• Journal of Environmental Impact Assessment
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• v.28 no.6
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• pp.604-615
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• 2019

In this study, we produce a new type of the algae soil conditioner(ASC) using discarded algae biomass through a composting process and evaluate its nutritional characteristics. As the main ingredient, the ASCs used algae biomass collected through the coagulation-floating method and made by adding a variety of additional supporting materials (sawdust, pearlite, oilcake etc.). ASCs were divided into 0% in blank, 11.7% in ASC1, 21.6% in ASC2, 37.6% in ASC3, 59.5% in ASC4, and composted during 127 days. ASCs showed a sharp increase in temperature by aerobic microbial reaction, and 6~7 high and low temperature peaks were observed. As a result of physicochemical analysis, mineralization proceeded according to decomposing the organic matter and there was a marked increase not only in macronutrients (TN, P₂O₅, K₂O), but also in secondary macronutrients (CaO, MgO). The microbial community change was found in stage 1 (bacteria, filamentous fungi) → stage 2 (actinomycetes, bacteria) → stage 3 (Bacillus sp.), depending on the maturation process. It was estimated that microbial transition was closely related to temperature change and nutritional behavior. The quality of soil conditioner can be determined according to the maturity of compost process, and it was determined that effective microbial activity could be induced by controlling algae biomass below 59.5% in this study. In conclusion, we found out the possibility of manufacturing and utilizing soil conditioner recycled algae biomass and if further technological development is made on the basis it can be used as an effective soil conditioner.

• Journal of Environmental Impact Assessment
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• v.8 no.2
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• pp.9-20
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• 1999

Until 1993, Nanji landfill has been the main solid waste treatment facility for Seoul, which is the capital of Korea. Since the landfill has not been properly lined, soil and ground water around the landfill has been contaminated. Due to the proximity, it has been speculated that the water quality of the Han River would have been also influenced by the leachate. In order to illuminate this, HELP model to estimate the quantity of the leachate from Nanji landfill and RMA model to simulate the change of water quality in Han River were applied in this research. The result indicates that the quantity of leachate from Nanji landfill has been overestimated by previous works and it was due to the failure to consider the water storage capacity of the landfill. The effect from Nanji landfill leachate on the water quality, in terms of COD input, proves to be smaller than those from other tributaries and influents to the River and the effect is larger when the flow of the River is reversed due to the tide.

• Korean Journal of Agricultural Science
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• v.46 no.1
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• pp.93-102
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• 2019

The materials of artificial soils in the production process of container seedlings have a great influence on plant growth. Peat moss, vermiculite, and perlite have been used as major components of artificial soils for many years; however, they could decrease carbon fixation carried out by the soil and cause environmental problems such as a change in the water quality. Thus, environmental friendly materials to replace them must be developed. The purpose of this study was to verify the optimum additive materials of artificial soils and their mixed ratios for the growth and seedling quality index (SQI) of Quercus serrata. Rice husk, mushroom sawdust, and pine bark were each used as an additive material and mixed into the growth medium at 10% and 20% of the total volume. There was no significant difference in the height growth of Q. serrata. The 20% mushroom sawdust decreased the root collar diameter by 23.4% compared to the control. The total dry weight was highest with the 10% rice husk and was significantly lower by 10.3% for the 20% mushroom sawdust compared to the control. Additionally, the SQI for all the treatments showed no tendency to increase compared with the control. Thus, this study showed the possibility of recycling biomaterials from agriculture and forest for seedling production. This method could reduce environmental problems and help eco-friendly nurseries to achieve a carbon negative impact by the recycling of by-products.

• Korean Journal of Environmental Agriculture
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• v.30 no.4
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• pp.414-418
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• 2011

BACKGROUND: Plastic mulches widely used in raised-bed culture mainly to conserve water, control weeds and raise soil temperature. The most widely used plastic mulch colour is black. Reflective red and far-red light can affect on growth and yield of various vegetable crops. Objectives of this study were to investigate the characteristics of reflective light of black and red plastic mulches, and to evaluate the reflective red and far-red light on the quality characteristics and yield of the Oriental melon (Cucumis. Melo L.) and tomato (Lycopersicon esculentum L.). METHODS AND RESULTS: Oriental melon and tomato were cultivated over the reflective red and black plastic mulches in plastic house. Reflected red and far-red light over the red plastic mulch were 2.6 times higher than those of black plastic mulch. Red to F-Red ratio of black plastic mulch, red plastic mulch and sunlight were 1.14, 0.93 and 1.16 respectively. Intensity of reflected red and far-red light over red plastic mulch were highest at surface height of 30 cm. The higher the height of the surface decrease the intensity of far-red light. Accordingly, Red to F-Red ratio were increased. Reflective red plastic mulch increased the weight of fruit and content of sugar in Oriental melon and tomato. CONCLUSION(s): Yield of Oriental melon over reflective red plastic mulch was higher than that of black plastic mulch. These results suggested that reflected red and far-red light over the red plastic mulch affected allocation of photosynthate in growing Oriental melon.

• The Journal of Engineering Geology
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• v.14 no.3 s.40
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• pp.301-311
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• 2004

This study is suggested a new dielectric tracer test method to understand geological structure of porous media and groundwater flow to use the dielectric constant which is one of electrical special quality of various geological materials. To measure their parameters, tracer material is made an ethanol mixing liquid(EML) having a same specific gravity of water. Also, soil materials are prepared a dielectric tracer test using the FDR system that could measure dielectric constant for saturated standard sand and river sand layers which have different initial porosity. To compare with their results, we discussed with the concentration variation of saline water having a saline concentration $3\%$ which is general tracer material by using the electro multi-meter system in the laboratory or field test. In two tracer experiment results, EML tracer test could confirm definitely EML concentration variation from each saturated soil layer as standard and river sands. However, tracer test of saline water $3\%$ concentration could not confirm permeating movement of water by degree of salinity change because these are settled at lower part column in a whole column area continuously. These causes are that specific gravity of saline water is heavier than water. That is, it could know that deposition of saline water is composed of lower part of soil column continuously independently of the direction of water into saturated soil material.

• Journal of Korea Water Resources Association
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• v.45 no.11
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• pp.1081-1091
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• 2012

SWAT model is applied to simulate rainfall-runoff and pollutant loadings in the Nakdong River basin as the condition for extreme droughts and floods. The year 1994 and 2002 are chosen as the drought and flood year, respectively, through the analysis of past rainfall data for 30 years. The simulation results show decreases in both runoff and pollutant loadings for the drought year but increases for the flood year. However, the pollutant loadings on some upper sub-basins increase for drought year due to highly-regulated dam discharge and soil moisture change. Collectively, extreme droughts and floods have negative impacts on water quality, showing elevated SS loadings during wet season and concentrated T-P concentrations during low flow season. The extent of these impacts is highly influenced by antecedent dry days and precipitation patterns.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.5
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• pp.327-332
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• 2013

This survey was conducted to obtain basic data about organic matter such as BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), DOC (Dissolved Organic Carbon) and TOC (Total Organic Carbon) in agricultural water in Gyeongnam province. BOD and COD are currently used for water quality indices, but adoption of TOC is being suggested. The surface water samples were collected at 39 locations in Gyeongnam province in April, July and October. Average concentrations of BOD, COD, DOC and TOC were 1.6, 3.3, 5.3 and $5.7mg\;L^{-1}$, respectively. In July, average concentrations of BOD and COD were 2.4 and $3.9mg\;L^{-1}$, respectively, showing these values were higher than other months. Average concentrations of TOC in April, July and October were 4.8, 7.4 and $4.8mg\;L^{-1}$, respectively. This suggested that the highest value of TOC was in July. Average decomposition efficiencies for BOD-C/TOC and COD-C/TOC were 11.4 and 23.9%, respectively. Correlation coefficient of TOC and DOC was higher by 0.995, whereas that of TOC and COD was lower by 0.763. Especially, TOC and DOC were highly related than others.

• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.94-99
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• 2011

This study was performed to investigate the effect of foliar feeding as the fertilization on creeping benrgrass green. Research results have showed that the visual quality of bentgrass as well as shoot density and chlorophyll index dramatically improved after foliar feeding. Shoot density of bent grass in foliar based fertilization was 2.8 ea/$cm^2$ higher than that of the liquid based fertilization during the experiment period, moreover that the foliar feeding is more effective to alleviate shoot density during the rainy season in summer. Results showed that foliar feeding was key role to achieve the stable visual quality, chlorophyll index and maintained Normalized Difference Vegetation Index (NDVI) throughout the year in addition to get fast recovery after aeration and dry spot. These were consistent with the previous research of foliar feeding which directly provided nutrient to the turfgrass leaf thus increased turfgrass growth within a short time. It is projected to be a especially adequate management program during the hot summer season in which the nutrition feeding is low. However, root growth was no significant difference between foliar based fertilization and liquid based fertilization. Golf Course managers also should consider about the number of frequent fertilizing. Lastly, it was no big change in chemical property by soil foliar based fertilization which is meaning of preventing the soil salinization, meanwhile, it is prone to reach the nutrient deficiency. It hopes to be settled as the general fertilization in golf course of Korea, since there are many advantages of foliar based fertilization program. It is suggested to study more practical process of foliar feeding through the further research.

• The Korean Journal of Ecology
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• v.23 no.2
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• pp.131-134
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• 2000

Forest vegetation in Korea can be largely divided into warm temperate, cool temperate and frigid forest zone. The cool temperate forest zone of them occupies the largest part of the Korean peninsula and it is generally divided into three subdivisions such as northern, central and southern subzone. The Forestry Research Institute established three long-term ecological research sites at Kwangnung Experiment Forest in the central subzone of the cool temperate forest zone, at the Mt. Kyebangsan Forest in the northern subzone of the cool temperate forest zone. and at the Mt. Keumsan Forest in the warm temperate forest zone. The objectives of long-term ecological research in the Forestry Research Institute, Korea are to study long-term changes of the forest ecosystems in energy fluxes, water and nutrient cycling, forest stand structure, biological diversity, to quantify nutrient budgets and fluxes among forest ecosystem compartments and to integrate ecological data with a GIS - assisted model. To achieve the objectives, forest stand dynamics. environmental changes in soil properties, stream water quality, nutrient cycling, air pollution and biological diversity have been investigated and plant phonology as an indicator of climate change has been monitored in the LTER sites.

• Journal of the Korean Society of Groundwater Environment
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• v.7 no.3
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• pp.133-140
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• 2000

The area of Chojung is famous for its mineral water quality. Because of this reason, massive groundwater development was induced in the area. As a result of excessive pumping. the depletion of the groundwater resources is expected seriously. This study was conducted to analyse groundwater flow in Chojung using a numerical model. Simulation results show the groundwater level change slowly in the mountain area but steep groundwater drawdown occurred in the pumping area in the downstream. This steep groundwater drawdown is due to excessive pumping in the hilly region. Because of this excessive, desiccation of water resources were predicted and proper countermeasure is in great demand.