• Journal of the Korean Society of Marine Environment & Safety
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• 제14권2호
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• pp.111-117
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• 2008

We estirmted the yearly and monthly variation in discharge from the Nakdong River Barrage. We studied the total monthly discharge, the mean daily discharge, and the maximum daily discharge based on the observational discharge data for the 11-year period 1996-2006. We also examined the correlation between the discharge and the meteorologiml factors that influence the river inflow. The results from this study are as follows. (1) The total monthly discharge for 11 years at the Nakdong River Barrage was $224,576.8{\times}10^6\;m^3$: The daily maximum was in 2003, with $56,292.3{\times}10^6\;m^3$. The largest daily mean release discharges occurred in August with $52,634.2{\times}10^6\;m^3$ (23.4% of the year), followed by July and September in that order with 23.1 and 17%, respectively. (2) The monthly pattern of discharge could be divided into the flood season for the period July-September (discharge =$1000{\times}10^6\;m^3$/day), the normal season from April to June and October (discharge=$300{\times}10^6\;m^3$/day), and the drought season from December to March (discharge < $300{\times}10^6\;m^3$/day). (3) Periods of high temperature, low evaporation loss, and short sunshine duration produced a much higher discharge in general. Conditions of low rainfall and high evaporation loss, as was the rose in 2003, tended to reduce the discharge, but high rainfall and low evaporation loss tended to increase the discharge as it did in 200l. (4) The dominant wind directions during periods of high discharge were NNE (15.5%), SW and SSW (13.1%), S(12.1%), and NE (10.8%) This results show that it run bring on accumulation of fresh water when northern winds are dominant, and it run flow out fresh water toward offslwre when southern winds are dominant.

• Asian-Australasian Journal of Animal Sciences
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• 제12권5호
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• pp.766-771
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• 1999

The first paper of this series compared the effects of rates and frequencies of application of dairy slurry on herbage yields and stand persistence of orchardgrass (Dactylis glomerata L.), reed canarygrass (Phalaris arundinacea L.), and alfalfa (Medicago sativa L.)-grass mixtures managed as a 4-cutting system. This paper compares the effects of rates and frequencies of application of dairy slurry on herbage yield and stand persistence of alfalfa, orchardgrass, tall fescue (Festuca arundinacea Schreb.), and alfalfa-orchardgrass mixture managed as a 5-cutting system. The results presented here are part of a larger study having a primary objective of comparing alfalfa, various grasses, and alfalfa-grass mixtures for utilizing nutrients from dairy slurry applied to established stands. A randomized complete block design with treatments in a split plot arrangement with four replicates was used. The main plots consisted of 9 fertility treatments: 7 slurry rate and frequency of application treatments, one inorganic fertilizer treatment, and an unfertilized control. The sub-plots were the forage species. Manure used for the study was composed from stored solids scraped from the alleyways of a free-stall dairy barn. Water was added to from a slurry having about 8 % solids. Slurry was pumped from the liquid spreader tank into 10.4 L garden watering cans for manual application to the plots. Herbage yields of alfalfa, tall fescue, and alfalfa-orchardgrass were generally not affected by slurry application rates and were not significantly different from the inorganic fertilizer treatment. Tall fescue significantly outyielded all other forage species at all manure and the inorganic fertilizer treatments in the second year when rainfall during the growing season was unusually high. Grasses generally had a greater response to manure applications than alfalfa and alfalfa-orchardgrass. Increasing rates of manure did not increase herbage yields of alfalfa and alfalfa-orchardgrass. Herbage yields within each species were not affected by frequency of application of the same total rate. Stand ratings of alfalfa, orcahrdgrass and alfalfa-orchardgrass were significantly lower for the very high manure application rate compared to the control treatment. Based upon the results of this study, multiple annual applications of slurry manure can be made onto these species at rates up to $1,700kg\;total\;N\;ha^{-1}\;yr^{-1}$ without detrimental effects on herbage yield and stand persistence.

• Korean Journal of Agricultural Science
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• 제45권1호
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• pp.19-27
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• 2018

To study the effect of natural anti-microbial chemicals on the growth and quality of chili peppers, chitosan ($100mg/L^{-1}$), stevia ($250mg/L^{-1}$), and the mixture of both chemicals at the same concentration were sprayed after planting at 1-week interval throughout the experimental period. Plant height was measured twice after the $3^{rd}$ and $4^{th}$ applications. Plant height was numerically reduced in all chemical treatments compared to that of untreated control; however, there was no statistical difference between treatments. The fruit quality was examined at commercial maturity, and only minor differences were found in fruit color, length, and dry matter content between the treatments. Although a statistical difference was not present for soluble sugars levels, total phenolics, and capsaicin contents, yield in all chemical treatments significantly increased compared to untreated control. The effect on yield increase was greater at the late harvest season regardless of treatments. Total yield of 4 harvests was higher for the chitosan treatment than other treatments. During the experiment, the entire experimental field was waterlogged for 1 day due to sudden heavy rainfall, which resulted in the occurrence of bacterial browning disease in all treatments. The rate of disease occurrence and the degree of severity, however, were much lower in the chitosan treatment. In conclusion, the potential of chitosan as an alternative antimicrobial agent was confirmed in chili peppers in this study. Further research is required on stevia as an alternative chemical for disease control in chili peppers.

• Korean Journal of Environmental Agriculture
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• 제24권4호
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• pp.319-325
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• 2005

Sediments of Mankyung and Dongjin river were examined on the physico-chemical properties and phosphorus fractionations. The content of total-P in sediment of Mankyung river ranged from 290.1 to 405.4 mg/kg (average = 363.4 mg/kg), while that in sediment of Dongjin river ranged from 304.1 to 431.7 mg/kg (average = 353.6 mg/kg). In both rivers, the total-P was highest in June to September. It is presumed that surficial sediment in arable land flowed into the rivers with rainfall-runoff. Phosphorus fractionations in Mankyung and Dongjin river were apatite-P 52.1% and 42.7%, residual-P 27.3% and 34.2%, nonapatite inorganic-P 18.1% and 22.5%, and adsorbed-P 0.6% and 0.6%, respectively. Adsorbed-P in sediment was the most scarcity fraction. It thus appears that adsorbed phosphorus was not effected in aquatic ecosystem. But nonapatite inorganic-P would be highly released under changes of redox condition and pH in aquatic ecosystem.

• Korean Journal of Microbiology
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• 제32권3호
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• pp.238-244
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• 1994

To investigate the bacterial potentials for utilizing dissolved organic matter in highly eutrophic estuary, the annual fluctuations of microbiological and physicochemical environmental parameters were analyzed in Naktong River Estuary. Total bacterial number ranged from 0.33 to $2.09{\times}10^7$ cells/ml, and correlated with the heterotrophic bacterial numbers in more eutrophic sites, especially. Bacterial biovolume and biomass varied between 0.064 and 0.156 2.09${\mu}m^3$/cell, 0.163 and 1.036 ${\mu}g$-C/ml, respectively. Bacterial secondary productivity ranged from 0.24 to 60.86 ${\mu}g$-C/l/h, and showed high correlations with the environmental parameters of pollution indicator. The seasonal variation pattern of bacterial productivity in freshwater sites was high in winter and low in summer, which was interpreted as the results of pollution loads varied with the amount of rainfall. In seawater site, the pattern was different from those of freshwater sites; high in summer and low in winter. In this site, the values of bacterial productivity showed positive correaltions with chlorophyll a, heterotrophic bacterial number, and temperature (r>0.5, p<0.05). These results suggested that the main source of organic matter which influences the bacterial productivity may be allochthonous materials in the upper freshwater zone of Naktong River Barrage, and autochthonous algal excretory products in the lower seawater zone of Naktong River Barrage.

• The Korean Journal of Mycology
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• 제32권2호
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• pp.71-78
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• 2004

This study was conducted to investigate the diversity and occurrence frequency of ectomycorrhizal fruit bodies by planting sites from June 2000 to October 2001. A total of 3 classes 3 subclasses 8 orders 22 families 41 genera and 72 species (including two varieties) including saprophytic and ectomycorrhizal fungi was investigated. The mushrooms are classified into 9 families 21 genera and 48 species in Agaricales, 5 families 11 genera and 13 species in Aphllophorales, 3 families 3 genera and 4 species in Heterobasidiomycetes and 5 families 6 genus and 7 species in Gasteromycetdae. A total of 7 families 11 genera 30 species (2,451 ea.) of ectomycorrhizal mushroom was investigated. The occurrence frequency of mushrooms was 1,225, 179 and 130 times for Laccaria vinaceoavellanea, Amanita longistriata and Laccaria amethystea, respectively. The mushroom occurrence of ectomycorrhizal fungi was closely related to climatic conditions such as high air temperature, relative humidity and lots of rainfall from July to August. Diversity and distribution of ectomycorrhizal fungi by plots were very different because of variable local environments and different host plants in experimental plots. Laccaria vinaceoavellanea has showed very low host range of plant specificity because of mushroom occurrence in only Quercus sp. and Amanita longistriata, Russula bella and Inocybe sp. have showed wide host range of plant specificity because of mushroom occurrence in coniferous and broadleaved trees. The environment which has a favorable influence of mushroom occurrence was soil pH, organic matter and T/N ratio of soil enviromental and humidity of climatic environment.

• Korean Journal of Soil Science and Fertilizer
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• 제45권6호
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• pp.882-889
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• 2012

This study was surveyed that water physiochemical characteristics and phytoplankton incidence of main stream and Lake Doam near to Daegwallyeong agricultural area. Based on above results, it was conducted to get information overall water characteristics in south Han upstream river. COD value of Lake Doam was $6.1mg\;L^{-1}$ and T-P (Total phosphorous) from there was $0.26mg\;L^{-1}$ which was higher than the value of grade VI based on lake water living environment standard. Suspended solid was an average of 9.77 NTU which was higher than value of lake living standard. Concentration of phytoplankton was over $2.0{\times}10^3Cell\;mL^{-1}$ from July to September. It was considered that cyanobacteria were occurred due to massive influx of nutrient material by high temperature and rainfall during this season. Compare to Ontario's sediment quality guidelines, T-N and T-P was middle value between LEL and SEL in Lake Doam. This value means that contamination in water is serious. Therefore, it is considered that systematic management was needed to reduce and block contamination source.

• Journal of Korean Society for Atmospheric Environment
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• 제26권1호
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• pp.34-47
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• 2010

Long-range transport of air pollutants was simulated using Comprehensive Acid Deposition Model (CADM) and Yonsei University-Sulfuric Acid Deposition Model (YU-SADM). For the simulation, weather patterns that represent the four seasons were derived through a clustering analysis with 5-years of meteorological data. The simulation result showed that in spring, influenced by strong low pressure from China, air pollutants of moved to the Korean Peninsula. In summer, humid air moved into the Korean Peninsula across the Yellow Sea while the north pacific high pressure extended, making the concentration of air pollutants lower than that in the other seasons. In autumn, air pollutants were transported by the northwest wind caused by the movement of high pressure over the Yellow Sea, while in winter air pollutants were influenced by northwest winds from continental highs. The amount of air pollutants in each season showed that high amount of pollutants were transported in winter due to the strong northwest wind. The in-flows were 3 to 8 times higher than those of the other seasons, and out-flows were about as twice as high. The amount of wet deposition in summer and autumn increased significantly compared to the amount in the other seasons due to the increase of rainfall. Source-receptor relationship analysis for sulfur showed that 70 to 91 precent of the total deposition came from the self-contribution by the Korean Peninsula. In winter, contribution from China was about 25 percent of the total deposition which was higher amount than any other season.

• Korean Journal of Soil Science and Fertilizer
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• 제31권3호
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• pp.211-215
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• 1998

Soil loss and runoff were investigated in a small watershed located in Sangeo-ri, Yeoju-eup, Yeoju-gun, Kyonggi-do. The watershed with the area of 35 ha consists of forest, grassland, uplands and mulberry. V-notch type water tank. flow-meter, automatic water sampler and rain gauge were installed at the main outlet stream. Out of $1.037.9Mg\;35ha^{-1}$ of total annual rainfall. 17.9% was lost via run-off. The total amount of soil eroded was $152.2Mg\;35ha^{-1}$, of which $78.6Mg\;35ha^{-1}$ was suspended load and $73.6Mg\;35ha^{-1}$ ha was sediment load. The soil losses under different land uses were $16.02Mg\;ha^{-1}$ for upland annual Crops. $2.69Mg\;ha^{-1}$ for mulberry field, $0.58Mg\;ha^{-1}$ for grassland and $0.55Mg\;ha^{-1}$ for forest. The predicted soil loss by Universal Soil Loss Equation was approximately 20% underestimated in forest, grassland and uplands, and 32% underestimated in mulberry field.

• Journal of Radiation Protection and Research
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• 제27권1호
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• pp.11-19
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• 2002

The seasonal variation of $^7Be$ and $^{137}Cs$ concentrations in airborne dust, precipitation and dry fallout collected at Daejeon during the period of 1998 - 1999 has been studied. The annual mean values of 7Be concentrations in airborne dust, precipitation and dry fallout were in the range of $3.80{\sim}4.29\;mBq\;m^{-3},\;1.25{\sim}1.67\;Bq\;l^{-1},\;19.7{\sim}22.3 MBq\;km^{-2}$, respectively. The annual mean values of $^{137}Cs$ concentrations in airborne dust, precipitation and dry fallout ranged $1.08{\sim}1.28{\mu}Bq\;m^{-3},\;0.44{\sim}2.66 mBq\;l^{-1}\;\;0.036{\sim}0.0455\;MBq\;km^{-2}$, respectively. While the concentrations of $^7Be$ and $^{137}Cs$ in airborne dust and dry fallout were relatively higher in the spring and autumn when the amount of dry fallout increased than in other season, their concentrations in precipitation were relatively lower in the summer when the rainfall increased. The total depositions of $^7Be$ and $^{137}Cs$ due to dry fallout and precipitation were in the range of $80.7{\sim}137MBq\;km^{-2}$ and $0.059{\sim}0.060MBq\;km^{-2}$, respectively. More than 80% of $^7Be$ deposition resulted from precipitation, whereas about 60% of $^{137}Cs$ deposition was due to dry fallout.