• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.6
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• pp.387-393
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• 2005

The effect of cattle manure with the rates of 2 and 4 ton $l0a^{-1}$ for winter rye and summer corn cultivation, respectively, on the dry matter (DM) yield and nitrogen (N) uptake were investigated during successive three­year conversion period from paddy to upland condition in paddy field. The changes in soil properties and soil N sup­plying capacity during repetitive manure application were a1so examined. Growth and DM yield of upland forage crops, especially. winter rye were hindered highly by poor soil condition in the first year after conversion from paddy to upland condition, so apparent recovery of cattle manure N by crops was very low in the first conversion year. But, DM yield and N uptake of upland forage crops were increased linearly by accumulative input of cattle manure along with mineral N enrichment in soil, which also increased apparent recovery of cattle manure-No It seemed that those increases were mainly due to the improvement of soil properties such as soil mineral N, soil organic matter (soil carbon), potentially mineralizable N and bulk density by accumulative input of cattle manure rather than the increase of soil N supply according to accumulative conversion period from paddy to upland condition. It was derived that conversion period from paddy to upland condition over 2 years is needed to obtain proper DM yield in paddy field and accumulative inputs of cattle manure during the conversion period is more influential to the continuous increment of DM yield and N uptake of upland crop as well as of potential N supplying capacity of soil.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.4
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• pp.194-201
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• 2005

Silicate (Si) fertilizers are well-known for soil amendment and to improve rice productivity as well as nitrogen efficiency. In this study, we investigated the possible reduction level of nitrogen fertilization for rice cultivation by amending Si fertilizer application. Field experiments were carried out to evaluate the productivity of rice (Oryza sativa L.) on a silt loam soil, where three levels of nitrogen (0, 110 and $165kg\;ha^{-1}$) were selected and Si fertilizer as a slag type was applied at 0, 1 and 2 times of the recommendation level (available $SiO_2\;130mg\;kg^{-1}$). Application of Si fertilizer increased significantly the rice yield and nitrogen efficiency. With increasing N uptake of rice, 1 and 2 times of recommended levels of Si fertilization could decrease nitrogen application level to about 76 and $102kg\;N\;ha^{-1}$ to produce the target yield, the maximum yield in the non-Si amended treatment. Silicate fertilizer improved soil pH and significantly increased available phosphate and Si contents. Conclusively, the Si fertilizer could be a good alternative source for soil amendment, restoring the soil nutrient balance and to reduce the nitrogen application level in rice cultivation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.1
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• pp.81-88
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• 1983

This experiment was conducted to study about influenced inorganic element contents of flag leaf and chaff with different nitrogen and silicate application in Jinan (sea level 303m). The recommended rate of fertilizer application above N 15kg/10a was poor for dry production increment in cold in July elevation and was demanded increment of silicate. In the elevation of cold in July high rates of nitrogen application produced more incomplete grain and a reduced cold tolerance. These effects were due to over-content of soluble nitrogen within flag leaf and disturbance of uptaking potassium and silicate. On the other hand, the application of silicate could increase yield by promoting resistance to cold- damage. The application of increasing level of nitrogen resulted in increasing the contents of total nitrogen and phosphate in both sterile and fertile glumes. The contents of potassium and calcium were the highest at the level of nitrogen 10 - 15kg/10a, but magnessium was rather high at low nitrogen levels. It is interesting that at any level of nitrogen, over 6% higher silicate contents were noted in the fertile chaff than in the sterile chaff. Application of increasing level of silicate fertilizer decreased total nitrogen contents, but increased the contents of phosphate, potassium. and silicate in the chaff. Increasing rate of silicate content by increasing silicate addition was remarkably higher in the fertile chaff than in the sterile chaff.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.3
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• pp.224-229
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• 1992

The objective of the study was to clarify the pattern of fertilizer absorption by tillering hybrid, IK$_1$/IRI. Nangano No.1 hybrid was included as non-tillering check hybrid. Hybrids were grown in pots and the plants were periodically analyzed for their chemical components like nitrogen, phosphorus, potassium, calcium and magnesium. The results obtained indicate that the amount of nitrogen, phosphorus and potassium absorbed by IK$_1$/IRI was slightly lower than that absorbed by Nangano No.1, except nitrogen in the maturity of IK$_1$ /IRI. However, no major differences were observed for the calcium and magnesium content between two hybrids. In most cases amount of nitrogen and calcium in the plant of two hybrids seemed to decrease as the plants mature, while amount of those chemicals in the ears increased. Nitrogen efficiency for IK$_1$ /IRI seemed a little lower than that for Nangano No.1.

• Korean Journal of Remote Sensing
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• v.38 no.2
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• pp.215-222
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• 2022

In this study, the effect of wavelength range and absorption cross-section used to retrieve nitrogen dioxide (NO₂) vertical column density (VCD) from Pandora was analyzed using Differential Optical Absorption Spectroscopy (DOAS). During the GEMS Map of the Air Pollution (GMAP) 2020 campaign, data from direct sunlight observation with Pandora instrument in Seosan was used, and NO₂ VCD was retrieved under four conditions. The average NO₂ VCD under the four conditions ranged from 1.22×10¹⁶~1.38×10¹⁶ molec. cm^-2, with a maximum difference of 0.16×10¹⁶ molec. cm^-2 between each condition. The fitting error averaged 3.19~9.59%, showing an error within 10% in all cases, and the RMS was 5.11×10^-3~7.16×10^-3 molec. cm^-2. The retrieved NO₂ VCD using 4 conditions shows a slope in the range of 0.98 to 1.09 and correlation of 0.96 to 0.98 in comparison with Pandonia Global Network (PGN).

• The Korean Journal of Ecology
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• v.25 no.5
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• pp.359-364
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• 2002

This study was conducted to examine the seasonal pattern of N and P uptake by reeds (Phragmites australis) planted in newly constructed Shihwa tidal freshwater marshes. Reed and soil samples were collected from the wetland periodically from June 2000 to May 2002. Reed samples were analyzed for dry weight and content of N and P Soil organic matter content and salinity were also determined. Dry matter content of reed increased during the growing season but decreased in the fall and winter. However, this seasonal pattern was not so evident in the second year. In particular, throughout the measurement period, dry matter content of reed was lowest at a site showing high soil salinity. Regression analyses between dry matter content of reed and soil EC(1:5) suggested that dry matter content per unit square meter would decrease by 1.5 kg with every 1 dS m/sup -1/ increase in soil EC(1:5). The amount of N and P assimilated by reed significantly decreased from the fall and was lowest in the spring. Net decrease in N content from reed during the fall and next spring was calculated as 34.5 and 24.6 g m/sup -2/ in the first and second years, respectively, while the corresponding P loss was 4.0 and 1.8 g m/sup -2/. Soil organic mailer content increased in the fall and winter, but decreased in the spring and summer. The results of this study suggested that the removal of N and P by reed would be considerable during the growing season but the nutrients taken up by reeds would return as detritus to the marshes in the fall and winter. Based on the results of the study, therefore, the harvest of the reed at the latter part of the growth would be recommended to prevent further water quality degradation. However, the long-term effects of reed harvest needs further study.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.74-82
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• 2004

This study was conducted to estimate the optimum application rate of fertilizer N based on $NO_3-N$ concentration in soils for tomato (Lycopersicon esculentum Mill.) cultivation in plastic film house. Tomato plants were cultivated with and without fertilizer in twelve soils which have different concentrations of $NO_3-N$ ranging from 46 to $344mg\;kg^{-1}$. Dry weight (DW) of above-ground part of tomato with no fertilizer ranged from 28.9 to $112.5g\;plant^{-1}$, depending on N-supplying capability of soils. The soil $NO_3-N$ was positively correlated with DW ($r=0.83^{**}$) and N uptake ($r=0.78^{**}$) by tomatoes in no fertilizer treatment, and negatively correlated with fertilizer effciencies resulted from the differences of DW and N uptake between fertilized and non-fertilized plot. The relationships between soil $NO_3-N$ concentration and DW, N uptake, and fertilizer efficiency were analyzed to determine the critical levels of soil $NO_3-N$ for tomato cultivation. The limit critical levels of soil $NO_3-N$ were estimated to be more than $280mg\;kg^{-1}$ for no application of fertilizer N and to be less than $50mg\;kg^{-1}$ for recommended application of fertilizer N. These critical levels of soil $NO_3-N$ were nearly the same as those calculated from regression equation between electrical conductivity(EC) and soil nitrate for critical levels of EC in recommendation equation of fertilizer N for tomato under the plastic film house by NationaI Institute of Agricultural Science and Technology. Consequently, the optimal application rate of ferdilizer N for tomato cultivation in the soils containing $NO_3-N$ concentration between $280mg\;kg^{-1}$ and $50mg\;kg^{-1}$ was estimated by the equation Y = -0.4348X＋121.74, where Y is the percent(%) to the recommended application rate of N fertilizer and X is the soil $NO_3-N$ concentration ($mg\;kg^{-1}$).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.2
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• pp.160-165
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• 1991

Growth performance of dry seeded paddy rice was studied at four N levels (10, 15, 20, and 25 kg/l0a) in tillage and no-tillage systems. Althougth the number of seedlings and maximum tillers tended to be higher and heading date was delayed by 2 days in tillage compared with those in no-tillage system, grainyield, yield components, lodging related characteristics, and N uptake were similar between two tillage ,systems. As N level increased, grain yield increased due to increased panicle number althougth the number of spikelets per panicle and percent ripended grains were similar and I, 000 grain weight decreased slightly. {Lodging index increased with increased N level due to higher plant height and decreased breaking strength and (culm base weigth, but lodging was not occurred in the field. Cellulose, hemicellulose, and lignin contents of culm base were similar among N levels. Concentration and uptake of N increased as N level increased.

• Journal of Bio-Environment Control
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• v.6 no.2
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• pp.97-102
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• 1997

To investigate the effect of nitrogen level on the yield and quality of watermelon(Citrullus vulgaris S. cv. Bocksubak), N levels of 250, 200, 140, and 0kg/ha with the conventional amount of K and P supply non-fertilization treatments were compared one anther. Plant height, leaf area, fresh weight and dry weight were better in nitrogen application treatments than no nitrogen and non- fertilization treatments. But there was no significant difference between nitrogen levels. Yield and fruit setting ratio were the highest in N level of 140kg/ha. Fruit weight was increased by N application, and soluble solids content was the highest as 12.5 $^{\circ}$Bx in N level of 140kg/ha. Nitrogen content of leaves was increased with the applied nitrogen amount and highest at the middle stage of growth. P content was no significant difference between treatments. Ca content was increased with the applied nitrogen amount and highest at the late stage of growth.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.2
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• pp.69-80
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• 1975

Relationships between yield and various nitrogen efficiencies, between efficiencies and between efficiency and nitrogen uptake amount of rice plant were proposed and tested using data from N.P.K simple trials about 30 to 50 locations, for three years. Established relationships are well in accordance with experimental results by showing highly significant correlations between them. The overall indications are that high yielding capacity of fields with fertilizer application, depends primarily on high fertilizer nitrogen uptake by increasing fertilizer use efficiency (Eu), secondly the efficiency (Ef) of absorbed fertilizer nitrogen (Nf) and fertilization efficiency (Fe) and also depends much on nitrogen efficiency for grain yield (E) to great extend and that the efficiency (Es) of soil nitrogen (Ns) contributes to E more than Ef does. All nitrogen efficiencies are negatively correlated with the uptake amount of corresponding nitrogen and counterpart efficiency. Es and Ef could be determined firstly by difference method and secondly E versus Cs (Cs=Ns/Ns+Nf) plotting and thirdly E-Cs plotting with labelled fertilizermethod using the equation E=Es Cs+B where B=Ef Cf but a constant under the given condition and at last Y-Ns plotting with labelled fertilizer using Eq Y=$Es{\cdot}Ns+B$ where B=$Ef{\cdot}Nf$. Es which seems not much variable from field to field is mostly greater (about 80% of tested fields) than Ef which is much variable and depends much on fertilizer form. The relationships tested and well agreed are as follows: 1. Y=$Es{\cdot}Ns+Ef{\cdot}Nf$ (Y is yield) 2. E=$Es{\cdot}Cs+Ef{\cdot}Cf$ where Cf=Nf/Nf+Ns 3. E=b-aN where E=E, Es or Ef and N=N, Ns or Nf respectively, (E=Y/N, N=Nf+Ns), b is theoretical maximum under the given system and a is tangent at N=O of the curve, Y=EN. 4. Fe=Ef Eu and Se=$Es{\cdot}Eu$ where Se is efficiency of soil available nitrogen. 5. E=$(Se{\cdot}Cs+Fe{\cdot}Cf)/Eu$ 6. Y=$Es{\cdot}Eu{\cdot}Sf+Ef{\cdot}Eu{\cdot}Fn$or Y=$Es{\cdot}Eu{\cdot}Ea{\cdot}Sn+Ef{\cdot}Eu{\cdot}Fn $where Sf=$Ea{\cdot}Sn$, Ea is soil available nitrogen equivalent to fertilizer(Sf) divided by total soil nitrogen (Sn).