• Korean Journal of Organic Agriculture
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• v.9 no.2
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• pp.101-115
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• 2001

Nitrogen applied as fertilizer for crop production is partly absorbed by plant , and the remaining nitrogen in soil might be leached out through complicated processes to the subsoil layer Especially, NO$_3$-N in leachate causes environmental pollution. The purpose of this study was focused on understanding of uptake of nutrients by plants, the behaviors of nutrients in soil and the possibility of leaching loss when nitrogen fertilizer and completely decomposed compost were applied. Lysimeters(Volume 0.15㎥, Diameter 62cm, Height 62.8cm) were installed for collecting leachate in the Jeju volcanic ash soils. Lysimeter study consisted of thirteen treatments : fallow, fallow with weeding, cropping without fertilizer and compost, three N fertilizer soil surface applications(16, 32, 64kg/10a), three N fertilizer and compost soil surface applications(16+800, 32+1600, 64+32kg/10a), two water dissolved N fertilizer applications(16, 32kg/10a), and low and high plant densities. N fertilizer was applied as urea. The growth of com(preceding crop) and potatoes(succeeding crop) and leaching loss were determined during the experimental period. The results obtained were summarized as follows ; With Increased N, pH of leachate tended to decrease and NO$_3$-N concentration of leachate increased. NO$_3$-N leaching loss was remarkably greater in soil from the bare plot without fertilization and the weed control than from plots with medium N rate and was least in the cropping plot without fertilization. NO$_3$-N concentration in leachates from the water dissolved N fertilizer application plots was 64% of that from the soil surface application plots. The concentration of Ca and K ions and the leaching loss of these ions were least from the cropping plot without fertilization and were greatest from bare plots(T1 and T2) without fertilization. The proportion of leaching and residual N in soil increased as N rate increased indicting that higher N rates increase the possibility of N leaching to subsoil layer The proportion of N leaching losses was lower at the low N rate and the high plant density. In future, fertilization prescription which can maximize fertilizer use efficiency and minimize the pollution of ground water will be needed for conserving the environments.

• Journal of Environmental Science International
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• v.11 no.7
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• pp.713-720
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• 2002

In order to provide the basic information on the environmental pollution of Kyungsan province, the contents of Pb, Cd, Cr, Cu, Mn and Zn in soil, stream water, aquatic sediment and groundwater were investigated, and also the values of pH, COD, $KMnO_4-C$,\;NH_3-N,\;NO_2-N,\;NO_3-N$ and $Cl^-$ of stream water and groundwater were determined. The results were as follows. The values of COD, $NH_3-N,\;NO_2-N$ and $NO_3-N$ of the stream waters were very low. The contents of Pb, Cd, Cr, Cu and Zn in the stream waters were respectively at range of $0.014~0.063 mg/{\ell},\;0.004~0.007 mg/{\ell$\mid$, 0~0.045 mg/{\ell},\;0~0.008 mg/{\ell}$\;and\;$0.001~0.175 mg/{\ell}$, and these values were much lower than those of contaminated stream water in Korea. The contents of Cd, Cr, Cu and Zn in the soils were respectively at range of 0.12~O.71 ppm, 0.88~2.65 ppm, 2.86~22.33 ppm and 3.89~26.39 ppm, and these values were much lower than those of ordinary polluted areas in Korea. The contents of Cd, Cr, Cu, As, Zn and Mn in the aquatic sediments were respectively at range of 3.05~3.81 ppm, 14.6~70.6 ppm, 13.74~61.59 ppm, 76.8~465.5 ppm, 12.56~190.83 ppm and 333.3~l188.3 ppm. The values of pH, $KMnO_4-C,\;NH_3-N$, and $NO_3-N$ of the groundwaters were respectively at range of 7.6~8.4, $0~3.95{\ell}$, 0.05~0.15 mg/{\ell}$ and 0.05~0.42 $mg/{\ell}$. The contents of Pb, Cd and Cr in the groundwaters were respectively at range of 0.015~0.061 $mg/{\ell}$, 0.O06~0.009 $mg/{\ell}$ and 0.005~0.045 $mg/{\ell}$.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.1
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• pp.68-74
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• 2010

Since ${NO_3}^-$ is amore favorable electron acceptor than Fe, high ${NO_3}^-$ loads function as a redox buffer limiting the reduction of Fe and following release of ${PO_4}^{3-}$ in flooded paddy soil. The effect ${NO_3}^-$ loaded through irrigation water on Fe reduction and ${PO_4}^{3-}$ release in paddy soil was investigated. Pot experiment was conducted where irrigation water containing 5 or 10 mg N $L^{-1}$ of ${NO_3}^-$ was continuously applied at 1 cm $day^{-1}$, and changes of ${NO_3}^-$, $Fe^{2+}$ and ${PO_4}^{3-}$ concentrations in soil solution at 5 and 10 cm depths beneath the soil surface were monitored as a function of time. Irrigation of rice paddy with water containing 5 mg N $L^{-1}$ of ${NO_3}^-$ led to reduced release of $Fe^{2+}$ and prevented solubilization of P at 5 cm depth beneath the soil surface. And application of irrigation water containing 10 mg N $L^{-1}$ of ${NO_3}^-$ could further suppress Fe reduction and solubilization of P through 10 cm depth soil layer beneath the surface. These results suggest that the introduction of high level ${NO_3}^-$ with irrigation water in rice paddy can strongly limit Fe reduction and P solubilization in root zone soil layer in addition to the excessive supply of N to rice plants.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.4
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• pp.290-295
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• 1989

An incubation study was conducted to examine the effect of soil pH and temperature on nitrification potential of 8 different soil series applied with no-N and 200 ugN/g soil as a compound fertilizer at 60 % moisture content of maximum water holding capacity for 8 weeks, whose series were ranged from acid to mild alkali as Gopyeong(Jincheon, pH 4.51), Yesan(Jincheon, pH 4.54), Jigog(Eumseong, pH 4.71), Songsan(Goesan, pH 5.01), Angye(Seongju, pH 5.34), Banho(Seongju, pH 5.73), Weongog(Jincheon, pH 5.93), and Banho(Seongju, pH 7.70), respectively. Interrelationship between the nitrifiable and the net $NO_3-N$(N added plot-no-N plot) accumulated in the soil and tobacco yield in the no fertilizer plot were investigated as well. 1. Nitrification response was various according to soil characteristics at each temperature condition showing that nitrifiable $NO_3-N$ values of the soils were much higher at $25^{\circ}C$ than $15^{\circ}C$. And difference of nitrification potential affected by temperature was markedly distinguishable from 2 weeks after incubation and was showing a tendency to reduce with increasing of soil pH. 2. At each temperature condition, net $NO_3-N$ accumulated at 2 and 4 weeks after incubation was positively correlated with soil pH. 3. Tobacco yield in the no fertilizer plot was more highly correlated with the values of nitrifiable and net $NO_3-N$ accumulated at $15^{\circ}C$ similar to soil temperature in rhizosphere of early stage of tobacco growth than those at optimum temperature($25^{\circ}C$).

• Journal of Korean Society of Environmental Engineers
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• v.27 no.11
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• pp.1174-1179
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• 2005

Up-flow sludge blanket(USB) reactors were used to investigate the effects of N/C(${NO_3}^--N/COD$) ratio on simultaneous denitrification and methanogenesis processes. Without nitrate feeding, 84% of the influent COD was converted into methane. With the increase of N/C ratio, nitrogen gas increased while methane production decreased and stopped finally at the N/C ratio over 0.20. Influent nitrate was completely denitrified into nitrogen gas while nitrate removal efficiency dropped below 40% at N/C ratio of 0.40 because of deficiency in organic carbon. Fraction of COD utilized by denitrification increased at higher N/C ratios. Methanogenesis started to be effected at N/C ratio of 0.05, which could explain the competition for organic carbon between these microorganisms such as denitrifiers and methanogens, rather than inhibitory effect of nitrate and its intermediates. Critical N/C ratio for simultaneous denitrification and methanogenesis was found to be 0.20. Influent COD was removed over 92% by denitrification, methanogenesis and other biochemical reactions including cell growth at these N/C ratios.

• Journal of Korean Society of Forest Science
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• v.79 no.3
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• pp.285-289
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• 1990

Soil N mineralization and nitrification can be measured conveniently using mixed bed (cation and anion) exchange resin bags. However, appropriate use of these resin bags requires pretreatment to avoid colorimetric interference and standardize N ion adsorption. Three pretreatments were evaluated : control (untreated), 2 M NaCl with a distilled water rinse, and 4 M NaCl. The 4 M NaCl treatment was effective at removing background levels of $NH_4{^+}$ and $NO_3{^-}$, but adsorbed low amounts (about 40%) of inorganic N from standard solutions. Untreated resin bags adsorbed a constant, higher amount of $NO_3{^-}$ (60%), but did not remove background levels of $NH_4{^+}$. The 2 M NaCl treatment followed by a distilled water rinse performed best : it removed background $NH_4{^+}$ and adsorbed a constant amount of both $NH_4{^+}$ (70%) and $NO_3{^-}$ (60%). Because the ion exchange resin is fairly expensive, we also tested if the resin bags could be reused. Resin bags were either loaded with $NH_4{^+}$ and $NO_3{^-}$ in the laboratory or incubated in soil in the field, desorbed with the 2 M NaCl treatment, and then loaded with standard $NH_4{^+}$ and $NO_3{^-}$ solutions. Lab loaded resin bags adsorbed about 60% of inorganic N then loaded with 2.5 or $5.0mgN\;1^{-1}$ and 70% when loaded at 10 or $20mgN\;1^{-1}$, whereas reused field incubated bags showed the opposite adsorption efficiency. These results demonstrate that resin bags can give reproducible results, but care must be taken to evaluate the effect of pretreatment and potential for reuse.

• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.99-104
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• 1988

Water polution status of urban streams in Daegu city were observed to provide the basic information for the effective purification of urban sewage and the conservation of Keumho river. Periodically, pH, DO, COD, nitrate and phosphate of water were investigated at Yee cheon, B$\ddot{o}$m$\ddot{o}$ cheon, Chilsung cheon, Dalseo cheon and Kongdan cheon. The results were as follows. 1) The ranges of average values of analyzed components for 12 months at six sampling sites were pH 7.3-8.2, DO trace-6.5ppm, COD 20.4-116.9ppm, T-N 23.2-31.7ppm, $NH_4$-N 18.3-27.7ppm, $NO_2$-N 0.08-1.89ppm, $NO_3$-N 0.19-1.51ppm, $PO_4$-P 2.50-17.28ppm. 2) At Kongdan cheon, the most heavily polluted site, average values of components were pH 8.2, DO trace, COD 116.9ppm, T-N 23.2ppm, $NH_4$-N 18.3ppm, $NO_2$-N 1.89ppm, $NO_3$-N 1.51ppm, $PO_4$-P 17.28ppm. 3) The values of pH, DO, COD, T-N and $NH_4$-N at winter urban streams were higher than those at summer urban streams. And the values of $NO_2$-N and $PO_4$-P were more or less higher at summer urban streams.

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.573-576
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• 2009

The reaction of $(en)Pd(NO_3)_2$ (en = ethylenediamine) with 1,4-bis(dimethyl-4-pyridylsilyl)benzene (L) affords cyclodimer, $[(en)Pd(L)]_2(NO_3)_4$, whereas the reaction of $(tmeda)Pd(NO_3)_2$ (tmeda = N,N,N’,N’-tetramethylethylenediamine) with L gives cyclotrimer, $[(tmeda)Pd(L)]_3(NO_3)_6$. Both complexes exist as catenane in water. The catenated cyclodimer is rigid whereas the catenated cyclotrimer is dynamic in water. The catenated cyclotrimers afford hydrogel containing 98.5% water below 2 ${^{\circ}C}$. The hydrogel changes to its sol around 38 ${^{\circ}C}$, and to its clear solution at 78 ${^{\circ}C}$. Such a notable difference between $[(en)Pd(L)]_2(NO_3)_4$ and $[(tmeda)Pd(L)]_3(NO_3)_6$ might be explained by their different dynamic behavior via ring size effects.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.6
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• pp.120-129
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• 2008

Removal rate of $NO_3-N$ and TN in a free water surface wetland system with litter layer on its bottom was compared with that without one. The system was established on floodplain in the down reach of the Gwangju Stream in 2001. Its dimensions were 31 meters in length and 12 meters in width. Water of the stream was funneled into it and its effluent was discharged back into the channel. Average litter layer of 9.6 cm was formed on its bottom in 2007. The layer and above-ground parts of reeds and cattails on the system were eliminated in Spring 2008. Volumes and water quality of inflow and outflow of the system were analyzed from May to November in 2007 and 2008, respectively. Inflow into the system both in 2007 and 2008 averaged approximately $40m^3/day$ and hydraulic residence time both in 2007 and 2008 was about 1.5 days. Average influent $NO_3-N$ concentration in 2007 and 2008 was 2.16 and 2.05 mg/L, respectively and influent TN concentration in 2007 and 2008 averaged 3.98 and 3.89 mg/L, respectively. With a 0.05 significance level, effluent temperatures, influent concentrations of $NO_3-N$ and TN, and stem numbers per square meter and height of the emergent plants showed no difference between the system with litter layer and without one. $NO_3-N$ removal in the system with litter layer and without it averaged 55.59 and 46.06%, respectively and TN retention averaged 57.24 and 48.97%, respectively. Both $NO_3-N$ and TN abatement rates in the system with litter layer were significantly high (p < 0.001) when compared with those without one. The wetland system having litter layer on its bottom was more efficient for $NO_3-N$ and TN retention than that without one.

• Korean Journal of Crystallography
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• v.18 no.1_2
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• pp.21-25
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• 2007

When a $CH_2Cl_2$ solution of the dipyridyl species L' (N,N'-bis-(1-pyridin-4-yl-ethylidene)-naphthalene-1,5-diamine) was layered onto the top of a MeOH solution of $Co(NO_3)_2{\cdot}6H_2O$, a molecular cobalt compound [$CoL_2(MeOH)(NO_3)_2$] (1), not a coordination polymer, was formed. X-ray structural analysis of compound 1 revealed that it contains the pyridyl-amine ligand L (N1-(4-imino-1-methyl-but-2-enylidene)-naphthalene-1,5-diamine), instead of L'. Structure of compound 1 strongly suggests that the original ligand L' has been hydrolyzed to ligand L during the reaction.