• Journal of Korean Society of Forest Science
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• v.83 no.3
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• pp.372-379
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• 1994

Timber harvesting impacts on soil microbial populations and respiration rates were examined in naturally regenerating trembling aspen(Populus tremuloides Michx.) stands on two contrasting soils, an Omega loamy sand (sandy mixed, frigid Typic Udipsamment) and an Ontonagon clay loam (very fine, mixed Glossic Eutroboralf). Five timber harvesting disturbances were simulated during winter of 1990 and spring of 1991, including commercial whole-tree harvesting(CWH), winter logging trail+CWH, logging slash removal+CWH(LSR), forest floor removal+LSR(FFR), and spring compaction+FFR. Regardless of soil types, total soil respiration rates of each stand decreased slightly or remained the same after harvesting while microbial population increased progressively during the first two years following harvesting. Microbial populations increased more rapidly and constantly at the sandy site than at the clayey site, which may indicate that the soil physical and chemical conditions changed more drastically for microbial activity following timber harvesting at the sandy site than at the clayey site. However, two kinds of treatment applications-three levels of organic matter removal and two levels of compaction-did not result in significant differences in microbial population or total soil respiration rate at each site during the first two post-harvest years. Total soil respiration of the aspen stands, sum of root respiration and microbial respiration, was a poor index for the microbial activity in this study because aspen kept an active root system for the successive root-sprouts even after harvesting, which resulted in a large portion of root respiration in total respiration.

• Journal of Ecology and Environment
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• v.42 no.4
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• pp.155-162
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• 2018

Background: In ecosystem carbon cycle studies, distinguishing between $CO_2$ emitted by roots and by microbes remains very difficult because it is mixed before being released into the atmosphere. Currently, no method for quantifying root and microbial respiration is effective. Therefore, this study investigated the relationship between soil respiration and underground root biomass at varying distances from the tree and tested possibilities for measuring root and microbial respiration. Methods: Soil respiration was measured by the closed chamber method, in which acrylic collars were placed at regular intervals from the tree base. Measurements were made irregularly during one season, including high temperatures in summer and low temperatures in autumn; the soil's temperature and moisture content were also collected. After measurements, roots of each plot were collected, and their dry matter biomass measured to analyze relationships between root biomass and soil respiration. Results: Apart from root biomass, which affects soil's temperature and moisture, no other factors affecting soil respiration showed significant differences between measuring points. At each point, soil respiration showed clear seasonal variations and high exponential correlation with increasing soil temperatures. The root biomass decreased exponentially with increasing distance from the tree. The rate of soil respiration was also highly correlated exponentially with root biomass. Based on these results, the average rate of root respiration in the soil was estimated to be 34.4% (26.6~43.1%). Conclusions: In this study, attempts were made to differentiate the root respiration rate by analyzing the distribution of root biomass and resulting changes in soil respiration. As distance from the tree increased, root biomass and soil respiration values were shown to strongly decrease exponentially. Root biomass increased logarithmically with increases in soil respiration. In addition, soil respiration and underground root biomass were logarithmically related; the calculated root-breathing rate was around 44%. This study method is applicable for determining root and microbial respiration in forest ecosystem carbon cycle research. However, more data should be collected on the distribution of root biomass and the correlated soil respiration.

• Korean Journal of Environment and Ecology
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• v.25 no.6
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• pp.887-892
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• 2011

This study was to find out influence of heavy metal concentration in plant on microbial activities during decomposition of Artenmisia princeps var. orientalis and Equisetum arvense collected from an abandoned mine and control site in Cheongyang-gun Chungcheongnam-do. Microbial respiration rate showed the highest value at the time of the first collection, and then tended to decline over time. The highest microbial respiration rate appeared in leaf litters with low heavy metal contents, and A. princeps var. orientalis and E. arvense collected and decomposed at the control site showed the fastest decomposition rate. For both A. princeps var. orientalis and E. arvense, litters with low heavy metal content appeared to have higher microbial biomass. There was apparent quantitative correlation between decomposition rate and cumulative respiration rate of leaf litters, and between decomposition rate and microbial biomass of leaf litters. Thus, the study result showed that leaf litter with higher heavy metal content had a negative impacts on the growth and activity of microbial decomposer during decomposition processes.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.26 no.3
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• pp.19-28
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• 2023

The purpose of this study is to estimate carbon dioxide emissions from soil microbial respiration by forest type of Sobaeksan National Park. As a result of estimating the annual soil microbiological respiration volume by forest type in Sobaeksan National Park, broad-leaved forests, coniferous forest, artificial forests were similar to around 19.5 CO₂-ton/ha/yr. In the case of coniferous forests in sub-alpine and grassland near Birobong Peak, 12.2 CO₂-ton/ha/yr and 8.1 CO₂-ton/ha/yr, respectively, were lower than general forest areas. And as a result of analyzing the changes in soil microbiological respiration rate according to forest type in Sobaeksan National Park, the soil microbiological respiration rate in coniferous forests, broad-leaved forests, artificial forests, and sub-alpine areas was the highest in the July survey in summer and the lowest in November in late autumn. The change in soil microbial respiratory volume according to the measurement time in Sobaeksan National Park was the highest between 12:00 and 16:00, when the soil temperature was generally the highest among the days. It is known that the soil temperature is relatively low and the amount of soil microbial respiration decreases during winter, and the change in respiratory volume over the measurement time during the day was the smallest in November, when the amount of soil microbial respiration was relatively smaller than the May-September survey. However, this study has limitations in revealing the causal relationship of various environmental factors that affect the soil microbial respiration. Therefore, it is suggested that long-term research and investigation of various factors affecting soil respiration are needed to understand the carbon cycle of forest ecosystems.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.1
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• pp.28-34
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• 2005

We review three methods of separating soil respiration into root and soil microbial contribution: (1) component integration, (2) root exclusion, and (3) isotopic method. Among these methods, component integration and root exclusion are most commonly used. Root respiration contribution to soil respiration estimated by the root exclusion method is higher than those by other two methods. Trenching has little environmental disturbances in soil or on surface of site compared to other methods in root exclusion such as root removal and gap formation. Isotopic method has an advantage over other methods because of minimal soil and root disturbances, but this method is costly and requires techniques for the complex analysis. Trenching seems to be an appropriate in situ method for calculating component contributions to soil respiration with minimum disturbances in site. However, the method overestimates the contribution of microbial respiration because of root decay, and realistic results could be obtained by estimating root decay or avoiding large roots in trenched plots.

• Journal of Wetlands Research
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• v.20 no.2
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• pp.116-123
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• 2018

The objective of this study was to examine effects of stand age on soil $CO_2$ efflux in plantation Pinus koraiensis, and to elucidate what extent plant (fine) root and soil microbial biomass contribute to the whole soil $CO_2$ efflux. In three age classes (20-yr-old. 40-yr-old, 70-yr-old) of plantation Pinus koraiensis, in-situ soil respiration, plant fine root biomass and soil microbial biomass were measured from April to November in 2004. Regardless of stand age, soil temperature and soil $CO_2$ efflux increased until July then slowly decreased. Soil respiration was higher in 70-yr-old stand than in 20- and 40-yr stands. Fine root biomass and soil microbial biomass was also higher in 70-yr-old stand. Root exclusion decreased soil respiration in 40-yr stand, but not in 70-yr stand. Soil microbial biomass was higher in 70-yr stand, but there was no monthly variation between July and November. The results suggest that soil respiration may increase as plant stand ages and microbial contribution could play more roles in older stands.

• Journal of Environmental Science International
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• v.11 no.12
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• pp.1327-1331
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• 2002

The cork have been preferred over the conventional materials, zeolite, ceramics, and lignite as a biofilter medium. During the 6 months of operation, the performance of the cork biofilter was considered good with 150ppm of mixture BTX vapor efficiencies greater than 90% at 60 second of EBCT. It was observed 56 % of removal efficiency under transition conditions at first stage, and then the removal efficiency was increased to above 90 %, and the sustainability of removal efficiency was maintained. At second stage, the performance of cork biofilter was not decreased 90 % efficiency with 150 ppm BTX at 30 sec. EBCT. The production of $CO_2$ due to microbial respiration was increased to the 40 % on the operation of cork biofilter.

• Korean Journal of Environmental Biology
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• v.27 no.4
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• pp.353-362
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• 2009

This study attempted to compare the litter decomposition rate of Arundinella hirta and Miscanthus sinensis var. purpurascens which collected from serpentine soil acting potentially toxic concentration of heavy metals and non-serpentine soil by using the microcosm method for 192 days under constant humidity and $23^{\circ}C$. The contents of Ni, Fe, Mg and Cr in the serpentine and nonserpentine soil originated litter showed high differences between them. The litter samples from serpentine site have lower C/N than non-serpentine litter, but the soluble carbohydrate content was shown almost similar between two plant litter. The mass loss rates of leaf litter from serpentine area were slower than those from non-serpentine site. During the experimental period, the remained dry weight of A. hirta and M. sinensis var. purpurascens litter collected from serpentine site were 64.7%, 65.0% of initial dry weight and litter samples from non-serpentine site showed 54.2%, 50.7%, respectively. K and Na were leached rapidly at the initial decomposition periods, but Ca showed immobilization and other metal elements reserved at the decomposing litter for a long time. The decomposing A. hirta litter from non-serpentine soil showed higher values of $CO_2$ evolution, microbial biomass-C, and microbial biomass-N than those in serpentine soil originated litter acting nutrient stresses and exhibited rapid decay rate. The microbial biomass and microbial respiration of decaying litter were positively correlated with litter decomposition rate, and these relationships showed more rapid slope in non-serpentine soil originated litter than that in serpentine soil.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.260-265
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• 2012

Soil respiration under flooded conditions is considered to be very small compared with aerobic soil respiration of soil organic matter. However, anaerobic decomposition of soil plays a key role in carbon cycling in flooded ecosystems. On the other hand, coal-ash wastes, such as fly ash and bottom ash, are known to function as a soil amendment for mitigating $CO_2$ emission and enhancing carbon sequestration in up land soils. In this study, we investigated bottom ash as a soil amendment for mitigating $CO_2$ emission, and thus enhancing carbon sequestration under anaerobic conditions. We observed that amendment of bottom ash without external organic source led to significant reduction in $CO_2$ emission rate and in total cumulative $CO_2$ emission flux over the incubation period, which was proportional to the amount of bottom ash applied. We also found that soil microbial biomass increased in response to application of bottom ash. These results suggest that bottom ash can be utilized to store $CO_2$ as a stable soil organic carbon in flooded ecosystems, as in aerobic situations.

• Korean Journal of Microbiology
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• v.23 no.2
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• pp.147-156
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• 1985

Seasonal and vertical variations of abiontic soil carboxymethylcellulase (CMCase) activities were assessed every other month for a year in two contrasting forest soils and evaluated the relationships between soil CMCase activity and environmental parameters. In climax deciduous soil, variations in CMCase activities caused by differences in sampling time were greater than those caused by differences in soil depth. On the other hand, counter phenomenon was obserned in coniferous soil at the stage of development. Correlation analyses showed that soil CMCase activities were significantly (p>0.01) correlated with microbial respiration rates ($O_2$ uptake) and all of the microbial population sizes. From these results, it is suggested that determination of abiontic soil CMCase activity is an useful additional index for evaluating the overall microbial growth and activity in soils.