• Journal of Microbiology
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• v.42 no.4
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• pp.267-277
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• 2004

Effects of elevated $CO_2$ on soil microorganisms are known to be mediated by various interactions with plants, for which such effects are relatively poorly documented. In this review, we summarize and syn­thesize results from studies assessing impacts of elevated $CO_2$ on soil ecosystems, focusing primarily on plants and a variety the of microbial processes. The processes considered include changes in microbial biomass of C and N, microbial number, respiration rates, organic matter decomposition, soil enzyme activities, microbial community composition, and functional groups of bacteria mediating trace gas emission such as methane and nitrous oxide. Elevated $CO_2$ in atmosphere may enhance certain micro­bial processes such as $CH_4$ emission from wetlands due to enhanced carbon supply from plants. How­ever, responses of extracellular enzyme activities and microbial community structure are still controversy, because interferences with other factors such as the types of plants, nutrient availabilitial in soil, soil types, analysis methods, and types of $CO_2$ fumigation systems are not fully understood.

• Journal of Ginseng Research
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• v.8 no.1
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• pp.65-74
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• 1984

This experiment was carried out to study the effects of light intensity and soil water regimes on the growth of ginseng seedling. The results were as follows: 1. The maximum light intensity and optimum temperature in 1,le photosynthesis of ginseng seedling were 10,000 lux and 23 $^{\circ}C$. Respiration rate was increased at high temperature. 2. Air and soil temperature under the shading were increased as the increase of light intensity but soil water contents were decreased as the increase of light intensity, whereas air and soil temperature were decreased as the increase of precipitation under the shade b5: soil water contents were increased as the increase of precipitation under the shade. 3. The higher the transmittance of the shade, the greater the specific leaf weight (S.L.W.) and stomatal density. In contrast, however, the contents of total chlorophyll, chlorophyll a and b, and stomatal length was decreased. There was no any significant difference light intensity of the a/b ratio of chlorophyll. 4. The highest photosynthesis was occurred in ginseng leaves grown under the shade 5% L.T.R. and net photosynthesis rates increased with increasing soil water contents. 5. Optimum condition for usable seedling yield were 5% L.T.R. and 3.3% precipitation under the shade. Useless seedling increased with increasing precipitation under the shade.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.4
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• pp.375-385
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• 1987

This study was carried out to investigate the effects of pesticides on soil respiration, microflora and enzymes in loam soil, and on pathogenic microorganisms in continuous pepper cropping soil. The results are summarized as follows. No significant effect of pesticides on soil respiration was shown, with the exception of propoxur which slightly increased at $10{\mu}g\;g^{-1}$ treatment. When pesticides were treated, the amount of soil microorganisms generally decreased at the early stage of incubation and the number of microflora was much more decreased at 60-day incubation. When pesticides were treated, the amount of soil enzyme activity was inhibited at the early stage of incubation and gradually recovered at the last stage of incubation. The amount of polygalacturonase activity was increased at the 20-and 30-day incubation in propoxur treatment plot. The amount of ${\beta}$-glucosidase and dehydrogenase activity was increased at 20-and 60-day incubation in carbofuran and acephate treatment plot. The amount of phosphatase activity was increased at 60-day incubation in propoxur and isoprocarb treatment plot. The amount of Fusarium generally decreased in continuous pepper cropping soil, with the exception of isoprocarb and acephate treatment plot which significantly increased. The amount of Pythium increased at 60-day incubation with the exception of captan treatment plot which significantly decreased.

• Korean Journal of Weed Science
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• v.17 no.2
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• pp.214-219
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• 1997

The influence of manure, chemical fertilizers, heavy metals and cleaner on the rate of degradation of alachlor in soil was studied. The degradation rate of alachlor in the soil followed first-order reaction kinetics. The half-life was 6.4 days. The degradation was accelerated by the amendment of manure. Adding chemical fertilizers to the soil enhanced alachlor degradation more in the presence of nitrogen than potassium. On the other hand, adding heavy metals or cleaner to the soil decreased the degradation rate. The half-life of alachlor in soil treated with Cd, Cr, Ni, Zn and Cu was 11.0, 8.3, 7.9, 7.2 and 6.7 days, respectively, and that of the cleaner is 7.5 days. The microbial biomass and the respiration rate in the soil were promoted by the amendment of manure and chemical fertilizers, and inhibited by the addition of heavy metals and cleaner. The degradation rate correlate positively with the microbial biomass and the respiration rate.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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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.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.242-251
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• 2010

In comparison with other terrestrial ecosystems, rice paddies are unique because they provide the primary food source for over 50% of the world's population, and act as major sources of global methane. The present paper summerizes a long-term field study that combine carbon isotopes, and canopy-scale flux measurements in an irrigated rice paddy, in conjugation with continuous monitoring of environmental, and vegetational factors. Both $CO_2$, and methane fluxes were largely influenced by soil temperature, and moisture conditions, especially across drainage events. Soil-entrapped $CO_2$, and methane showed a gradually increasing trend throughout growing season, but rapidly decreased upon flood water drainage. These variations in flux were well correlated with changes in concentration, and isotope ratio of soil $CO_2$, and methane, and of atmospheric $CO_2$, and methane within, and above the canopy. The isotopic signature of the gas exchange process varied markedly in response to change in contribution of soil respiration, belowground storage, fraction of $CO_2$ recycled, magnitude, and direction of $CO_2$ exchange, transport mechanism, and fraction of methane oxidized. Our results clearly demonstrate that stable isotope analysis can be a useful tool to study underlying mechanisms of gas exchange processes under natural conditions.

• Journal of Ecology and Environment
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• v.41 no.12
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• pp.336-344
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• 2017

Background: Because of climate change, interest in the development of carbon pools has increased. In agricultural ecosystems, which can be more intensively managed than forests, measures to control carbon dioxide ($CO_2$) emission and absorption levels can be applied relatively easily. However, crop residues may be released into the atmosphere by decomposition or combustion. If we can develop scientific management techniques that enable these residues to be stocked on farmland, then it would be possible to convert farmlands from carbon emission sources to carbon pools. We analyzed and investigated soil respiration (Rs) rate characteristics according to input of carbonized residue of red peppers (Capsicum annuum L.), a widely grown crop in Korea, as a technique for increasing farmland carbon stock. Results: Rs rate in the carbonized biomass (CB) section was $226.7mg\;CO_2\;m^{-2}h^{-1}$, which was 18.1% lower than the $276.9mg\;CO_2\;m^{-2}h^{-1}$ from the red pepper residue biomass (RB) section. The Rs rate of the control was $184.1mg\;CO_2\;m^{-2}h^{-1}$. In the following year, Rs in the CB section was $204.0mg\;CO_2\;m{-2}h^{-1}$, which was 38.2% lower than the $330.1mg\;CO_2\;m^{-2}h^{-1}$ from the RB section; the control emitted $198.6mg\;CO_2\;m^{-2}h^{-1}$. Correlation between Rs and soil temperature ((Ts) at a depth of 5 cm) was $R^2=0.51$ in the RB section, which was higher than the other experimental sections. A comparison of annual decomposition rates between RB and CB showed a large difference, 41.4 and 9.7%, respectively. The results showed that carbonization of red pepper residues reduced the rates of decomposition and Rs. Conclusions: The present study confirmed that the Rs rate can be reduced by carbonization of residue biomass and putting it in the soil and that the Rs rate and Ts (5 cm) were positively correlated. Based on the results, it was determined that approximately $1.2t\;C\;ha^{-1}$ were sequestered in the soil in the first year and $3.0t\;C\;ha^{-1}$ were stored the following year. Therefore, approximately $1.5t\;C\;ha^{-1}year^{-1}$ are expected to be stocked in the soil, making it possible to develop farmlands into carbon pools.

• Journal of Soil and Groundwater Environment
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• v.26 no.6
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• pp.36-46
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• 2021

The Soil Health Index (SHI) developed by Park et al. (2021) is used to evaluate soil health on remediated soils collected from several remediation project sites and monitored the changes of SHI during the remediation process of land farming, soil washing, and thermal desorption. In the case of land farming, the soils remediated below a legal standard didn't show any significant changes in indices of SHI except the downgrade of available phosphate from medium to a low level. The SHI scores were ranged from 52 to 56 in the contaminated soil and 54 to 57 in the remediated soil. With soil washing, bulk density changed from high to a low level, and available phosphate was lowered from medium to low level. As the SHI scores were evaluated as 58 to 63 for contaminated soil and 38 to 42 for remediated soils. For thermal desorption, soil respiration rate was reduced from high to low level and SHI was scored as 50 to 51 for contaminated soils and 43 to 47 for remediated soils. Even though any abrupt changes of the SHI in remediated soils were not identified in the soils used in this study, it is expected that soil in different conditions such as types and concentrations of contaminant and soil characteristics would result in distinguished changes of the SHI. There is a room for more studies collect diverse information on SHI across the country.

• Journal of Wetlands Research
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• v.16 no.3
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• pp.315-325
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• 2014

Valuation of ecosystem services through organic carbon distribution and cycling in the Quercus mongolica forest at Mt. Worak national park were investigated from May 2012 through April 2013. The amount of carbon allocated to above and below ground biomass was 81.94 and 20.53 ton C/ha. Amount of organic carbon in litter layer was 6.49 ton C/ha. Amount of organic carbon within 50 soil depth was 141.23 ton C $ha^{-1}$ $50cm-depth^{-1}$. Total amount of organic carbon in this Quercus mongolica forest was estimated to 250.19 ton C $ha^{-1}$. The estimated amount of won in this Quercus mongolica forest in terms of total organic carbon was about 5.27 million won $ha^{-1}$. The amount of carbon evolved through soil respiration was 7.31 ton C $ha^{-1}yr^{-1}$. The amount of carbon evolved through microbial respiration and root respiration was 3.58 and 3.73 ton C $ha^{-1}yr^{-1}$, respectively. The amount of organic carbon absorbed from the atmosphere of this Quercus mongolica forest was 1.61 ton C $ha^{-1}yr^{-1}$ when estimated from the difference between net primary production and microbial respiration. This amount will come to about 33,000 won $ha^{-1}yr^{-1}$ in Korean currency.

• Journal of Wetlands Research
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• v.17 no.4
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• pp.332-338
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• 2015

Valuation of ecosystem services through organic carbon distribution and cycling in the Pinus densiflora forest at Mt. Worak National Park were investigated from January 2013 through December 2013. The amount of carbon allocated to above and below ground biomass was 32.17 and 8.04 ton C $ha^{-1}$. Amount of organic carbon in litter layer was 5.55 ton C $ha^{-1}$. Amount of organic carbon within 50cm soil depth was 58.62 ton C $ha^{-1}$ 50cm-$depth^{-1}$. Total amount of organic carbon in this Pinus densiflora forest was estimated to 104.38 ton C $ha^{-1}$. The estimated amount of won in this Pinus densiflora forest in terms of total organic carbon was about 10.44 million won $ha^{-1}$. The amount of carbon evolved through soil respiration was 4.44 ton C $ha^{-1}yr^{-1}$. The amount of carbon evolved through microbial respiration and root respiration was 2.18 and 2.27 ton C $ha^{-1}yr^{-1}$, respectively. The amount of organic carbon absorbed from the atmosphere of this Pinus densiflora forest was 0.44 ton C $ha^{-1}yr^{-1}$ when estimated from the difference between net primary production and microbial respiration. This amount will come to about 44,000 won $ha^{-1}$ in Korean currency.