• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.122-128
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• 1999

Three rice cultivars, Namweonbyeo (early maturing), Hwaseongbyeo (medium maturing) and Dongjinbyeo (medium-late maturing) were trans-planted with 3 different seedling ages to investigate their growth habits and to improve the cultural method in paddy fields in the southern plain area of the Honam region in 1993. The 10-day old seedlings had more vigorous elongation of plant height and higher tillering ability but lower effective tiller rate, when compared with 35-day or 40-day old seedlings. Leaf area index and top dry weight were lower in 10-day old seedlings up to 40 days after transplanting but thereafter, were not different among seedlings ages. CGR was later in 10-day old seedlings, up to 30 days after transplanting, but in 30 to 40 days after transplanting, it was reversed. RGR was the highest in infant seedlings to 40 days after trans-planting, while in 50 days after transplanting, it was reversed. Panicle number and spikelet number per square meter were the highest in 40-day old seedlings, next highest in 35-day old seedlings and the lowest and in adult seedlings up to 40 days after transplanting, while spikelet number per panicle was vice versa. Milled rice yield did not vary significantly by seedling ages, but among the varieties, it was less in Hwaseongbyeo compared with Naweonbyeo and Dongjnbyeo.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.957-966
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• 1996

An attempt was made to measure the availability of waste heat, released from the cooling system of a small engine, which can be utilized for grain drying. An engine powered flat-bed rough rice dryer was constructed and the performance of the dryer with available engine-waste heat was analyzed for 10 , 20, 30 and 40 cm rough rice bulk depths with a constant dryer base area of 0.81$m^2$/min. The waste heat was sufficient to increase the drying air temperature 7 to 12$^{\circ}C$ at an air flow rate of 8.8 to 5.7㎥/min, while the average ambient temperature and relative humidity were 24$^{\circ}C$ and 70%. The minimum energy requirement was 3.26 MJ/kg of water removed in drying a 40 cm deep grain bed in 14h. A forty to fifty centimeter deep grained seems to be optimum in order to avoid over-drying in the top layers. On the basis of minimum energy requirement (3.26 MJ/kg ) , an estimation was made that the waste heat harvest from an engine of a power range of 1 to 10.5PS can dry about 0.1 to 1 metric on of rough rice from 23% to 15% m.c. (w.b) in 12 h at an average ambient temperature and relative humidity of $25^{\circ}C$ and 80%, respectively. The engine-waste heated grain dryer can be used in the rural areas of non industrialized countries where electricity is not available.

• Korean Journal Plant Pathology
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• v.1 no.3
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• pp.169-172
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• 1985

Natural sclerotia of Rhizoctonia solani causing rice sheath blight were inoculated at 10 day intervals from June 15 to July 15 in paddy field, Icheon, Korea. Percentage of infected stems, top lesion height and percentage of. lesion height vs. plant height were higher in the early inoculated plots than in the late inoculated ones. However, rio significant differences among inoculation dates of sclerotia were found on the basis of degree of damage at maturing stage and rice yield. These results suggest that the time of initial symptom appearance under the same inoculum potential may not affect the damage of rice plants by the fungus.

• Journal of the Korean Society of Food Culture
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• v.11 no.4
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• pp.431-438
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• 1996

The dietary intake of nutritional elements by Koreans as determined by the Ministry of Health and Welfare's National Nutrition Survey have been reported for $1969{\sim}1993$. But these data were based on not dish but food. Therefore, the purpose of this study was to compare dish sources of energy and macronutrients (carbohydrate, fat, protein) in the diets of three area (large city, small city and rural). Dish sources were evaluated from two-day record obtained in the secondary analysis of the 1993 Korean National Nutrition Survey. The result, large city and small city had higher fat and protein intake than did rural. Otherwise, carbohydrate intake among rural was higher than those among large and small city (p<0.05). The primary dish source of energy and macronutrients was cooked rice for all area. The percentage of cooked rice in daily carbohydrate intake was 52.64% for nationwide, 48.40% for large city, 50.52% for small city, 61.79% for rural. The cumulative percent of top 10 dish sources to carbohydrate for large city, small city, rural were 78.02%, 81.16%, 85.69%, respectively. These was higher than cumulative percent of other macronutrients. The milk as good protein source ranked 3 for large city, 6 for small city, 22 for rural. The major dish sources to fat were cooked rice and pork that prepared by various cooking way. These results show that the major dish sources of energy and macronutrients were cooked rice based of Korea traditional consumption pattern. The most of nutrient intake consumed some dishes for all area. The dish consumption pattern was generally similar between large and small city. But rural was different from other area. Threfore, nutrition educations and interventions should be targeted to each area and should be attended with studies that comparision of dish sources to nutritional elements by specific age-sex groups.

• Korean Journal of Environmental Agriculture
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• v.37 no.1
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• pp.15-20
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• 2018

BACKGROUND: The global mean surface temperature change for the period of 2016~2035 relative to 1986~2005 is similar for the four representative concentration pathway (RCP)'s and will likely be in the range of $0.3^{\circ}C$ to $0.7^{\circ}C$. Climate change inducing higher temperature could affect not only crop growth and yield, but also dynamics of carbon in paddy field. METHODS AND RESULTS: This study was conducted to evaluate the effect of elevated temperature on the carbon dynamics in paddy soil and rice growth. In order to control the elevated temperatures, the experiments were set up as the small scale rectangular open top chambers (OTCs) of $1m(width){\times}1m(depth){\times}1m(height)$ (Type 1), $1 m(W){\times}1m(D){\times}1.2m(H)$ (Type 2), and $1m(W){\times}1m(D){\times}1.4m(H)$ (Type 3). The average temperatures of Type 1, Type 2, and Type 3 from July 15 to October 30 were higher than the ambient temperatures at $0.4^{\circ}C$, $0.5^{\circ}C$, and $0.9^{\circ}C$, respectively. For the experiment, Wagner's pots (1/2,000 area) were placed inside chambers. The pots were filled with loamy soil, and chemical fertilizer and organic compost were applied as recommended after soil test. The pots were flooded with agricultural water and rice (Shindongjin-byeo) was planted. It was observed that TOC (total organic carbon) of the water increased by the elevated temperatures and the trend continued until the late growth stage of the rice. Soil TOC contents were reduced by the elevated temperatures. C/N ratios of the rice plant decreased by the elevated temperature treatments. Thus, it was assumed that the elevated temperatures induced to decompose soil organic matter. Elevated temperatures significantly increased the culm length (P<0.01) and culm weight (P<0.05) of rice, but the number and weight of rice panicle did not showed significant differences. CONCLUSION: Based on the results, it was suggested that the elevated temperatures had an effect on changes of soil and water carbons under the possible future climate change environment.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.749-759
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• 2012

A field experiment was conducted to selection of ground-based remote sensor and reflectance indices to estimate rice production, estimation of suitable season for ground-based remote sensor and N top dressing fertilizer application rate in 2010. Fertilizer application was determined by "Fertilizer management standard for crops" (National Academy of Agricultural Science, 2006). Four levels of N-fertilizer were applied as 0%, 70%, 100% and 130% by base N-fertilizer application and were fertilized as 70% of basal dressing and 30% as top dressing. Rice (Oryza sativa L.) of Chucheong and Joonam (Korean cultivar) were planted on May 22, 2010 in sandy loam soil and harvested on October 6, 2010. Reflectance indices were measured 7 times from July 5 to August 23 by Crop circle-amber and red version and GreenSeeker-green and red version. Remote sensing angle from the sensor head to the canopy of rice was adjusted to $45^{\circ}$, $70^{\circ}$ and $90^{\circ}$ degree because of difference in the density of plant and the sensing angle. The reflectance indices obtained ground-based remote sensor were correlated with the biomass of rice at the early growth stage and at the harvest with $70^{\circ}$ and $90^{\circ}$ degree of sensor angle. The reflectance indices at the 52th Day After Transplanting (DAT) and the 59th DAT, critical season, were positively correlated with dry weight and nitrogen uptake. Specially NDVI at the 59th was significantly correlated with the mentioned parameters. Based on the result of this study, rNDVI by GreenSeeker on $70^{\circ}$ degree of angle at the 59th DAT in Chucheong and rNDVI by Crop Circle on $70^{\circ}$ degree of angle and gNDVI by GreenSeeker on $70^{\circ}$ degree of angle at the 59th DAT in Joonam can be useful for estimation of dry weight and nitrogen uptake. Moreover, sufficiency index estimated by reflectance index at the 59th DAT can be useful for the estimation of N-fertilizer level application and can be used as a model for N-top dressing fertilizer management.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.981-986
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• 2010

This study was carried out to investigate the effects of fertilizer and organic resource annual dressing for 30 years of Jeonbug series (silt loam) on soil properties and rice N uptake in paddy field soil. In the study field, treatments including control (NPK), NPK+rice straw, NPK+rice straw compost and nitrogen fertilization levels at 0, 100, 150, 200, 250 kg $ha^{-1}$ have been imposed for 30 years. Soil hardness and bulk density decreased from 15.7 mm and 1.381 Mg $m^{-3}$ in the control to 12.5 mm and 1.244 Mg $m^{-3}$ in NPK+rice straw compost treatment, respectively, indicating improvement of soil physical conditions such as porosity. Co-application of straw compost with NPK also result in a better chemical properties than NPK alone as it increased available phosphate (from 96 to 133 mg $kg^{-1}$), available silicate (from 81 to 116 mg $kg^{-1}$), and cation exchange capacity (from 9.8 to 11.4 $cmol_c\;kg^{-1}$). Soil organic matter concentration of top soil (0 to 7.5 cm in depth) was higher in NPK+rice straw and NPK+rice straw compost than in control. Fertilizer N uptake amount was much higher in NPK+rice straw (nitrogen fertilization level; 250 kg $ha^{-1}$) and NPK+rice straw compost (nitrogen fertilization levels; 200, 250 kg $ha^{-1}$) plots compared to the control (nitrogen fertilization level; 100 kg $ha^{-1}$) plot. Nitrogen use efficiency was showed significantly high in the NPK+rice straw compost (nitrogen fertilization levels; 100, 150 kg $ha^{-1}$) plot compared to the control (nitrogen fertilization level; 100 kg $ha^{-1}$) plot. Therefore, it was suggested that application of organic inputs is helpful in improving soil fertility and physical conditions and thus in N uptake.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.4
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• pp.329-337
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• 2010

Radiotracer experiments were performed over two years using pot cultures in a greenhouse to investigate soil-torice seeds transfer factors of radioiodine and technetium for paddy fields around the radioactive-waste disposal site in Gyeongju. Before transplanting rice seedlings, the top about 20 cm soils were thoroughly mixed with $^{125}I$ (2007) and $^{99}Tc$ (2008), and the pots were irrigated to simulate flooded rice fields. Transfer factors were determined as the ratios of the radionuclide concentrations in dry rice seeds (brown rice) to those in dry soils. Transfer factors of radioiodine and technetium were in the ranges of $1.1{\times}10^{-3}{\sim}6.4{\times}10^{-3}$ (three soils) and $5.4{\times}10^{-4}{\sim}2.5{\times}10^{-3}$ (four soils), respectively, for different soils. It seems that the differences in the clay content among soils played a more important role for such variations than those in the organic matter content and pH. As the representative values of radioiodine and technetium transfer factors for rice seeds, $2.9{\times}10^{-3}$ and $1.1{\times}10^{-3}$, respectively, were proposed. In order to obtain more highly representative values in the future, investigations for the sites of interest need to be carried out continuously.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.3
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• pp.259-265
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• 1998

A field experiment was conducted to investigate changes of $NH_4-N$, N uptake, N use efficiency and rice yield by the Latex coated urea(LCU) application on wet-seeding rice from 1994 to 1997. Nitrogen deficiency symptom appeared when LCU was applied as basal dressing continuously until the ripening stage during normal temperature year, but was completed at heading stage during year at high temperature. Percentage recovery of fertilizer N was higher in LCU than in urea but decreased in high temperature. Turn over of N applied as LCU to grain increased more during years high temperature than the normal year. Rice yield with LCU treatment compared to conventional treatment was similar during the normal year but decreased by 6% during year of high temperature. Top dressing of urea at panicle initiation stage in addition to basal dressing of LCU increased rice yield to 12%.

• Journal of Mushroom
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• v.13 no.3
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• pp.250-255
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• 2015

In this study spent mushroom substrate has ingredient raising rice bed soil. spent mushroom substrates are organic content is 60.72% were nitrogen - phosphoric acid - potassium is 1.39 - 0.89 - 0.81% of the chemical characteristics determine. Post-harvested mushroom substrates of the stabilization process, the temperature of the 20 days time progress in the pH of the rise and fall of temperature down were germination index also 77, as identified, Spent mushroom substrate bed soil for raising rice Ingredient to take advantage of the 20 days or more stabilization process needed to be investigated. Rice seed germination characteristic is in the common bed soil for raising rice ingredients manufactured control group and the comparison in spent mushroom substrate is 10% or less of a mixed experimental population of the germination rate is 82% was more than average days to germination and germination energy, even a statistical significant difference is or control group than good level was ok. Growth initial also spent mushroom substrate is 10% or less of a mixed experimental population of shoot dry matter (top) and grave less than control group higher as confirmed spent mushroom substrates are bed soil for raising rice ingredients are likely to take advantage of the high, as was the judge.