• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.2
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• pp.90-96
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• 2023

The aim of this study was to investigate the effect of application rate of rice straw compost on soil chemical properties and soil organic carbon stock (SOC stock). The experiments were performed with no fertilizer (NF), inorganic fertilizer (NPK), NPK + rice straw compost 7.5 ton ha^-1 (NPKC7.5), NPK + rice straw compost 15 ton ha^-1 (NPKC15), NPK + rice straw compost 22.5 ton ha^-1 (NPKC22.5), and NPK + rice straw compost 30 ton ha^-1 (NPKC30). The SOC and SOC stock were highest in the NPKC30 treatment at 22.8 g kg^-1 and 71.2 Mg C ha^-1, respectively. Rice production was in the range of 621.2-654.4 kg 10a^-1 in NPKC22.5 and NPKC30 treatments, which was higher than that in the NPK treatment. However, with increase in compost application, the exchangeable K and Ca of the soil increased, and the exchangeable K and Ca were higher than the optimum range in NPKC22.5 and NPKC30 treatments. Excessive application of compost can have negative impacts on the environment, including nutrient accumulation in the soil and water pollution from nutrient runoff. Therefore, applying the standard amount of compost according to the agricultural environment would be appropriate, despite the relatively lower rice production and SOC stock than that observed with the application of 22.5 and 30 ton ha^-1.

• Journal of Ecology and Environment
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• v.46 no.3
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• pp.250-258
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• 2022

Background: To assess the carbon sequestration capacity and net ecosystem productivity (NEP) of Quercus glauca forests, we analyzed the net primary productivity (NPP), carbon storage, and carbon emission of soil in a Q. glauca forest on Jeju Island (South Korea) from 2016 to 2018. Results: The average carbon stock in the above- and below-ground plant biomass was 223.7 Mg C ha^-1, while the average amount of organic carbon fixed by photosynthesis was 9.8 Mg C ha^-1 yr^-1, and the average NPP was 9.6 Mg C ha^-1 yr^-1. Stems and branches contributed to the majority of the above- and below-ground standing biomass and NPP. The average heterotrophic carbon emission from the soil was 8.7 Mg C ha^-1 yr^-1, while the average NEP was 1.1 Mg C ha^-1 yr^-1. Although the carbon stock, carbon absorption, and soil respiration values were higher than those reported in other oak forests in the world, the NEP was similar or lower. Conclusions: These results indicator that Q. glauca forests perform the role of a large carbon sink through the CO₂ absorption in the plants in terms of carbon balance. And it is judged to be helpful as data for assessment of carbon storage and flux in the forests and mitigation of elevated CO₂ in the atmosphere.

• Journal of Korean Society of Forest Science
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• v.102 no.1
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• pp.82-89
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• 2013

Harvest is one of the major disturbances affecting the soil carbon (C) dynamics in forests. However, researches on the long-term impact of periodic harvest on the soil C dynamics are limited since they requires rigorous control of various factors. Therefore, we adopted a modeling approach to determine the long-term impacts of harvest interval, harvest intensity and post-harvest residue management on soil C dynamics by using the Korean Forest Soil Carbon model (KFSC model). The simulation was conducted on Pinus densiflora S. et Z. stands in central Korea, and twelve harvest scenarios were tested by altering harvest intervals (50, 80, and 100-year interval), intensities (partial-cut harvest: 30% and clear-cut harvest: 100% of stand volume), and the residue managements after harvest (collection: 0% and retention: 100% of aboveground residue). We simulated the soil carbon stock for 400 years for each scenario. As a result, the soil C stocks in depth of 30 cm after 400 years range from 50.3 to 55.8 Mg C $ha^{-1}$, corresponding to 98.1 to 108.9% of the C stock at present. The soil C stock under the scenarios with residue retention was 2.5-11.0% higher than that under scenarios with residue collection. However, there was no significant impact of harvest interval and intensity on the soil C stock. The soil C dynamics depended on the dead organic matter dynamics derived from the amount of dead organic matter and growth pattern after harvest.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.6
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• pp.826-831
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• 2016

he land use, land-use change, and forestry (LULUCF) is one of the greenhouse gas inventory sectors that cover emission and removals of greenhouse gases resulting from land use such as agricultural activities and land use change. Particularly, LULUCF-Cropland sector consists of carbon stock changes in soil, $N_2O$ emissions from disturbance associated with land use conversion to cropland, and $CO_2$ emission from agricultural lime application. In this paper, we conducted the study to calculate the greenhouse gases emission of LULUCF-Cropland sector in South Korea from 1990 to 2014. The emission by carbon stock changes, conversion to cropland and lime application in 2014 was 4424, 32, and 125 Gg $CO_2$-eq, respectively. Total emission from the LULUCF-Cropland sector in 2014 was 4,582 Gg $CO_2$-eq, increased by 508% since 1990 and decreased by 0.7% compared to the previous year. Total emission from this sector showed that the largest sink was the soil carbon and its increase trend in total emission in recent years was largely due to loss of cropland area.

• 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.

• Journal of Ecology and Environment
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• v.43 no.1
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• pp.43-60
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• 2019

Background: Tropical montane forests played an important role in the provision of ecosystem services. The intense degradation and deforestation for the need of agricultural land expansion result in a significant decline of forest cover. However, the expansion of agricultural land did not completely destruct natural forests. There remain forests inaccessible for agricultural and grazing purpose. Studies on these forests remained scant, motivating to investigate biomass and soil carbon stocks. Data of biomass and soils were collected in 80 quadrats ($400m^2$) systematically in 5 forests. Biomass and disturbance gradients were determined using allometric equation and disturbance index, respectively. The regression modeling is employed to explore the spatial distribution of carbon stock along disturbance and environmental gradients. Correlation analysis is also employed to identify the relation between site factors and carbon stocks. Results: The result revealed that a total of 1655 individuals with a diameter of ${\geq}5cm$, representing 38 species, were measured in 5 forests. The mean aboveground biomass carbon stocks (AGB CS) and soil organic carbon (SOC) stocks at 5 forests were $191.6{\pm}19.7$ and $149.32{\pm}6.8Mg\;C\;ha^{-1}$, respectively. The AGB CS exhibited significant (P < 0.05) positive correlation with SOC and total nitrogen (TN) stocks, reflecting that biomass seems to be a general predictor of SOCs. AGB CS between highly and least-disturbed forests was significantly different (P < 0.05). This disturbance level equates to a decrease in AGB CS of 36.8% in the highly disturbed compared with the least-disturbed forest. In all forests, dominant species sequestrated more than 58% of carbon. The AGB CS in response to elevation and disturbance index and SOC stocks in response to soil pH attained unimodal pattern. The stand structures, such as canopy cover and basal area, had significant positive relation with AGB CS. Conclusions: Study results confirmed that carbon stocks of studied forests were comparable to carbon stocks of protected forests. The biotic, edaphic, topographic, and disturbance factors played a significant variation in carbon stocks of forests. Further study should be conducted to quantify carbon stocks of herbaceous, litter, and soil microbes to account the role of the whole forest ecosystem.

• Journal of Climate Change Research
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• v.6 no.4
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• pp.303-310
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• 2015

This study was conducted to estimate of carbon stock and greenhouse gas (GHGs) removals by tree species and forest type at Gangwon province. We used a point sampling data with permanent sample plots in national forest inventory and national emission factors. GHGs emissions was caclulated using the stock change method related to K-MRV and IPCC guidance. Total carbon stock and greenhouse gas removals were high in deciduous forest and species than in coniferous. The range of annual net greenhouse gas emissions in other deciduous species was from $-11,564.83Gg\;CO_2\;yr^{-1}$ to $-13,500.60Gg\;CO_2\;yr^{-1}$ during 3 years (2011~2013). On the other hand, coniferous forest was temporally converted to source due to reducing of growing stock in 2012. It was that growing stocks and forest area were likely to reduce by the deforestation and clear cutting. This study did not consider other carbon pools (soil and dead organic matter) due to the lack of data. This study needs to complement the activity data and emission factors, and then will find the way to calculate the greenhouse gas emissions and removals in the near future.

• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.330-338
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• 2023

To investigate the impact of forestry projects on the carbon stocks of forests, we estimated the carbon stock change of above-ground and soil before and after forestry projects using forest type maps, forestry project information, and soil information. First, we selected six map sheet with large areas and declining age class based on forest type map information. Then, we collected data such as forest type maps, growth coefficients, soil organic matter content, and soil bulk density of the estimated areas to calculate forest carbon storage. As a result, forest carbon stocks decreased by about 34.1~70.0% after forestry projects at all sites. In addition, compared to reference studies, domestic forest soils store less carbon than the above-ground, so it is judged that domestic forest soils have great potential to store more carbon and strategies to increase carbon storage are needed. It was estimated that the amount of carbon stored before forestry projects is about 1.5 times more than after forestry projects. The study estimated that it takes about 27 years for forests to recover to their pre-thinning carbon stocks following forestry projects. Since it takes a long time for forests to recover to their original carbon stocks once their carbon stocks are reduced by physical damage, it is necessary to plan to preserve them as much as possible, especially for highly conservative forests, so that they can maintain their carbon storage function.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.1
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• pp.5-11
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• 2022

This research evaluated the long-term application effects of different soil amendments on yield, dissolved organic carbon, nitrogen and soil organic carbon stock in rice paddy. The experiment consisted of four different fertilizations; Inorganic fertilization (NPK), NPK+Lime (NPKL), NPK+Silicate (NPKS), NPK+Compost (NPKC). There was no significant difference in rice yield between the treatment groups in 1995, but the rice yields in the NPKL and NPKC treatments in 2019 increased by 4.3% and 14.3% compared to NPK. In terms of soil properties, the pH of NPKS(6.7) and NPKL(6.4) in 2019 increased the most compared to the soil pH before experiment(5.2). The organic matter(OM) content from NPKC treatment increased upto 34 and 27 g kg^-1 in year of 1995 and 2019, respectively, compared to before the test. In NPKS and NPKL treatment, labile carbon and nitrogen content, used as a soil quality indicator, increased by 1.1-1.9 times over the control. From these result, it is suggested that type and application rate of soil amendment should be determined based on the soil analysis before cultivation for sustainable agricultural environment and productivity.

• Journal of Ecology and Environment
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• v.38 no.1
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• pp.75-84
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• 2015

Tropical forests play a critical role in mitigating climate change, and therefore, an accurate and precise estimation of tropical forest carbon (C) is needed. However, there are many uncertainties associated with C stock estimation in a tropical forest, mainly due to its large variations in biomass. Hence, we quantified C stocks in an intact lowland mixed dipterocarp forest (MDF) in Brunei, and investigated variations in biomass and topography. Tree, deadwood, and soil C stocks were estimated by using the allometric equation method, the line intersect method, and the sampling method, respectively. Understory vegetation and litter were also sampled. We then analyzed spatial variations in tree and deadwood biomass in relation to topography. The total C stock was 321.4 Mg C $ha^{-1}$, and living biomass, dead organic matter, and soil C stocks accounted for 67%, 11%, and 23%, respectively, of the total. The results reveal that there was a relatively high C stock, even compared to other tropical forests, and that there was no significant relationship between biomass and topography. Our results provide useful reference data and a greater understanding of biomass variations in lowland MDFs, which could be used for greenhouse gas emission-reduction projects.