• The Journal of Natural Sciences
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• v.8 no.2
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• pp.129-136
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• 1996

The direct conversion of solid potassium chloride to solid potassium nitrate by the reaction of the chloride with gaseous nitrogen dioxide is suggested for the preparation of potassium nitrate. Thermodynamic calculations indicate that the free energy change is favorable at ordinary temperatures and that the reaction is exothermic. Experiments are described in which it was found that the reaction takes place at ordinary temperatures in the presence of a small amount of water with good yield. Nitrosyl chloride is produced simultaneously.

• Journal of Plant Biology
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• v.27 no.4
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• pp.253-261
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• 1984

Leaf discs isolated from the pea seedling grown in nutrient solution containing 5mM ammonia or nitrate exhibited a half level of photorespiration as compared with the nitrogen free control. The manifestation of the ammonia effect appeared somewhat earlier than that of nitrate effect, but this difference subsided as the culture periods was extended. The total amount of ${CO}_2$ fixed by leaves from nitrogen-supplemented seedlings showed approximately 1.5 fold increase over the control with the ammonia effect being manifested earlier than the nitrate effect. The activities of peroxisomal serine: glyoxylate aminotransferase were always higher with ammonia than nitrate, the two types of nitrogen source, however, had similar effect on conversion rate of glyoxylate into glycine. These results indicate that exogenous ammonia does not act directly as an effector of this aminotransferase in vivo. But changes in the level of the pool size of glycine and serine, both of which are the intermediates of photorespiratory process, suggest that exogenous ammonia inhibit the transformation of serine from glycine metabolically.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.2
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• pp.147-154
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• 1999

A field experiment with 200, 400 and 600kg-N/ha/year application levels was carried out to study the nitrate nitrogen accumulation of sorghum sudangrass hybrids(Xtragraze II and Civa 1990) at Iksan College Farm in 1995. The nitrate nitrogen content of Xtragraze II and Civa 1990 was increased by the application of nitrogen and decreased as the plant matured, then the nitrate nitrogen content was below the toxic level of ruminant at the level of 200kg-N application during the whole growing period. The nitrate nitrogen content of Xtragraze II and Civa 1990 exceeded the safe level of ruminant at the level of 400kg-N application, and that in Xtragraze II decreased at the low level in the later stage of growth, but that in Civa 1990 was almost kept constantly at the same level. The nitrate nitrogen accumulation of Civa 1990 had a greater tendency than that of Xtragraze II. A sum exceeding 200kg-N does not necessarily result in increase the amount of nitrate nitrogen in sorghum sudangrass hybrids. It is suggested that 400kg-N application may results in toxic level of nitrate nitrogen, and special attention must be given in feeding them.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2B
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• pp.187-192
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• 2011

Nitrate nitrogen is common contaminant in groundwater aquifers, its concentration is regulated many countries below 10 mg/L as N (As per WHO standards) in drinking water. An attempt was made to get optimal results for the treatment of nitrate nitrogen in groundwater by conducting various experiments by changing the experimental conditions for ZVI bipolar packed bed electrolytic cell. From the experimental results it is evident that the nitrate nitrogen removal is more effective when the reactor conditions are maintained in acidic range but when the acidic environment changes to alkaline due to the hydroxide formed during the process of ammonia nitrogen there by increasing the pH reducing the hydrogen ions required for reduction which leads to low effectiveness of the system. In the ZVI bipolar packed bed electrolytic cell, the packing ratio of 0.5~1:1 was found to be most effective for the treatment of nitrate nitrogen because ZVI particles are isolated and individual particle act like small electrode with low packing ratio. It is seen that formation of precipitate and acceleration of clogging incrementally for packing ratio more than 2:1, decreasing the nitrate nitrogen removal rate. When the voltage is increased it is seen that kinetics and current also increases but at the same time more electric power is consumed. In this experiment, the optimum voltage was determined to be 50V. At that time, nitrate nitrogen was removed by 94.9%.

• Journal of Animal Science and Technology
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• v.47 no.3
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• pp.481-490
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• 2005

Nitrate contamination in water system is a critical environmental problem caused by excessive application of chemical fertilizer and concentration of livestock. In order to prevent further contamination, therefore, it is necessary to understand the origin of nitrate in nitrogen loading sources and manage the very source of contamination. The objective of this study was to examine the nitrate contamination sources in different agricultural system by using nitrogen isotope ratios. Groundwater and runoff water samples were collected on a monthly basis from February 2003 to November 2003 and analyzed for nitrogen isotopes. The nitrate concentrations of groundwater in livestock fanning area were higher than those in conventional and organic fanning area and exceeded the national drinking water standard of 10mg N/ l. The ${\delta}^{15}N$ranges of chemical fertilizer and animal manure were - 3.7${\sim}$+2.3$\textperthousand$ and +12.5${\sim}$26.7$\textperthousand$, respectively. The higher ${\delta}^{15}N$ of animal manure than those of chemical fertilizer reflected isotope fractionation and volatilization of '''N. The different agricultural systems and corresponding average nitrate concentrations and ${\delta}^{15}N$ values were: conventional farming, 5.47mg/e, 8.3$\textperthousand$; organic fanning, 5.88mg/e, 10.1$\textperthousand$; crop-livestock farming, 12.5mg/e, 17.7%0. These data indicated that whether conventional or organic agriculture effected groundwater and runoff water quality. In conclusions, relationship between nitrate concentrations and ${\delta}^{15}N$ value could be used to make a distinction between nitrate derived from chemical fertilizer and from animal manure. Additional investigation is required to monitor long-term impact on water quality in accordance with agricultural systems.

• Molecules and Cells
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• v.40 no.3
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• pp.178-185
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• 2017

Nitrogen is one of the most important mineral elements for plant growth. We studied the functional roles of Oryza sativa DNA BINDING WITH ONE FINGER 18 (OsDOF18) in controlling ammonium uptake. The growth of null mutants of OsDOF18 was retarded in a medium containing ammonium as the sole nitrogen source. In contrast, those mutants grew normally in a medium with nitrate as the sole nitrogen source. The gene expression was induced by ammonium but not by nitrate. Uptake of ammonium was lower in osdof18 mutants than in the wild type, while that of nitrate was not affected by the mutation. This indicated that OsDOF18 is involved in regulating ammonium transport. Among the 10 ammonium transporter genes examined here, expression of OsAMT1;1, OsAMT1;3, OsAMT2;1, and OsAMT4;1 was reduced in osdof18 mutants, demonstrating that the ammonium transporter genes function downstream of OsDOF18. Genes for nitrogen assimilation were also affected in the mutants. These results provide evidence that OsDOF18 mediates ammonium transport and nitrogen distribution, which then affects nitrogen use efficiency.

• Journal of Soil and Groundwater Environment
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• v.26 no.4
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• pp.8-19
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• 2021

In this study, the evaluation standard for nitrate nitrogen contamination degree (WELCUP) was established using six factors that influence the groundwater quality in Jeju Island. To do this, weightings, ranges, and ratings were assigned for each factor and the relative possibility of nitrate nitrogen contamination degree was evaluated using WELCUP index for each well. As a result of calculating the WELCUP index using groundwater quality data of 5,112 wells in Jeju Island for 27 years (1993-2019), all 61 wells with the WELCUP index value higher than 100 are distributed in Daejung and Hangyung watershed with relatively large area of farmland in Jeju Island. In particular, as the ratio of private wells is more than 64%, it is necessary that systematic management is needed for private wells in terms of nitrate nitrogen contamination. Consequently, based on the results of applying the WELCUP evaluation standard, it is necessary to select the prioritization of nitrate nitrogen contamination pathways project for groundwater wells in Jeju Island.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.4
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• pp.35-44
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• 1999

In this study, it was attempted to remove nitrate and carbon in a single-stage reactor using acetate as substrate. Hybrid type upflow sludge baffled filter reactor was adopted using anaerobic sludge. Sludge bed in the bottom of reactor was intended to remove carbon and nitrate by denitrification and methanogenesis. And floating media in the upper part of reactor were intended to remove remaining carbon which was not removed due to the inhibition of nitrogen oxide on methane producing bacteria. The reactor removed over 96% of COD and most of nitrate with volumetric loading rate of $4.0kgCOD/m^3{\cdot}day$, hydraulic retention time of 24hr, 4,000mgCOD/L, and $266mgNO_3-N/L$. Nitrate in anaerobic sludge was converted to nitrogen gas(denitrification) or ammonia (ammonification) according to pH of influent, COD removal efficiency was easily affected by the change of volumetric loading rates and nitrate concentration. And when influent pH was about 4.7, most nitrate changed to ammonia while when influent pH was about 6.8~7.0, most nitrate denitrified independent of $COD/NO_3-N$ ratio. Most granules were gray and a few were black. In gray-colored granule, black inner side was covered with gray substance and SEM illustrated Methanoccoci type microorganisms which were compact spherical shape. Anaerobic filter removed residual COD effectively which was left in sludge bed due to the inhibition of nitrogen oxide.

• Journal of The Korean Society of Grassland and Forage Science
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• v.20 no.3
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• pp.199-206
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• 2000

This experiment was conducted to evaluate the effect of winter forage rye and green manure hairy vetch on soil mineral nitrogen and corn nitrogen uptake. Soil nitrate at corn seeding decreased slightly with cultivation of winter rye, but soil nitrate did not decreased by cultivation of winter hairy vetch. Soil nitrate nitrogen increased 60~70 kgN/ha higher by hairy vetch green manure than winter rye and fallow at 6-leaf and harvest stage of corn, respectively, and much soil nitrate nitrogen such as 85, 125 kgN/ha was remained at N fertilizer 100, 200 kgN/ha of hairy vetch green manure at harvesting time, respectively. Corn yield was not different among treatments of winter crop and N rate, but nitrogen concentration of corn stover increased by hairy vetch green manure. Increase of total corn nitrogen uptake by hairy vetch green manure was 50~60 kgN/ha compared with winter rye and fallow. It is thought that basal fertilizer nitrogen 100 kgN/ha could be reduced by hairy vetch green manure in considering soil nitrate and nitrogen uptake at harvesting time.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.1
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• pp.43-48
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• 2003

The effect of rare earth(RE) at three difference levels of nitrogen on the growth and nitrate content of chicory (Cichorium intybus L.) were studied in terms of leaf size, fresh and dry weight increase, and chlorophyll and nitrate content grown in plastic pots within glasshouse. Leaf size was enlarged as the level of nitrogen applied was high, and leaf within, length, and thickness of leaf were increased by RE treatment showing significant difference at high nitrogen(N+1) plot. As the level of nitrogen applied was high, as fresh and dry weight per plant was increased significantly(p<0.05), and sprinkling cabbage with RE increased fresh and dry matter yield to 2∼12, 4∼6.2% more, respectively. Dry matter content of Chinese cabbage was increased by RE sprinkling. At all levels of nitrogen fertilized chlorophyll contents were increased by RE treatment. As the level of nitrogen was high, as the content of chlorophyll was highly increased by RE. Nitrate was accumulated more at high level of nitrogen application, but nitrate was decreased by RE application, 40% decrease at very high nitrogen plot(N+2). RE stimulated the growth of chicory with high chlorophyll content, and showed the possibility producing high quality agricultural products low in nitrate content.