• Journal of the Korean Wood Science and Technology
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• v.23 no.3
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• pp.23-27
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• 1995

Several characteristic results of physical and optical properties of paper treated by UV light were obtained in the previous papers(Kim et al. 1988). In this paper, folding endurance and brightness of paper prepared by spraying photostabilizer were examined in order to elucidate photodegradation phenomena, UV light absorber and radical scavenger were most effective in preventing of folding endurance decrease. These results may be indicated that depolymerization of cellulose and hemicellulose chains leading to degradation of paper mechanical properties mainly caused by radical reaction. Ineffective hydroperoxide decomposer may be explained because of auto-oxidation reactions before forming stable compound from hydroperoxide.

• Korean Journal of Environmental Agriculture
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• v.20 no.4
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• pp.203-210
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• 2001

In order to environmentally use wood chips manufactured from low valued forest resources by forest tendering, wood chips were used for the evaluation on chips characteristics, decomposition capability of organic wastes, and field experiment and determination of conditions for decomposer. Bioclusters manufactured by Cryptomeria japonica, commercially available wood chips in Japan, showed higher pore ratio, water reservation and water resistance, and higher cellulose content with lower hot water solubles than domestic wood chips. The useful size of wood chips for swine manure decomposition was 10 (length) ${\times}$ 5 (width) ${\times}$ 2 (thickness) mm, and cellulose contents and alkali solubles of Pinus densiflora and Populus tomentiglandulosa were similar to those of bioclusters. According to the decomposition ratio depending on wood species, it was ordered as Pinus densiflora > Pinus koraiensis > Cryptomeria japonica. The swine manure decomposition ratio depending on treatment hours by Pinus koraiensis was constant with the ratio of 15 to 16 g per hour by 1 kg of chip, indicating of daily swine decomposition amount of 390 kg by 1 ton of chips which was equal to the amount of daily swine manure production by 70 swines. Analyzing by long term used wood chips during 40 days treatment, the treated wood chips characteristically showed stable total nitrogen content, suitable pH, high accumulation of inorganic contents such as calcium, phosphorus, potassium and sodium, and no odor. During winter, the inner temperature of decomposer was kept at $43^{\circ}C$, but air bubble was occurred due to high pH and viscosity of swine manure. The most appropriate mixing ratio between wood chips and swine manure was 1 versus 2 or 3, and at more than ratio 1 versus 3, ammonia gas was caused because of anaerobic fermentation status by high moisture content of wood chips. The mixing interval of decomposer was 3 mins. per hour for the best swine decomposition.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.104-108
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• 2004

This study was conducted to investigate the decomposition rates of rice straw in paddy soil with application of liquid pig manure (LPM). Decomposition rate of rice straw was dramatically increased to 52.3% for 60days after LPM application, the rate was higher in soils of tillage than in soils of no-tillage with higher levels of LPM application. C/N ratio in the tice straw was decreased in soils of tillage with higher levels of LPM application. Contents of $NH_4-N$ and $NO_3-N$ in paddy soils were increased with tillage and higher levels of LPM application. The number of cellulose decomposer, and ammonia-oxidizing and denitrifying bacteria in paddy soils at 90 days after LPM application were more than $1.4{\times}10^5$, $2.6{\times}10^2$ and $1.4{\times}10^2cfu\;g^{-1}$ dry soil, respectively, the numbers were higher in soils of tillage with higher levels of LPM application, Soil tillage after LPM application could enhance the decomposition of rice straw in paddy soil.

• 보존과학연구
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• s.19
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• pp.133-158
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• 1998

There are about 2,000 species of termite in the World, but one species of termite inhabits in the southern part of Korean peninsula. Termites are social insects that live in colonies. The colonies are composed of king, queen, soldiers and workers. Termite food consists of cellulose obtained from wood. Protozoa in their digestive tracts convert the cellulose into usable food. Korean termite is a subspecies of Reticulitermes speratus Kolbe, Rhinotermitidae. It's subterranean termite and the scientic name is R. speratus kyushensis Morimoto. The subterranean termite must nest in the soil in order to survival, and infest soft-wood which contact with the soil near the nest. There are several ways which subterranean termite infestations can be noticed. Atcertain times of the year during daylight hours, king and queen termites emerge from the colonies. The propose of these flight is to establish new colonies. The termite is a decomposer of biological ecosystem, but an invader in the preservation of cultural properties as like wood buildings. There are serveral control methods for the prevention of wood building from termite's damages. Those are biological control, ecological control, physical control and chemical control. Ecological and Physical control are the best methods in the new constructing wood-building. Fumigation which is a method of chemical control, is the best method for the building damaged by the termite. After the fumigation, we have totake wood & soil treatments for the building and nearby in order not to be reinvaded by the termites.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.4
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• pp.356-362
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• 1995

This experiment was carried out to investigate the effects on the seasonal population change of microflora of long-term application of organic matters in Fluvio-Alluvial plain of Jeonbug series. As organic matters, rice straw and compost of 5 and 10ton/ha, which were applied with the different nitrogen fertilizer level of 0, 150kg/ha into the soil 15cm deep, respectively. A number of total aerobic bacteria were gradually increased from just after water-logging before rice transplanting to pancle formations stage, afterthat decreased at harvest. The other side, a number of actinomycetes, fungi and cellulose-decomposers were slightly fluctuated until panicle formation stage and increased at havesting stage. In general, microorganism numbers were higher in organic matter with long-term nitrogen fertilizer applied plot, while cellulose-decomposers were higher in only organic matter applied plot. The microorganisms of ammonia-oxidizing, nitrate-reducing and nitrite-oxidizing, and denitrifying bacteria showed the maximum number at harvest stage, at panicle formation stage and at early tillering stage, respectively, while that of ammonifying bacteria were variable if nitrogen fertilizer applied or not at the respective periods in nitrogen cycle under water-logging. These bacteria were numerous in the organic matter plots combined with nitrogen fertilizer, especially, denitrifying bacteria in rice straw, others no difference.

• The Korean Journal of Mycology
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• v.46 no.3
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• pp.213-225
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• 2018

Trichoderma (Hypocreaceae) is one of the most ubiquitous genera worldwide. This genus has an excellent ability to adapt to diverse environments, even under poor nutritional conditions, such as in freshwater. However, little is known about the diversity of Trichoderma species in freshwater environments. In this study, we isolated diverse fungal strains from algae, plant litter, and soil sediment in streams in Korea. The strains were identified based on molecular phylogenetic analyses of internal transcribed spacer (ITS) rDNA and translation elongation factor 1 ($TEF1{\alpha}$) sequences. We also investigated their morphological characteristics by microscopic observation and determination of cultural features on different media. As a result, six Trichoderma species were found in Korea: T. afroharzianum, T. capillare, T. guizhouense, T. paraviridescens, T. reesei, and T. saturnisporum. Interestingly, T. paraviridescens showed both cellulose activity and hypoxia stress tolerance phenotypes, indicating its role as a decomposer in freshwater ecosystems. Our study revealed that freshwater environment could be a good candidate for investigating the species diversity of Trichoderma.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.2
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• pp.127-135
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• 2002

This study was conducted to investigate the physico-chemical and microbiological properties in profile depth during composting process with different turning times when pig manure was composted with ground rice hulls at the rate of same for the promotion of the composting. The moisture contents, C/N rate and pH value decreased according to composting progresses as run into turning times, but increased those inside layer of the pile. $NH_4-N$ and $NO_3-N$ contents were high in the outer layer mostly, as the result the $NH_3$ flux was high in there, but it decreased as composting progresses. The number of aerobic bacteria were $10^7{\sim}10^9\;cfu\;g^{-1}$, increased as the turning times, the number of their showed high in the outer layer. The number of fungi were $10^2{\sim}10^4\;cfu\;g^{-1}$ at the early period of composting, but did't almost survive inside layer as composting progresses. The number of cellulose decomposer and thermophilic bacteria were $10^6{\sim}10^7\;cfu\;g^{-1}$ and $10^6{\sim}10^9\;cfu\;g^{-1}$, respectively, they showed high inside layer of the pile. Therefore, the turning of composting can reduce the change difference of microorganisms in the pile. Turning frequence for the promotion of composting showed approximately 2~3 times.