• Korean Journal of Soil Science and Fertilizer
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• v.48 no.1
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• pp.30-35
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• 2015

This study was conducted to investigate investigated the effect of nitrogen fertilizer on nitrate concentration in soil solution and to determine the relationship between yield and nitrate concentration in soil solution for cucumber cultivation under plastic film house. Nitrogen as urea was applied at rates of 0, 120, 240, 360, and $480kg\;N\;ha^{-1}$ as an additional fertilizer by trickle irrigation during cucumber cultivation. Monitoring of nitrate concentration in soil solution was investigated using porous cups at 25 cm depth under soil surface. Nitrate concentration in soil solution increased with increasing the rate of additional nitrogen. Correlation coefficient between EC value and nitrate concentration was positive in soil and soil solution (p<0.05). An additional nitrogen of about $300kg\;ha^{-1}$ was shown the highest yield of cucumber, and improved yield by 5% compared to N recommendation of $240kg\;N\;ha^{-1}$. The highest yield was determined at nitrate concentration of $82mg\;L^{-1}$ in soil solution by regression equation ($Y=74.2+0.73X+0.000504X^2$, $R^2=0.629^*$). These results means indicate that nitrate concentration in soil solution would be useful method to rapid determination for additional nitrogen during cucumber cultivation under plastic film house.

• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.3
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• pp.146-152
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• 1987

Sorghum cv. Pioneer 93 1, sorghum-sudangrass hybrid cv. Sioux and maize plant cv. Blizzard were assayed for toxic concentrations of nitrate-nitrogen ($NO_3$-N) and their relationship to morphological characteristics and environmental temperature in a field and phytotron trial. In the phytotron, sorghum and maize plants ranging from emergence to heading stage, were grown under different day/night temperatures of 30125, 25/20,28/18 and 1818 degree C. Nitrate-nitrogen in sorghum and maize plants was accumulated mainly in stems. Therefore nitrate concentration in the young plants was increased as development of stalks advanced and was highest at the stage of 3-4 leaves, when the plants had a leaf weight ratio 0.78-0.80 g/g plant weight. However, nitrate concentrations of the plant decreased as morphological development progressed, especially from the stage of growing point differentiation. Correlation coefficients showed a positive correlation of nitrate concentration with leaf weight ratio, leaf area ratio and specific leaf area, while plant height, dry matter percentage and absolute growth rate showed a negative association with TEX>$NO_3$-N ($P{\le}0.1$%). Cyanogenic glycosides, total nitrogen and crude protein were close associated with nitrate accumulation, and positively significant ($P{\le}0.1$%). High temperature over 30/25^{\circ}C.$ for 3 weeks increased N-uptake and dry matter accumulation, but reduced nitrate concentration. Under cold temperature below 18/8^{\circ}C.$ concentration of nitrate-N was increased in spite of its limited nitrogen uptake and plant growth.

• Journal of Bio-Environment Control
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• v.15 no.1
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• pp.84-90
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• 2006

This study was conducted to anticipate nitrate reduction state in tree through measurement of nitrate reductase activity (NRA) and investigate the effect of nitrogen concentrations (100, 200, 400, and 600 $mg\;L^{-1}$) on growth, the nitrogen content of various tissue, and NRA of pear (Pyrus pyrifolia cv. Niitaka) seedlings in sand culture. Nutrient solutions used in this experiment were adjusted to pH 6.5 and fixed the ratio of ammonium and nitrate to 1:3 and trickle-irrigated 3 times a day. Tree height and dry weight of various organs in seedlings were higher in low nitrogen concentration (100 and 200 $mg\;L^{-1}$) than in high nitrogen concentration (400 and 600 $mg\;L^{-1}$). The shoot growth in 600 $mg\;L^{-1}$ was extremely poor by nitrogen over supply. Increasing the nitrogen concentration, the concentration of nitrate-N in leaves and roots were insignificantly changed but that of stems increased. The accumulation of total and reduced nitrogen in all organs with increasing concentrations of nitrogen supply were increased at 30 days after treatment but those of all organs at 60 and 90 days after treatment were highest in 600 $mg\;L^{-1}$, whereas there were no significant changes among other nitrogen concentration. The in vivo (${+NO_3}^-$) NRA of all organs did not relate to nitrogen concentration but the in vivo (${-NO_3}^-$) NRA of leaves except roots increased with increasing the nitrogen concentration. Therefore, the proper nitrogen concentration to promote growth and nitrate reduction of pear tree was 200 $mg\;L^{-1}$.

• 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.

• Journal of the Korean earth science society
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• v.44 no.4
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• pp.291-306
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• 2023

Shallow groundwater in rural areas is primarily polluted by agricultural activities. Nitrate-nitrogen is an indicator of artificial pollution. In this study, the hydrochemical characteristics and nitrate-nitrogen pollution of shallow groundwater were examined in two agricultural villages (Hyogyo-ri and Sinan-ri) in Chungcheongnam-do Province, Korea. Physicochemical quality analysis of shallow groundwater and stream water in the field, and chemical analysis in the laboratory were conducted from July 2020 to October 2021. In Hygyo-ri and Sinan-ri villages, shallow groundwater mainly belonged to the Ca-Cl, Ca-H CO₃, Na-HCO₃, and Na-Cl types, whereas stream water predominantly belonged to the Ca-HCO₃ type. The nitrate-nitrogen concentration in shallow groundwater varied depending on the season, displaying an increased concentration of nitrate-nitrogen in the dry season compared to the rainy season. Stream water may be influenced by runoff into villages from the surrounding area, although both shallow groundwater and stream water are affected by artificial pollution. In addition, the nitrate-nitrogen concentration in stream water was lower than that in shallow groundwater.

• Journal of Plant Biology
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• v.34 no.4
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• pp.253-260
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• 1991

Spirodela polyrhiza and Lemna aequinoctialis often occurred at the sites of high ammonium concentration and at the sites of high nitrate concentration, respectively. We investigated the different distribution between two species in relation to the type of nitrogen sources and their concentrations. Our experiments showed that L. aequinoctialis grew faster than S. polyrhiza in nitrate media with lower than 15 mM concentration. The nitrate uptake was also faster in L. aequinoctialis than in S. polyrhiza. However, neither differences in growth nor in uptake patterns between these two species were observed in ammonium media. Glutamine synthetase (GS), glutamate dehydrogenase (GDH) and glutamate synthetase (GOGAT) activities were higher in L. aequinoctialis. In particular, nitrate reductase activity (NRA) in L. aequinoctialis was 12.1 times as high as that in S. polyrhiza. These results showed that the two species responded varyingly to the types of nitrogen sources and their concentrations. Therefore, the difference in geographic distribution between the two species appeared to reflect the interspecific differences in enzyme activities and, subsequently, nitrogen absorption abilities.

• Korean Journal of Environmental Agriculture
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• v.12 no.3
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• pp.281-297
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• 1993

Nitrogen is an element required to meet optimal plant growth. However, when it was applied (as chemical fertilizer or animal waste) more than the demand of plant and managed it unreasonably can be accumulated in subsoil and leached from soil system. Nitrogen also can be act as an pollutant to soil and water through water contamination if its concentration exceed the critical level. The concentration and downward movement of nitrate in soil is influenced by cultural practices and soil properties. High level of nitrate nitrogen in drinking water is harzadrous for animal and human health, especially for infants and the restoration of the quality of groundwater is impossible by now. Therefore it is the only way to prevent from leaching of nitrate nitrogen to keep the quality of groundwater as vital water resource. The aims of the presentation of this review paper are to understand the relationship between agricultural practices and the concentration of nitrate nitrogen in groundwater and to suggest further informations for the rational management methods to reduce the leaching of nitrate nitrogen in soil.

• Journal of the Society of Disaster Information
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• v.16 no.3
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• pp.542-549
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• 2020

Purpose: As nitrate nitrogen produced during fermentation of liquid fertilizer is a pollution indicator of water, in this study, four research areas where liquid fertilizer was sprayed were selected, and a model was designed to estimate the concentration of nitrate nitrogen pollution. Method: Prior to shooting on site, a spectrum library was constructed by dividing the ratio of liquid fertilizer into 5 groups: 0%, 25%, 50%, 75%, and 100%. PLSR (Partial least squares regression) method was applied to hyperspectral images acquired in the study area based on the aspect of spectrum. Result: The behavior of nitrate nitrogen was confirmed by 1st and 2nd differentiation of the spectrum of the constructed liquid fertilizer. PLSR concentration estimation modeling was implemented using images from field experiments and compared with actual concentration of nitrate nitrogen. Conclusion: When comparing the PLSR concentration estimation model with the actual concentration of nitrate nitrogen, it was measured that the detection is possible in high concentration areas where the concentration of nitrate nitrogen is 70mg/kg or more.

• Clean Technology
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• v.15 no.4
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• pp.280-286
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• 2009

To evaluate the feasibility of electrodialysis for nitrate-nitrogen removal from wastewater, the effect of operating parameters on the removal of nitrate-nitrogen was experimentally estimated. The limiting current density (LCD) linearly increased with the nitrate concentration and the flow rate. The time when the nitrate concentration of diluate reached at 20 mg/L was linearly proportional to concentration of diluate, and the concentration of concentrate did not affect the removal rate. Increase in the flow rate gave a positive effect on the removal rate and became insignificant at How rates greater than 1.6 L/min. The removal rate increased with the applied voltage, but the increment in the removal rate decreased as the applied voltage approached the LCD. From the operation of the electrodialysis module used in this research, the flow rate of 1.6 L/min and the voltage corresponding to the 80~90% of LCD were found be the optimum operating condition for the nitrate removal from highly concentrated nitrate-nitrogen solutions.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.4
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• pp.542-549
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• 2009

An in vitro study was conducted to determine the effect of nitrate-nitrogen used as a sole dietary nitrogen source on ruminal fermentation characteristics and microbial nitrogen (MN) synthesis. Three treatment diets were formulated with different nitrogen sources to contain 13% CP and termed i) nitrate-N diet (NND), ii) urea-N diet (UND), used as negative control, and iii) tryptone-N diet (TND), used as positive control. The results of 24-h incubations showed that nitrate-N disappeared to background concentrations and was not detectable in microbial cells. The NND treatment decreased net $CH_4$ production, but also decreased net $CO_2$ production and increased net $H_2$ production. Total VFA concentration was lower (p<0.05) for NND than TND. Suppression of $CO_2$ production and total VFA concentration may be linked to increased concentration of $H_2$. The MN synthesis was greater (p<0.001) for NND than UND or TND (5.74 vs. 3.31 or 3.34 mg/40 ml, respectively). Nitrate addition diminished methane production as expected, but also increased MN synthesis.