• 한국작물학회지
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• 제49권5호
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• pp.363-367
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• 2004

The deep irrigation of rice plants brings about some beneficial effects such as reduced tiller production which results in the formation of bigger panicles, prevention of chilling injury, reduced weed growth, etc. The present study was carried out to examine the involvement of ethylene in the suppression of tiller production due to deep water irrigation in rice (cv. Dongjinbyeo). The ethylene production was induced in leaf sheath within 24 hours after the deep water irrigation and has increased even until 30 days after the treatment, recording 4.5-fold increase as compared to the shallow-irrigated rice plants. In the deep water irrigated rice plants, ethylene was accumulated to a high concentration in the air space of submerged leaf sheath as the irrigated water deterred the diffusion of ethylene out of the leaf sheath and ethylene biosynthesis was accelerated by the deep irrigation as well. The ethylene concentration recorded 35-fold increase in the deep-irrigated rice plants for 35 days. The tiller production was reduced significantly by the deep irrigation with water, the tiller bud, especially tertiary tiller bud differentiation being suppressed by the deepwater irrigation treatment, whereas the rice plants deep-irrigated with solutions containing $10^{-5}$ M or $10^{-6}$ M silver thiosulfate (STS), an action inhibitor of ethylene, showed the same or even higher production of tillers than those irrigated shallowly with water. This implies that the ethylene is closely linked with the suppression of tiller production due to deep water irrigation. In conclusion, ethylene, which was induced by hypoxic stress and accumulated in the leaf sheath due to submergence, played a key role in suppressing the tiller production of the deepwater irrigated rice.

• 농업과학연구
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• 제29권2호
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• pp.135-148
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• 2002

In recent years, domestic market environment of rice production is confronted with the problems of excessive production and decrease in per capita consumption, resulting in steady decline of domestic rice price. Moreover, as new trade negotiations of WTO or FTA are being forwarded, cheap price of imported rice will also make the rice production environment being worse off. One of the possible production strategies to relieve this situation could be expanding farm size, which increases market competitiveness in terms of cost-saving. Since 1990's, one of the main agricultural policies for rice production in Korea has been expanding farm size. This study aims at 1)exploring brief history of Korean government's agricultural policy for expanding farm size, 2)examining economic effect of farming size expansion, and 3)discussing major role of government to promote appropriate programs for rice-farming and producers. Main conclusion suggests that appropriate farming size should be expanded upto at least five hectares per farm, with producers' effort to reduce farming costs and continuous investments on agricultural infrastructures including irrigation systems, etc. Continuous government's investment on operation and maintenance on water facility is also one of the important factors in expanding farm size.

• 한국유기농업학회지
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• 제25권4호
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• pp.805-819
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• 2017

The study was carried out to develop a mathematical model for evaluating the effect of organic fertilizers in organic rice production systems. A function to simulate the nitrogen mineralization process in the paddy soil has been developed and integrated into ORYZA2000 crop growth model. Inorganic nitrogen in the soil was estimated by single exponential models, given temperature and C:N ratio of organic amendments. Data collected from the two-year field experiment were used to evaluate the performance of the model. The revised version of ORYZA2000 provided reasonable estimates of key variables for nitrogen dynamics and crop growth in the organic rice production systems. Coefficient of determination between the measured value and simulated value were 0.6613, 0.8938, and 0.8092, respectively for soil inorganic nitrogen, total dry matter production, and rice yield. This means that the model could be used to quantify nitrogen supplying capacity of organic fertilizers relative to chemical fertilizer. Nitrogen dynamics and rice growth simulated by the model would be useful information to make decision for organic fertilization in organic rice production systems.

• 한국작물학회지
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• 제65권1호
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• pp.22-29
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• 2020

Rice is very sensitive to high temperatures during the reproductive stage, particularly during the flowering and anthesis periods. To determine how high temperatures result in sterility during the flowering period in Korean rice cultivars, groups of 11 cultivars were subjected to different temperature regimes (24, 28, 30, and 33℃) during the flowering stage using sunlit phytotrons. At an average of 33℃, all 11 rice cultivars reached anthesis earlier than at the other temperatures. Microscopy analyses revealed significant differences in pollen germination and pollen viability in cultivars grown at 33℃ compared to those cultured at lower temperatures. At 33℃, the cultivars had significantly lower fertility rates (47% reduction) than cultivars grown at 24℃. These findings are important as rice pollination and fertility depend on the pollen viability and germination. The present study shows that rice fertility is negatively affected by excessively high temperatures.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.231-231
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• 2017

Drought limits rice production under upland condition. This study quantified the effect of rhizobacteria inoculation on rice root system developmental response to drought and its role in maintaining high soil water use, and dry matter production under drought using NSIC Rc192 (rainfed lowland rice variety). The source of inoculant was Streptomyces mutabilis, a recently isolated rhizobacteria containing plant growth promoting compounds such as ACC deaminase, indole-3-acetic acid and phosphatase (Cruz et al., 2014, 2015). In the first experiment, pre-germination inoculation of seeds with S. mutabilis significantly increased the shoot and root (radicle) length as well as root hair lengths, relative to the non-inoculated control. In the second experiment, rice plants inoculated with S. mutabilis and grown in rootbox with soil generally had greater total root length under drought regardless of the timing of inoculations, relative to the non-inoculated control. Consequently, improved root system development contributed to the increase in soil water uptake under drought and thus, dry matter production. Among inoculation treatments, one-time inoculation of S. mutabilis either at pre-germination or pre-drought stress at 14 days after sowing (DAS), had significantly greater shoot dry matter production than three-time inoculation at pre-germination, at thinning (3 DAS) and at pre-drought (14 DAS). This study demonstrated the effectiveness of rhizobacteria (S. mutabilis) containing growth promoting compounds for enhancing drought dehydration avoidance root traits and improving the growth of rice plants under drought condition.

• Animal cells and systems
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• 제8권4호
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• pp.281-288
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• 2004

The change in relationships between methane production and sulfate reduction was investigated in reclaimed rice field soils at different time points after reclamation of tidal flat in Korea. Sulfate concentrations of soils in the ca. 60-year-old and 26-year-old reclaimed rice fields were much lower than that in a natural tidal flat. During 60 d of anaerobic incubation, total methane production and sulfate consumption of the soil slurries were 7.0 ${\mu}$mol $CH_4$/g and 8.2 ${\mu}$mol $SO_4^{2-}$/g in the 60-year-old rice field, 5.6 ${\mu}$mol $CH_4$/g and 12.7 mmol $SO_4^{2-}$/g in the 26-year-old rice field, and ca. 0 mmol $CH_4$/g and 22.4 ${\mu}$mol $SO_4^{2-}$/g in a natural tidal flat. Relative percent electron flow through sulfate reduction in the 60-year-old rice field was much lower (50.8%) compared with the 26-year-old rice field (69.3%) and the tidal flat (99.9%). The addition of an inhibitor of methanogenesis (2-bromoethanesulfonate) had no effect on sulfate reduction in the soil slurries of the reclaimed rice fields. However, instant stimulation of methane production was achieved with addition of an inhibitor of sulfate reduction (molybdate) in the soil slurries from the 26-year-old reclaimed rice field. The specific inhibitor experiments suggest that the relationship of methanogenesis and sulfate reduction might become mutually exclusive or syntrophic depending on sulfate content in the soil after reclamation. Sulfate, thus sulfate reduction activity of sulfate-reducing bacteria, would be an important environmental factor that inhibits methane production and determines the major pathway of electron and carbon flow in anaerobic carbon mineralization of reclaimed rice field soils.

• Journal of Microbiology and Biotechnology
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• 제31권7호
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• pp.1028-1034
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• 2021

The effect of medium composition on enzyme and β-glucan production by Aspergillus oryzae KCCM 12698 was investigated. Brown rice, rice bran, nitrogen, and ascorbic acid are key components of the synthetic medium used in liquid-state fermentation. To determine the optimal concentrations of these components for enzyme and β-glucan production, we conducted one factor at a time experiments, which showed that the optimal concentrations were 30 g/l brown rice, 30 g/l rice bran, 10 g/l soytone, and 3 g/l ascorbic acid. Pretreatment of brown rice for 60 min prior to inoculation enhanced fungal biomass, while increasing the production of enzymes and β-glucan using solid-state fermentation. Maximum fungal biomass of 0.76 mg/g, amylase (26,551.03 U/g), protease (1,340.50 U/g), and β-glucan at 9.34% (w/w) were obtained during fermentation. Therefore, solid-state fermentation of brown rice is a process that could enhance yield and overall production of enzymes and β-glucan for use in various applications.

• 농촌지도와개발
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• 제14권1호
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• pp.171-195
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• 2007

Gyeonggi rice has been placed relatively favorable market position in the domestic rice market. With the superiority of its quality, gyeonggi rice has been well recognized to consumers. The price of gyeonggi rice has placed higher position than that of others. But, gyeonggi rice are facing crisis on the competition by regional brands. Therefore, this study was carried out to find the differentiated marketing strategies on problem related with the product differentiation and brand marketing of gyeonggi rice. In order to find out how much the effort on the product differentiation of gyeonggi rice affects the price and brand recognition, fifty RPCs in gyeonggi province were surveyed. As the results, $22{\sim}23%$ of harvested rice which was gathered into RPC was come out 'obscurity of production origin' when we consider material hull rice in the original production territory by collecting time and channel. With comparing sales weight of gyeonggi rice by the place of shipment, agricultural cooperative channel was the highest by 44.7%. And, wholesaler comes to 17.7%, discount outlet store was 13.9%, large quantity delivery in business was 11.1%, and department store was only 5.2%. Finally, we could consider to adopt the traceability system on gyeonggi rice distribution system from production to consumers' table to get consumers' credibility and compete imported high quality rice.

• 한국생활과학회지
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• 제6권2호
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• pp.173-185
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• 1997

This study intends to suggest the considerations in the planning of production space of rice farming houses, based on their needs on the space and machinery for rice production. The 30 rice farming houses, in a village in Chungbuk province, responded for this study. Larger stalls and new built storehouses for grain or machinery showed changes in attached buildings after 1970s. Despite of the broad use of machinery in rice terming, however, only 1 or 2 houses in a village own and run it, and the planning of storehouse for machinery has to be done respectively. The sort and location of attached houses depend on the scale of rice farming. And because the production activities in the riceplanting or harvesting period collide with household ones, the considerations on the planning of efficient activity-oriented production space are offered in this study.

• Journal of Biosystems Engineering
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• 제18권1호
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• pp.71-77
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• 1993

This study was conducted in order to figure out the energy consumption pattern in rice production system of Korea, with literature investigation focused on energy requirement in rice production system in worldwide. The investigation reveals that 24,994 MJ/ha was needed to produce 4,500kg of rice production or 5.55 MJ/kg was consumed. The major enegry consumptions are resulted from the application of nitrogen fertilizer, fuel for farm machinery, and farm machinery embodied energy, which showed somewhat different energy consumption pattern than that of the developed country, like, U.S.A. Based on the machinery chosen in this investigation, it was found that 32.7% of the fuel energy, 2,431.8MJ, was consumed in drying operation, 32.2%, 2.402MJ, in tillage and land preparation. 25.8%, 1.923.6MJ in harvest. A linear relationship was found in pre harvest energy input and output of rice production.