• Korean Journal of Organic Agriculture
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• v.18 no.1
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• pp.75-82
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• 2010

The purpose of this study is to investigate an occurrence rate of rice stripe virus disease under different rice transplanting time and different rice cultivars. After final harvest, the yield of rice infected by rice stripe virus was obtained on Wangchal cultivar compared to uninfected rice. The results obtained as following: 1) Yield of rice infected by rice stripe virus was decreased by 64% with reduction of culm length, pancile length, number of spike, number of spikelet, and grain filling compared to uninfected rice, 2) An occurrence rate of rice stripe virus disease under different rice planting season was high as order of May 30 > June 15 > July 1. In additional, to reduce a rice stripe virus disease on higher disease occurrence region and susceptible cultivars, rice planting season will be accepted on and after June 15, and 3) Eighteen cultivars were resistance cultivars such as Hwayeongbyeo, Onnuri, Ilmibyeo, Nampyongbyeo, Dongjin2ho, Hopumbyeo, Hwangkeumnuri, Malgeumi, Saenuri, Pungmi1ho, Haechanmulgyeo, Hwangkeumnodeul, Chilbobyeo, Dongjinbyeo, Younganbyeo, Junambyeo, Samkwangbyeo, and Nakdongbyeo. Twenty-one cultivars were susceptible cultivars such as Odaebyeo, Unkwangbyeo, Shinungbong1ho, Manabyeo, Hopyongbyeo, Borami, Damibyeo, Hwangchalbyeo, Sulgengbyeo, Nongrim6ho, Sasanishigi, Yunishigari, Chungmubyeo, Dongjin1ho, Huknambyeo, Guromy, Shanghehanghulna, Heukchalbyeo, Heukhwangbyeo, and Aranghwangchalbyeo.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.4
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• pp.554-566
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• 2018

The rice husk contains nutrients which can be easily utilized by microorganisms, and also has a water retaining ability, which played a crucial part in enabling it to become a biofilter media. In this study, we evaluated the applicability of rice husk pellet bio-scrubber as a microbiological carrier. The pelletization experiment of rice husk as a biological media was performed using PVA and EVA binder. Also, the feasibility tests of rice husk as a biological media for odor removal were carried out in order to know whether rice-husk contains useful components as a media for microbiological growth or not. Lastly, a combined test for odor gas absorption and biological oxidation was conducted using a lab scale bio-filter set-up packed with rice-husk pellets as wet-scrubber. The major components of the rice husk were carbon, hydrogen, nitrogen, and oxygen, while carbon acted as the main ingredient which comprised up to 23.00%. The C : N : P ratio was calculated as 45 : 1 : 2. Oxygen uptake rate, yield and decay rate of the rice husk eluent was calculated to be $0.0049mgO_2/L/sec$, 0.24 mgSS/mgCOD and 0.004 respectively. The most stable form of rice husk pellets was produced when the weight of the rice husk, EVAc, PVAc, and distilled water was 10 : 2 : 0.2 : 10. The prepared rice husk pellets had an apparent density of 368 g/L and a porosity of 59.00% upon filling. Dry rice husks showed high adsorption capacity for ammonia gas but low adsorption capacity for hydrogen sulfide. The bio-filter odor removal column filled with rice husk pellets showed more than 99.50% removal efficiency for NH3 and H2S gas. Through the analysis of circulation water, the prime removal mechanism is assumed to be the dissolution by water, microbial nitrification, and sulfation. Finally, it was confirmed that the microorganisms could survive well on the rice husk pellets, which provided them a stable supply of nutrients for their activity in this long-term experiment. This adequate supply of nutrients from the rice husk enabled high removal efficiency by the microorganisms.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.2
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• pp.75-80
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• 2001

This study was conducted to identify the optimum proper nitrogen (N) application rate for tillering in ridge direct seeding on dry paddy of rice culture. During 1998, a series of experiments was carried out at paddy field (Chonbuk series) of the National Honam Agricultural Experiment Station, RDA using Dongjinbyeo. Leaf area index and top dry weight increased with higher N levels, especially in the 100 kg/ha seeding rate compared with the 60 kg/ha seeding rate. N use efficiency increased at increased by 50~75% of the N topdressing rate at tillering. Heading date, ripened grain rate, and 1,000-grain weight of brown rice did not vary among the rate of topdressing for tillering and seeding rates. The highest grain number per unit area was at the level of increased by 75% in N topdressing at tillering stage. Milled rice yield increased 5% at the 60 kg/ha seeding rate and increased 16~17% at the 100 kg/ha seeding rate at increased by 50~75% of topdressing N compared with 48 kg/ha topdressed N of 60 kg/ha seeding rate.

• Journal of Environmental Science International
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• v.31 no.5
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• pp.413-422
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• 2022

To identify rice (Oryza sativa L.) cultivars suitable for Italian ryegrass (Lolium multiflorum Lam.)-rice double cropping systems, we investigated the yield and grain quality of four different midseason maturing rice cultivars ('Daebo', 'Haepum', 'Haiami', and 'Samdeog') and four midseason-to-late maturing rice cultivars ('Hyunpoom', 'Saeilmi', 'Saenuri', and 'Samkwang') in single rice cropping and Italian ryegrass-rice double cropping systems in paddy fields of Miryang, South Korea. We found that organic matter and available P₂O₅ content slightly decreased, whereas Na content increased, in the soil where Italian ryegrass was cultivated during winter compared to that in the soil that remained fallow during winter. The pH, electrical conductivity, organic matter, and contents of K⁺, Ca²⁺, Mg²⁺, and Na⁺ decreased, whereas the available P₂O₅ content slightly increased, in the soil where rice was harvested in both single and double cropping systems. However, compared to the optimum soil conditions for rice cultivation, available P₂O₅ and K⁺ content were high and Mg²⁺ content was low in both single and double cropping systems. At the heading stage, the culm length and leaf color slightly increased in most of the rice cultivars, whereas the panicle length and number slightly decreased, in the double cropped system. After harvesting, spikelet number and milled rice yield did not show a significant difference between single and double cropping systems. However, the ripened grain rate and weight per thousand grains increased slightly in the 'Saeilmi' and 'Samkwang' cultivars but remained either stable or slightly low in other cultivars in the double cropping system. The milled rice yield was high (> 500 kg/10a) in 'Daebo' and 'Haepum' among midseason maturing rice cultivars, and in 'Saeilmi' and 'Saenuri' among midseason-to-late maturing rice cultivars, in both single and double cropping systems. The head rice rate was high in midseason maturing rice cultivars in the double cropping systems, reaching > 70% in 'Haepum' and 'Haiami' cultivars, whereas it decreased in most midseason-to-late maturing rice cultivars (excluding 'Samkwang' cultivar), in double cropping systems. Particularly, it exceeded > 70% in the 'Saenuri' cultivar in both single and double cropping systems. The protein content in milled rice increased, whereas the amylose content either remained stable or slightly increased, in double cropping systems. The Toyo taste value decreased in all midseason-to-late maturing rice cultivars and slightly increased in the 'Daebo' and 'Haiami' cultivars among midseason maturing rice cultivars in double cropping systems. However, Toyo taste values in the 'Haepum', 'Haiami', and 'Saenuri' cultivars exceeding > 80% in both single and double cropping systems. Therefore, we recommend 'Haepum', 'Haiami', and 'Saenuri' cultivars as candidates for Italian ryegrass-rice double cropping systems due to high yield, head rice rate, and Toyo taste value.

• The Korean Journal of Food And Nutrition
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• v.12 no.2
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• pp.142-149
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• 1999

Moisture absorption rate of rice according to the soaking time was higher at $25^{\circ}C$ than 4$^{\circ}C$ and the op-timum soaking time was 1hr at $25^{\circ}C$. When the ratios of added water for rice cooking were 1.3 in an elec-tric cooker and pressure cooker and 1.7 in an Dookbaeki sensory an mechanically evaluation of cooked rice were highly evaluated. The total number of peak on gas chromatography profile were 89 in an press-ure cooker 56 in an electric cooker and 83 in an Dookbaeki and major volatile compounds of cooked rice were aliphatic hydrocarbons cyclic hydrocarbons aromatic hydrocarbons aldehydes alcohols ketones and thiourea. Furan that is in sweety was not detected in volatile components of cooked rice of electric cooker.

• Journal of the East Asian Society of Dietary Life
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• v.13 no.1
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• pp.1-8
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• 2003

The purpose of this study was to investigate the university students' recognition and preference of Korean rice cakes. Self administered questionnaires were collected from 302 students in Incheon area. Statistical data analysis was completed using a SPSS 10.0 program. The recognition of Korean rice cake was generally high: Injeolmi, Garaeddeok, Bakseolgi, Songpyun, Patsirooddeok, Bindaeddeok, Yaksik Julpyun, Gyungdan, Moojigaeddeok were high1y recognized, but Gaesungjooak, Sugyibyung, Seunggeomchopyun poorly recognized by university students. The most common consumption frequency rate of students was once or twice a month (Male 31.9%; Female 41.6%). Most students ate rice cakes as snack with water, Kimchi, fruits, beverage(Cola, Cider) and Korean traditional beverage(Sujunggwa, Sighye). The sales possibility of Korean rice cake at university canteens was dependent on the characteristics different from those of rice cafes itself, for example,. nutritional labelling, mass, atmosphere and package, etc.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.3
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• pp.266-272
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• 2015

High temperature impairs rice grain yield and quality. To understand the effect of high temperature on leaf physiological activity and grain filling, two cultivars of rice that Dongan and Ilpum were exposed to high temperature during ripening stage. Grain filling rate, perfect grain ratio and grain weight of high temperature ($27^{\circ}C{\pm}4^{\circ}C$) treated both rice cultivars were decreased than those of control temperature ($22^{\circ}C{\pm}4^{\circ}C$) treated. The reduction rates of grain filling ratio, perfect grain ratio and grain weight of high temperature treated to control treated rice were higher in Ilpum than Dongan. Chlorophyll contents of rice leaves under high temperature at early ripening stage were higher than those of control temperature, but those were slowly decreased with no difference between temperature treatment since at mid ripening stage. Although chlorophyll a/b ratio under high temperature was decreased from heading to 15 days after heading, that was gradually increased since 15 days after heading. Protein concentrations of rice leaves for ripening stage was a similar pattern with chlorophyll changes. The rate of photosynthesis at 14 days after heading under high temperature was higher than those of control temperature, but there was no difference at those of 7 and 34 days after heading between two temperature treatment. Free sugars under high temperature treated leaves were lower than control temperature. Consequently, these results exhibit that high temperature accelerate leaf physiological activity as chlorophyll synthesis and photosynthesis rate unlike the deterioration of grain filling.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.1
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• pp.45-54
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• 1994

Cooking characteristics of ninety five non-glutinous and twenty six glutinous varieties were checked for understanding the varietal variation and interrelationship between the cooking and physicochemical properties of rice grain. The greatest variation in non-glutinous and glutinous rice varieties was observed in iodine blue value and the next large variation was recognized in amount of soluble solid in cooking water. Average values of volume expansion rate, iodine blue value and amounts of soluble solid in cooking water were different among domestic-bred japonica, Korean local and foreign rice varieties. Korean-bred japonica rice cultivars can be classified into several groups having same cooking quality such as <Jangan.·Seoan>, <Jinmi·Ilpum· Daeseong>, <Seohae·Namwon·Yeongduk>, <Chucheong·Bongkwang>, <Odae·Keumo> and <Hwacheong·Donghae·Palgong> by the distribution on the plane of 1st and 2nd principal components contracted from four cooking characteristics. Glutinous rice cultivars can be grouped into several different cooking quality types such as <Nonglimna 1·Suwon 357·Jodo·Inbujinado>, <Sangnambatbyeo·Jeokdo>, <Mujudo·Daigol-mochi>, <Daegoldo·Jindo>, <Jinbuchal·Colored Daegoldo>, <Shinseonchal·Hung-Tsan> and <Agudo·Irakdo> by the same analysis. Positive correlation was found between volume expansion rate and water absorption rate at 21℃. Iodine blue value was correlated negatively with amounts of soluble solid, and positively with amylose content in non-glutinous rices. In glutinous rices volume expansion rate showed positive relationship with iodine blue value, amounts of soluble solid and gel consistency. Iodine blue value was also positively correlated with alkali digestion value in glutinous rice.

• Journal of Aquaculture
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• v.11 no.2
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• pp.125-132
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• 1998

The results of experimental culture for Koran mitten crab, Eriocheir japonicus at different outdoor culture methods such as rice field, pond, and vinyl house from July 21, 1994 to October 23, 1995 were summaried as fellows. 1. The water temperature was 2${\circ}C$~32${\circ}C$ during the culture periods from July 21, 1994 to October 23, 1995, and it ranged from 15${\circ}C$ to 30${\circ}C$ during the terms showing the intake habit of feed with these temperature maintained for 281 days of 460days of the total cultur periods. 2. The gain weight of Korean mitten crabs was 1,711.3g at the rice field, and 1,565.4g at the pond, and 1.220.0g at the vinyl house. The survial rate was 22.7% at the pond, and 18.7% at the rice field, and 18.3% at the vinyl house with the average survial rate of 19.9%. The daily growth rate of cauapace width was 0.64% at the rice field, and 0.61% at the pond, and 0.59% at the vinyl house. And the gain weight and the daily growth rate were the best at the rice field. 3. When the culture was finished, the frequency of carapace width of 4.0~4.9cm was 57.1% at the rice field, and 33.3% at the vinyl house. Therefore, culture at the rice field for the cultur of mitten card was considered to be the best outdoor culture method from the point of view in the fast growth and polyculture feasibility with paddy rice.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.490-496
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• 1996

This study was undertaken in order to elucidate the elimination of phenthoate residues by washing and cooking processes of rice which if the most important food crop in Korea. When contaminated rice was washed with distilled water three times, the removal rate of total phenthoate was 51%. The removal rate in the successive washings was 37.3% (wash filtrate 7.8%, wash sediment 29.5%) in the first, 14.3% (wash filtrate 6.2%, wash sediment 8.1%) in the second and 8.9% (wash filtrate 5.8%, wash sediment 3.1%) in the third washings. More than half of the residue was removed by the first washing and most residues were found in the sediment rather than in the filtrate of the rice washings. The residue rate of phenthoate after cooking by an electric rice cooker was 41%, indicating that the removal rate after cooking was 59%, because phenthoate is thermally stable at the cooking temperature. In conclusion, phenthoate residues contaminated in rice grains are grcatly removed in the washing process and it is desirable to wash the grains before cooking in order to decrease the hazards from pesticide residues such as phenthoate. Reduction factor of phenthoate in rice cooking is proposed to be 0.4.