• Particle and aerosol research
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• v.9 no.2
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• pp.89-102
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• 2013

24-hr $PM_{2.5}$ samples were collected from January 19 through February 27, 2009 at an urban site of Gwangju and analyzed to determine the concentrations of organic and elemental carbon(OC and EC), water-soluble OC(WSOC), eight ionic species($Na^+$, $NH^{4+}$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, $Cl^-$, ${NO_3}^-$ and ${SO_4}^{2-}$), and 22 elemental species. Haze phenomena was observed during approximately 29%(10 times) of the whole sampling period(35 days), resulting in highly elevated concentrations of $PM_{2.5}$ and its chemical components. An Asian dust event was also observed, during which $PM_{2.5}$ concentration was 64.5 ${\mu}g/m^2$. Crustal materials during Asian dust event contributed 26.6% to the $PM_{2.5}$, while lowest contribution(5.1%) was from the haze events. OC/EC and WSOC/OC ratios were found to be higher during haze days than during other sampling days, reflecting an enhanced secondary organic aerosol production under the haze conditions. For an Asian dust event, enhanced concentrations of OC and secondary inorganic components were also found, suggesting the further atmospheric processing of precursor gases during transport of air mass to the sampling site. Correlations among WSOC, EC, ${NO_3}^-$, ${SO_4}^{2-}$, and primary and secondary OC fractions, which were predicted from EC tracer method, suggests that the observed WSOC could be formed from similar formation processes as those of secondary organic aerosol, ${NO_3}^-$ and ${SO_4}^{2-}$. Results from principal component analysis indicate also that the observed WSOC was strongly associated with formation routes of the secondary organic and inorganic aerosols.

• Korean Journal of Poultry Science
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• v.31 no.4
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• pp.221-228
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• 2004

This study was conducted to determine the effects of two chemical additives on nitrogen (N) and soluble reactive phosphorus (SRP) contents in litter (rice hull) after broiler chicks were raised for 42 days. Two different additives were applied as a top dressing to the litter at a rate of 200 g ferrous sulfate $(FeSO_4)$ or 200 g aluminum sulfate [$Al_2(SO_4)_3$ $\cdot$ $14H_2O$, Alum] per kg litter, while the control group did not have the two chemicals added to the litter. A total of 64 broiler chicks (4 treatments$\times$4 replicates$\times$4 birds) were fed the experimental diets for 6 weeks. There was no difference in pH between the two chemical treatments and control group, but SRP content was significantly affected on it (P<0.01). SRP contents from ferrous sulfate and alum treated litter at 6 weeks were reduced by $79\%$ and $60\%$, respectively, as the two chemical treatments decreased the pH compared to the control group. In the ferrous sulfate treated litter, EC, TC, $NH_4-N$, $NO_3$-N, and IN contents did not show any difference between $FeSO_4$ treatment and control. However, the differences between $FeSO_4$ treatment and control were found in moisture, TN, ON, AN, PAN, C:N, and C:ON contents (P<0.01). As seen in the alum treated litter, there were differences in moisture, TC, TN, $NH_4-N$, IN, AN, PAN, and C:N contents between alum treatment and control (P<0.05 and 0.01) but no differences in EC, $NO_3-N$, ON, and C:ON. In conclusion, the results of this research show that ferrous sulfate and alum-treatment of poultry litter has the potential to increase N and reduce SRP content by lowering litter pH and moisture content.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.544-550
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• 2012

This study was conducted to investigate the characteristic factors which have been influenced on nitrous oxide ($N_2O$) emissions related to the environment change of nitrogen application level, rainfall and temperature during the potato cultivation at black volcanic ash soil from 2010 to 2011. During the potato cultivation, the more amount of nitrogen fertilizer applied, $N_2O$ emissions amounts were released much. $N_2O$ emissions with the cultivation time were released much at the first and middle of cultivation with heavy rainfall, but it was released very low until the end of cultivation and drought season. $N_2O$ emissions mainly were influenced by the rainfall and soil water content. The correlation (r) with $N_2O$ emissions, soil wate, soil temperature in 2010 were very significant at $0.6251^{**}$ and $0.6082^{**}$ respectively, but soil EC was not significant to 0.10824. In 2011, soil temperature was very significant at $0.4879^{**}$, but soil water and soil EC were not significant at 0.0468 and 0.0400 respectively. Also, $NH_4$-N was very significant at $0.7476^{**}$, but $NO_3$-N and soil nitrogen ($NO_3-N+NH_4-N$) were not significant at 0.0843 and 0.1797, respectively. During the potato cultivation period, the average emissions factor of 2 years released by the nitrogen fertilizer application was presumed to be 0.0040 ($N_2O-N\;kg\;N^{-1}\;kg^{-1}$). This factor was lower about 2.5 times than the IPCC guideline default value (0.0100 $N_2O-N\;kg\;N^{-1}\;kg^{-1}$).

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.2
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• pp.156-163
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• 2007

This study was conducted to evaluate the liquefying efficiency of mixed organic fertilizer in different conditions. The organic fertilizer was composed of sesame oil cake, rice bran, fish meal, ground bone meal etc, and made by fermenting process. It included $23g\;kg^{-1}$, $17.0g\;kg^{-1}$, $23.9g\;kg^{-1}$, $290g\;kg^{-1}$ of N, $P_2O_5$, $K_2O$, organic matter, respectively. In one test, the mixed organic fertilizer was added in the proportion of 10% to water 90% and aerated continuously, for 2, 8 hours per day, and not aerated as control. In the other test, ratios of organic fertilizer to water were 5%, 10%, 20% and aerated for 2 hours a day. With the increase of liquefying time, pH, EC and $NH_4-N$ increased without relation to aeration time. After 10 days, liquid organic fertilizer aerated for 2 hours a day contained $634mg\;N\;kg^{-1}$, $68.1mg\;P_2O_5\;kg^{-1}$, $453mg\;K_2O\;kg^{-1}$, which was not significantly different from 8 hours a day or continuous aeration. Then extraction ratios of inorganic contents were 27.6%, 4.0% and 18.9%, respectively. Continuous aeration resulted in increasing the viable number of aerobic bacteria, spore forming bacteria and fungi in liquefied solution. Higher ratio of organic fertilizer to water increased EC, $NH_4-N$ and other inorganic matter contents, but decreased extraction ratio of nutrients in liquid fertilizer. The liquid organic fertilizer of 20% contained $1,140mg\;N\;kg^{-1}$, $35.4mg\;P_2O_5\;kg^{-1}$, $544mg\;K_2O\;kg^{-1}$ after 10 days. Then extraction ratios were 24.8%, 2.4% and 13.6%, respectively. The ratio of organic fertilizer to water was positively correlated with only spore forming bacteria, Pseudomonas spp. among microorganisms.

• Environmental Engineering Research
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• v.11 no.5
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• pp.285-291
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• 2006

Biofiltration is a simple, effective, economically viable and the most widely used gas treatment technique for treating malodors at low concentrations and high flow rates. This paper reports the performance of two lab scale immobilized cell biofilters operated in continuous mode for hydrogen sulfide ($H_2S$) and ammonia ($NH_3$) removal. The removal efficiency (RE, %) and the elimination capacity (EC, $g/m^3{\cdot}hr$) profiles were monitored by subjecting the biofilters to different loading rates of $H_2S$ (0.3 to $8\;g/m^3{\cdot}hr$) and $NH_3$ (0.3 to $4.5\;g/m^3{\cdot}hr$). The removal efficiencies were greater than 99% when inlet loading rate to the biofilters were upto $6\;gH_2S/m^3{\cdot}hr$ and $4\;gNH_3/m^3{\cdot}hr$ respectively. The performance of the biofilters were also ascertained by conducting shock loading studies at a loading rate of $10\;gH_2S/m^3{\cdot}hr$ and $6\;gNH_3/m^3{\cdot}hr$. The results from this study show high removal efficiency, good recuperating potential and stability of the immobilized microbial consortia to transient shock loads.

• Journal of Bio-Environment Control
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• v.26 no.3
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• pp.201-207
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• 2017

Objective of this research was to investigate the influence of pre-plant nitrogen levels in root media on plug seedling growth of radish cv. Soksungbommu. To achieve the research purpose, a root medium, the mixture of perlite, coir dust, and peatmoss (volume percentage of 30:35:35) was formulated and the N levels incorporated during mixing were controlled to 0, 100, 250, 500, 750, 1,000, and $1,500mg{\cdot}L^{-1}$. Then, the seeds were sown into 72-cell plug trays in which the root medium was packed. The measurements of growth and analysis of tissue and root media were conducted 2 and 4 weeks after sowing. Elevation of pre-plant N levels raised EC and turned down pH of root media. But, as seedling grew, the pH rose and EC get lowered in all treatments. The EC as well as $NH_4-N$ and $NO_3-N$ concentrations of root media declined gradually until week 2, but those declined sharply between weeks 2 to 4. The seedling growth 2 weeks after sowing showed quadratic response to pre-plant N levels with the highest growth in $250mg{\cdot}L^{-1}$ treatment and lagging growth in the treatments of lower or higher N levels than $250mg{\cdot}L^{-1}$. The seedling growth 4 weeks after sowing showed also quadratic response with the highest growth in $500mg{\cdot}L^{-1}$ treatment. The tissue N contents were get higher and those of K, Ca, and Mg were get lower as pre-plant N levels were elevated. Above results suggest that lower than $250mg{\cdot}L^{-1}$ in pre-plant N levels is optimistic for growth of plug seedling and avoidance of toxic injury in very young stage.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.1
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• pp.28-40
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• 2015

To investigate the seasonal variations of carbonaceous aerosol in Daejeon, OC (organic carbon), EC (elemental carbon) and WSOC (water soluble organic carbon) in $PM_{2.5}$ samples collected from March 2012 to February 2013 were analyzed. $PM_{2.5}$ concentrations were estimated by the sum of organic matter ($1.6{\times}OC$), EC, water-soluble ions ($Na^+$, $NH_4{^{+}}$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, $SO_4{^{2-}}$, $NO_3{^{-}}$). The estimated $PM_{2.5}$ concentrations were relatively higher in winter ($29.50{\pm}12.04{\mu}g/m^3$) than those in summer ($13.72{\pm}6.92{\mu}g/m^3$). Carbonaceous aerosol ($1.6{\times}OC+EC$) was a significant portion (34~47%) of $PM_{2.5}$ in all season. The seasonally averaged OC and WSOC concentrations were relatively higher in winter ($6.57{\times}3.48{\mu}gC/m^3$ and $4.07{\pm}2.53{\mu}gC/m^3$ respectively), than those in summer ($3.07{\pm}0.8{\mu}gC/m^3$, $1.77{\pm}0.68{\mu}gC/m^3$, respectively). OC was correlated well with WSOC in all season, indicating that they have similar emission sources or formation processes. In summer, both OC and WSOC were weakly correlated with EC and also poorly correlated with a well-known biomass burning tracer, levoglucosan, while WSOC is highly correlated with SOC (secondary organic carbon) and $O_3$. The results suggest that carbonaceous aerosol in summer was highly influenced by secondary formation rather than primary emissions. In contrast, both OC and WSOC in winter were strongly correlated with EC and levoglucosan, indicating that carbonaceous aerosol in winter was closely related to primary source such as biomass burning. The contribution of biomass burning to $PM_{2.5}$ OC and EC, which was estimated using the levoglucosan to OC and EC ratios of potential biomass burning sources, was about $70{\pm}15%$ and $31{\pm}10%$, respectively, in winter. Results from this study clearly show that $PM_{2.5}$ OC has seasonally different chemical characteristics and origins.

• Journal of Korean Society on Water Environment
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• v.23 no.2
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• pp.260-265
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• 2007

This study was carried out to complement water quality standards and to establish new concept for water quality standards reflecting current state of water quality in small streams. By this purpose, discriminant analysis was performed and Water Quality Level Model (WQLM) was developed using the data such as EC, BOD, $COD_{Mn}$, SS, T-N, T-P, $NH_3-N$ in 224 agricultural streams. To give water quality level for water quality parameters, it divided into 20% respectively in the order of excellent water quality. On the basis of the lowest water quality level, water quality level of small streams is granted. As a result of it, number of stream corresponding to Level I was no, Level II was 2 streams, Level III was 22 streams, Level IV was 70 streams, and Level V was 130 streams. Average of water quality in each level was the highest in Level V. EC, SS, and T-N of 7 parameters were selected in variance concerned water quality level. By standardized canonical discriminant function coefficient, EC of three variances was the highest in 0.625 at the discriminant power. The next was T-N (0.509), SS (0.414). By discriminant function for water quality level, Level II was equal to $-2.973+19.376{\times}(EC)+0.647{\times}(T-N)+0.009{\times}(SS)$, Level III was equal to $-3.288+19.190{\times}(EC)+0.733{\times}(T-N)+0.041{\times}(SS)$, Level IV was equal to $-4.462+27.097{\times}(EC)+0.792{\times}(T-N)+0.053{\times}(SS)$, and Level V was equal to $-9.117+40.040{\times}(EC)+1.305{\times}(T-N)+0.111{\times}(SS)$. As a result of test at real agricultural watershed of Jeongan and Euidang in Gongju city, the fitness of WQLM was high to 88.78%. But, to get accomplished water quality assessment more exactly in agricultural streams, we had to concentrate and get vast data, and WQLM was modified and complemented continually.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.1
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• pp.33-39
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• 1994

This survey was conducted to investigate the factors affecting on salt accumulation and chemical components of soils cultivated with horticulture crops in plastic film houses. The soil samples were taken from 40 sites in the northern central areas of Korea and were analyzed for the chemical properties and soil separates. The data were evaluated with soil texture and years of cultivation as major factors. The results are summarized as follows : 1. The chemical properties of surface soils in plastic film house were pH 5.80, EC $3.59mScm^{-1}$, O.M. 4.20%, Av. $P_2O_5$ 1,178ppm, $NO_3-N$ 180ppm, Av. $SO_4{^{2-}}$ 353ppm, $Cl^-$ 240ppm, Ex. Na 0.40me/100g. 2. Compared to the outside soil of plastic film house, the inside soil had 2.5~3 times higher contents of $NO_3-N$, Av. $SO_4{^{2-}}$ and $Cl^-$, 1.2~1.8 times higher exchangeable base elements, and 2.8 times higher electrical conductivity. But pH value of the inside soil was lower than the outside soil by 0.3 pH unit. 3. Soil texture classification showed that sandy loam, loam and silt loam were 32.5 %, 37.5 %, and 30.0 %, respectively. The contents of $NO_3-N$, Av. $SO_4{^{2-}}$, $NH_4-N$ and EC value were very high in silt loam soils. Av. $P_2O_5$ content and pH value of sandy loam soils were higher than those of silt loam and loam soils. 4. The contents of O.M. and Av. $P_2O_5$ were higher in long term cultivation, but the contents of $NO_3-N$, Av. $SO_4{^{2-}}$, $Cl^-$, Ex. Mg and Ex. Na including EC of the soil with 2~4 years cultivation were higher than those of the soil with above 5 years cultivation. 5. Multiple linear regression analysis showed that contribution degree of soil chemical properties to the EC was high in the order of $NO_3-N$ > Av. $SO_4{^{2-}}$ > Ex. Na > $Cl^-$ > Av. $P_2O_5$ > $NH_4-N$ > Ex. Mg>Ex. Ca. Among the soil chemical properties the contribution of anions was remarkably high. 6. EC value correlated with ${\sum}A$(total content of anions)as $r=0.932^{**}$ and with ${\sum}C$(total content of cations) as $r=0.452^{**}$.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.1
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• pp.24-31
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• 2003

Objective of this study was to assess rice growth and percolation water salinity under the irrigation of the discharge waters from the municipal wastewater treatment plant and from the industrial wastewater treatment plant as alternative water resources during transplanting season. Three kinds of waters were irrigated; the discharge water from an industrial wastewater treatment plant (DIWT), the discharge water from the municipal wastewater treatment plant (DMWT), and groundwater. Concentrations of $COD_{er}$, $NH_4{^+}_-N$, $Mn^{2+}$, and $Ni^+$ in DIWT, SS content and $PO_4-P$ concentrations in DMWT were higher than those of reuse water criteria of other country for agricultural irrigation. The plant height in the irrigation of DMWT was shorter by 2 cm than the groundwater irrigation except for 10 days irrigation. However, the number of tillerings was not significantly different between DMWT and the groundwater. For the harvest index, there were no significant difference between DMWT and DIWT for 20 days irrigation, but slightly higher in DIWT than that of DMWT for 30 days irrigation regardless of soil types. The salinity of percolation water in the rhizosphere with irrigation of DIWT had more twofold than DMWT, but SAR value from DMWT had no significantly different from the groundwater irrigation. The average $EC_i$ values in the rooting zone irrigated with DIWT and DMWT for 30 days after rice transplanting were 4.7 and $3.4dS\;m^{-1}$ in clay loam soil, and were 3.5 and $2.5dS\;m^{-1}$ in sandy loam soil, respectively. There was dramatic decrease in $EC_i$ value at 30 days after rice transplanting even though $EC_i$ of DIWT had more twofold than DMWT. However, $EC_i$ from DMWT had no significant difference from the groundwater. Therefore, it might be considered that there was limited possibility to irrigate DMWT to overcome drought injury of rice transplanting season in paddy field.