• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.9
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• pp.1335-1339
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• 2010

A total of 550 samples were analysed for nitrate contents using HPLC-UV. Nitrate contents of leaf vegetables were higher than those of root vegetables and fruit vegetables. The average nitrate content of the radish leaves (4875.8 mg/kg) was the highest, followed by marsh mallow (4711.7 mg/kg), crown daisy (4546.9 mg/kg) and vitamins (4239.5 mg/kg). The nitrate content in fruits of strawberry and banana averaged at 24.0 mg/kg and 438.5 mg/kg, respectively. Nitrate was not detected in other fruits. In fruiting vegetables nitrate contents were less than 1000 mg/kg. In onion, lotus root and radish, nitrate contents were 253.7mg/kg, 352.4mg/kg and 2849.0 mg/kg, respectively, with no detection in garlic. Nitrate contents in mushrooms were less than 100 mg/kg.

• Journal of Environmental Science International
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• v.9 no.4
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• pp.319-323
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• 2000

Nitrate-selective ion exchange resin which have bulky tertiary amine as functional group have been synthesized by the reaction of chloromethylated polystyrene-divinylbenzene copolymer and the corresponding tertiary amine [$NR_3=NE_{t3} 1, N{(C_2 H_4 H_3)}_32]$in ethanol, while commercial resin has $NMe_3$ as functional group. The fundamental properties such as bulk density, water content, appearance index, exchange capacity, effective size, uniformity coefficient of synthesized anion exchange resin (1) have been measured. The ion exchange resin (1) and (2) exhibited the better selectivity for nitrate than sulfate in both batch and continuous column experiments.

• Clean Technology
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• v.3 no.2
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• pp.31-33
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• 1997

Nitrate contamination in surface water and ground water have increased in Korea. This trend has raised concern because nitrates caused methemoglobinemia in infants. To remove nitrates from waters, various purification processes including ion-exchange, biological denitrification, and chemical denitrification are currently in use for the treatment of water. However, little economically advantageous process exists for the industrial scale treatment of effluents highly polluted with nitrates. A new process has been developed for nitrate and other salts removal from polluted waters. Alumina cement and lime served as precipitating agents to remove nitrate with stirring at basic pH. Decreasing alumina content in alumina cement result in a increasing in nitrate removal yield. Stable removal of nitrate(1000mg/L) was readily achieved by two-stage removal process.

• Analytical Science and Technology
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• v.12 no.6
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• pp.583-586
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• 1999

The quantitative analysis of nitrate and nitrite in rain, milk and infant formula was done by Ion Chromatography. The nitrite was not detected(<0.1 mg/L) in all the samples. However, the nitrate was detected in the range of 0.1~4.9 mg/L in rain, 9.8~19.8 mg/L in milk, and 80~300 mg/L in infant formula, respectively. Some content of nitrate is close to the maximum contaminant level(MCL) which is 10 mg/L as $NO_3-N$, 44.3 mg/L as $NO_3$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.231-238
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• 2005

Nitrate contents of lettuce and chinese cabbage which aye consumed mostly in vegetables in Korea were $403\~6,935$ (mean 3,088), $31\~5,391$ (mean 2,412), and $310\~6,374$ (mean 3,017) mg/kg, respectively. Nitrate contents of root vegetables and fruit vegetables were lower than those of leaf vegetables. There was no different of nitrate content in vegetables by area, but the nitrate contents of summer vegetables were higher than those of winter vegetables. Nitrate contents of Danmugi, Kimchi, and Young radish Kimchi were 346, 1,411, and 3,240 mg/kg, respectively. Nitrate contents of juice of Danmugi, Kimchi, and younger radish Kimchi were 340,979, and 1,383 mg/kg, and there was no different of nitrate content by area.

• Korean Journal of Organic Agriculture
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• v.7 no.1
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• pp.115-127
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• 1998

Under the visual judgement of consumers, to reduce nitrate intake through vegetables, this experimentation analyzed the content of nitrate, in heading leaf vegetables such as chinese cabbage(Brassica campestris L. ssp. perkinensis (Lour.) Rupr), cabbage(Brassica oleracea L. var. capitata) and lettuce(Lactuca sativa L.) by the leaf number. And the result is summarized as follows In the nitrate content change by the leaf number, the nitrate content is increased as it goes by from inner leaf to outer leaf and the nitrate content in leaf midrib is higher than that in leaf blade. In case of chinese cabbage, the nitrate content in the leaf midrib from the most inner leaf to the most outer leaf changed 40-3,177ppm and in the leaf blade it changed 40-2,887ppm. But the nitrate content in the leaf blade of cabbage from the most inner leaf to the most outer leaf changed 89~2,297ppm and in the leaf blade it changed 25~765ppm. In case of lettuce, the nitrate content change of the leaf midrib by the leaf position was 419~4,349ppm, and in the leaf blade it changed 260~2894ppm. It was conclude that the outer leaf of chinese cabbage, cabbage and lettuce should be removed to keep the lower nitrate intake by population before it is consumed.

• Korean Journal of Agricultural Science
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• v.41 no.4
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• pp.399-404
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• 2014

Soil moisture is an important factor for the availability and circulation of nutrients in arable soil. The purpose of this study was to set thresholds moisture content on soil nitrate concentration in the solution for real-time diagnosis. Sandy loam, silt loam, and sandy loam was filled with $1.2g\;cm^{-3}$ at Wagner pots, 0, 100, and $200mg\;L^{-1}$ of $KNO_3$ was saturated. Nitrate in standard solution was recovered about 95% by passing the porous cup. Nitrate concentrations in sampling of soil solution were examined by using a porous cup. The soil solution was higher in accordance with sandy loam> silt loam> clay loam, limited water filled pore space for sampling soil solution was 33.7, 56.4, and 62.2%, respectively. Nitrate concentration in the soil solution was negligible at sandy loam and silt loam during sampling periods, which was decreased about 50~82% in clay loam compared to the initial $NO_3$-N concentration in the saturated $KNO_3$ solution. Over limitation of soil solution sampling, soil EC and $NO_3$-N content were increased with the saturated $NO_3$-N concentration, regardless of soil texture (p<0.05). Conclusively, soil solution by using a porous cup was possible, regardless of the soil texture, which was useful for the diagnosis in nitrate concentration of soil solution. However, because nitrate concentration of soil solution in a clay loam changes, it was necessary for careful attention in order to take advantage for the real-time diagnosis of nitrogen management in soil.

• Journal of Bio-Environment Control
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• v.10 no.1
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• pp.50-54
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• 2001

Effect of NO$_3$:NH$_4$ratio and pH of nutrient solution on nitrate content of leaves was investigated for leaf lettuce(Lactuca sativa L.) grown by a deep flow technique. Ratios(in me.L$^{-1}$ ) of NO$_3$:NH$_4$tested were 12:1, 10:3 and 8:5. The treatment of 8:5 NO$_3$:NH$_4$ratio had two solutions, one with uncontrolled pH and the other with automatically controlled pH. Solution pH continuously increased in 12:1 NO$_3$:NH$_4$treatment. Solution pH decreased gradually more as NH$_4$ratio increased. Treatment of 8:5 NO$_3$:NH$_4$with automatic pH control satisfactorily maintained the solution pH in the range of pH 5.5-6.0. Nitrate content in leaves was the greatest in treatment of 12:1 NO$_3$:NH$_4$ and the least in treatment of 8:5 NO$_3$:NH$_4$with automatic pH control. Fresh weight decreased in treatments of 10:3 and 8:5 NO$_3$:NH$_4$, whereas it increased in treatments of 12:1 and 8:5 NO$_3$:NH$_4$with pH control. It was concluded that the growth and leaf nitrate content were the greatest in high NH$_4$treatment with automatic pH control.

• The Korean Journal of Ecology
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• v.10 no.4
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• pp.175-182
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• 1987

Soybeans(Glycine max Merr. cv. Kwanggyo), inoculated with Rhizobium japonicum 110 and then sand-cultured with nitrate gradients (0, 1, 3, 10 and 30mM KNO3). were studied on the growth analysis, nitrogen fixation and nitrogen economy during the growing period. The maxium values of total leaf area, biomass and nitrogen quantity were increased 139%, 122% and 161%, respectively with higher concentration of nitrate treatment. Nodulation showed significant linear correlation with leaf area growth for each treatment of nitrate concentration increased. The more nitrate concentration increased, the more distribution ratios of dry matter and nitrogen to nodule decreased, and the more T/R ratios, CGR and N content increased. On the other hand, F/C ratios and RGR showed little changes. The amounts of nitrogen fixation of soybean alloted to 0, 1, 3, 10 and 30mM nitrate treatments were 100, 46, 14, 0.1 and 0.004% for the total nitrogen assimilation, respectively. The nitrogen utility of soybean plant was smaller than that of other plants and ranged from 23 to 30 at varying nitrate gradients.