
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• 2016

Catchment Hydrologic Cycle Assess Tool (CAT) is a model for hydrologic cycle assessment based on physical parameters. In this study, CAT was applied for short-term runoff simulation and connected with model-independent parameter estimation (PEST) for auto-calibrating parameters. The model performance was compared with HEC-HMS, which is widely used for short-term runoff simulation. The study area is the Pangyo Watershed ($22.9km^2$), which includes the Unjung-Cheon and Geumto-Cheon tributaries of the Tan-Cheon stream. Simulation periods were selected from six rainfall events of a two-year period (2006-2007). For the runoff simulation, CAT was applied using three types of infiltration methods (excess rainfall, Green and Ampt and Horton). Sensitivity analysis was carried out to select the parameters and then CAT was optimized using PEST. The model performance of HEC-HMS and CAT-PEST for the rainfall events were within an acceptable limit with Nash Sutcliffe efficiencies (NSE) of 0.63-0.91 and 0.42-0.93, respectively. The simulation results of HEC-HMS have high accuracy in the case of rainfall events that have a sensitive relationship between initial soil moisture conditions and runoff characteristics. The results of CAT-PEST indicated the possibility of reflecting a real runoff system using various physical parameters.

• Korean Journal of Organic Agriculture
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• v.23 no.4
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• pp.875-886
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• 2015

The upland soils (56 samples) from organic farms in Gyeonggi-do (12 sites), Gangwon-do (8 sites), Chungcheong-do (14 sites), Gyeongsang-do (4 sites), Jeollado (18 sites) in Korea were collected and their physical and chemical properties were analyzed by RDA's methods. In the results of physical property, the bulk density of soils averaged $1.14Mgm^{-3}$ (surface soil), $1.38Mgm^{-3}$ (subsoil), respectively. The porosity of them was 57%, 48%. Organically managed soil's (OS) bulk density was lower than conventional soil's but OS's porosity was a little higher than conventionally managed soil in surface soil. The depth of plough layer in organically managed soils was 21.2 cm indicating that the organic farming had good effect on soil physical property. In the results of chemical property, the surface soil pH was 6.9 and the contents of organic matter (OM) was $26gkg^{-1}$, available phosphate (Avail. $P_2O_5$) was $554mgkg^{-1}$, exchangeable calcium (Exch. Ca) was $8.9cmol_ckg^{-1}$, exchangeable potassium (Exch. K) was $0.89cmol_ckg^{-1}$, exchangeable magnesium (Exch. Mg) was $2.0cmol_ckg^{-1}$. The subsoil pH was 6.8 and the contents of OM was $21gkg^{-1}$, avail. $P_2O_5$ was $491mgkg^{-1}$, exch. Ca was $7.9cmol_ckg^{-1}$, exch. K was $0.68cmol_ckg^{-1}$, exch. Mg was $1.8cmol_ckg^{-1}$. The nutrient accumulation emerged in organic farming. Compared to the optimum nutrient range for the conventional upland soils, the exceed rate of pH, OM, available phosphate, and exchangeable Ca, K, and Mg was 79, 52, 64, 84, 66% and 55%, respectively, which mainly resulted from the over-application of lime materials or livestock manure compost. With these results it is suggested that organic farm need to reduce the use of inputs, which make soil alkalification or nutrient accumulation. More study on effects of inputs on lowering soil pH from alkalification could help organically managed soil to be improved.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.59-65
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• 2004

Interactions of phosphorus and zinc in soils are important to determine the availability of the elements because those elements are closely related in the agricultural environment. The objective of this study was to investigate the interactions of P and Zn using desorption quantity (Q)-intensily(I) isotherms. Physically and chemically different soils, acidic Egan, acidic sandy Egeland, calcareous Glenham, and neutral Maddock, were used. The soils were enriched with different concentrations of P and Zn as $KH_2PO_4$ and $ZnSO_4$ solutions, respectively. Zinc enrichments affected availability of P in the Egan soil, which contained higher amounts of clay, organic matter, and exchangeable Fe than the other soils tested. After Zn enrichments, the pH drastically decreased in Egeland sandy soil, not changed in the calcarious Glenham soil, and slightly decreased in Egan and Maddock soil systems. The values of $Q_{max}$ and $I_0$ of phosphorus decreased with increasing Zn concentrations enriched in all soils, the changes of those values did not influence the P buffering power, |$BP_o$| values, in most soils. The influences of P treatment on Zn availability were varied. The values of Zn buffering capacity, $BC_{Zn}$, were lowest in the Egeland soil that had the lowest soil pH, amounts of clay minerals, organic matter, CEC, and exchangeable Fe, and were highest in the calcareous Glenham soil. The $BC_{Zn}$ values ranged from 202 to 4480. With P application, the changes of $BC_{Zn}$ values were more affected by the changes of soil solution Zn contents (I) than the changes of DTPA extractable Zn contents(Q). The change of Q and I values was found to be dependent upon soil properties, especially, soil pH.