• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.2
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• pp.123-128
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• 1998

Legume winter cover crop hairy vetch(Vicia villosa Roth, HV) can supply mineral nitrogen for silage corn by HV cover killed. The purphose of this study was to understand changes of soil mineral N, yield and N uptake of silage corn by N level (0, 135kgFN/ha) and cover cmp(no cover crop: NCC, hairy vetch cover crop: HVC) at field of Crop Experiment Station in 1996. HV growth decreased soil mineral N concentration before seeding corn, but killed HV cover increased concentration of soil mineral N at surface soil (0~7.5cm) at six-leaf stage of corn. Total dry matter(DM) and N uptake of corn averaged over N level was more decreased in HVC than in NCC at silk stage, but N uptake of corn after silk was more increased in HVC than in NCC by N mineralized fiom HV killed, especially in OkgFNJha. N fertilization increased total DM and and N uptake of corn averaged over cover crop, especially more increased the DM and N uptake before silk stage. Early application of N fertilizer was recommendable in netillage silage corn using hairy vetch cover crop.

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.3
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• pp.147-154
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• 1974

Relationship among grain yield (Y) nitrogen efficiency (E) and nitrogen uptake amount (N) was investigated using the data from Korea and Japan in order to find out the way of increase nitrogen efficiency. The relationship between E and N could be grouped in various classes. In each class the equation. Y=EN=(b-aN)N, is valid where b is a theoretical maximum of E and a is the E/N at theoretial maximum yield. Present technique for high yield in the rice research seems to achieve 56.8 of nitrogen efficiency with 15.5kg of nitrogen uptake. Future target appears to be 63 of efficiency with 17kg of nitrogen uptake at which some farmers in Japan might reach already. It seems that the increase of nitrogen uptake for high yield is restricted without increase of nitrogen efficiency. The increase of efficiency and uptake amount of soil nitrogen seems essential to increase total nitrogen efficiency.

• The Microorganisms and Industry
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• v.14 no.3
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• pp.23-26
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• 1988

자연계에 있어서 질소는 대기중의 분자상질소를 비롯하여 초산, 암모니아와 같은 무기태질소, 단백질, 핵산 등의 유기태질소 등 다양한 형태로 존재하며 생물권내에서 흡수, 고정, 대사, 분해되는 등 다양한 순환을 거듭하고 있다. 대기중의 분자상질소는 Rhizobium, Azotobacter, Klebsielle, Clostridium, Blue-green algae 및 광합성세균 등에 의해 고장되어 암모니아의 형태로 환원된다. 한편 대부분의 식물들은 초산이나 암모니아 형태의 질소를 흡수 동화하여 핵산, 단백질을 만들고 이들 구성물은 사후 암모니아로 재분해 된다. 또한 동식물의 유체내지는 배설물들도 각기 분해되어 암모니아의 형태로 변화되는데 이와같은 일련의 질소순환(nitrogen cycle)은 초화세균, 탈질세균 내지는 질소고정균등 대부분의 미생물에 의해 크게 지배를 받고 있다.

• 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.3
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• pp.222-228
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• 1988

This experiment was carried out to investigate the effects of N levels (0,10,20,30kg/10a) and N split rates [the rates of basal＋top dressing 15 days after transplanting (DAT) : top dressing 25 days before heading (DBH) was 100 : 0, 80 : 20, 60 : 40 ] on the growth, yield, yield components, and N uptake of Seomjinbyeo (J) and Samgangbyeo (I${\times}$J). The maximum tillering stage occurred in the middle of July in both varieties, but Samgangbyeo showed the second maximum tillering stage in the middle of August probably due to the retarded early growth caused by low temperature in the tillering stage and to favoring temperature in August. Grain yield of Seomjinbyeo was similar among the N levels from 10 to 30 kg/10a without occurrence of rice blast and lodging, but that of Samgangbyeo increased as N level increased upto 30 kg/10a. Grain yield of Seomjinbyeo was higher when N was applied three times (basal and two top dressings 15 DAT and 25 DBH) compared with two times (basal and top dressing 15 DAT), but that of Samgangbyeo was not different among the N split rates. Total N uptake and the proportion of fertilizer N to the total N uptake increased as N level was higher. N uptake tended to be higher as proportion of basal＋top dressing 15 DAT increased in early growth stage, but it was higher as proportion of N applied 25 DBH increased in the late growth stage. The N efficiency to produce grain per absorbed N unit decreased as N level decreased in Seomjinbyeo, but similar in Samgangbyeo.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.5
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• pp.458-465
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• 1993

Water culture experiments were carried out to elucidate the effects of N availability, temperature and water potential of culture solution on the uptake and assimilation of N and dry matter accumulation by barley seedlings. N assimilation and dry matter accumulation at 3 to 4 leaves stage in barley plants were maximized at about 3.4 % of N concentration in leaf. N assimilation by barley plants increased with increase of nitrate concentration up to 80ppm in the solution. Over this level nitrate began to accumulated in the leaves and stems proportionally to the N availability in culture solution. Nitrate reductase activity increased in parallel with the increase in the concentration of reduced N in leaves. N uptake by barley plants decreased markedly when water potential reduced below -2 bar or when temperature dropped below 5$^{\circ}C$. These results suggest that the basal application rate of N, 60kg per hectare, for the barley crop needs to be re-examined under the concept of N use efficiency with taking into consideration of temperature and soil N availability because about a half of N accumulated in the leaves of barley plant before wintering is known to be lost by winter killing of above-ground part of the plant.

• Applied Biological Chemistry
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• v.25 no.4
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• pp.232-238
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• 1982

From ^{15}N$ labelled nitrogen experiments on 13 fields use efficiency by difference method was higher than that by labelling method in 80% of fields tested indicating augmentation of soil nitrogen uptake by fertilizer nitrogen. Both methods showed very similar trend among fields. Sulfur coated urea(SCU) and point application increased fertilization efficiency(yield increment per fertilizer nitrogen applied, Fe) to 23 from 15 of split application through the increase of fertilizer use efficiency from 29(Eu) to 50 but tended to decrease efficiency of absorbed fertilizer nitrogen(yield increment per nitrogen derived from fertilizer, Ef) from 50. to 46 High yielding capacity of Tongil line appears to be attributed to the higher Ef, translocation efficiency and soil nitrogen preference index(soil nitrogen increment in plant per the increment of fertilizer nitrogen in plant, PI). This studies confirmed that yield under fertilizer application system depends on Fe which is the multiplication of Eu and Ef and that the improvement of fertilizer management(form, application method and time) increases principally Eu, the limit of which is controlled by Ef that is attributed mainly to varietal characteristics.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.253-259
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• 2001

The purpose of this study was loused on understanding of uptake of nutrients by plants, the behaviors of nutrients in soil and the possibility of leaching loss when N fertilizer (urea) and mature compost were applied. Lysimeters (volume 0.15㎥, diameter 62cm, height 62.8cm) were installed for collecting leachate in the Jeju volcanic ash soils. Lysimeter study consisted of thirteen treatments: fellow, fellow with weeding, cropping without fertilizer and compost, three N fertilizer soil surface applications (16, 32, and 64 kg/10a), three N fertilizer and compost soil surface applications (16+800i 32+1600, and 64+3200 kg/10a), two water dissolved N fertilizer applications(16 and 32 kg/10a), and low and high plant densities. The growth of corn (preceding crop) and potatoes (succeeding crop) and leaching loss were determined during the experimental period. The amount of leachate from lysimeter was remarkably greater at bare conditions than at cropping conditions for corn and potatoes. The N content of plants (corn and potatoes) tended to increase as fertilizer rate increased. Fertilization of urea dissolved in water to soil was more efficient than surface fertilization for the growth, yield, and the N uptake N of corn and potatoes. There were no differences in dry matter yield of plants between medium and high N rates, but N, Ca, K and Mg concentrations of plants were higher at higher N rates. There were significant correlations between N uptake and each of Ca, K and Mg uptakes in corn and potatoes. Total N uptake by plants increased with increased N fertilizer and compost applications. Plane absorbed 54.9% of applied N at low N rate and 31.0 to 34.0% at high N rates. The proportion of N leaching losses was lower at low N rate and high plant density.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.4
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• pp.312-318
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• 2010

This study was carried out to develop and test a prototype program that recommends the nitrogen topdressing rate using the color digital camera image taken from rice field at panicle initiation stage (PIS). This program comprises four models to estimate shoot N content (PNup) by color digital image analysis, shoot N accumulation from PIS to maturity (PHNup), yield, and protein content of rice. The models were formulated using data set from N rate experiments in 2008. PNup was found to be estimated by non-linear regression model using canopy cover and normalized green values calculated from color digital image analysis as predictor variables. PHNup could be predicted by quadratic regression model from PNup and N fertilization rate at panicle initiation stage with $R^2$ of 0.923. Yield and protein content of rice could also be predicted by quadratic regression models using PNup and PHNup as predictor variables with $R^2$ of 0.859 and 0.804, respectively. The performance of the program integrating the above models to recommend N topdressing rate at PIS was field-tested in 2009. N topdressing rate prescribed for the target protein content of 6.0% by the program were lower by about 30% compared to the fixed rate of 30% that is recommended conventionally as the split application rate of N fertilizer at PIS, while rice yield in the plots top-dressed with the prescribed N rate were not different from those of the plots top-dressed with the fixed N rates of 30% and showed a little lower or similar protein content of rice as well. And coefficients of variation in rice yield and quality parameters were reduced substantially by the prescribed N topdressing. These results indicate that the N rate recommendation using the analysis of color digital camera image is promising to be applied for precise management of N fertilization. However, for the universal and practical application the component models of the program are needed to be improved so as to be applicable to the diverse edaphic and climatic condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.2
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• pp.98-104
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• 2010

Excess nitrogen (N) uptake of rice, which could cause much lodging, disease and reduction of rice quality, could be occurred at the paddy field with previous upland condition at which much soil N could be mineralized by soil-drying effect. N fertilizers of 0, 3, and 6 kg N $10a^{-1}$ were applied to early-maturity rice, cultivar Joanbyeo at the paddy field of first and second year after upland condition, and rice growth and nitrogen uptake were investigated to know the increase of rice N uptake at the paddy field with previous upland condition for one-year. Total dry matter (DM) and N uptake of rice at the paddy field with previous upland condition increased more than continuous paddy field. Total DM and N uptake of rice at the paddy field with previous upland condition increased linearly to N fertilizer 6 kg $10a^{-1}$ at the paddy field owing to vigorous growth compared to continuous paddy field. Rice N uptake was higher at the paddy field of the first year than the second year after upland condition in considering N uptake at the plot of no N fertilizer. Vigorous growth at the paddy field with previous upland condition resulted in higher rice yield which was related with high panicle and spikelet, but much N fertilizer as much as 6 kg $10a^{-1}$ at the paddy field with previous upland condition resulted in higher lodging and protein content of brown and milled rice. Particularly, protein content of brown and milled rice increased more when the same N fertilizer was applied two times splitly at transplanting and panicle initiation stage than when N fertilizer was applied one time at transplanting as basal N. N application with under 3 kg $10a^{-1}$ as only basal N was recommended at the paddy field with previous upland condition to obtain high quality rice without lodging.