• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.2
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• pp.137-144
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• 2002

To investigate the short-term effects of N-supply form ( $NO_3\;^-$ or $NH_4\;^+$ ) and their level (0.2, 1.0 and 6.0 mM) on N assimilation and C metabolism were examined in perennial ryegrass (Lolium perenne L.). The increase in shoot fresh for $NH_4\;^+$-fed plants much less than $NO_3\;^-$ fed ones. Nitrate concentration in $NO_3\;^-$ -fed plants tended to increase with increasing the supply level, while that of $NH_4\;^+$-fed plants was nearly stable. Nitrate reductase activity (NRA) responded much quickly, showing a proportional increase within 24 h of feeding. NRA in $NO_3\;^-$ -fed plants at 72 h increased by 13.7, 40.3 and 84.0% in 0.2, 1.0 and 6.0 mM $NO_3\;^-$ -fed, but it was not changed in$NH_4\;^+$-fed plants regardless of the supply level. After 72 h of treatment the sugar accumulation in the plants supplied with 0.2 and 1.0 mM -$NH_4\;^+$fed was remarked. After 72 h of feeding, fructan hydrolysis was observed in all levels fur $NH_4\;^+$-fed plants, but only in 6.0 mM for $NO_3\;^-$ -fed plants.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.4
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• pp.433-442
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• 2010

BER at different packing ratios of bio-ring media(BRM) was tested to investigate the effect of varying hydraulic retention time (HRT) and current density on the nitrate removal and current efficiency. In the preliminary batch mode experiment of BERs, current density was applied at 2.0 A/$m^2$, 4.0 A/$m^2$, 4.8 A/$m^2$, which correspond to the designation of reactor #1, #2, #3, respectively. The reactor #2 showed a highest nitrate removal rate of 162.0 mg $NO_3{^-}$-N/L/d, and the kinetics of nitrate removal rate was defined as the Zero order reaction. In the primary experiment of BERs, four BERs packed with BRM were operated in varying HRT and current, and the packing ratios of reactor #1, #2, #3 and #4 were 0%, 8%, 16%, 24%. respectively. This results of the experiments indicated that the nitrate removal rate and current efficiency were increased significantly cause of growing of autotrophic denitrification microorganisms on the surface of cathode and media by increasing of the current density and decreasing of HRT. However, The decreasing of nitrate removal rate and current efficiencies were observed in the condition of HRT of 5.25 hr and 4.8 A/$m^2$ of current density. With more increasing current density and decreasing of HRT, the hydrogen inhibition occurred at the surface of cathode. Moreover, nitrate removal rate by autotrophic denitrification microorganisms attached on the media surface was observed to be limited by no longer increasing dissolved hydrogen concentration of each reactor. In conclusion, the highest nitrate nitrogen removal and current efficiency could be achieved when the BER was operated at the conditions of 7 hr HRT, current density of 4.0 A/$m^2$, and 16% packing ratio. And it was found that the amount of nitrate removal by microorganisms attached on the surface of cathode and media (BRM) was 178.2 mg/L and 52.2 mg/L respectively. and the amount of nitrate removal per MLVSS was 0.435 g $NO_3{^-}$-N/g $MLVSS{\cdot}d$ and 0.336 $NO_3{^-}$-N/g $MLVSS{\cdot}d$.

• Horticultural Science & Technology
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• v.31 no.4
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• pp.393-399
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• 2013

The effect of solution temperature and nitrogen form on cucumber (Cucumis sativus L.) growth, photosynthesis and nitrogen metabolism was investigated in hydroponic culture. Cucumber plants were grown for 35 days in a greenhouse at three constant solution temperatures ($15^{\circ}C$, $20^{\circ}C$, and $25^{\circ}C$) within a natural aerial temperature ($15-30^{\circ}C$). Four nitrate:ammonium ($NO{_3}^-:NH{_4}^+$) ratios (10:0, 8:2, 5:5, and 2:8 $mmol{\cdot}L^{-1}$) at constant nitrogen (N) concentration of $10mmol{\cdot}L^{-1}$ were applied within each solution temperature treatment. Results showed an increasing solution temperature enhanced plant growth (height, dry weight, and leaf area) in most N treatments. Dry weight accumulation was greatest at the 10:0 $NO{_3}^-:NH{_4}^+$ ratio in the $15^{\circ}C$ solution, the 5:5 ratio in the $20^{\circ}C$ solution and the 8:2 ratio in the $25^{\circ}C$ solution. Photosynthetic rate (Pn) response to solution temperature and $NO{_3}^-:NH{_4}^+$ ratio was similar to that of plant growth. Probably, the photosynthate shortage played a role in the reduced biomass formation. Increasing solution temperature enhanced the nitrate reductase (NR) activity, and further reduced shoots nitrate content. Our results indicate that the optimal ratio of nitrate to ammonium that promotes growth in hydroponic cucumber varies with solution temperature.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.1
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• pp.38-45
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• 2006

Movement of nitrate ($NO_3-N$) through a soil profile under no tillage (NT) or conventional tillage (CT) practices was monitored to identify the effects of tillage systems on nitrate leaching and retention in the soil profile at two commercial farms in central Illinois from 1993 through 1994. Anhydrous ammonia was applied in the 1993 growing seasons, while a mixture of urea and ammonium nitrate solution (URAN) was applied in three separate applications during the spring and early summer of the 1994 season. $NO_3-N$ of each plot through a 100 cm soil depth was found to be significantly high around $20mg\;kg^{-1}$ soil in the early 1993 season. However, downward movement of $NO_3-N$ occurred during the growing season. At the end of growing season, Flanagan and Ipava soils generally retained more $NO_3-N$ through the soil profile for both the CT plots and the NT plots than the Saybrook and Catlin soils. However, there was no significant difference between the nitrate content of the two soil types in each year. $NO_3-N$ content in NT fields were slightly higher than that observed in CT fields throughout the season before harvest. It means that NT plots may reduce the nitrate leaching to the ground water.

• Journal of Soil and Groundwater Environment
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• v.20 no.7
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• pp.80-89
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• 2015

Nitrate is on the most seriou pollutant encountered in shallow groundwater aquifer in agricultural area. There are various remediation technologies such as ion exchange, reverse osmosis, and biological denitrification to recover from nitrate contamination. Biological denitrification by indigenous microorganism of the technologies has been reviewed and applied on nitrate contaminated groundwater. In this work, we selected the site where the annual nitrate (NO₃⁻) concentration is over 105 mg/L and evaluated denitrification process with sampled soil and groundwater from 3 monitoring wells (MW4, 5, 6). In the results, the nitrate degradation rate in each well (MW 4, 5, and 6) was 25 NO₃⁻ mg/L/day, 6 NO₃⁻ mg/L/day, and 3.4 NO₃⁻ mg/L/day, respectively. Nitrate degradation rate was higher in batch system treated with 2 times higher fumarate as carbon source than control batch system (0.42M fumrate/1M NO₃⁻), comparing with batch system with soil sample. This result indicates that increase of carbon source is more efficient to enhance denitrification rate than addition of soil sample to increase microbial dynamics. In this work, we also confirmed that monitoring method of functional genes (nirK and nosZ) involved in denitrification process can be applied to evaluated denitrifcation process possibility before application of field process such as in-situ denitrification by push-pull test.

• Journal of the Korean Chemical Society
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• v.41 no.5
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• pp.256-265
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• 1997

A rapid and sequential method was studied, which can determine nitrite, nitrate and ammonium ion in soil or water samples with flow injection analysis. Geometric factors including injection volume, length of the reaction coil and flow rate of carrier solution were investigated prior to sample measurement. Nitrite was determined at 540 nm by Griess reaction producing azo dye between N-(1-naphthylethylenediamine dihydrochloride) and sulfanilamide. Nitrate was also measured under the help of reduction mechanism toward nitrite with hydrazine. Ammonium was analyzed at 440 nm with Nessler's reagent. At the optimum condition, the detection limit(S/N=3) has been shown 0.1 ㎍/mL N(NO2-), 0.4 ㎍/mL N(NO3-) and 0.3 ㎍/mL N(NH4+) respectively. The results measured by colorimetry, ion chromatography and FIA were compared showing 80%-125% reasonable match each other. Injection throughput rate could be performed better than 30 times per hour.

• Journal of Environmental Science International
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• v.4 no.3
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• pp.229-237
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• 1995

This study was investigated with denitrification of wastewater containing nitrate using upflow sludge blanket process. Contents of this study were the NO3--N removal efficiency by various hydrogen donor addition, determination of optimum COD/$NO_3^--N$ ratio and characteristics of granular sludge.

• Journal of Environmental Science International
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• v.4 no.3
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• pp.77-77
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• 1995

This study was investigated with denitrification of wastewater containing nitrate using upflow sludge blanket process. Contents of this study were the NO3--N removal efficiency by various hydrogen donor addition, determination of optimum COD/$NO_3^--N$ ratio and characteristics of granular sludge.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.84-88
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• 1997

To establish N fertilizer recommendation method based on nitrate content of the soil for the Chinese cabbage grown in the plastic film house. Chinese cabbage was grown in the pots containing the plastic film house soils with various levels of $NO_3{^-}-N$ and different levels of fertilizer N. The nitrate nitrogen showed the positive correlation with nitrogen uptake amount by plant and the negative correlation with fertilizer nitrogen use efficiency of plant. The content of nitrate nitrogen in soil for maximum yield of Chinese cabbage was 310 mg/kg. An equation for the recommendation of fertilizer N for Chinese cabbage based on $NO_3{^-}-N$ in the soil was suggested.

• Korean Journal of Environmental Agriculture
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• v.1 no.1
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• pp.59-64
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• 1982

Studies on the effect of soil moisture, different seasons, harvesting periods and nitrogen application on the nitrate content of radish(Raphanus sativus L. var. niger(Mill.) S. Kerner) were carried out in pot and green house. The results are as follows; The low level of soil moisture leads to an increased nitrate accumulation in radish root. The nitrate content was found to be higher in spring crops and lower in summer ones. It was decreased during harvesting period. The application of nitrogen fertilizer increased the nitrate content in radish root. We found the highest content in petioles with lesser content in roots and leaf blades in that order. The multiple regression analysis and the nutritional value of nitrate content in radish were discussed.