• Journal of the Korean Society of Food Science and Nutrition
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• v.1 no.1
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• pp.5-8
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• 1972

Ordinary biological methods of evaluating protein quality are subjected to various sources of error, such as preliminary feeding, body weight of the animals, length of feeding period, endogenous nitrogen metabolism, etc. (1). Wide variations in the reported data may be partly due to this fact. The author postulated that by applying labelled protein these shortcomings may be avoided and that a balance study using nitrogen-15 would give most reliable data, uninfluenced by other factors which are unavoidable in ordinary balance studies using unlabelled nitrogen (2). However, the most important prerequisite for testing this assumption is to obtain labelled protein. As it has been known long since that chlorella contains a large amount of protein and can be easily cultured in quantity (3, 4), it was thought that labelled protein might be obtained by adding $N^{15}$ into the culture media. In this study it has been tried to find out, therefore, whether it is possible to obtain labelled protein by incorporating $KN^{15}\;O_3$ into the culture fuid and at what stage of growth the incorporation of the label into chlorella occurs.

• Korean Journal of Materials Research
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• v.31 no.12
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• pp.697-703
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• 2021

Aluminum nitride having a dense hexagonal structure is used as a high-temperature material because of its excellent heat resistance and high mechanical strength; its excellent piezoelectric properties are also attracting attention. The structure and residual stress of AlN thin films formed on glass substrate using TFT sputtering system are examined by XRD. The deposition conditions are nitrogen gas pressures of 1 × 10^-2, 6 × 10^-3, and 3 × 10^-3, substrate temperature of 523 K, and sputtering time of 120 min. The structure of the AlN thin film is columnar, having a c-axis, i.e., a <00·1> orientation, which is the normal direction of the glass substrate. An X-ray stress measurement method for crystalline thin films with orientation properties such as columnar structure is proposed and applied to the residual stress measurement of AlN thin films with orientation <00·1>. Strength of diffraction lines other than 00·2 diffraction is very weak. As a result of stress measurement using AlN powder sample as a comparative standard sample, tensile residual stress is obtained when the nitrogen gas pressure is low, but the gas pressure increases as the residual stress is shifts toward compression. At low gas pressure, the unit cell expands due to the incorporation of excess nitrogen atoms.

• Horticultural Science & Technology
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• v.34 no.4
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• pp.578-586
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• 2016

In this study, we evaluated the effects of soil incorporation of crotalaria as a green manure on the growth and yields of 'Seolhyang' strawberry and inorganic soil nitrogen levels in a greenhouse. Four different N treatments were used, as follows: zero N fertilizer (control), crotalaria, crotalaria with 50% urea, and 100% urea. The recommended N requirement (100% urea) for strawberry was $86kgN{\cdot}ha^{-1}$ and 50% of the recommended N (50% urea) was $43kgN{\cdot}ha^{-1}$. Crotalaria was sowed on June $17^{th}$, 2011 and cultivated for 37 days. The amount of N supply from soil incorporation of crotalaria was $104kgN{\cdot}ha^{-1}$. Strawberry was planted on September $9^{th}$, 2011 and cultivated for 255 days after planting. The concentrations of soluble solids and acidity of strawberry fruits for the crotalaria treatment were higher than for the crotalaria with 50% urea and 100% urea treatments. On the other hand, the growth and yield of strawberry was the highest for the crotalaria with 50% urea and 100% urea treatments, followed by the crotalaria treatment, and the lowest for the control. Soil inorganic N concentration for the crotalaria treatment was continuously decreased to $24mg{\cdot}kg^{-1}$ at the end of the growing season, while crotalaria with 50% urea and 100% urea treatments maintained an inorganic N concentration that ranged from 35 to $50mg{\cdot}kg^{-1}$. These results indicate that the amount of N supply from soil incorporation of crotalaria may not be enough because strawberry yield was lower than for other N treatments. Therefore, additional nitrogen, such as 50% urea after soil incorporation of crotalaria, is recommended.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.5
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• pp.381-387
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• 2003

Winter hairy vetch (HV) can be used as green manure with conventional tillage system (CT), in which chemical N fertilizer required for cultivation of sub-sequent com could be fully saved, or as cover crop with no-tillage system (NT) in which soil could be protected from erosion, control of weed, and the reduction of N fertilizer application. This experiment was carried out to compare the enrichment of soil mineral nitrogen (SMN) at corn root zone, and the changes of com growth and N uptake according to HV amounts (winter fallow, above-ground HV removed, intact HV, and HV added from aboveground HV removed) under two tillage systems in the upland field of National Crop Experiment Station, Suwon, Korea in 1996. HV cultivation during winter decreased SMN a little at com planting. HV incorporation with CT increased SMN rapidly during early growth stage according to rapid decomposition of Hv. SMN by HV cover with NT was increased slowly and its increase was higher in the surface soil (soil layer 0-7.5cm) compared to deep soil layer 7.5-22cm. Com growth and N status at corn silking stage, com yield and N uptake at harvest were increased in proportion to aboveground HV amounts regardless of tillage system. Average hairy vetch nitrogen (HV-N) uptake efficiency by com was 10% higher with CT than with NT in which average HV-N uptake efficiency was 43 %. Corn yields were not different between two tillage systems, but corn N uptake was increased by 33 kgN/ha more with CT than with NT due to the increase of corn N concentration. The increase of SMN and com N uptake from HV cover with NT could not be disregarded though those with CT were higher than with NT

• Korean Journal of Environmental Agriculture
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• v.38 no.4
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• pp.237-244
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• 2019

BACKGROUND: Impact of incorporating hairy vetch into soil on mitigating nitrous oxide (N₂O) emissions from maize field in South Korea has not been investigated, whereas impacts on soil properties and nutrients for crops have been investigated. Therefore, this study was conducted to examine N₂O emission from upland soil incorporated with hairy vetch for one year in maize field. METHODS AND RESULTS: Hairy vetch was grown in an upland soil from November, 2017 to May, 2018 and incorporated into soil on May 25 of 2018. Control and conventional treatment (NPK) were included for comparison. Gas samples were collected weekly for a year to examine N₂O emissions from the soil. Chemical nitrogen (N) fertilizer stimulated N₂O emission in short term resulting in the greatest cumulative N₂O emission in NPK (6.72 kg N₂O ha^-1) compared to the control (4.04 kg N₂O ha^-1) and hairy vetch-incorporated field (5.43 kg N₂O ha^-1), and the greatest yield of maize from NPK, because total N input was much greater by NPK (186 N kg ha^-1) than by hairy vetch (81.6 N kg ha^-1). CONCLUSION: Incorporation of hairy vetch reduced N₂O emissions from the maize compared to the NPK-treated field. However, further research on improving crop productivity with incorporation of hairy vetch is needed.

• Journal of Animal Environmental Science
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• v.18 no.sup
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• pp.73-80
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• 2012

Nitrogen included in animal manure can be used as organic fertilizer if it is treated properly but it may cause serious air and water pollution without proper management. Significant amount of nitrogen losses happen in the form of ammonia when the manure staying in animal house and storage facilities and being composted and applied to the field. In order to maximize the manure nitrogen utilization, it is important to understand the mechanisms of nitrogen loss during the diverse manure handling and treatment procedures. The plant available nitrogen portion of total nitrogen in excreted manure was evaluated based on animal type, animal manure collection system, manure treatment process, and application method. About 27% of nitrogen included in excreted pig manure could be plant available if it is applied to the filed after composting process. The plant available nitrogen portion varies from 29% (surface application) to 54% (solid injection) based on application method of digestated piggery slurry. Plant can use 18% of manure nitrogen if the composted cattle and poultry manure applied to the field using surface application method. Manure treatment and application methods need to be carefully selected to control and utilize the manure nitrogen properly.

• Korean Journal of Environmental Agriculture
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• v.25 no.4
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• pp.346-351
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• 2006

The study was performed to investigate the effect of incorporation of green manures (GM) into a sandy loam soil for organic vegetable production in the condition of plastic film house, relating to growth and yield of tomato crop. Three species of GM as perennial ryegrass, sudangrass and soybean are cultivated during the rest time of summer season and incorporated into soil just after the harvest. Thereafter tomato crop was transplanted as the following crop to soil incorporated GM. Among GM, soybean was proper as GM crop for organic farming, due to the effect of yield increase by continuous supply of nitrogen on following the tomato crop. Yield of tomato crop after soybean incorporation into soil was $4.2Mg\;ha^{-1}$ similar to $4.4Mg\;ha^{-1}$ of N-P-K standard fertilization (conventional) treatment. But perennial ryegrass and sudangrass were improper, because the biomass yield of perennial ryegrass was very low due to growth retardation by high temperature during summer season and soil incorporation of sudangrass as GM results in yield decrease of following the tomato crop caused by high C/N ratio of sudangrass itself. In conclusioa soybean incorporation into soil had advantage of producing conventional level on following the tomato yield and therefore it could recommend as GM for organic vegetable production.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.5
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• pp.608-619
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• 1998

The small and the large intestine of swine represent the organs that extract nutrients from feedstuffs through digestion and fermentation and that allow their absorption and incorporation into the blood circulation. Special attention is directed towards the small intestine of young pigs since the transition to a solid diet at weaning exerts major impacts on the structural and functional integrity of the small intestine. Dietary factors involved in postweaning changes of gut morphology and biochemistry such as removal of bioactive compounds in sows milk at weaning, anti-nutritional factors in weaner diets, dietary fiber and the role of voluntary feed intake will be elucidated. The microbial function of the large intestine which is carried out by a diverse population of microorganisms is dependent on substrate availability. Short chain fatty acids as main fermentation products contribute to the energy supply of the host but they are also important for the maintenance of the morphological and functional integrity of the epithelium in the colon. As a result of bacterial nitrogen assimilation in the large intestine, nitrogen is shifted from the urinary to the fecal excretion route thus saving metabolic energy to the pig because less ammonia would become available for conversion to urea.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.11a
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• pp.90-93
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• 1992

In this paper, MOS characteristics of gate dielectrics prepared by furnace oxidation of Si in an $N_2O$ ambient have been studied. Compared with the oxides grown in $O_2$, $N_2O$ oxides show significantly improved breakdown field and low flat band voltage. Also, $N_2O$ oxide is more controllable for ultrathin film growth than $O_2$ oxide. This improvement is caused by nitrogen incorporation into the $N_2O$ oxide. Therefore, the nitrogen-rich-layer at the Si/$SiO_2$ interface formed during $N_2O$ oxidation not only strengthen $N_2O$ oxide structure at the interface and improves the gate dielectric quality, it also acts as a oxidant diffusion barrier that reduces the oxidation rate significantly.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.1
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• pp.16-21
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• 2005

This study was conducted to establish the elaborate nitrogen fertilization method to enhance N use efficiency in direct-seeded rice on flooded paddy. The nitrogen uptake by rice plants was insignificant until 25 days after seeding, and increased gradually thereafter. During this early growth stage, rice plants absorbed only the $4\%$ of basal applied N, while the $45\%$ of N fertilizer remained in the paddy soil. The absorption of basal N by rice plants was almost completed at 46 days after application. Nitrogen top-dressed at 5-leaf stage was well matched to crop nutrient demand, so it could be absorbed so actively in 8days after application. As a result, we could cut down the amount of N fertilizer to $36\%$ of the basal N level without significant difference in yield. Plant recoveries of fertilizer $^{15}N$ applied with different application timings were $7.8\%$ for basal, $9.4\%$ for 5-leaf stage, $17.1\%$ for tillering stage, and $23.4\%$ for panicle initiation stage, respectively. When urea was applied with nitrogen fertilization practice based on basal incorporation (BN), plant recovery of $^{15}N$ at harvest was $31.0\%$, which was originated from $13.7\%$ for grain, and $21.3\%$ of the fertilizer $^{15}N$ remained in the soil, and the rest could be uncounted. Plant recovery of fertilizer $^{15}N$ applied with nitrogen fertilization practice based on topdressing at 5-leaf stage (TN), where N rate was reduced by $18\%$ compared with BN, was $35.1\%$ (grain $15.6\%$), and $19.9\%$ of the fertilizer $^{15}N$ remained in the soil, and the rest could be uncounted. TN showed a higher $^{15}N$ recovery than BN because it was to apply N fertilizer at a time to well meet the demand of rice plant direct-seeded on flooded paddy. We concluded that TN would be the nitrogen fertilization method to enhance N use efficiency in direct-seeded rice on flooded paddy.