• 한국환경과학회지
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• 제10권5호
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• pp.315-321
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• 2001

This study was conducted to estimate the decomposition capacity for organic matter by microbe of tidal flat sediments (Hajae, Dongjin and Mankyung). The decomposition rate constants (K') have been determined by Thomas slope method and compared with the values of each tidal flats. The decomposition rates of organic matter by microbe were initially very slow, but at the end of 12 hours, very sharply increased. The values of decomposition rate constant for Dongjin, Mankyung and Hajae tidal flat sediment were 1.364$day^{-1}$/, 1.080d$day^{-1}$ and 0.735$day^{-1}$, respectively. The decomposition rate constant of Dongjin tidal flat sediment which affected by livestock wastewater was higher than others. The decomposition quantity (mg/g/day) of organic matter by microbe of tidal flat sediments was 0.4mg/g/day for Dongjin, 0.36mg/g/day for Mankyung and 0.36mg/g/day for Hajae. The average of decomposition quantity was 0.37mg/g/day. To calculate purification capacity (kg/ha) of organic matter by microbe, we applied to two assumption ; 1) biological action by microbe is occur within 0.1cm under surface 2) specific gravity of sediment are 2.5g/$\textrm{cm}^2$. The purification capacity of organic matter by microbe of tidal flat sediment was calculated to 9.25kg/ha. The relationships between decomposition rate constant (K') and ignition loss (I. L), chemical oxygen demand by sediment (CO $D_{sed}$), total carbon(TC), silt and clay as index of organic matter were a high positive($R^2$=0.97~1.00).

• Journal of Ecology and Environment
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• 제43권1호
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• pp.14-21
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• 2019

Background: Stoichiometry plays an important role in understanding nutrient composition and cycling processes in aquatic ecosystems. Previous studies have considered C:N:P ratios constant for both DOM (dissolved organic matter) and POM (particulate organic matter). In this study, water samples were collected in the six major rivers in Korea and were incubated for 20 days. C:N:P ratios were determined during the time course of the incubations. This allowed us to examine the changes in N and P contents of organic matter during decomposition. Results: POM and DOM showed significant differences in N and P content and the elemental ratios changed during the course of decomposition; DOM showed higher C:N and C:P ratios than POM, and the C:N and C:P ratios increased during decomposition, indicating the preferential mineralization of P over N and N over C. Conclusions: The N and P contents of organic matter in aquatic ecosystem are far from constant and vary significantly during decomposition. More detailed information on the changes in C:N:P ratios will provide improved understanding of decomposition processes and improved modeling of aquatic ecosystems.

• 한국토양비료학회지
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• 제46권3호
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• pp.203-208
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• 2013

This study was conducted to investigate decomposition of livestock manure in soils cultivated with Chinese cabbage along an alitude gradient. The experiments were conducted in Kangreung (17 m above sea level), Bongpyeong (430 m above sea level), and Daekwanryeong (800 m above the sea level) in order to assess the decomposition rate and accumulations of livestock manures depending on different altitudes. During chinese cabbage cultivation, the decomposition ratios of organic matter derived form livestock manure expressed as % of the initial organic matter content were 42~48% for Kangreung, 26~29% for Bongpyeong and 10~14% for Daekwanryeong. Changes in air temperature with altitude might be a main factor affecting manure decomposition rates.

• 한국토양비료학회지
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• 제48권6호
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• pp.648-657
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• 2015

Soil organic matter (SOM) plays an important role in the continuous production and environmental conservation in arable soils. In particular, the decomposition of organic matter in soil might promote soil organic matter and fertility due to the mineralization of N. In this study, to evaluate the effect of organic matter amendment on the C mineralization and N dynamic, $CO_2-C$ flux, extractable N and $N_2O$ emission were determined using closed chamber for 4 weeks at 10, 15, $20^{\circ}C$ of incubation temperature after the mixture of $2Mgha^{-1}$ rice straw compost and rye in sandy loam and clay loam. Regardless of soil texture, decomposition rates of rice straw compost and rye at $10{\sim}20^{\circ}C$ of incubation temperature ranged from 0.9 to 3.8% and 8.8 to 20.3%, respectively. Rye application in soil increased $NH_4-N$ and $NO_3-N$ content as well as the $N_2O$ emission compared to the rice straw compost. After incubation for 4 weeks, total C content in two soils was higher in rice straw compost than in rye application. In conclusion, application of rice straw compost and rye to soil was able to improve the soil organic matter and fertility. However, organic matter including the recalcitrant compounds like rice straw compost would be effective on the management of soil organic matter and the reduction of greenhouse gases in soil.

• 한국수산과학회지
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• 제24권5호
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• pp.356-361
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• 1991

This study was conducted to determine the decomposition rate constants of organic matter and to evaluate the process of regeneration of inorganic nutrients in coastal and open seawater. The mixture solution of glucose and glutamic acid, and night soil were used as the test organic matter. Oxygen uptake of test solution was observed every day for 5 days for evaluation of decomposition rate constants, and nutrient contents were analyzed every day for 40 days. The decomposition rate constants have been determined by Thomas slope method and compared with the values of each waters. The values of rate constants for open seawater and coastal water containing the mixture of glucose and glutamic acid were 0.23/day and 0.21/day, and those containing night soil 0.23/day and 0.20/day, respectively. The difference of decomposition rate constants between test materials was not found and the valus for each seawater was equal to each other. The nitrification process took place after 22 days for open seawater when night soil was added to the waters.

• 한국토양비료학회지
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• 제44권3호
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• pp.415-424
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• 2011

This research was conducted to verified the effectiveness of a sintered porous media coated with organic matter as nutrient source and microorganisms as decomposer effective in TPH decomposition for a closed-typed biopole system. The organic matter content in the sintered porous media which was developed with bentonite increased with increasing dilution ratio of pig slurry and the sintered porous media as well as decrease in the particle size of sintered porous media. The decomposition rate of TPH was significantly increased with increasing aeration than that under atmospheric condition. Also the sintered porous media containing organic matter and microorganisms proved that the decomposition was enhanced with addition of nutrients sources in addition to aeration periodically.

• 아시안잔디학회지
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• 제9권2호
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• pp.109-117
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• 1995

An investigation was performed to reveal the relation of the production and decomposition of the Zoysia japoni ica and Miscanthus sinensis litters on Mt.Kwanak. The decay constant k of litters was as follows; k of Zoysia japonica, k=0.44, k of Miscanthus sicensis, k=0.33 The time required for the decomposition of half of the accumulated organic matter of Zoysia japonice and Miscanthus sinensis was 1.6 and 2.1 years, respectively. The amount of mineral nutrients returned annually to soil is faster in the ZQvsia japonica grassland than in the Miscanthus sinensis grassland on Mt. Kwanak. Key words: Organic rnatter synthesis, Decomposition balance.

• 생태와환경
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• 제46권1호
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• pp.75-85
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• 2013

이 연구는 경안천 토양에서 기후 조건의 차이, 식물의 유무, 질소 농도의 차이에 따른 토양의 생물학적 유기물 분해속도의 변화가 대기 중 온실가스($CH_4$, $CO_2$) 발생에 미치는 영향을 알아보고자 하였다. 본 연구 결과, 유기물 분해속도와 $CH_4$, $CO_2$ flux 모두 환경 조건이 동시에 변화하는 경우에 영향을 받음을 알 수 있었다. 유기물 분해 속도는 기후 조건의 차이와 질소농도의 차이, 기후 조건 차이와 식물의 유무가 있는 경우에 영향을 받음을 알 수 있었다. $CH_4$ flux는 기후 조건 차이와 질소 농도의 차이, 기후 조건 차이와 식물의 유무, 식물의 유무와 질소 농도의 차이가 있는 경우에 영향이 있었으며 $CO_2$ flux는 기후 조건 차이와 식물의 유무, 식물의 유무와 질소 농도의 차이가 있는 경우에 영향이 있음을 통해 기후 조건 차이와 식물의 유무, 질소 농도의 차이가 유기물 분해속도에 영향을 주어 대기 중 온실가스 발생에 영향을 줄 수 있음을 알 수 있었다. 기후 조건 차이는 토양의 분해를 증진시켜 대기로 방출되는 온실가스 또한 가중시킬 수 있다고 알려져 있으나, 본 연구를 통해 기후변화가 유기물의 분해와 대기로의 온실가스 방출을 감소시킬 수 있다는 결과를 도출할 수 있었으며 기후 조건 차이 외의 질소가 유입될 경우, 순영향(positive effect)을 주게 됨을 알 수 있었다. 그러나 식물의 영향이 작용할 경우 질소의 유입으로 인한 순영향을 감소시킬 수 있음을 알 수 있었으며, 이에 따른 추가적인 연구가 필요할 것으로 판단된다.

• 한국해양학회지:바다
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• 제6권2호
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• pp.63-70
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• 2001

퇴적물과 해수가 충진된 수조에서 배양실험을 수행하여 해수중 용존산소, pH, 암모니아, 질산염, 철 및 망간 농도의 시간에 따른 변화를 측정하였다. 농도변화 자료를 초기속성작용의 화학 반응식에 적용시켜 퇴적물 내 유기물 분해 초기에 나타나는 유기탄소와 유기질소의 분해정도를 파악하였다. 배양실험은 237 hr 동안 진행되었으며 , 각 화학종의 농도변화 양상에 따라 모두 4개의 시간구간으로 나눌 수 있었다($0{\sim}9\;hr,\;9{\sim}45\;hr,\;45{\sim}141\;hr,\;141{\sim}237\;hr$). 각 시간구간의 농도변화로부터 계산된 유기탄소와 유기질소의 C/N비는 각각 6.63, 1.49, 0.81, 0.02로 시간경과에 따라 감소하였다. C/N비의 감소는 유기물분해 초기에 퇴적물중 유기질소가 유기탄소보다 먼저 선택적으로 분해되어 용출됨을 시사한다. 현장에서 채취한 퇴적물 시료와 배양실험 종료 후 수조에서 수거한 퇴적물중 유기탄소 및 유기질소, 공극수중 암모니아 및 유기탄소 등의 농도변화를 상호 비교한 결과도 유기질소의 선택적 분해를 시사하였다.

• Environmental Engineering Research
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• 제22권4호
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• pp.347-355
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• 2017

This study investigated how the combined changes in environmental conditions and nitrogen (N) deposition influence the mineralization processes and carbon (C) dynamics of wetland soil. For this objective, we conducted a growth chamber experiment to examine the effects of combined changes in environmental conditions and N deposition on the anaerobic decomposition of organic carbon and the emission of greenhouse gases from wetland soil. A chamber with elevated $CO_2$ and temperature showed almost twice the reduction of total decomposition rate compared to the chamber with ambient atmospheric conditions. In addition, $CO_2$ fluxes decreased during the incubation under the conditions of ambient $CO_2$ and temperature. The decrease in anaerobic microbial metabolism resulted from the presence of vegetation, which influences the litter quality of soils. This can be supported by the increase in C/N ratio over the experimental duration. Principle component analysis results demonstrated the opposite locations of loadings for the cases at the initial time and after three months of incubation, which indicates a reduction in the decomposition rate and an increasing C/N ratio during the incubation. From the distribution between the decomposition rate and gas fluxes, we concluded that anaerobic decomposition rates do not have a significantly positive relationship with the fluxes of greenhouse gas emissions from the soil.