• Animal cells and systems
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• v.10 no.4
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• pp.191-196
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• 2006

This study was carried out to evaluate soil carbon cycling of a 36-year-old larch (Larix leptolepis) stand in Korea. The aboveground and soil organic carbon storage, litterfall, and soil respiration rates were measured over twoyear periods. The estimated aboveground biomass carbon storage and increment were 4220 gC $m^{-2}$ and 150 gC $m^{-2}\;yr^{-1}$, respectively. Mean organic carbon inputs by needle and total litterfall were 118 gC $m^{-2}\;yr^{-1}$ and 168 gC $m^{-2}\;yr^{-1}$, respectively. The aboveground carbon increment of the stand was similar to the annual input of carbon from total litterfall. The soil respiration rates correlated exponentially with the soil temperature at a depth of 20 cm ($R^2$ = 0.86). In addition, the exponential regression equation indicated a relatively strong positive relationship between the soil respiration rates and soil temperature, while there was no significant relationship between the soil respiration rates and the soil moisture content. The annual mean and total soil respiration rates were 0.40 g $CO_2\;m^{-2} h^{-1}$ and 3010 g $CO_2\;m^{-2}\;yr^{-1}$ over the two-year study period, respectively.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.1097-1107
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• 2020

Assessment of soil carbon stock is essential for climate change mitigation and soil fertility. The digital soil mapping (DSM) is well known as a general technique to estimate the soil carbon stocks and upgrade previous soil maps. The aim of this study is to calculate the soil carbon stock in the top soil layer (0 to 30 cm) in Jeolla Province of South Korea using the DSM technique. To predict spatial carbon stock, we used Cubist, which a data-mining algorithm model base on tree regression. Soil samples (130 in total) were collected from three depths (0 to 10 cm, 10 to 20 cm, 20 to 30 cm) considering spatial distribution in Jeolla Province. These data were randomly divided into two sets for model calibration (70%) and validation (30%). The results showed that clay content, topographic wetness index (TWI), and digital elevation model (DEM) were the most important environmental covariate predictors of soil carbon stock. The predicted average soil carbon density was 3.88 kg·m-2. The R2 value representing the model's performance was 0.6, which was relatively high compared to a previous study. The total soil carbon stocks at a depth of 0 to 30 cm in Jeolla Province were estimated to be about 81 megatons.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.6
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• pp.396-402
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• 2006

Soil organic carbon has long been considered as the most critical factor to evaluate the soil quality, fertility, and fertilizer prescription. In addition, soil organic carbon may impact on greenhouse gas effects and global warming. Because of that, the management of soil organic carbon is increasingly important not only for improving soil quality but also for managing soil as a greenhouse gas source. Both wet and dry combustion have been used to determine soil organic carbon. Many benefits, such as automation and less labor, could the dry combustion method become more popular. Inorganic form of carbon could overestimate soil organic carbon when the dry combustion method was applied. Determination of soil inorganic carbon may contribute to the improved accuracy of soil organic carbon analysis using dry combustion method. Objectives of this research were 1) to develop soil inorganic carbon determination method using modified digital pressure calcimeter and 2) to evaluate soil organic carbon from calcareous soils using the dry and wet combustion method. Results showed that the significant linear relationship was found between soil inorganic carbon content and pressure calcimeter output. Inorganic carbon ranged from 22% to 28% of total carbon in the calcareous soil samples. Soil organic carbon content by dry combustion for calcareous soil was determined by subtracting inorganic carbon measured by the digital pressure calcimeter from total carbon. Soil organic carbon determined by dry combustion method was significantly correlated with that by wet combustion method. In conclusion, the digital pressure calcimeter may use to improve soil organic carbon determination for the calcareous soils by subtracting of soil inorganic carbon from total carbon determined by dry combustion method.

• Journal of Ecology and Environment
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• v.29 no.1
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• pp.23-27
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• 2006

This study was conducted to evaluate forest carbon cycling and soil $CO_2$ efflux rates in a 42-year-old pine (Pinus densiflora) stand located in Hamyang-gun, Korea. Aboveground and soil organic carbon storage, litterfall, litter decomposition, and soil $CO_2$ efflux rates were measured for one year. Estimated aboveground biomass carbon storage and increment in this stand were $3,250gC/m^2\;and\;156gC\;m^{-2}yr^{-1}$, respectively. Soil organic carbon storage at the depth of 30 cm was $10,260gC/m^2$ Mean organic carbon inputs by needle and total litterfall were $176gC\;m^{-2}yr^{-1}\;and\;235gC\;m^{-2}yr^{-1}$, respectively. Litter decomposition rates were faster in nne roots less than 2 mm diameter size ($<220\;g\;kg^{-1}yr^{-1}$) than in needle litter ($<120\;g\;kg^{-1}yr^{-1}$). Annual mean and total soil respiration rates were $0.37g\;CO_2m^{-2}h^{-1}$ and $2,732g\;CO_2m^{-2}yr^{-1}$ during the study period. A strong positive relationship existed between soil $CO_2$ efflux and soil temperature (r=0.8149), while soil $CO_2$ efflux responded negatively to soil pH (r=-0.3582).

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.340-340
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• 2017

Rice straw is very important to maintain fertility in agricultural soil with several aspects such as carbon and nitrogen cycles in Korea. Recently, concerning about climate change, carbon sequestration in agricultural land has become one of the most interesting and debating issues. Rice straw is most representative source of organic material produced in agricultural sectors. In order to evaluate changes of soil carbon treated by rice straw during cultivating rice in paddy field, we carried out to treat rice straw with 0, 0.5, 1, 1.5, and $2.0ton\;ha^{-1}$ at $50{\times}50{\times}20cm$ blocks made of wood board, and analyze contents of fulvic acid and humic acid form, and total carbon periodically. The experiment was conducted in 2013-2016, and sampled with interval in a month. The organic material was applied to treatment blocks in 2 weeks ago in rice transplanting of each year. Total carbon in beginning time is low as $7.9g\;kg^{-1}$. The contents of total carbon with treatments of rice straw after experiment are recorded as 8.7, 11.2, 9.5, 10.5, and $10.9g\;kg^{-1}$ applied by 0, 0.5, 1, 1.5, and $2.0ton\;ha^{-1}$, respectively. When trend lines were calculated on changes of soil carbon in periods of experiments, The trend equations of soil carbon changes with treatments of 0, 0.5, 1, 1.5, and $2.0ton\;ha^{-1}$ were Y=0.0015X+8.479, Y=0.073X+8.2577, Y=0.0503X+8.4477, Y=0.0822X+8.2103, and Y=0.082X+8.5736. These trends suggested several results. When rice straw was applied in cultivating paddy fields, most carbon in rice straw would be decomposed regardless the amount of rice straw in soil. We calculated sequestration rate of applied rice straw as about 0.1% per year during rice cultivation in paddy fields. It means that if farmer want to increase 1% soil organic matter by using application of rice straw returned after cultivation, famer should apply rice straw continuously for ten years. The change of soil carbon as fulvic acid, humic acid, and humane is showed that only content of carbon as mumine is increased significantly while fulvic acid and humic acid were changed in range of 10 to 30% among total carbon in soil. In conclusion, to sequestrate soil carbon with rice straw, it is important for rice straw to apply continuously every year. The amount of rice straw applied is not much effected to increase soil organic matter.

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.891-897
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• 2021

There is a need for a technology that can quickly and accurately analyze soil carbon contents. Existing soil carbon analysis methods are cumbersome in terms of professional manpower requirements, time, and cost. It is against this background that the present study leverages the soil physical properties of color and water content levels to develop a model capable of predicting the carbon content of soil sample. To predict the total carbon content of soil, the RGB values, water content of the soil, and lux levels were analyzed and used as statistical data. However, when R, G, and B with high correlations were all included in a multiple regression analysis as independent variables, a high level of multicollinearity was noted and G was thus excluded from the model. The estimates showed that the estimation coefficients for all independent variables were statistically significant at a significance level of 1%. The elastic values of R and B for the soil carbon content, which are of major interest in this study, were -2.90 and 1.47, respectively, showing that a 1% increase in the R value was correlated with a 2.90% decrease in the carbon content, whereas a 1% increase in the B value tallied with a 1.47% increase in the carbon content. Coefficient of determination (R²), root mean square error (RMSE), and mean absolute percentage error (MAPE) methods were used for regression verification, and calibration samples showed higher accuracy than the validation samples in terms of R² and MAPE.

• Journal of the Korean GEO-environmental Society
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• v.22 no.3
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• pp.37-43
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• 2021

This study aimed to calculate the amount of change in soil carbon due to changes in land cover. Among the various soil carbon models, the InVEST Carbon Storage and Sequestration module was used. LULC is one of the leading factors affecting soil carbon. Therefore, this study compared the total amount of soil carbon due to changes in LULC in 2000 and 2010 across the Republic of Korea, and calculated the changes in each administrative district (city). Changes in LULC in Korea were mainly due to the increase in developed and dry areas and the decrease in grassland, indicating changes in soil carbon. The total amount of soil carbon changes in South Korea has been reduced by 11.48 (millions) in 10 years. The amount of soil carbon by administrative region decreased in most cities and provinces, but Jeju Island, in exception, showed an increase in soil carbon. Among the cities and provinces except Jeju Island, Seoul showed the smallest decrease, with a decrease of 0.033 (million t). On the contrary, the largest number of attempts to decrease was to Gyeongsangbuk-do, which saw a total decrease of 2.893 (million t). Jeju Island is the only soil carbon-increasing area with an increase of 0.547 (millions) and the agricultural area has increased 2.1 times in 10 years. In the case of soil carbon, the construction of ground observation data at the national unit is insufficient, and verification will need to be carried out through linked analysis using multiple models in the future.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.2
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• pp.1-9
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• 2009

Due to the increase of carbon dioxide in the atmosphere and global warming, the importance of forest ecosystems, as a place of carbon accumulation and emission, has received a great amount of recognition lately. This study was performed to help understand and provide the current status of carbon cycle in the pinus densiflora stand, Korea. The samples were collected from average 35-years-old Pinus densifiora rands in Gongju, Youngdong, Chungsan, Muju, Mupung, and Jangsu regions. Total thirty aboveground sample trees were cut, and ten roots were sampled, and soil samples were collected. Average carbon concentrations in foliage, branch, stem bark, stem wood, and root were 55.7%, 56.0%, 56.0%, 57.3%, and 56.5%, respectively. Carbon content was estimated by the model $Wt=aD^b$ where Wt is oven-dry weight in kg and D is DBH in cm. Total carbon content (aboveground and root) was 42.39tonC/ha in the Pinus densiflora stand. The proportion of each tree component to total carbon content was high in order of stemwood, root, branch, stem bark, and foliage. Total net primary production (aboveground and root) was estimated at 6.51tonC/ha/yr in Pinus densiflora stand. The proportion of each tree component to total net primary carbon content was high in order of sternwood, root, branch, foliage and stembark. Soil carbon contents in the study sites was 43.51tonC/ha at 0-50cm soil depth.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.1
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• pp.65-70
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• 2017

Soil was regarded as infinite resources but recently, soil is considered as invaluable resources that we need to protect and conserve. Main objective of this research was to evaluate soil value in terms of soil carbon contents. Soil was classified into forest, paddy, upland, and grass. Carbon contents in each soil was calculated based on soil chemical properties. Calculated soil carbon contents was ranged $15.31-108.86mg\;kg^{-1}$. Based on soil carbon contents, soil value was assumed adapting economic concepts. Calculated total soil value based on soil carbon contents was about 18.46 trillion won. Among others, carbon contents in forest was the highest and value was assumed 11.95 trillion won followed by paddy field (3.7 trillion won).

• Economic and Environmental Geology
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• v.54 no.4
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• pp.409-425
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• 2021

Carbon dioxide has been known to be a typical greenhouse gas causing global warming, and a number of efforts have been proposed to reduce its concentration in the atmosphere. Among them, carbon dioxide capture and storage (CCS) has been taken into great account to accomplish the target reduction of carbon dioxide. In order to commercialize the CCS, its safety should be secured. In particular, if the stored carbon dioxide is leaked in the arable land, serious problems could come up in terms of crop growth. This study was conducted to investigate the effect of carbon dioxide leaked from storage sites on soil fertility. The leakage of carbon dioxide was simulated using the facility of its artificial injection into soils in the laboratory. Several soil chemical properties, such as pH, cation exchange capacity, electrical conductivity, the concentrations of exchangeable cations, nitrogen (N) (total-N, nitrate-N, and ammonia-N), phosphorus (P) (total-P and available-P), sulfur (S) (total-S and available-S), available-boron (B), and the contents of soil organic matter, were monitored as indicators of soil fertility during the period of artificial injection of carbon dioxide. Two kinds of soils, such as non-cultivated and cultivated soils, were compared in the artificial injection tests, and the latter included maize- and soybean-cultivated soils. The non-cultivated soil (NCS) was sandy soil of 42.6% porosity, the maize-cultivated soil (MCS) and soybean-cultivated soil (SCS) were loamy sand having 46.8% and 48.0% of porosities, respectively. The artificial injection facility had six columns: one was for the control without carbon dioxide injection, and the other five columns were used for the injections tests. Total injection periods for NCS and MCS/SCS were 60 and 70 days, respectively, and artificial rainfall events were simulated using one pore volume after the 12-day injection for the NCS and the 14-day injection for the MCS/SCS. After each rainfall event, the soil fertility indicators were measured for soil and leachate solution, and they were compared before and after the injection of carbon dioxide. The results indicate that the residual concentrations of exchangeable cations, total-N, total-P, the content of soil organic matter, and electrical conductivity were not likely to be affected by the injection of carbon dioxide. However, the residual concentrations of nitrate-N, ammonia-N, available-P, available-S, and available-B tended to decrease after the carbon dioxide injection, indicating that soil fertility might be reduced. Meanwhile, soil pH did not seem to be influenced due to the buffering capacity of soils, but it is speculated that a long-term leakage of carbon dioxide might bring about soil acidification.