• Korean Journal of Plant Resources
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• v.19 no.4
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• pp.497-508
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• 2006

This study was conducted to obtain the basic information on rice cold damage and relationship to be connected with cold tolerance. The 20 rice varieties were screened to cold tolerance under low water temperature condition. The water gradient were controlled to $17^{\circ}C$ at the inlet and $21^{\circ}C$ at outlet of screening field. In the relationship between cold water irrigation and growth of rice varieties, effect on medium maturing cultivars were higher than early maturing cultivars. In relationship of shorting of culm length and panicle exsertion, culm length and panicle exsertion showed positive correlation. Yield of cultivars and culm length and percent of fertile grain showed positive correlation. However, heading date presented negative correlation. In the early maturing cultivars, except 'Kumobyeo', all cultivars range of discoloration value (1-3) was resistant. In the medium maturing cultivars, 'Donghaebyeo' was resistant in both the seedling stage whereas 'Hwajinbyeo' was resistant only in tiller stage. Cold water irrigation reduced spikelet number per panicle and percent of filled grain. Unhulled rice yield was increased according to water temperature gradient from inlet to outlet. There was varietal differences in head rice recovery by cold water treatment.

• Journal of Food Hygiene and Safety
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• v.4 no.3
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• pp.165-170
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• 1989

To isolate the aflatoxin producing strains from agricultural products in Youngnam districts, rice(59), meju(30), corn(32), barley(58), soil(33), peanut(30), soybean(45), and unhulled barley(60) were collected from markets or homes. From 342 sample sources, 280 strains of Aspergillus spp. were isolated. As a result of screening by TLC, 29 strains expressed fluorescent spot and four strains have a same Rf value of standard aflatoxins, and the percentage of contamination from aflatoxin producing strains was 1.3%, and those strains were estimated as Aspergillus flavus group by the examine of characteristics and morphology.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.4
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• pp.174-178
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• 1982

These studies were conducted to investigate the relation among soil morphological characteristics, soil group for management, suitability class and rice yield on nonfertilizer for four years (1976 to 1979) in paddy soils. The obtained results were summarized as follow ; 1. The best soil characteristics were that drainage was imperfectly drained, taxture family was fine loamy, and available soil depth was more than 100cm. 2. The mean of relative unhulled rice yield per 10a for highly productive, non-paddification, sandy, poorly drained and saline soil were 525, 492, 484, 474 and 263kg, respectively. 3. Those for 1st, 2nd, 3rd and 4th suitability class were 532, 510, 464 and 349kg, respectively.

• Applied Biological Chemistry
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• v.8
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• pp.61-63
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• 1967

1. This experiment was carried out, as part of virgin soil application project conducted by Chung Buk Province in 1966, to determine the effect of application of field red soil to rice paddy for enhancing the fertility of sterile paddy soil. 2. This applied field soil from the mountain near Chung Buk College contains 1.31% of active iron. 3. The plots of 15,000 kg, 22,500 kg, 30,000 kg, and 7,500 kg had increased yields of 11%, 9%, 8%, and 6% in weight of unhulled rice, respectively. 4. Although any significance was not recognized among the levels of treatment at 5% level in F test, the plot of 15,000 kg was highly significant, and those of 22,500 kg and 30,000 kg significant, where as that of 7,500 kg was non-significant compared with the control. 5. It seems that the most effective amount of application is 15,000 kg/10 a in this experiment. 6. The infection rate of rice blast and neck rot decreased with the increased amount of application.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1157-1163
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• 2012

This study was performed a comparative life cycle assessment (LCA) among three rice production systems in order to analyze the difference of greenhouse gases (GHGs) emissions and environment impacts. Its life cycle inventory (LCI) database (DB) was established using data obtained from interview with conventional, without agricultural chemical and organic farming at Gunsan and Iksan, Jeonbuk province in 2011. According to the result of LCI analysis, $CO_2$ was mostly emitted from fertilizer production process and rice cropping phase. $CH_4$ and $N_2O$ were almost emitted from rice cultivation phase. The value of carbon footprint to produce 1 kg rice (unhulled) on conventional rice production system was 1.01E+00 kg $CO_2$-eq. $kg^{-1}$ and it was the highest value among three rice production systems. The value of carbon footprints on without agricultural chemical and organic rice production systems were 5.37E-01 $CO_2$-eq. $kg^{-1}$ and 6.58E-01 $CO_2$-eq. $kg^{-1}$, respectively. Without agricultural chemical rice production system whose input amount was the smallest had the lowest value of carbon footprint. Although the yield of rice from organic farming was the lowest, its value of carbon footprint less than that of conventional farming. Because there is no compound fertilizer inputs in organic farming. Compound fertilizer production and methane emission during rice cultivation were the main factor to GHGs emission in conventional and without agricultural chemical rice production systems. In organic rice production system, the main factors to GHGs emission were using fossil fuel on machine operation and methane emission from rice paddy field.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.148-155
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• 1985

This study was conducted to find out the effect of rice straw and wollastonite applied to the paddy soil on the growth and yield of the rice plant. The soil was treated with two level of straw 0 and 88gr per pot, of which respectively combined with 4 levels of wollastonite, 0 (Avail $SiO_2$: 50 ppm), 27 (Avail. $SiO_2$: 150 ppm), 85 (Avail. $SiO_2$: 300 ppm) and 185 (Avail. $SiO_2$: 450 ppm) gr per pot. The results for two years experiment were as follows. 1. Application of rice straw and wollastonite, respectively, suppressed the growth of the plant at early stage. As a consequence the hight and number of tiller of the plant were comparatively smaller, but the combined effect of rice straw and wollastonite treatment on the plant growth appeared after the maximum tillering stage and got a better yield as compared with single treatment of rice straw or wollastonite. 2. At the pot of no rice straw and 27 gr wollastonite treatment, and also pot of rice straw and 85gr (in the year of 1983 experiment) as well as 135gr wollastonite treatment (in the year 1984 experiment), the yield of total dry material and unhulled rice of the plant were respectively higher than other pots in different treatment and the plant height showed similar tentency. Application of rice straw in paddy soil appeared to require more wollastonite for growth of the rice plant as compared with no rice straw application. 3. The highest yield was obtained at the pot with rice straw and 85gr of wollastonite treatment in the year of 1983 experiment, were its yield had 25% increament as compared with the control pot, while being studied for residual effect of rice straw and wollastonite application in the next year, the highest yield was obtained at the pot with rice straw and 135gr wollastonite treatment, where its yield had 30% increament as compared with the control pot.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.2
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• pp.101-106
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• 1987

A pot experiment was conducted to find out the effectiveness of ammonium sulfate absorbed Zeolite on the yield of rice and the changes of some plant nutrients under the condition of two levels of water percolation. The results were as follows: 1. Unhulled rice yield was increased in the plot of the percolation of 10 mm/day than the percolation of 30 mm/day due to the increase of panicle number and ripening ratio. 2. $NH^+_4-N$, $K^+$ and $SiO_2$ concentration in soil leachates were lower in the percolation rate of 10 mm/day than in the early stage of rice growth were decreased by the application of Zeolite 1.0 T/10a. 3. Plant uptakes of K and N in the harvesting stage were more accelerated in the percolation of 10 mm/day comparing with the percolation of 30 mm/day, and the silica uptake of plant was the reverse against the case of former elements. 4. The optimum rates of Zeolite for maximum yield were about 1T/10a.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.2
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• pp.119-123
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• 2011

To use barley as a green manure crop, this study has been conducted in Suwon, Gyeonggi-do to establish the barley green manure (BGM)-rice cropping system with emphasis on soil incorporation date and BGM density. The nitrogen (N) contents of rye and barley, grass green manure crops, were 1.4~2.4% at early growth stage and decreased rapidly to 0.6~1.0% at late growth stage. The biomass of barley was 449 kg/l0a at heading stage (HS) and increased to 421 kg/10a at 10 days after heading stage (DAH), 473 kg/10a at 20 DAH. C/N ratio of BGM was the lowest 26.3 at HS. The N contents of BGM was in the range of 0.9~1.5%, the highest at HS and gradually decreased, and the output of N were 4.3-6.3 kg/10a. The total amount of nitrogen, phosphorous and potassium of BGM showed the highest level at 10 DAH. Culm length of rice was relatively longer as the BGM application time was delayed. The application of BGM into soil increased plant height of rice by 7.2~7.7 em as compared to the plants treated with commercial fertilizer at recommended rate. but panicle length of rice showed a similar tendency in both the soil-applied of BGM and commercial fertilizer. N contents of unhulled rice was the highest at HS of BGM and followed by 10 DAH of BGM and 20 DAH of BGM. This trend could also be seen in rice straw. The yield of rice in the soil-applied of BGM was 10~15% lower than in the soil-applied of commercial fertilizer. Based on this study, application of BGM made it possible to save 30~50% of application amount of nitrogen fertilizer for following crops.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.280-289
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• 2002

This study was conducted to evaluate the effects of annual application of slowle cooled slag silicate fertilizer on rice yield and soil chemical properties. Field experiment was done on the condition of fertilization of silicate fertilizer 1,500 and $2,500kg\;ha^{-1}$ to the clay loam paddy field during 26 years from 1975 to 2000. The results obtained were as follows; Rice yield of NPK+silicate fertilizer $1,500kg\;ha^{-1}$ and $2,500kg\;ha^{-1}$ were increased by 15%, 8% respectively incomparion with NPK control plot in 2000($26^{th}$ year). Changes in average rice yield for 5 years interval were continually showed increase in the treat of silicate fertilizer $1,500kg\;ha^{-1}$ compared to NPK and NPK+silicate fertilizer $2,500kg\;ha^{-1}$ treated plot. The amounts of N, $K_2O$, CaO and MgO in the treat of silicate fertilizer $1,500kg\;ha^{-1}$ were much more than those of silicate fertilizer 2,500kg treated plot, and the treat of silicate fertilizer $1,500kg\;ha^{-1}$ showed higher in nutrients availability and fertilizers use efficiency than other treated plots at harvesting stage. Amount of N, $P_2O_5$, $K_2O$ and MgO in unhulled rice grain, those of CaO, MgO and $K_2O$ in rice straw and those of $K_2O$ and $SiO_2$ in rice root were positively recognized significant relationships with grain yield. According to soil analysis after experiment in 2000, the silicate fertilizer $2,500kg\;ha^{-1}$ annually applied plot were increased especially in soil organic matter, CEC and available phosphate content in comparison with NPK+silicate fertilizer $2,500kg\;ha^{-1}$ applied plot.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.4
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• pp.391-418
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• 1983

Urea and ammonium sulfate without and with sulfur group, respectively, were compared with respect to their nutritive effects on the rice plants, Suweon 264 and Jinheung, under the nursery trial on the protected upland and lowland seedbed, the pot trials with their various combination ratios and with added sodium sulfate to urea and the trials on the paddy fields which have undergone urea and ammonium sulfate application for many years. The rice seedlings fertilized with ammonium sulfate surpassed those with urea in growth performance and nutrients absorption of the rice seedlings at nursery period. Such stimulating effect of ammonium sulfate on the growth and nutrients uptake was more remarkable under the upland nursery than under the lowland one. The pot trial with the various combination ratios of urea and ammonium sulfate revealed that the chlorophyll content in leaf blade increased with the increment of sulfate ratio in the combination and the sole application of urea caused the chlorosis of leaf which was more conspicuous in Suweon 264 than in Jinheung. Fertilized with the same active ingradient amount of nitrogen, the rice plants supplied with ammonium sulfate surpassed those with urea in the chlorophyll content consistently under the nursery, the pot and the paddy field trials. The photosynthesis of flag leaf at heading stage increased with the combination rate of ammonium sulfate in the pot trial. The sulfur applicated as supplementary element of nitrogen in the nursery, the pot and the field trials were observed to be in positive relationship to the nitrogen and potassium content, but to be in negative correlation to the calcium content. The sulfur content in the rice plants was higher at early growth stage and decreased with the advance in growth stage. The nitrogen content also showed a similiar tendency to the sulfur content, and the N/S ratio was higher at early growth stage than at later one. The N/S ratio was negatively correlated with the chlorophyll content. In the field experiment, ammonium sulfate surpassed urea in the number of productive tiller, dry matter production and unhulled rice yields, but much stimulating effect of ammonium sulfate on the grain production was shown to be less effective than that on the straw production. The nitrogen and major nutrients content in the rice straw at harvest were higher in the paddy field with long-term ammonium sulfate application than in that with long-term urea application, suggesting that the former might have greater potentiality in nutrients supply than the latter.