• Journal of Korea Soil Environment Society
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• v.3 no.3
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• pp.109-116
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• 1998

Treatability tests of a soil washing device were performed for the remediation of eil-contaminated soil. The contaminant-containing soil with water was first fed into a oc-current screw conveyor and then into a counter-current washer. Surfactant was introduced into the washer and feeding soil was continuously separated on the basis of #40 mesh at the same time. A washing efficiency of 97.9% was achieved by the the soil washing device optimized.

• Korean Journal of Agricultural Science
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• v.40 no.2
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• pp.101-106
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• 2013

To know how much damages occurred by nematodes in plastic vinyl house field, soil samples were collected from strawberry cultivation areas at Buyeo and Nonsan in Chungnam and Jinju in Kyeongnam, melon cultivation area at Gocksung in Junnam and cucumber field at Gongju in Chungnam. And then, nematode samples were separated from each soil sample, and identified the kind of plant-parasitic nematodes. Plant-parasitic nematodes were separated from 52 soil samples. Among samples, Meloidogyne spp., Pratylenchus spp. and Helicotylenchus spp. were isolated from 45 (86.5%%) and 33 (63.5%) and 47 collected soil samples (90.4%), respectively. As a result of identification of plant-parasitic nematodes from regional collected soil samples, distribution of Helicotylenchus spp. was higher than any other plant-parasitic nematode. And the population of Meloidogyne spp. and Pratylenchu spp. were also higher, and a occurrence ratio of Meloidogyne spp. is higher than Pratylenchu spp. except the cucumber growing area at Gongju.

• KSBB Journal
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• v.4 no.1
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• pp.8-10
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• 1989

Mutagenic characteristics deactivation of 7, 12-dimethylbenz(a)anthraracene was studied in a nonacclimated sandy loam soil at low and neutral pH soil conditions. Soil extracts containing transformation products were separated into three fractions based on HPLC retention time(polarity). Highly polar transformation products of 7, 12-dimethylbenz(a)anthracene demonstrated a negative mutagenic response with the Ames mutagenicity assay, strain TA-100, for both low and neutral pH soils. Moderate and low polar fractions, however, induced mutagenicity for both soil samples with mutagenic ratios similar to those of the parent compound.

• Journal of Forest and Environmental Science
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• v.37 no.2
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• pp.116-127
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• 2021

Predicting carbon distribution of soil aggregates is difficult due to complexity in organo-mineral formation. This limits global warming mitigation through soil carbon sequestration. Therefore, knowledge of land use effect on carbon stabilization requires quantification of soil mineral cations. The study was conducted to quantify carbon and base cations on soil mineral fractions in Natural Forest, Plantation Forest and Farm Land. Five 0.09 ha were demarcated alternately along 500 m long transect with an interval of 50 m in Natural Forest (NF), Plantation Forest (PF) and Farm Land (FL). Soil samples were collected with soil cores at 0-15, 15-30 and 30-45 cm depths in each plot. Soil core samples were oven-dried at 105℃ and soil bulk densities were computed. Sample (100 g) of each soil core was separated into >2.0, 2.0-1.0, 1.0-0.5, 0.5-0.05 and <0.05 mm aggregates using dry sieve procedure and proportion determined. Carbon concentration of soil aggregates was determined using Loss-on-ignition method. Mineral fractions of soil depths were obtained using dispersion, sequential extraction and sedimentation methods of composite soil samples and sieved into <0.05 and >0.05 mm fractions. Cation exchange capacity of two mineral fractions was measured using spectrophotometry method. Data collected were analysed using descriptive and ANOVA at α_0.05. Silt and sand particle size decreased while clay increased with increase in soil depth in NF and PF. Subsoil depth contained highest carbon stock in the PF. Carbon concentration increased with decrease in aggregate size in soil depths of NF and FL. Micro- (1-0.5, 0.5-0.05 and <0.05 mm) and macro-aggregates (>2.0 and 2-1.0 mm) were saturated with soil carbon in NF and FL, respectively. Cation exchange capacity of <0.05 mm was higher than >0.05 mm in soil depths of PF and FL. Fine silt (<0.05 mm) determine the cation exchange capacity in soil depths. Land use and mineral size influence the carbon and cation exchange capacity of Gambari Forest Reserve.

• Tunnel and Underground Space
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• v.27 no.5
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• pp.312-323
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• 2017

In this study, an influence of mixing ratio among firing oyster shell, non-firing oyster shell, magnetic separated converter steel slag and fly ash used as admixtures on strength properties of soil cement was evaluated by correlation analysis among compressive strength, deformation modulus and mixing ratio of admixtures. As a result, the strength of the specimens containing non-firing oyster shells was found to be larger than that of firing oyster shells, and it was confirmed that firing oyster shells could negatively affect the strength of soil cement specimens unlike previous studies. In addtion, there was a positive correlation between the ratio of magnetic separated converter slag and strength properties, so it is confirmed that it can be used as an admixture.

• Membrane and Water Treatment
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• v.11 no.3
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• pp.189-193
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• 2020

In this study, electrokinetic remediation equipment was used to remove cesium (Cs) from clay soil and waste solution was treated with sorption process. The influence of electrokinetic process on the removal of Cs was evaluated under the condition of applied electric voltage of 15.0-20.0 V. In addition to monitoring the Cs removal, electrical current and temperature of the electrolyte during experiment were investigated. The removal efficiency of Cs from soil by electrokinetic method was more than 90%. After electrokinetic remediation, Cs was selectively separated from soil waste solution using sorbents. Various adsorption agents such as potassium nickel hexacyanoferrate (KNiHCF), Prussian blue, sodium tetraphenylborate (NaTPB), and zeolite were compared and KNiHCF showed the highest Cs removal efficiency. The Cs adsorption on KNiHCF reached equilibrium in 30 min. The maximum adsorption capacity was 120.4 mg/g at 0.1 g/L of adsorbent dosage. These results demonstrated that our proposed process combined electrokinetic remediation of soil and waste solution treatment with metal ferrocyanide can be a promising technique to decontaminate Cs-contaminated fine soil.

• Proceedings of the Korean Society of Crop Science Conference
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• 2019.09a
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• pp.21-21
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• 2019

Approximately 80% of rice field in Africa conducts in rainfed (Nishimaki 2017). The rice is damaged by water stress because fields like rainfed lowland repeat drying and humidity of soil because of impossible water control. Then water stress is one of the major limiting factors for decreasing rice yield. So, in initial growth stage, quick and efficient root development is useful way to avoid drought stress by getting water from deeper soil layer with roots elongation as the hypothesis. Daniel et al (2016) reported that NERICA1 and NERICA4 show different patterns of root plasticity for drought stress. NERICA1 has greater development of lateral root in shallow soil layer, while NERICA4 has greater development in deep root elongation to underground. This study was aimed to evaluate the effect of root development in initial growth stage on growing NERICA1 and NERICA4 under different soil moisture condition in rainfed lowland rice field. They were grown in same water condition until 35 days after sowing (35DAS), and after that each varieties were separated in dry and wet condition. The rice plants were grown until 60DAS. The results of soil moisture, the root extension angle, shoot dry weight and bleeding ratio showed that NERICA4 can mitigate dry stress from surface soil compered to NERICA1.

• Journal of Ecology and Environment
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• v.46 no.4
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• pp.282-291
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• 2022

Background: The Arctic permafrost stores enormous amount of carbon (C), about one third of global C stocks. However, drastically increasing temperature in the Arctic makes the stable frozen C stock vulnerable to microbial decomposition. The released carbon dioxide from permafrost can cause accelerating C feedback to the atmosphere. Soil organic matter (SOM) composition would be the basic information to project the trajectory of C under rapidly changing climate. However, not many studies on SOM characterization have been done compared to quantification of SOM stocks. Thus, the purpose of our study is to determine soil properties and molecular compositions of SOM in four different Arctic regions. We collected soils in different soil layers from 1) Cambridge Bay, Canada, 2) Council, Alaska, USA, 3) Svalbard, Norway, and 4) Zackenberg, Greenland. The basic soil properties were measured, and the molecular composition of SOM was analyzed through pyrolysis-gas chromatography/mass spectrometry (py-GC/MS). Results: The Oi layer of soil in Council, Alaska showed the lowest soil pH and the highest electrical conductivity (EC) and SOM content. All soils in each site showed increasing pH and decreasing SOC and EC values with soil depth. Since the Council site was moist acidic tundra compared to other three dry tundra sites, soil properties were distinct from the others: high SOM and EC, and low pH. Through the py-GC/MS analysis, a total of 117 pyrolysis products were detected from 32 soil samples of four different Arctic soils. The first two-axis of the PCA explained 38% of sample variation. While short- and mid-hydrocarbons were associated with mineral layers, lignins and polysaccharides were linked to organic layers of Alaska and Cambridge Bay soil. Conclusions: We conclude that the py-GC/MS results separated soil samples mainly based on the origin of SOM (plants- or microbially-derived). This molecular characteristics of SOM can play a role of controlling SOM degradation to warming. Thus, it should be further investigated how the SOM molecular characteristics have impacts on SOM dynamics through additional laboratory incubation studies and microbial decomposition measurements in the field.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.2
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• pp.94-99
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• 2015

The performance of chamber and bag digesters for solid state anaerobic digestion (SS-AD) of separated solid fraction of swine manure was investigated using lab-scale digester (4,460 mL total volume and 1,800 mL of effective volume) operating at $37^{\circ}C$ for 63 days. The performance of two different digester types was evaluated in terms of the kinetic constants of methane production obtained from the Gompertz and Gaussian equations. Methane production potential of chamber and bag digester was 202 and $218N{\cdot}mL$ $CH_4/g$ VS. Time to produce 95% methane production potential (T95) and calculated effective anaerobic digestion time were 55.5 days and 41.8 days for chamber digester and 52.8 days and 43.5 days for bag digester, respectively. Our results reveal that the performance was not significantly different between chamber and bag digester.

• Journal of Soil and Groundwater Environment
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• v.15 no.4
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• pp.13-20
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• 2010

The purpose of this study was to develope the remediation method of contaminated soils with metals and petroleum. The diesel degrading strain was isolated and identified from the soil contaminated by petroleum at industrial sites. Diesel biodegradation experiment was performed by diesel degrading bacteria in both solution and soil slurry. Contaminated soils by Zn or As and diesel were treated consecutively by steam-vapor extraction, biodegradation, and acid washing. The strain was identified as Pseudomonas aeruginosa, and named as Pseudomonas aeruginosa TPH1. The optimal culture conditions of TPH1 were $20^{\circ}C$ and pH 7.0, 3% of diesel concentration. Biodegradation of diesel was performed using the separated strain in liquid medium, and 63% of diesel was degraded in 72 hours. And 52% of diesel was removed in the tested soils. In the treatment of contaminated soils with diesel and Zn or As, 29% ~ 44% of diesel was reduced by steamvapor extraction, 60% ~ 71% of diesel was removed after biodegradation. 47% of Zn and 96% of As were removed after acid(mixture of sulfuric and oxalic acids) washing. It is recommended that consecutive treatment method of steam-vapor extraction, biodegradation and acid washing is effective for remediation of complex contaminated soils with metals and petroleum.