• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.2
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• pp.140-144
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• 2018

To investigate the impact of nitrogen (N) mineral on reproductive potential of Brassica napus L, plants were treated with different levels of N treatment ($N_0$; $N_{100}$; $N_{500}$). The half of N content for each treatment were applied at the beginning of the early vegetative stage and the rest was applied at the late vegetative stage. Nitrogen content in plant tissues such as root, stem and branch, leaf, pod and seed was analyzed and harvest index (HI) was calculated as percentage of seed yield to total plant weight. Biomass and nitrogen content were significantly affected by different levels of N supply. Biomass was significantly decreased by 59.2% in nitrogen deficiency ($N_0$) but significantly increased by 50.3% in N excess ($N_{500}$), compared to control ($N_{100}$). Nitrogen content in all organs was remarkably increased with nitrogen levels. N distribution to stem and branches, and dead leaves was higher in N-deficient ($N_0$) and N excessive plants ($N_{500}$) than in control ($N_{100}$). However, nitrogen allocated to seed was higher in control ($N_{100}$) than in other treatments ($N_0$ or $N_{500}$), accompanied by higher HI. These results indicate that the optimum level of N supply ($N_{100}$) improve HI and N distribution to seed and excessive N input is unnecessary.

• The Korean Journal of Ecology
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• v.19 no.2
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• pp.179-189
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• 1996

Growth and nitrogen retention of Persicaria thunbergii were investigated in the wetland microcosms which contained the plants growing on soil bed. Nitrogen solution was supplied to the microcosms with the same amount of $NH_4^{+}-N\; and\; NO_3^{-}-N$ at the rates of 0.00, 0.78, 1.57, 3.14g $N{\cdot}m^{-2}{\cdor}wk^{-1}$ from May 1 to August 31, 1995. The solution was detained for 5 days to react with soil and plant and then allowed to leach. The contents of NH_4^{+}-N\;and\; NO_3^{-}-N$ in the leachate, total Kjeldahl nitrogen, plant biomass, and soil characteristics were determined. Nitrogen retained by plant was estimated as the increment of TKN in plant biomass. The addition of 0.78 and 1.57g $N{\cdot}m^{-2}{\cdot}wk^{-1}$ resulted in significant increase of plant biomass. However, plant growth was inhibited when nitrogen was added at the rate of 3.14g $N{\cdot}m^{-2}{\cdot}wk^{-1}$. Overall, the plant biomass was positively correlated with the amount of nitrogen retained by plant and soil system. The amounts of $NO_3^{-}-N$ leached from the microcosms were 5~10 times higher than those of $NH_4^{+}-N$. While total nitrogen added ranged from 143.2 to 576.5g $N/m^2$, total leaching loss of inorganic nitrogen and nitrogen retained by plant was as little as 1.04~22.71g $N/m^2$, and 5.46~12.91g $N/m^2$, respectively. Then, the plant seemed to contribute to KDICical and microbial immobilization of nitrogen in the soil. Finally, it is suggested that a large portion of nitrogen added was lost into the air by denitrification and volatilizaton, and / or leached in organic forms.

• The Korean Journal of Ecology
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• v.26 no.2
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• pp.71-74
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• 2003

Effects of nitrogen addition on the growth of Indigofera pseudo-tinctoria (Leguminosae) in the waste landfill site was investigated. Nitrogen fertilization in the nitrogen poor soils of waste landfill may influence the growth of nitrogen fixing plants beneficially or detrimentally. When I. pseudo-tinctoria was fertilized with three different levels of nitrogen, the coverage of plants treated with 46 g N/$m^2$ and 460 g N/$m^2$ was significantly less than that of plants treated with 23 g N/$m^2$. The growth rates of plant height treated with 46 g N/$m^2$ and 460 g N/$m^2$ were significantly less than those of plants treated with 23 g N/$m^2$. The growth rates of plant diameter treated with 46 g N/$m^2$ and 460 g N/$m^2$ were significantly less than those of plants treated with 23 g N/$m^2$. Dry weights of whole plants in control sites were higher than those of all the others nitrogen treatment sites. Nodule numbers were higher in control plants than those of plants in all the other nitrogen treatment sites. It is suggested that nitrogen fertilizer addition over 23 g N/$m^2$ affect the growth of some nitrogen fixing plants, such as I. pseudo-tinctoria, negatively.

• Journal of Korean Society on Water Environment
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• v.30 no.5
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• pp.503-511
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• 2014

The temporal and spatial analyses of total nitrogen (TN) fractionation were conducted in order to understand 1) total nitrogen components in streams and 2) their patterns in rainy and dry seasons. The result showed that the concentration of nitrogen components in stream water was lower in non-urban area and getting higher in urban area. Dissolved total nitrogen (DTN) was 95~97.7% of total nitrogen in streams, and the proportion of dissolved organic nitrogen (DON) and ammonia nitrogen ($NH_3-N$) was higher with increasing urban area. The concentration of total nitrogen and nitrate nitrogen ($NO_3-N$) were highest in winter among four seasons. The result was showed that concentration of $NH_3-N$ was same variation as concentrations of TN and $NO_3-N$ in urban-rural complex and urban areas, except rural areas. During rainy season, concentrations of particulate organic nitrogen (PON) and $NH_3-N$ increased in rural areas and decreased in both urban-rural complex and urban areas. Correlation between total nitrogen components and land uses was positively correlated with site > paddy, and negatively correlated with forest. The variation of total nitrogen concentration was determined by $NO_3-N$ in non-urban areas, by $NO_3-N$ and $NH_3-N$ in urban-rural complex and by $NH_3-N$ in the urban areas.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.5
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• pp.192-195
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• 2007

Structural and electronic properties of bulk GaN with nitrogen vacancy($V_N$), oxygen substitution on nitrogen site($O_N$), and complex of nitrogen vacancy and oxygen substitution on nitrogen site($V_N-O_N$) were investigated using the first principle calculations. It was found that stability of defect formation is dependent on the epilayer growth conditions. The complex of $V_N-O_N$ is energetically the most favorable state in a condition of Ga-rich, however, oxygen substitution in nitrogen site is the most favorable state in N-rich condition. The electronic property of complex with negative charge states at $\Gamma$ point was changed from semiconductor to metal. On the contrary, the properties of nitrogen vacancy except for neutral charge state have shown the semiconductor characteristics at $\Gamma$ point. In the oxygen substitution on nitrogen site, the energy differences between conduction band minimum and Fermi level were smaller than that of defect-free GaN.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.5
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• pp.294-299
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• 2000

Hairy vetch (Vicia villosa Roth) winter annual is very effective on reducing chemical nitrogen fertilizer for subsequent com by fixed organic green manure nitrogen fixed during hairy vetch growth. In this experiment, hairy vetch produced above-ground dry matter of 5 ton/ha, nitrogen yield 200 kgN/ha, at com planting on the average during 1997 and 1998. Changes in com yield and nitrogen uptake for two years were investigated after application of nitrogen fertilizer 0, 60, 120, 180, 240 kgN/ha on plot of winter fallow and hairy vetch green manure, respectively. Nitrogen status such as ear-leaf N%, SPAD value at silk and dough stage, and com yield decreased in proportion to reduction of nitrogen fertilizer at winter fallow, but nitrogen status and yield of com were not different among nitrogen fertilizer rate at hairy vetch green manure. Com yield (total dry matter) at 0 kgN/ha plot of hairy vetch was 22, 20 ton/ha in 1997, 1998, respectively and com could produce more dry matter 9, 13 ton/ha by hairy vetch green manure compared with winter fallow under the condition of no nitrogen fertilizer in 1997, 1998, respectively. Com yield (total dry matter) at 60kgN/ha of hairy vetch green manure was higher than that of high N fertilizer rate such as 180, 240 kgN/ha of winter fallow. Nitrogen uptake of com at plot of hairy vetch-no nitrogen fertilizer slightly decreased than at plot of hairy vetch - nitrogen fertilizer, but com absorbed more nitrogen of 141, 159 kgN/ha by hairy vetch green manure compared with winter fallow under no nitrogen fertilizer condition in 1997, 1998, respectively. Nitrogen fertilizer reduction for com by hairy vetch green manure was 149, 161kgN/ha in 1997, 1998, respectively. Still more, com could absorb more soil nitrogen by nitrogen fertilizer 60kgN/ha of hairy vetch green manure than by high nitrogen fertilizer such as 180, 240 kgN/ha at winter fallow. It is concluded that nitrogen fertilizer for corn could be reduced by winter cultivation and soil incorporation of hairy vetch at com planting.

• Journal of Nutrition and Health
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• v.28 no.5
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• pp.406-414
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• 1995

Nitrogen(N) concentration of preterm(PT) and term (T) milk in various fractions, such as total, protein, nonprotein, whey protein and casein were determined at 2-5 days, 1, 2, 4 and 6 weeks of postpartum. The purpose of this study was to investigate the nitrogen concentration of human milk from mothers delivering at preterm and term, and the propriety of preterm milk for premature infants. The concentration of total N, nonprotein N, protein N, whey protein N and casein N in preterm milk was decreased significantly with time postpartum. Total N was 374mg/이 at colostrum, 232mg/dl at mature milk. Whey protein N was decreased from 42mg/dl at 2-5 days to 32mg/dl at 4-6 weeks. Protein N was 332mg/dl at colostrum, 202mg/dl at mature milk. The proportion of whey protein N and casein N were 39:61 at colostrum, 28:72 at mature milk. No difference were found between T and PT milk for total nitrogen excepted 2 weeks. In this report we show that nitrogen concentration except casetpt casein N is smaller in milk from mothers giving birth prematurely than in milk from mothers giving birth at term, over the first two weeks of lactationl But protein N was higher in preterm milk than term milk, whey protein nitrogen was lower. By comparing predicted nitrogen intakes to estimated requirements of preterm infants fed 150 to 200ml/kg/day of their own mother's milk, we predict that the quantities of protein provided would be adequate to meet the requirements of the prematured infants during the early weeks of life.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.2
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• pp.100-105
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• 2017

Various methods for assessing soil total nitrogen (TN) and inorganic N content have been developed to manage nutrient and to understand N cycle in soil. This paper address the technical procedures in arable soil samples to conduct soil sampling, sample preparation, and measuring total N and inorganic N. Among various methods for measuring soil total nitrogen contents, Kjeldahl distillation and Indophenol blue method have widely used due to reliability and economic advances. Also, two methods can analyze more samples at the same time compared with other nitrogen measuring methods. For evaluating inorganic N content, mainly in forms of nitrate-N ($NO_3{^-}-N$) and ammonium-N ($NH_4{^+}-N$), extraction with a single reagent such as 2M KCl has been employed, followed by Kjeldahl distillation or indophenol blue methods.

• Journal of environmental and Sanitary engineering
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• v.13 no.2
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• pp.57-65
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• 1998

In this research, Effect of C/N ratio on nutrient removal in intermittently aerated activated sludge system(IAASS) was investigated with dormitary, building and swine wastewater. Three types (2-stage, 4-stage, modified) of IAASS were operated. Time interval of aeration/nonaeration in IAASS was 1hr/1hr. In treatment of Dormitary wastewater(BOD/T-N ratio : 4.4), Building wastewater (BOD/T-N ratio : 3.14) and swine wastewater(BOD/T-N ratio : 3.84), Nitrogen removal efficiency of 80, 70 and 90.4% was achieved, respectively. Nitrogen removal in IAASS was a great influenced on influent C/N ratio, efficient nitrogen removal was achieved at BOD/T-N ratio over 4. In IAASS operation, $\Delta $BOD mg/L/$\Delta $ nitrogen mg/L ratio was about 4-6. Simultaneous removal of organic, nitrogen and phosphorus in IAASS can achieved. And influent organic was efficiently utilized in denitrification. IAASS could be one of the best alternative process for the retrofit of conventional activated sludge system for the removal of nutrients.

• Animal Bioscience
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• v.36 no.3
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• pp.492-497
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• 2023

Objective: The objectives were to demonstrate that the nitrogen and energy in pig urine supplemented with hydrochloric acid (HCl) are not volatilized and to determine the minimum amount of HCl required for nitrogen preservation from pig urine. Methods: In Exp. 1, urine samples of 3.0 L each with 5 different nitrogen concentrations were divided into 2 groups: 1.5 L of urine added with i) 100 mL of distilled water or ii) 100 mL of 6 N HCl. The urine in open plastic containers was placed on a laboratory table at room temperature for 10 d. The weight, nitrogen concentration, and gross energy concentration of the urine samples were determined every 2 d. In Exp. 2, three urine samples with different nitrogen concentrations were added with different amounts of 6 N HCl to obtain varying pH values. All urine samples were placed on a laboratory table for 5 d followed by nitrogen analysis. Results: Nitrogen amounts in urine supplemented with distilled water decreased linearly with time, whereas those supplemented with 6 N HCl remained constant. Based on the linear broken-line analysis, nitrogen was not volatilized at a pH below 5.12 (standard error = 0.71 and p<0.01). In Exp. 3, an equation for determining the amount of 6 N HCl to preserve nitrogen in pig urine was developed: additional 6 N HCl (mL) to 100 mL of urine = 3.83×nitrogen in urine (g/100 mL)+0.71 with R² = 0.96 and p<0.01. If 62.7 g/d of nitrogen is excreted, at least 240 mL of 6 N HCl should be added to the urine collection container. Conclusion: Nitrogen in pig urine is not volatilized at a pH below 5.12 at room temperature and the amount of 6 N HCl required for nitrogen preservation may be up to 240 mL per day for a 110-kg pig depending on urinary nitrogen excretion.