• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.1-6
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• 2016

Carbonized biomass could be used as a mechanism for long-term storage of C in soils. However, experimental results are variable. Objective of this study was carried out to evaluate the effect of carbonized biomass made from soybean residue on soil organic carbon and seed yield during soybean cultivation. The carbonized biomass was made by field scale mobile pyrolyzer. Pyrolyzer was performed in a reactor operated at $400{\sim}500^{\circ}C$ for 2 hours using soybean residue. The treatments consisted of four levels as the control without input and three levels of carbonized biomass inputs as $357kg\;ha^{-1}$, C-1 ; $714kg\;ha^{-1}$, C-2 ; $1,428kg\;ha^{-1}$, C-3. It was appeared that seed yield of soybean was $2,847kg\;ha^{-1}$ for control, $2,897kg\;ha^{-1}$ for C-1, $2,946kg\;ha^{-1}$ for C-2 and $3,211kg\;ha^{-1}$ for C-3 at the end of experiment. It was shown that the contents of SOC were $5.21g\;kg^{-1}$ for C-1, $5.93g\;kg^{-1}$ for C-2, $7.00g\;kg^{-1}$ for C-3 and $4.73g\;kg^{-1}$ for the control at the end of experiment. Accumulated SOC contents linearly significantly (P < 0.001) increased with increasing the carbonized biomass input. The slopes (0.00162) of the regression equations suggest that SOC contents from the soil increase by $0.162g\;kg^{-1}$ with every $100kg\;ha^{-1}$ increase of carbonized biomass rate. Consequently the carbonized biomass for byproducts such as soybean residue could increase SOC. It might be considered that the experimental results will be applied to soil carbon sequestration for future study. More long-term studies are needed to prove how long does SOC stay in agricultural soils.

• 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.

• The Plant Pathology Journal
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• v.26 no.2
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• pp.198-202
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• 2010

A study was conducted to find out the relationship of physico-chemical properties (viz. organic carbon(OC), pH, electrical conductivity, nitrogen, phosphorus and potassium content) of ginger growing soil with incidence percentage of rhizome rot and wilt disease complex of ginger. Organic carbon content and pH of the ginger soil contributed significantly (93%) in the prediction of ginger rhizome rot and wilt disease complex incidence with negative correlation. Soil having weak acidic reaction with OC percent greater than 2.25 was observed to have the lower average incidence of the disease.

• Journal of Forest and Environmental Science
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• v.32 no.1
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• pp.20-26
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• 2016

DTPA (Diethelene-triamine pentaacetic acid) extractable micronutrients of surface soil samples from six different locations of Cox's Bazar and Chittagong districts were studied. All the soils under study were sufficient in DTPA extractable Fe, Mn and Cu contents. The available Zn contents in soils of Dulhazara, Chengchhari and Faissakhali under study were also above the critical limit while soils at Fulchhari, Hasnabad and CU were deficient in available Zn. The study also showed that DTPA extractable Fe content had the significant and positive relationships with clay and soil organic carbon. On the hand, negative and significant relationship was observed between extractable Mn and soil pH while DTPA extractable Zn and Cu were positively and significantly correlated with soil organic carbon of the studied area.

• Korean Journal of Environmental Agriculture
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• v.39 no.1
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• pp.65-74
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• 2020

BACKGROUND: Soil carbon sequestration has been investigated for a long time because of its potential to mitigate the greenhouse effect. No- or reduced tillage, crop rotations, or cover crops have been investigated and practiced to sequester carbon in soils but the roles of soil biota, particularly microorganisms, have been mostly ignored although they affect the amount and stability of soil organic matters. METHODS AND RESULTS: In this study we analyzed the organic matter and microbial community in organically cultivated corn field soils where no-tillage (NT) or conventional tillage (CT) had been practiced for about three years. The amounts of organic matter and recalcitrant carbon pool were 18.3 g/kg dry soil and 4.1 g C/kg dry soil, respectively in NT soils, while they were 12.4 and 2.5, respectively in CT soils. The amounts of RNA and DNA, and the copy numbers of bacterial 16S rRNA genes and fungal ITS sequences were higher in NT soils than in CT soils. No-tillage treatment increased the diversities of soil bacterial and fungal communities and clearly shifted the bacterial and fungal community structures. In NT soils the relative abundances of bacterial phyla known as copiotrophs, Betaproteobacteria and Bacteroidetes, increased while those known as oligotrophs, Acidobacteria and Verrucomicrobia, decreased compared to CT soils. The relative abundance of a fungal phylum, Glomeromycota, whose members are known as arbuscular mycorrhizal fungi, was about two time higher in NT soils than in CT soils, suggesting that the higher amount of organic matter in NT soils is related to its abundance. CONCLUSION: This study shows that no-tillage treatment greatly affects soil microbial abundance and community structure, which may affect the amount and stability of soil organic matter.

• Korean Journal of Microbiology
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• v.53 no.1
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• pp.9-19
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• 2017

We studied soil composition, $N_2O$ production, a number of denitrifying bacteria, community structure and T-RFLP patterns of denitrifying bacteria dependent on agricultural methods with the change of seasons. Analyses of the soil chemical composition revealed that total carbon and total organic carbon contents were 1.57% and 1.28% in the organic farming soil, 1.52% and 1.24% in the emptiness farming soil, and 1.40% and 0.95% in traditional farming soil, respectively. So, the amount of organic carbon was relatively high in the environment friendly farming soils than traditional farming soils. In case of $N_2O$ production, the amount of $N_2O$ production was high in May and November soils, but the rate of $N_2O$ production was fast in August soil. The average number of denitrifying bacteria were $1.32{\times}10^4MPN{\cdot}g^{-1}$ in the organic farming soil, $1.17{\times}10^4MPN{\cdot}g^{-1}$ in the emptiness farming soil, and $6.29{\times}10^3MPN{\cdot}g^{-1}$ in the traditional farming soil. It was confirmed that the environment friendly farming soil have a larger number of denitrifying bacteria than the traditional farming soil. As a result of the phylogenetic analyses, it was confirmed that six clusters were included in organic farming soil among total 10 clusters. And the result of PCA profile distribution of T-RFLP pattern on agricultural methods, the range of distribution showed wide in the organic farming method, relatively narrow in the conventional farming method, and middle in the emptiness farming method. Therefore, we could concluded that the distribution and the community structure of denitrifying bacteria were changed according to the agricultural methods and seasons.

• Journal of Ecology and Environment
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• v.42 no.4
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• pp.163-173
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• 2018

Background: Deforestation and degradation are currently affecting the ecosystem services of forests. Among the ecosystem services affected by deforestation and degradation are the amount of soil organic carbon (SOC) and total nitrogen (TN) stored in forest soils which have greater impacts in global climate change. This study aimed at examining the amount of SOC and TN in the forest fragments which were separated from the continuous tracts of forests of Jibat and Chillimo through fragmentation processes over four decades. Methods: We have sampled soils from 15 forest fragments of Chillimo and Jibat in the central highlands of Ethiopia. The soil samples obtained in two separate soil depths (0-30 and 30-60 cm) were bulked, dried, and sieved for analysis. Results: Our results have shown that the two sites (Jibat and Chillimo forest fragments) differed in their SOC and TN contents. While the values for Jibat were found to be 29.89 Mg/ha of SOC and 2.84 Mg/ha for TN, it was 14. 06 Mg/ha of SOC and 1.40 Mg/ha for TN for Chillimo. When all forest fragment soil samples were bulked together, Jibat site had twice the value of SOC and TN than Chillimo. When disaggregated on the basis of each fragments, there existed differences in SOC (1.86 Mg/ha and 42.15 Mg/ha) and TN (0.24 Mg/ha and 4.23 Mg/ha) values. Among the forest fragments, fragment four ($F_4$) had the highest Relative Soil Improvement Index (RSII) value of 3826.82% and fragment fifteen ($F_{15}$) had the lowest RSII value (726.87%) which indicated that the former had a better quality of soil properties than the latter. Conclusion: SOC and TN differed across sampled fragments and sites. Variations in soil properties are the reflections of inherent soil parent material, aboveground vegetation, human interferences, and other physical factors. Such differences could be very important for identifying intervention measures for restoration and enhancing ecosystem services of those fragments.

• Journal of Korean Society on Water Environment
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• v.29 no.4
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• pp.489-496
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• 2013

Ground water underlying soil is vulnerable to pollution by organic chemicals through their percolation through the soil system. This study was conducted to provide information on the seepage behavior of organic chemical contaminants in clay, silty and sandy soils. Chloroform, 1,1,1-trichloroethane and trichloroethylene are readily transported through the soil; their percolated mass were 4.6-19.2 percent of the total mass applied. Tetrachloroethylene, 1,2-dichlorobenzene and 1,3-dichlorobenzene were retarded by soils due to sorption. Between 0.6 and 4.8 percent of the material applied to the surface percolated within the experimental period. Carbon tetrachloride was attenuated considerably by passage through soils. Only 0.1-0.4 percent of the mass reached the groundwater. Significant degradation of bromoform was observed. Apparent breakdown of intermediates of the brominated compounds were detected. Transformations of the brominated compounds appear to be the result of both biological and chemical processes. The effect of soil type on the mobility of organic chemical contaminants was considerable. The organic contaminants moved faster in sandy soil than in either clay or silty soils.

• Proceedings of the Korean Geotechical Society Conference
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• 1997.03a
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• pp.179-186
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• 1997

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.246-249
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• 2002

Black shale that has relatively high organic carbon content was tested to determine its sorption phenomena and capacity for TCE. Conventional batch sorption tests were peformed at room temperature. The parameters that were thought to affect the TCE sorption were solution pH and dissolved organic matter. The effect of solution pH on TCE sorption was minimal, but the dissolved organic matter increased the amount of TCE sorbed on black shale. Thus, using black shale as sorbent for TCE in groundwater could save material costs by replacing high cost conventional activated organic carbon.