• Journal of Bio-Environment Control
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• v.29 no.1
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• pp.89-95
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• 2020

Livestock facilities in Korea are on their way of enlargement resulting in increment of livestock manure. When the livestock manure treated inappropriate way during application to the agricultural area, environmental damage can be occurred such as bad smell, water and air pollution. Therefore it is important to make a good management plan for livestock manure treatment. In order to effectively apply organic fertilizer made by livestock manure in terms of quantity and quality, the current status of nutrient in agricultural land should be calculated quantitatively by scientific way. The OECD suggest member countries to calculate the nutrient balance as an agricultural environment indicator which represents the difference between nutrient inputs and outputs of the amount of nutrients in various ways. In this paper, we calculated the nutrient balances according to three cities which have different characteristics such as urban or rural areas. To reduce the nutrient balance, we considered how to reduce the amount of chemical fertilizer by using organic fertilizer made by livestock manure. And public treatment facilities for livestock manure can be a good solution except civil complaints for location selection. Among the options, manure fertilizer application to the agricultural area for cultivation of forage crops was mainly considered to reduce the nutrient balance by decreasing input of chemical fertilizers and increasing output of crop production. Using the field monitoring data, it can be calculated that the daily nitrogen reductions by 116.5 kg/ha and the daily phosphorus increments by 2.7 kg/ha.

• Ecology and Resilient Infrastructure
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• v.7 no.3
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• pp.189-198
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• 2020

Wetlands, which provide various ecological services, have been regarded as an important nature-based solution for, for example, sustainable water quality improvement and buffering of impacts from climate change. Although the importance of conserving wetlands to reduce the impacts of various perturbations (e.g., changes of land use, climate, and hydrology) has been acknowledged, the possibility of applying these efforts as a nature-based solution in a macro-scale (e.g., landscape) has been insufficient. In this study, we examine the possibility of ecological network analysis that provides an engineering solution as a nature-based solution. Specifically, we analyzed how land use change affects the structural and functional characteristics (connectivity, network efficiency, and clustering coefficient) of the ecological networks by using the ecological networks generated by multiple dispersal models of the hypothetical inhabiting species in wetlandscape. Changes in ecological network characteristics were analyzed through simultaneously removing wetlands, with two initial conditions for surface area, in the zones where land use change occurs. We set a total number of four zones of land use change with different wetland densities. All analyses showed that mean degree and network efficiency were significantly reduced when wetlands in the zones with high wetland density were removed, and this phenomenon was intensified especially when zones contained hubs (nodes with high degree). On the other hand, we observed the clustering coefficient to increase. We suggest our approach for assessing the impacts of land use change on ecological networks, and with additional analysis on betweenness centrality, we expect it can provide a nature-based engineering solution for creating alternative wetlands.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.212-220
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• 2010

Effects of sediment and toxic cyanobacterium Microcystis aeruginosa on feeding behaviors of an omnivorous fish, gold fish (Carassius auratus) were examined in laboratory and in situ mesocosm. Laboratory feeding experiments were performed in small aquaria (7 L) with cyanobacterial blooms (mainly M. aeruginosa) under the condition of sediments and no-sediments, and toxic (NIES-298) and non-toxic M. aeruginosa (NIES-101). In situ feeding experiments were conducted at the shore of eutrophic lake (Lake Ilgam, Seoul) in the mid-July, 2005. Results showed that fish introduction decreased the concentration of Chlorophyll-a (Chl-a) at higher rate in no sediment-containing aquaria. In contrast, there was a drastic increase of Chl-a in the sedimentcontaining aquaria. Fish effectively removed the M. aeruginosa cells without algal toxin (microcystin). Fish also selectively removed the large size Chl-a (>$50{\mu}m$), although all kinds of nutrients were increased after fish introduction, especially ammonia. Our results indicate that the strategic introduction of domestic omnivores Carassius auratus, to control cyanobacterial bloom in eutrophic lake will negatively play in the water quality improvement via a sediment disturbance and a density-dependent digestion.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.15
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• pp.99-113
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• 1974

This experiment was carried out to find reasonable semi. hot seedbed system for early transplanting of "Tongil"rice cultivar. The quality of the young rice-plants, yield, and the occurrence of the reddish dry leaves were not significant differences between the seedbed with polyethylene tunnel and that of Rat covering. The per cent of healthy seedling of the soil preparation with the dry soil plowing was increased than that of the water soil plowing. The stability of the seedling cultivation of the thin layer straw mulching seedbed beneath the polyethylene film was higher than that of the common flat seedbed system.ed system.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.10
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• pp.551-557
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• 2016

Fusing satellite images and site-specific observations have potential to improve a predictive quality of environmental properties. However, the effect of the utilization of satellite images to predict soil properties in a wetland is still poorly understood. For the reason, block kriging and regression kriging were applied to a natural wetland, Water Conservation Area-2A in Florida, to compare the accuracy improvement of continuous models predicting total phosphorus in soils. Field observations were used to develop the soil total phosphorus prediction models. Additionally, the spectral data and derived indices from Landsat ETM+, which has 30 m spatial resolution, were used as independent variables for the regression kriging model. The block kriging model showed $R^2$ of 0.59 and the regression kriging model showed $R^2$ of 0.49. Although the block kriging performed better than the regession kriging, both models showed similar spatial patterns. Moreover, regression kriging utilizing a Landsat ETM+ image facilitated to capture unique and complex landscape features of the study area.

• The Korean Journal of Ecology
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• v.27 no.6 s.122
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• pp.375-381
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• 2004

We investigate the biological treatment of processed-leachate from SUDOKWON landfill site in Korea by the reed (Phragmites australis)-bed with a continuous flow system. The reed individuals showing superior growth in processed-leachate experiment were selected among the reeds of thirteen natural habitats by means of the comparisons between the removal rates of nutrient salts, eco-physiological responses and growth. The reed-beds (combination of the reed individuals showing superior growth with helper microorganisms) were continuously supplied with processed-leachate. We monitored the effluents that passing through the reed-beds during the experiment period. After five weeks, analysis results of effluent from each reed-bed were as follows; chromaticity, total nitrogen, total phosphorus, biological oxygen demand, chemical oxygen demand, total dissolved solid and salinity decreased $29.5{\sim}36.9\%,\;49.4{\sim}67.2\%,\;42.1{\sim}94.6\%,\;74.5{\sim}88.8\%,\;15.6{\sim}20.8\%,\;17.5{\sim}35.4\%\;and\;15.3{\sim}34.7\%$, respectively. These results represented the substantial improvement of water-quality after passing through reed-bed in a continuous flow system.

• Journal of the Korean GEO-environmental Society
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• v.22 no.2
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• pp.15-23
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• 2021

A method of improving the post-management end system of a landfill that reflected total pollutant load was applied to the SUDOKWON 1st Landfill Site. Modeling results showed that the ratio of remaining methane, when compared to the total maximum potential of 2,521 × 106 Nm3, was estimated to be 8.8% in 2020, 7.0% in 2030, and 6.5% in 2040. If the average oxidation rate of 89.1% in 2005-2019 was applied, the ratio decreased by 1.01% in 2020, 0.76% in 2030, and 0.70% in 2040. This suggests that if the amount of methane generated is all emitted from the surface of the landfill after 2025, the real amount emitted to the atmosphere is less than that in 2019; therefore, the post-management end is possible. According to the results of trend analysis of the quality of leachate water, effluent criteria for Biochemical Oxygen Demand (BOD) can be satisfied in 2024, while those for Chemical Oxygen Demand (COD) and Total Nitrogen (T-N) can be satisfied in 2047 and 2117, respectively. If the post-management end system changed based on total pollutant load, the post-management can be terminated BOD today and COD within a few years; however, the fact that T-N could be terminated only after 2041 shows the need to fundamentally change management methods.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.2
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• pp.85-91
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• 1988

A field experiment was conduted to determine the effects of shading degrees (O: full sunlight, 25, 50 and 75%) on the proximate components, cell wall constituents (CWC), digestibility, water soluble carbohydrates (WSC) and nitrate nitrogen ($NO_3$-N) concentration of grasses grown in forest. For the test different artificial shading houses were established and pasutre species used were orchardgrass, timothy, perennial ryegrass and ladino clover. the experiment was performed at LES in Suwon, 1985 1. Considering proximate components, CWC and digestibility of grasses, ladino clover showed the best quality, and then perennial ryegrass. 2. The contents of crude protein, crude ash, and digestibility of grasses were increased with shadking, regardless of pasture species. As the shading degrees are increased, the contents of crude fibe in orchardgrass, perennial ryegrass and timothy were decreased, while that in ladino clover was increased with shading. 3. Grasses grwon in spring showed higher digestibility than those grwon in summer season. 4. The content of WSC was the highest in perennial ryegrass, and then ladino clover, orchardgrass, and timothy, in that order. Also WSC was decreased as the shading degrees are in creased. 5. The content of $NO_3$-N was the highest in perennial ryegrass, and then orchardgrass, ladino clover and timothy, in that order. Also the $NO_3$-N was significantly increased with higher shading level. In the regression equation between shading degrees and $NO_3$-N ($r^2=0.90^{**},\;r^2=0.95^{**}$), shading degree of 43 to 44% was critical level, causing nitrate poisoning to animal. 6. Considering grass quality, dry matter yield and $NO_3$-N, less than 40% of shading degree (over 60% of full sunlight) was desirable for better grassland improvement, management and utilization in the forest.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.3
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• pp.85-91
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• 1988

A field experiment was conducted to determine the effects of shading degrees (0: full sunlight, 25, 50 and 75%) on the proximate components, cell wall constituents (CWC), digestibility, water soluble carbohydrates (WSC) and nitrate nitrogen ($NO_3$-N) concentration of grasses grown in forest. For the test different artificial shading houses were established and pasture species used were orchardgrass, timothy, perennial ryegrass and ladino clover. The experiment was performed at LES in Suwon. 1985. 1. Considering proximate components, CWC and digestibility of grasses, ladino clover showed the best quality, and then perennial ryegrass. 2. The contents of crude protein, crude ash, and digestibility of grasses were increased with shading, regardless of pasture species. As the shading degrees are increased, the contents of crude fiber in orchardgrass, perennial ryegrass and timothy were decreased, while that in ladino clover was increased with shading. 3. Grasses grown in spring showed higher digestibility than those grown in summer season. 4. The content of WSC was the highest in perennial ryegrass, and then ladino clover, orchardgrass, and timothy, in that order. Also WSC was decreased as the shading degrees are increased. 5.The content of $NO_3$-N was the highest in perennial ryegrass, and then orchardgrass, ladino clover and timothy, in that order. Also the $NO_3$-N was significantly increased with higher shading level. In the regression equation between shading degrees and $NO_3$-N ($r^2$=0.90**, TEX>$r^2$=0.95**), shading degree of 43 to 44% was critical level, causing nitrate poisoning to animal. 6 Considering grass quality, dry matter yield and $NO_3$-N, less than 40% of shading degree (over 60% of full sunlight) was desirable for better grassland improvement, management and utilization in the forest.

• Korean Journal of Food Science and Technology
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• v.13 no.4
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• pp.319-327
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• 1981

In order to reproduce and improve the Korean traditional Kochujang(fermented hot pepper-soybean paste), traditional and improved Kochujang Koji were prepared according to the standard method investigated in Chunrabookdo area and combined the raw materials of Kochujang by the traditional habit. Amino nitrogen contents were higher in improved Kochujang than in traditional one, those were in the range from 83 to 106 mg% immediately after brewing and 191 to 313 mg% at the end stage of brewing. Water soluble and ammonia nitrogen contents were most high in the improved Kochujang which was mixed with sodium chloride and brewed soysauce as seasoning. The content of reducing sugar of traditional Kochujang was higher than that of improved one during the brewing. Ethyl alcohol contents of all Kochujang samples were 0.04% at the early stage of brewing and that reached above 2.5% after $40{\sim}50$ days brewing.