• Korean Journal of Soil Science and Fertilizer
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• v.16 no.2
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• pp.131-155
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• 1983

Though it has been widely known the nitrogen effects are influenced by soils, varieties, and mineral nutrients in the rice culture, few analyses in relation to the factors increasing nitrogen effect have been studied in Korea. The effects of potassium and silica on the factors increasing nitrogen effects in paddy soils were investigated in accordance with soil improvement practices and nitrogen application methods for the cultivated varieties. The results obtained are as follows. 1. For 413 paddy fields, the yield from soils without nitrogen application ranged from 200 to 850kg/10a and that from nitrogen application did 350 to 1,051kg/10a. The yield increament by nitrogen application varied 50 to 650kg/10a depending on soils. 2. Soil chemical characteristics for high yield were different between with nitrogen and without nitrogen application. In the without nitrogen application, however, contents of organic matter, phosphorous, potassium and calcium of high yield soils were lower than those of low yield, while the available silica content was higher in the former. 3. The yield increased with nitrogen application up to 22.4kg/10a and thereafter it decreased. These phenomena were supposed to be not be decrease of nitrogen uptake but by lowered silica uptake. 4. Clay soil incorporation, deep plough, and inorganic constituents control such as Ca, Mg, and $Sio_2$ were effective as soil improvement praitices. It was appeared that increases of silica content and Ca/Mg ratio were important to increase nitrogen effects. 5. For the correlation between yield and yield components, it was high between yield and panicle in low nitrogen level and so was it between grain yield and ripening rate in high nitrogen. 6. In the urea and super granule urea application plot, recovery rate of nitrogen by plant and soil was high and yield was remarkable high. 7. Regardless of fertilizer types such as ammonium sulfate and urea, the residual nitrogen was about 4kg/10a in both plots of 5.8 and 11.6kg/10a. N applied. 8. The potassium application to soil enhanced the nitrogen efficiency. It was more effective in low potassium soil. 9. Optimum pH value for gel formation in the 4% sodium silicate solution was approximately 6.6. 10. It was suggested that silica could affect to rice plant growth as the inorganic and organic chemical components.

• Korean Journal of Agricultural Science
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• v.9 no.2
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• pp.484-493
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• 1982

This study was conducted to clarify the effects of daminozide (butanedioic acid mono-(2,2 - dimethylhydrazide)) sprayed 2 days be fore harvest and floral preservative solutions on longevity, quality and ethylene production of 'Georgia' cut lily for prolonging vase life and improving quality of cut lily flowers. And also the relation between ethylene production and flower senescence of cut lily was studied. 1. Lilies held in silver nitrate ($AgNO_3$) at 25 and 50 ppm were increased in solution uptake, fresh weight, and flower longevity. The solution of 2.5% sucrose+50 ppm $AgNO_3$+200 ppm aluminum sulfate+10 ppm 6-benzylamino purine prolonged vase life and improved quality of cut lily flowers. 2. Lilies sprayed with 500 ppm daminozide 2 days be fore harvest and then held in the preservative solution (5% sucrose+50 ppm $AgNO_3$+150ppm 8-hydroxyquinoline) after harvest were significantly increased in fresh weight and vase life as compared with non-sprayed (control) flowers. 3. Ethylene production from cut lily was increased by ethephon ((2-chloroethyl) phosphonic acid) treatment. The flowers producing a lot of ethylene, however, were senesced slowly instead of rapid wilting. 4. The preservative solution markedly reduced ethylene production of cut lily but prolonged vase life for only a few days. 5. These results suggest that ethylene be one of the most important factors promoting flower senescence of cut lily, but it be very difficult to prolong vase life remarkably by only inhibition of ethylene production in cut lily.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.790-795
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• 2010

This experiment was conducted to clarify the effects of cycloheximide and holding solution on vase life of cut 'Blue Magic' iris. The vase life of iris flowers held in 3% sucrose (S) + $100mg{\cdot}L^{-1}$ hydroxy quinoline sulfate (HQS) + $50mg{\cdot}L^{-1}$ $AgNO_3$ + $100mg{\cdot}L^{-1}$ Benzylaminopurine (BA), 3% S + $100mg{\cdot}L^{-1}$ HQS + $10{\mu}M$ cycloheximide (CHI), or 3% S + $100mg{\cdot}L^{-1}$ HQS + $50{\mu}M$ CHI were much longer than those held in distilled water. Squeeze stem phenomenon that showed at a holding solution containing $200mg{\cdot}L^{-1}$ HQS disappeared at a holding solution containing $100mg{\cdot}L^{-1}$ HQS. The holding solution containing 3% S + $100mg{\cdot}L^{-1}$ HQS + $50mg{\cdot}L^{-1}$ $AgNO_3$ + $100mg{\cdot}L^{-1}$ BA extended the most effective treatments on vase life, fresh weight, water balance, and flowering of cut iris flowers. However, the holding solution containing 3% S + $100mg{\cdot}L^{-1}$ HQS + $10{\mu}M$ CHI and 3% S + $100mg{\cdot}L^{-1}$ HQS + $50{\mu}M$ CHI was not effective in solution uptake or transpiration, but did result in high water balance. Iris flowers treated with CHI at the half-open flower stage showed increases in ornamental value, such as full flower opening and extended vase life. To improve flower quality and prolonging vase life of cut iris flowers, a holding solution containing $50{\mu}M$ CHI can be used continuously from the half-open stage.

• Applied Biological Chemistry
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• v.29 no.1
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• pp.62-72
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• 1986

At present, the definition and chemical analysis method of available soil phosphorus for plants have not been standardized because of the complexity of crop and soil characteristics in Korea and many analysis methods have been suggested with different extraction conditions. Suitable analytical method of available soil P should be established by the trial of various methods based on crop nutrition and soil conditions. To establish the most suitable analysis method of available soiIP, a pot experiment with young maize was conducted over 44 different upland soils collected over the land of Korea. The amount of uptaken P by the plant was determined by ten different chemical methods for the available soil P. The results obtained were as follows: 1. Total phosphorus content in the sample soils ranged ranged $533{\sim}4917\;ppm$, and showed significant positive correlation with the content of organic matter. 2. The P content was relatively low in the acid sulfate soil and very high in the volcanic ash soil although both types of soil contained high level of orgic matter. 3. The amount of extractable P determined by ten different methods were varied more or less, and the ratios of the extractable P to the total soil P were in the range of $1{\sim}48%$. 4. The relative values to the amount of extractable soil P by different methods were in the order of $H_2O(5\;min.)\;1.0\;<\;H_2O(60min.)\;2.27\;<\;NH_4HCO_3\;5.57\;<\;NaHCO_3\;7.42\;<\;Double\;lactate\;9.71\;<\;Bray\;No.1\;12.53\;<\;Lancaster\;17.63\;<\;Nelson\;25.96\;<\;AcOH\;27.6\;<\;CAL-method\;50.27$ 5. The amount of extractable P determined by all of applied methods was very low in acid sulfate soil, volcanic ash soil and coarse textured soil. 6. Soil pH and total soil P generally showed significant positive correlation with the chemically extracted P, and soil organic matter was negatively correlated with the determined by Nelson-and CAL-method. Olsen method which showed significant correlation with exchangeable calcium seemed to be recommendable for calcareous soils. 7. Total amount of uptaken P by Young maize through continuos twice cropping was 4.05% of total soil P in average, and the uptake in the second cropping was twice as much as that of the first cropping. 8. Three determination methods, i.e. Soltanpour-, Double lactate and Bray No. 1-method seemed to be more suitable than Lancaster method which is widely practiced at present in Korea. However, further study should be carried out with other crops and soils to most adequate chemical method for determination of available soil P.