• 동아시아식생활학회지
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• 제22권6호
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• pp.782-794
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• 2012

The objective of this study was to determine the optimal conditions for preparation of cooked brown rice by blending brown rice, white rice and glutinous rice to improve the palatability. Formulations composed of brown rice (10~100%), white rice (0~90%) and glutinous rice (0~90%) were generated from an extreme-vertices of mixture experimental design, which showed ten experimental points for brown rice, with white rice and glutinous rice as the independent variables. The sensory evaluation, color, and texture profile analysis (TPA) of cooked brown rice and pasting characteristics of blending cereals flour were measured as response variables. Regression analysis showed that all responsible variables fit linear, quadratic or special cubic models (p<0.1), except for the cohesiveness of TPA. The goals of optimization of the blending ratio of brown rice, white rice and glutinous rice were given as appearance, flavor, texture and overall acceptability (lower: 5.50, target: 6.62). The optimal conditions were determined to be 34.55% brown rice, 42.71% white rice and 22.74% glutinous rice.

• 한국토양비료학회지
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• 제45권6호
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• pp.1187-1193
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• 2012

Water control is mainly one of the key factors that can affect nitrous oxide ($N_2O$) emissions from soils. This study was undertaken to determine the effect of intermittent drainage compared to continuous flooding (conventional water regime) on $N_2O$ emission to global warming potential (GWP) with NPK (standard cultivation practice), NPK+Straw, and PK fertilizations. Nitrous oxide emission rates were collected twice a week using a closed chamber method. With continuous flooding, nitrogen (N) application increased $N_2O$ emission by 106.6% ($0.64kg\;ha^{-1}$ in NPK) with respect to the PK treatment ($0.31kg\;ha^{-1}$), and straw addition to NPK enhanced 148.3% of seasonal $N_2O$ flux ($0.77kg\;ha^{-1}$ in NPK+Straw). Although seasonal $N_2O$ emission slightly increased by 16.1-42.9% with intermittent irrigation, its seasonal $CH_4$ emission drastically reduced at 43.5-52.8% resulting in a lower GWP at 48.9-58.5% with respect to that of continuously flooded treatments ($4.51Mg\;CO_2\;ha^{-1}$, PK; $7.60Mg\;CO_2\;ha^{-1}$, NPK; $14.55Mg\;CO_2\;ha^{-1}$, NPK+Straw). Rice yield, at similar fertilization with the continuously-flooded rice field, was not affected by intermittent irrigation. Conclusively, intermittent irrigation can be very effective and a rational soil management strategy to mitigate GWP with considering rice productivity in a temperate paddy rice field like Korea.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.319-319
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• 2017

Methane is the main greenhouse gas released from rice paddy field. Methane from paddy fields accounts for 11 % of the global total methane emission. The global warming potential (GWP) of methane is 25 times more than that of carbon dioxide on a mass basis. It is well known that most effective practice to mitigate methane in paddy is related to the water management during rice growing season and the use of organic matters. This study was conducted to investigate the effects of tillage and cultivation method on methane emission in paddy. Tillage (tillage and no-tillage) and cultivation methods (transplanting and direct seeding) were combined tillage-transplanting (T-T), tillage-wet hill seeding (T-W), tillage-dry seeding (T-D) and no-till dry seeding (NT-D) to evaluate methane mitigation efficiency. Daily methane emission was decreased on seeding treatments (T-W, T-D, NT-D) than transplanting treatment (T-T). Amount of methane emission during rice growing season is highest in T-T ($411.7CH_4\;kg\;ha^{-1}y^{-1}$) and lowest in NT-D treatment (89.7). In T-W and T-D treatments, methane emissions were significantly decreased by 36 and 51 % respectively compared with T-T. Methane emissions were highly correlated with the dry weight of whole rice plant ($R^2=0.62{\sim}0.93$). T-T treatment showed highest $R^2$ (0.93) among the four treatments. Rice grain yields did not significantly differ with the tillage and cultivation methods used. These results suggest that direct seeding practice in rice production could mitigate the methane emissions without loss in grain yield.

• 농촌지도와개발
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• 제10권1호
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• pp.103-114
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• 2003

The purpose of this study is to examine Japonica rice farming of China. Asian rice is divided into Japonica and Indica species. Japonica rice represents only less than 20% of Chinese rice output, but it can compete with Korea rice in both price and quality. The rise of income level has expanded the scale of production of Japonica rice in China. China’s adhesion to the World Trade Organization (WTO) has forced Chinese policy makers to face their obligations and responsibilities such as abolishing subsidies on agricultural exports. But being member of the WTO entry also helps China exercise and enhance its influential place in the global economy. Because of geographical proximity and the fact that Korea is ranked second among countries with which China still has a trade deficit, China may seek and plead for an opening of the protected Korean rice market to stabilize prices and prevent excess supply of Chinese rice. Though Korean rice farmers feel that prices are still low, Chinese rice remains far cheaper than Korean rice with the price gap is still on the rise. In anticipation of such fierce competition, Korea must carefully review its current policies and closely follow the evolution of rice production, marketing, and trade in China. This study also suggests some of the possible research using more recent data that should be conducted in the future.

• Journal of Biosystems Engineering
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• 제38권4호
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• pp.255-263
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• 2013

Purpose: It is not easy to drive a rice-transplanter avoiding underlapped or overlapped transplanting in paddy fields. An automated guidance system for the riding-type rice-transplanter would be necessary to operate the rice-transplanter autonomously or to assist the beginning drivers as a driving aid. Methods: A prototype of guidance system was composed of embedded computers, RTK-GPS, and a power-steering mechanism. Two Kalman filters were adopted to overcome sparse positioning data (1 Hz) from the RTK-GPS. A global Kalman filter estimated the posture of rice-transplanter every one second, and a local Kalman filter calculated the posture from every new estimation of the global Kalman filter with an interval of 200 ms. A PID controller was applied to the row-following mode control. A control method of U-turning mode was developed as well. A stepping motor with a reduction gear set was used to rotate the shaft of steering wheel. Results: Test trials for U-turning and row-following modes were done in a paddy field after some parameters have been tuned at the ground speed range of 0.3 ~ 1.2 m/s. The minimum RMS error of offset was 3.13 cm at the ground speed of 0.3 m/s while the maximum RMS error was 13.01 cm at 1.2 m/s. The offset RMS error tended to increase as the ground speed increased. The target point distance, LT also affected the system performance and PID controller parameters should be adjusted on different ground speeds. Conclusions: A target angle-based PID controller plus stationary steering angle controller made it possible for the rice-transplanter to steer autonomously by following a reference line accurately and even on U-turning mode. However, as condition in paddy fields is very complicated, the system should control the ground speed that prevents it from deviating too much due to ditch and slope.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.350-350
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• 2017

The study was conducted to evaluate differences of growth characteristics of rice cultivated in two different regions (Cheonan and Jeonju). It focused on nutritional composition and anti-nutritional factors of rice straw produced from 21 rice varieties including GM rice (Iksan 483). The range of general nutrition ingredient is that crude was 0.97 ~ 3.2 %, carbohydrate was 67.45 ~ 80.01 %, crude protein was 1.46 ~ 4.81 %, crude ash was 6.52 ~ 18.96 %, crude fiber was 25.77 ~ 40.02 %, NDF was 51.84 ~ 67.77 %, ADF was 27.11 ~ 40.44 %, calcium was 0.49 ~ 5.18 mg/g and phosphorous was 0.26 ~ 2.77 mg/g. The general nutritional contents of GM rice were included above range. The range of phytic acid of rice straws cultivated in Cheonan and Jeonju was 0 ~ 0.056 mg/ml and 0 ~ 0.059 mg/ml, respectively. The phytic acid content of GM was 0.033 mg/ml, which was in the range of the content of rice straw in Cheonan and Jeonju. The range of trypsin inhibitor of rice straws cultivated in Cheonan and Jeonju was 0.061 ~ 0.461 TIU/mg and 0 ~ 1.278 TIU/mg, respectively. The trypsin acid content of GM was 0.461 TIU/mg, which was in the range of the content of rice straw in Cheonan and Jeonju. In addition, we investigated microbial community from each soil sample by using metagenomics sequencing based on rRNA microbial diversity in order to inspect indirect changes of soil environment with cultivation of GM rice. Metagenomics analysis was carried out using soil samples cultivated with GM and non-GM rice for before transplanting, young panicle differentiation stage, heading stage, and ripening stage. Beta diversity of microbial community in both soil environments were calculated by using Bray-Curtis distance method and showed low value with an average of 0.24 (dissimilarity = 1). As a result, it was confirmed that the cultivation of GM does not give a significant effect on the change of microbial composition in soil. Therefore, Our study demonstrates that there is no difference in the composition of soil microorganism due to GM and non-GM rice.

• 한국농림기상학회지
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• 제3권1호
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• pp.55-70
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• 2001

It was unusual crop weather for 1998 and 1999 compared with normal in Korea. The consecutive days of the optimum ripening period for rice plant that had daily mean temperature 21~23$^{\circ}C$ for 40 days after flowering, increased with long anomalies in 1998~99. The air temperature during ripening period was much higher than the optimum temperature and lower sunshine hour than norm in the local adaptability tests of newly developed rice lines during those years. In response of rice cultivation to warming and cloudy weather during crop season, the yield shall be decreased. Most scientists agree that the rate of heating is accelerating and temperature change could become increasingly disruptive. Weather patterns should also become more erratic. Agrometeorologists could be analyzed yearly variations of temperature, sunshine hour and rainfall pattern focused on transient agroclimate change for last a decade. Rice agronomists could be established taking advantage of real time agricultural meteorology information system for fertilization, irrigation, pest control and harvest. Also they could be analyzed the characteristics of flowering response of the recommended and newly bred rice cultivars for suitable cropping plan such as cultural patterns and sowing or transplanting date. Rice breeders should be deeply considered introducing the characteristics of basic vegetative type of flowering response like Togil rices as prospective rice cultivars corresponding to global warming because of the rices needed higher temperature at ripening stage than japonica rices, photoperiod-sensitive and thermo-sensitive ecotypes.

• The Journal of Asian Finance, Economics and Business
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• 제9권5호
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• pp.313-324
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• 2022

We investigate the impacts of tariff, tariff-rate quota, conformity assessment, and traceability requirements set by the rice importers using panel data of 17 rice exporters exporting to 119 countries in two years 2015 and 2018, using both Ordinary least square (OLS) and Poisson pseudo maximum likelihood (PPLM) methods. Results from our gravity models strongly indicate that tariff and tariff rate quota remain significantly detrimental to the world's rice exporters because these measures place downward pressure on the rice exporters' prices and the importers' import quantity, creating barriers to market participation. Our study also provides strong evidence about the role of origin certificates in allowing rice exporters to gain access to foreign markets. Meanwhile, regulatory standards such as traceability requirements and logistical and distributional requirements imposed by the rice importers are found to be major obstacles to rice importation from less-developed countries. Our study provides insights into tariff and non-tariff barriers existing in the global rice market, which is likely to assist policymakers operating in developing countries to help shape their policies and bolster rice competitiveness.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.757-759
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• 2003

Understanding the area of the rice paddy fields is important, and suitable for it the remote sensing. SAR is effective to the monitor in Southeast Asia with the rainy season. The detection of the filled rice paddy fields by RADARSAT was tried in the north part of Bangkok Thailand, and in the Mekong river valley Cambodia, which ware the main rice production country in Southeast Asia. We get observation data by RADARSAT and fields all through a year around Bangkok. However, because the flood had occurred on the study area in 2002 observed, the detection only of the rice fields ware difficult.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2003년도 추계 학술발표회 요지
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• pp.36-41
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• 2003