• Journal of Korea Soil Environment Society
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• v.4 no.3
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• pp.35-43
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• 1999

Biotransformation of inorganic nitrogens, which are possible contaminants of bank filtered water, in soil of near bank filtration site was investigated based on oxygen consumption and changes of chemical parameters in respirometer. Biotransformation activities of inorganic nitrogens at different conditions of pH. water content. and added initial${NH_4}_2$$SO_4$were compared. At original low pH and 20% of water content, nearly no biotransformation activity of inorganic nitrogen was observed, in addition, control and NH$_4$-added sets did not show any significant differences of oxygen consumption. Among tested conditions, the highest activity was observed at 25% water content and pH 8. Nearly 98% nitrification activity was observed at sets amended with 400 mg $NH_4$-N/kg soil as${NH_4}_2$$SO_4$in the condition of pH 8 and 20~23% water content. However, considerable activity of subsequent denitrification was not observed.

• Korean Journal of Organic Agriculture
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• v.17 no.3
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• pp.381-391
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• 2009

Crop production can be secured by the cycle of green manure crops as an alternative of the chemical fertilizer. Recently, rapeseed (Brassica napus L.) has been cultivated in the south part of Korea for the production of biodiesel. In this research, we focused on recycling rapeseed residue, which is produced after harvesting the rapeseed for biodiesel, as a potential source of nitrogen to the succeeding crop. Pot experiment was conducted to evaluate the effects of winter rapeseed as green manure on mineralization and uptake of nitrogen to the succeeding corn (Zea mays L.). Result showed that total nitrogen and C/N ratio of rapeseed at the harvesting stage was 0.54% and 63, respectively. The incorporation of rapeseed without decomposition period slightly inhibited nitrogen uptake to the succeeding corn compared to those with 30 days decomposition period. The pH and EC values of soils increased by increasing the period of decomposition of rapeseed from 5.2 to 6.4 and from 0.05 dS/m to 0.21 dS/m, respectively. Significant amounts of $NH_4^+$ and $NO_3^-$ are released by incorporation of rapeseed. The succeeding corn took up 86% and 88% of inorganic nitrogen released from the rapeseed with and without decomposition period, respectively. The overall results suggested that the utilization of rapeseed residue as green manure can be an alternative source of nitrogen in corn-rapeseed double cropping system.

• Journal of Wetlands Research
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• v.19 no.1
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• pp.90-102
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• 2017

In this study, various types of nutrient models were tested by using two tears's water quality data collected from the stormwater wetland in Korea. Based on results, most important factor influencing nitrogen removal was hydraulic loading rate, which indicates that surface area of wetland is more important than its volumetric capacity, and model proposed by WEF was found to give a least error between measured and calculated values. For the phosphorus, in case assuming a power relationship between rate constant and temperature, the best prediction result were obtained, but temperature was most sensitive parameter affecting phosphorus removal. In addition, denitrification was always a limiting step for the nitrogen removal in this particular wetland mostly due to the lack of carbon source and high dissolved oxygen concentration. In this paper, several alternatives to improve nitrogen removal, including proper arrangement and designation of wetland elements and use of floating plants or synthetic fiber mat to control oxygen level and to capture the algal particles were proposed and discussed.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.380-386
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• 2011

Tip burn has been reported as one of the most serious physiological disorder in Chinese chives (Allium tuberosum Rottl.) cultivated in plastic film house. In this study, a physiography and chemical properties of 132 plastic film house soils were investigated to elucidate factors affecting tip burn symptom. Also influence of soil properties on tip burn was statistically determined by path analysis and association analysis including a chi-square test or logistics analysis. Probability distribution of inorganic aqueous species, such as ammonia (g) was calculated using MINTEQ program. Soil order and chemical properties, especially pH, exchangeable calcium and inorganic nitrogen, showed a significant relationship with tip burn of Chinese chives. Tip burn symptoms occur mainly in an alkaline soil classified as Alfisols. Result of linear regression and path analysis exhibited that formation of ammonia (g) from soil solution depend upon soil pH and were associated with ammonium resulting from soil organic matter or nitrate. These results indicate that tip burn symptom of Chinese chives is directly affected by ammonia gas originated from alkaline soil condition.

• Applied Biological Chemistry
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• v.44 no.4
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• pp.240-245
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• 2001

Suppression of nitrate accumulation in vegetables through foliar application of micronutrients was investigated. Spinach and lettuce were grown in pots under greenhouse condition. Micronutrient solutions containing Cu, Mn, Mo, and Zn were used; chitosan was added into one and the other contained chitosan oligomers. The micronutrient solutions were sprayed on the leaves at 3 and 4 weeks after transplanting of 20-day-old seedlings. Plants were harvested at 5-weeks after transplanting. Yield, contents of chlorophyll, Brix value, micronutrient, and nitrate, and nitrate reductase activity were measured. Fresh weights of lettuce and spinach were significantly increased by the foliar application of micronutrients. Contents of chlorophyll and micronutrients were higher in micronutrient-treated plants, while those of nitrate were reduced by about 10 and 14-23% in lettuce and spinach, respectively. Compared to the control plants, nitrate reductase activity was higher in plants treated with micronutrients. Results of this study indicate the effect of micronutrients on the suppression of nitrate accumulation was relatively small in comparison to the contents of nitrate in leaves of spinach and lettuce. To maximize the effect, nutrient composition in solution, application time, and frequency should be further examined, taking into consideration nitrogen level in soil and other environmental factors including light condition.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.1
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• pp.33-39
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• 1999

In order to understand the importance of tidal action and $NH_4{^+}$ -nitrification in the removal of dissolved oxygen (DO) and $NH_4{^+}$, concentrations of DO, $NH_4{^+}$, $NO_2{^-}$ and $NO_3{^-}$ were measured with time for water samples collected at different tidal state in the eutrophic macrotidal Han River estuary. Field measurements indicated that most environmental parameters, except for the water temperature and DO concentration, were tightly controlled by the eutrophic freshwater runoff and large-scale tidal action. Dark incubation of the water sample at $25^{\circ}C$ showed that the removal rates of DO and $NH_4{^+}$ in high tide sample were 2.76 ${\mu}M\;O_2\;d^{-1}$ and 1.76 ${\mu}M\;N\;d^{-1}$ respectively, and increased to 5.66 ${\mu}M\;O_2\;d^{-1}$ and 3.36 ${\mu}M\;N\;d^{-1}$ respectively, in low tide sample. These changes indicated that microbial degradation and uptake of organic matter and inorganic nutrients were more active during low tide. $NH_4{^+}$-nitrification responsible for total DO removal in low tide (23.81%) and $NH_4{^+}$ turnover rates due to $NH_4{^+}$-nitrification in low tide (0.18 $d^{-1}$) were approximately 3.7 times and 3 times, respectively, higher than those in high tide. These results indicated that $NH_4{^+}$ -nitrifying bacteria introduced into the Han River estuary during low tide played a significant role in the removal of DO and $NH_4{^+}$. The decreasing removal rates in DO and $NH_4{^+}$ with the increasing tidal level seemed to be associated with the salinity impact on the halophobic freshwater $NH_4{^+}$-nitrifying bacteria. The results implied that anthropogenic $NH_4{^+}$ sources should be treated prior to the freshwater runoff into the estuary for the effective control of $NH_4{^+}$ in the Han River estuary. These results also suggest that parallel ecological studies on the chemoautotrophic nitrifying bacteria are essential for the elucidation of nitrogen cycles in the eutrophic Han River estuary.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.2
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• pp.74-80
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• 2008

Removal of nitrogen compound under nitrification related with denitrification by biofilm which developed on the porous media was investigated. With the investigation of $NH_4-N$ nitrification and autotrophic denitrification supplied with sulfur media as electron donor, conclusions were retrieved as follows. When $F/M_N$ ratio of $NH_4-N$ was increased from $0.0062-0.034gNH_4-N/g\;MLVSS{\cdot}day$ by the change of influent concentration and HRT the nitrification rate decreased as the increase of loading rate. Also under the same conditions of $F/M_N$ ratio, the alkalinity consumption rate of operation was higher at 8 hours of HRT than at 6 hours of HRT. Accordingly the influent loading rate variation by detention time with influent flow influenced more on the nitrification efficiency than the influent loading rate variation by the influent concentration did. Denitrification rate with various EBCT(Empty Bed Contact Time) showed average 25% at 8.4hrs of EBCT but sharply decreased average 5% at 4.6hrs of EBCT, so the operation would be more effective at above 8.4hrs of EBCT. Also denitrification rate was known to be adversely increased as $NO_3-N$ loading rate per unit volume of sulfur-media was decreased within the range of $0.5{\sim}2.0kgNO_3-N/m^3{\cdot}day$.

• Korean journal of applied entomology
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• v.16 no.3 s.32
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• pp.149-154
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• 1977

Effect of Simazine(2-chloro-4,6-bis (ethylamino)-s-triazine), Nitrofen (2, 4-dichloro-4' -nitrodi­phenylether), Propanil (:3, 4-dichloropropionanilide), and Butachlor (2-chloro-2, 6-diethyl N-(buthoxy­menthyl) acetanilide on urea hydrolysis and subsequent nitrification was investigated in an upland soil incubated at $20\pm1^{\circ}C$. 1. All the herbicides tested had no effect on the hydrolysis of urea to ammonia at the recommended rates. Butachlor, at ten and fifty times the recommended rate, and Nitrofen, at fifty times the recommeded rate, depressed urea hydrolysis, resulting in reduction of ammonia. But the depressive effects were temporary, disappearing soon. Simazine and Propanil had no detrimental effect on urea decomposition at all the treated rates. 2. Also, all the chemicals tested had no effect on the nitrification process at the recommended rates. At higher concentrations of ten and fifty times the recommended rate Butachlor and Nitrofen inhibited the oxidation of nitrite, and propanil long inhibited the oxidation of ammonium to nitrite, but was inactive against nitrite oxidizer. These inhibitive effects of the chemicals, however, disappeared in the later period of incubation. Simazine had no effect on the nitrification process at all the treated rates. 3. The trend of change in soil pH of both the treated and untreated plots well reflected the change of soil nitrogen forms during incubation. No direct effect of the chemicals on soil pH was obserbed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.655-668
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• 1994

Conventional deodorization filters using soil and compost reach the capacity limitation of deodorization in short period, because its removal mechanism primarily depends on adsorption. Therefore, in this study the experiment was performed on the removal of ammonia which is a strong inorganic malodor, frequently emitted from night soil treatment plants and sewage treatment plants, by seeding activated sludges on the bio-peat containing higher organic contents, water conservation capacity, permeability and lower pressure drop. As a result, in raw peat filter natural ammonia outlet was observed in consequence of pH increase resulted from ammonia ionizing in liquid phase. Ammonia removal mechanism primarily depended on the adsorption onto the anion colloidal substances in peat. In peat bio-filter, theoretical ammonium salts ratio was higher than that of raw peat, resulted from slight pH increase by microorganism activity, however, the experimetal value of ammonia-nitrogen accumulated in bio-peat was lower than that of raw peat because of nitrification by nitrifying bacteria. In the initial reaction period, adsorption was predominant in the ammonia removal mechanism, but nitrification was conspicuous after the middle period. Mass balance of nitrogen was established using experimental data of input $NH_3$ loading, output $NH_3$ loading, $NH_4{^+}$-N, $NO_x$-N, and Org-N. The critical time of unsteady state, which is the maximum activating point of microorganism in bio-filter, was determined using experimental data, and the ammonia adsorption curve was computed using regression analysis. On the basis of the results obtained by above analysis, the delay days for the saturation of adsoption capacity in peat bio-filter was calculated.

• Journal of Korean Society of Forest Science
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• v.69 no.1
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• pp.13-18
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• 1985

Forest soils mixed with organic matters (green needle, flesh needle litter and needle litter in F layer of Pinus koraiensis, and green leaf of Quercus dentata and Q. variabilis) were incubated under a constant $30^{\circ}C({\pm}1)$ for 53 days to measure the changes of inorganic nitrogen and $CO_2$ evolution rate. The results obtained were summarized as follows; 1) In the early incubation period the amounts of total inorganic nitrogen in soils by mixture of organic matters decreased rapidly because of immobilization by microbial uptake, and thereafter their amounts increased with further incubation. 2) The rate of immobilization of organic nitrogen in mixed organic matters was the highest in green needle among green needle, flesh needle litter and needle litter in F layer of P. koraiensis, but lower than that of green leaf of Q. variabilis and Q. dentata. 3) The rates of $CO_2$ evolution from soils mixed with organic matters increased sharply in the early time, and then decreased slowly with increasing time. The order of the $CO_2$ evolution rate was green leaf of Q. variabilis > green leaf of Q. dentata > green needle of P. koraiensis > flesh needle litter of P. koraiensis > needle litter of P. koraiensis in F layer from the largest to the least. 4) Nitrate nitrogen concentrations showed a tendency to increase throughout incubation time, so that their concentrations after 53 days were higher than that of ammonium nitrogen.