• Korean Journal of Soil Science and Fertilizer
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• v.43 no.1
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• pp.44-50
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• 2010

This study was carried out to analyze physico-chemical properties and to determine stability of the 19 commercially available horticultural substrates in Korea by European standard methods (EN methods). The average pH, EC, T-N, $P_2O_5$ were 5.44, 0.62$dS{\cdot}m^{-1}$, 0.98% and 10.54$mg{\cdot}L^{-1}$, respectively. Dry bulk density and particle density were in the range of 124.47~243.16$kg/m^3$ and 2073.94~2249.99$kg/m^3$, respectively. Seventeen out of 19 horticultural substrates used in this study were 'very stable'. The other2 substrates were classified as 'stable'. Korea's own criteria of stability for the organic materials such as growing substrates and compost need to be developed so that farmers can use the optimum organic materials without anxiety.

• Korean Journal of Food Science and Technology
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• v.7 no.4
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• pp.194-199
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• 1975

The physiological and chemical investigations to explain the after-ripening processes in got green pepper fruit were carried out by treating the fruit with ethephon either alone or with phenylalanine. The studied metabolic changes in fruit during after-ripening period was carbon dioxide and oxygen concentration in interior of the pepper fruit, total carotenoid, ${\beta}-carotene$, total sugar, and free reducing sugar in pepper fruit. These metabolic changes were explained inrelation to the color enhancement judged by the color score to explain the after-ripening processes. Ethephon treatment at 500 ppm significantly accelerated color enhancement as compared to the control and further ethephon treatment increased the number by 20 percent which was not possible in control during same after-ripening period. The oxygen concentration in interior of the pepper fruit during after-ripening period was increased in control when the color score (color enhancement) increased rapidly. However, with ethephon treatment, the oxygen concentration was decreased when the color score increased. Although total and free reducing sugar content were decreased during the after-ripening period total carotenoid and ${\beta}-carotene$ content was increased by 50 and 200 percent, respectively, over control. Also the capsaicin contents was increased by 20 percent by ethephon treatment over control. Although phenylalanine treatment did not affect the capsaicin content, capsaicin content tended to be increased by phenylalanine treatment when treated with ethephon. Acknowledgements: This work was supported by funds from Korean Traders Scholarship Foundation.

• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.219-228
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• 2009

The construction procedures and artificial turf maintenance program on golf course definitely influence on the distortion of its environment. Soil microbial communities in soil profile were affected directly by those practises on turf areas. In Jeju island, the environmental impact assessment has been required to apply the first quality class granular activated carbon(GAC), which has a high absorbent character to agricultural chemicals, on the soil profiles of golf green system to reduce the pesticide leaching to ground water. This research was carried out to analyze the changes of microbial communities and chemical properties on soil profiles where GAC had been applied at the construction stage at two golf courses in Jeju. The changes of soil microbial population and chemical properties associated with construction methods of soil profile and agrochemical management program were analyzed by monthly at the surface and sub-soil profiles during April through October, 2007. The total numbers of bacteria and fungi, soil moisture content, soil physio-chemical properties were measured on greens and fairways of the both golf courses with different GAC treatment on the green and fairway soil profiles. The results showed that GAC had positive effects on the water holding capacity, pH and EC, however, it did not improved the holding capacity of available nutrients ${NO_3}^-,{NH_4}^+$, and phosphorus by its sorption phenomenon. In microbial count test, the total numbers of bacteria and fungi showed a great variation during sampling dates. That may directly relate to the agrochemical application, however, the ratio of total bacterial number versus total fungus number showed a constant value on a sub-soil of 15~30cm depth. Thus, the construction method of GAC in soil profile, and application of fertilizer and pesticide, both impacted on the changes of microbial population. It's means that the construction method of soil profile and turf management using agro-materials might greatly affect on the turfgrass culture and the environment of golf course.

• Korean Journal of Environment and Ecology
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• v.22 no.6
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• pp.658-665
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• 2008

One of the characteristics of fluvial river channel with sand bed-material is the existence of movable sand bars not occupied with vegetation. However, sand bars at the Hahoe's reach of the Nakdong River showing a double-meandering channel has been changed into expanding vegetation area. Moreover, sand material, in recent years, has stopped moving to downstream in channel and the number and area of bare bars which did not occupied by vegetation have been decreased. In order to find out the mechanism, we carried out the channel characteristics surveys such as hydro-geomorphologic, soil physio-chemical and vegetation surveys were conducted twice on autumn season in 2005,2006. The results so far achieved showed that the reduced discharge of transported sediment and duration of dry season might be critical factors for the spread of luxuriant vegetation. The vegetation area was significantly expanded by floods exceeding the subsequent dominant flow discharge. Furthermore, the expansion of vegetation area was highly correlated with the supply of organic matter, nutrients and alteration of soil texture by sediment deposition during the flooding event.

• Korean Journal of Food Science and Technology
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• v.3 no.1
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• pp.29-36
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• 1971

When a low-temperature treatment was given to a small sweet pepper variety Zairaisisi, the seed browning effect appeared soon. This change attracted the studies to determine and discuss the browning metabolites, polyphenolic compounds, and changes in their between-step components. (1) Chlorogenic acids were found as a polyphenolic compound in seed, whereas no flavanol-type polyphenol was observed. (2) There was sharp increase in total polyphenol content and chlorogenic acid with a low-temperature treatment. The contents of these substrates dropped below that of room-temperature treatment after the browning effect took place. (3) A marked increase in between-step metabolites phenylalanine, tyrosine, shikimic acid contents, and thus assumed activated shikimate pathway in this process. (4) It was suggested by determining the effect of specific metabolic inhibition and respiratory inhibitor administrations on enzymes that active biosynthesis of polyphenolic compounds takes place in shikimate pathway with combination of phosphoenolpyruvate and erythrose-4-phosphate connected to TCA cycle jaming after an active EMP pathway was gone through with sugars in pepper seeds at a low-temperature. (5) It was also suggested from the observation of increased K ion flow-out in pepper seeds with a low-temperature treatment that there is an abnormality in the plasma membrance.

• Korean Journal of Food Science and Technology
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• v.3 no.1
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• pp.37-43
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• 1971

(1) Relatively active polyphenol oxidase influence was seen at $0{\circ}C$, and the optimal pH level for the enzyme from the seeds of a small type sweet pepper Zairaisisi is 6.5. (2) The starting stage of the brown coloration with low-temperature injuries showed a strong activity of polyphenol oxidase, and the activity drops to 0 as the entire seed became brownish. (3) The browning effect with enzyme solution of polyphenol extracts suggested that the brown coloration continues in vitro even if polyphenol oxidase activity is nil. (4) Although cytochrome oxidase activity dropped when an abnormality occurrs in electron pathways of respiration at the starting stage of the browning with low temperature injuries, there was no marked influence of it on the total respiration, indicating the fact that polyphenol oxidase can take place of terminal oxidase in the compensatory respiration process.

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.356-364
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• 2009

In 2006 and 2007, there was a big outbreak of the Ussur Brown Katydid, Paratlanticus ussurriensis in the central part of Korea attacking some orchard trees. Until 2000, the katydid had not been regarded as an agricultural pest because they were distributed widely in Korea with low population density and their habitats were confined mainly to hillsides of forested areas. The fact that katydid attacked orchard trees with a higher population density seemed to be related to a change in feeding environment. And the shift of their habitats from oak woodlands to commercial orchards was thought to be related to the nutritional contents of their feed. In an attempt to understand these relationships, we conducted an ecological study of the affected areas. When the katydids changed their habitats in early May of 2008 and 2009, they shifted their host plants from oak trees to peach trees. The habitat shift was closely related to the nitrogen (N) content of the host plant leaves. When katydid moved to the hillside adjacent to orchard farm, N content of oak tree leaves decreased dramatically from 5.3% to 2.2%. At that time N content of peach tree leaves were higher than the 2.2% of oak leaves, showing 3.5~5.0%. This range of N content of peach tree leaves has been consistent until late June. And feed preference analysis carried out in the laboratory showed that katydid prefered peach tree leaves to peach fruit to oak tree leaves.

• Economic and Environmental Geology
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• v.29 no.2
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• pp.215-225
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• 1996

All the radionuclides in high-level nuclear waste will decay to harmless levels eventually but for some radionuclides decay is so slow that their radiation remains dangerous for times on the order of tens or hundreds of thousands of years. At the present time, the most favorite disposal plan for high-level radioactive waste is a mined geological disposal in which canister enclosing stable solid form of radioactive waste is placed in mined cavities locating hundred meters below the surface. The chief hazard in such disposal is dissolution of radionuclides from the waste in the groundwater that will eventually carry the dissolved radionuclides to surface environments. The hazard from possible escape of the radionuclides through groundwater can be delayed by engineered and geologic barriers. The engineered barriers can become useless by unexpected geologic catastrophe such as volcanism, earthquake, and tectonic movement and by fraudulent work such as careless construction, improperly welded canisters within the first few decades or centuries. As a result, dangerously radioactive waste which is still intensively radioactive is directly exposed to attack by moving groundwater. All the more, it is almost impossible to control repositories for times more than 10,000 years. Therefore, naturally controlled geologic, barriers whose properties will not be changed within 10,000 years are important to guarantee the safety of repositories of high-level radioactive waste. In Sweden and France, the suitability of granite for the mined geological disposal of high-level waste has been studied intensively. According to the research in Sweden and France, granites has the following physio-chemical characteristics which can delay the transportation of radionuclide by groundwater. First, the permeabilities of granites decreases as the depth increases and is $10^{-8}{\sim}10^{-12}m/s$ at depth below 300 m. Second, groundwater at depth below 300 m has pH=7-9 and reducing condition (Eh=-0.1~0.4). This geochemical condition is desirable to prevent both canister and solid waste from corrosion. Third most radionuclides are not transported by low solubilities and some radionuclide with high solubility such as Cs and Sr are retarded by absorption of geologic media through which ground water flows. Therefore, if high-level waste is disposed at depth below 300 m in the granite body which has a low permeability and is geologically stable more than 10,000 years, the safety of repositories from the hazard due to radionuclide escape can guaranteed for more than 10,000 years.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.1
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• pp.121-133
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• 2016

It was required to evaluate ecological restorations in a comprehensive way in order to systematically manage conservation areas such as DMZ and national parks in South Korea. In this research we developed a new approach to evaluating ecological restorations with more various indexes than vegetation covering-related indexes. By analyzing damaged areas in the vicinity of DMZ, major damaged types were identified as six classes: landform modification, surface loss, soil pollution, soil physio-chemical modification, vegetation decline and vegetation damaged. From literature review, 39 indexes were selected and were grouped into four divisions: soil property, vegetation growth & structure, habitat property and landscape structure & functions. By conducting a survey with the selected indexes targeting relevant experts, data on relative importance among the divisions and indexes by damaged type were collected. As a result, it was found that the orders and values of weighted values of the divisions were different by damaged type: for example, soil property (0.402), vegetation growth & structure (0.209), habitat property (0.225), landscape structure & function (0.163) for "landform modification"; but soil property (0.171), vegetation growth & structure (0.401), habitat property (0.270), landscape structure & function (0.158) for "vegetation decline". Similarly, evaluation indexes showed different orders and values of relative importance, easiness in field measurement and representativeness for the division by damaged type, and the values were used for calculating importance factor for each index. In the evaluation table, score1 and score2 were made by the importance factors of indexes multiplied by distribution values which present grades and by the weighted values of divisions. In conclusion, while dealing with the damaged type was considered significant for evaluating and managing restorations, further tests on this table with a range of cases were needed to improve its quality.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.478-485
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• 2017

The effect of high carbon dioxide and ethylene treatment on postharvest ripening regulation of red kiwifruit (Actinidia melanandra) was investigated during cold storage. Physio-chemical properties such as weight loss, firmness, SSC, acidity, and market quality were analysed in red kiwifruit held at $10^{\circ}C$ compared to the fruit treated with carbon dioxide and ethylene during 75 days of storage. No significant weight loss was detected in red kiwifruit treated with carbon dioxide until 75 days of storage while the most rapid loss was found in fruit treated with ethylene. In ethylene-treated fruit, the firmness was dramatically reduced from 4.2kg on the first day to 1.2 kg after 27 days of storage at $10^{\circ}C$. However, the firmness of the carbon dioxide-treated fruit was 1.8kg after 54 days of storage. The highest level of SSC(%) was investigated within the 27 storage days at $10^{\circ}C$ for fresh red kiwifruit treated with exogenous ethylene, whereas the carbon dioxide-treated fruit exhibited a greatly increased SSC after 64 days. The carbon dioxide-treated red kiwifruit maintained statistically(p<.01) higher levels of acidity compared to the control and the exogenous ethylene-treated ones during 41 days of storage at $10^{\circ}C$. The SSC/Acid ratio of fruit treated with carbon dioxide was significantly lower (p<.01) maintained than the other two treatments (ethylene-treated and control fruit)throughout the 75-day experiment. Based on the quality characteristics of postharvest red kiwifruit, it could be concluded that the carbon dioxide treatment significantly delayed the ripening process and maintained the market quality of harvested red kiwifruit, which can be a potential application for commercial use in the kiwi industry.