• Mycobiology
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• v.41 no.4
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• pp.221-224
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• 2013

Aphids are one of the most destructive pests in crop production such as pepper, cucumber, and eggplants. The importance of entomopathogenic fungi as alternative pest control agents is increasing. Conidia of entomopathogenic fungi are influenced by environmental conditions, such as temperature and relative humidity, and cause slow and fluctuating mortality. These factors have prevented wider application and use of biocontrol agents. For investigation of means of mitigation of such problems, we conducted bioassays with 47 fungal culture filtrates in order to evaluate the potential of secondary metabolites produced by entomopathogenic fungi for use in aphid control. Among 47 culture filtrates cultured potato dextrose broth, filtrate of Beauveria bassiana Bb08 showed the highest mortality (78%) against green peach aphid three days after treatments. Filtrate of Bb08 cultured in Adamek's medium showed higher toxicity as 100% to third instar nymphs of the aphid compared with seven other filtrates cultured in different broths amended with colloidal chitin or oil. The culture filtrates and fungal cultures from media amended with colloidal chitin or oil had lower control efficacies than filtrates without these additives in three different media. These results indicate that the fungal culture fluid or culture filtrate of B. bassiana Bb08 cultured in Adamek's medium has potential for development as a mycopesticide for aphid control.

• Proceedings of the Korean Society of Crop Science Conference
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• 2023.04a
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• pp.157-157
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• 2023

Pre-harvest sprouting (PHS) in rice (Oryza sativa L.) is one of the main problems associated with seed dormancy. PHS causes yield loss and reduction of grain quality under unpredictable humid conditions at the ripening stage, thus affecting the economic value of the rice crop. To resolve this issue, it is important to understand the molecular mechanism underlying seed dormancy in rice. Recent studies have shown that seed dormancy is affected by a large number of genes associated with plant hormones. However, the effect of heat stress on seed dormancy and plant hormones is not well understood. In this study, we compared the PHS rate as well as the transcriptome and small RNAome of the seed embryo and endosperm of two different accessions of rice, PHS-susceptible rice (low dormancy) and PHS-resistant rice (high dormancy) under three different maturation stages. We identified and verified the candidate genes associated with seed dormancy and heat stress-related responses in rice using quantitative real-time PCR. We newly discovered hormone-related genes, heat shock protein-related genes, and miRNAs potentially involved in PHS. These findings provide a foundation for understanding the dynamics of transcriptome and small RNAome of hormone- and heat stress-related genes, which affect PHS during seed maturation.

• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.4
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• pp.62-70
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• 1988

This study was conducted to solve the problems for the unsuitable parameters and the uncertainty of design flood can be appeared by low outliers were inclined to the lower part from the trend of the balance of the data. Derivation of reasonable design flood was attempted finally by modification of low outliers with analysis of flood frequency by means of Log Pearson Type Ill distribution. Three subwatersheds were selected as studying basins with the annual maximum series including low outliers along Geum River basin. The results through this study were analyzed and summarized as follows. 1. Log Pearson Type In distribution was confirmed as a reasonable one by X$^2$ goodness of fit test at Gong Ju, Gyu Am, og Cheon watershed along Geum River basin. 2. Probable flood flows for each watershed were derivated by flood frequency curve with outliers. 3. Weighted skew coefficient for each watershed was calculated for the evaluation of freq- uency factor which is needed for the modification of low outlier. 4. It was confirrned that adjusted frequency curve has a lower tendency than that of deletion of low outlier in common at all watersheds. 5. Final probable flood flows were derivated by modification with evaluation of modified basic statistics for three watersheds. 6. In comparison with a frequency curve with modification and one with outlier, The former has a higher probable flood flow within three years of return periods than that of the latter, and vice versa over three years of return periods.

• Journal of Korean Society of Rural Planning
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• v.13 no.4
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• pp.69-77
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• 2007

The purpose of this study is to analyze the problems of operating the Direct Payment Program for Rural Landscape Preservation and to derive the way of improvement based on case study for three areas in Bonghwa-gun, Cheongwon-gun, Hongseong-gun. The most important factor for the program is farmer's consciousness and positive participation of the farmer who are the subject of this project. Even if farmers are not satisfied with the amount of direct payment income, they try to create income by utilizing landscape preservation crops. Particularly current unit payment dose not surpass the for the crops farm operating costs and payment time is not appropriate for the farming cycle. Hence, it needs to be considered increasing unit payment and rearranging the payment time. Also, we need to introduce incentive system based the degree of fulfillment of the Direct Payment Program in each areas. In general the Direct Payment Program for Rural Landscape Preservation has potentiality to contribute farmer's income stability and the vitalization of region with three revisions.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.3
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• pp.5-17
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• 2000

The story of route of wet-rice diffusion to Korean peninsular is so far known only piecemeal. It is however commonly agreed that wet-rice technology may have spread the western coastal area in Korea from the lower and middle reaches of the yangzi river in China and to the Shandong peninsular and Bohai Bay region and was then transmitted overland to the area in Korea. Recently excavated three prehistoric paddy fields in Korea provide crucial evidence that helps to solve many of the important problems associated with technological diffusion. Research on the paddy field system and irrigation technology of prehistoric wet-rice has been so far especially productive in Japanese archaeology. Judging from the fact that the Yayoi wet-rice agricultural technology in Japan was transmitted by the Korean Strait from the southern part of Korea it is assumed that people in both regions may have practiced the same technology in prehistoric time. This paper examines three prehistoric paddy fields system(the Majon-ri site the Kwanchang-ri site and the Mujon-dong site) in relation to those of japanese data. The conclusions are as follows ; First early wet-rice agriculture in korea was limited by the level of technology and the size of labour. Secondly the location of field itself was restricted to the lower land and valley bottom area. Thirdly the layout of channel and field network is not very much different from the modern paddy field system.

• Current Research on Agriculture and Life Sciences
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• v.29
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• pp.29-35
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• 2011

The relationship between hydrologic processes and scale is one of the more complex issues in surface water hydrology. Disturbances that change vegetation and/or soil properties have been known to subsequently alter the landscape. The primary objective of this study was to estimate the grain size of soils with different properties from the hydraulic conductivity using pedotransfer functions. The double ring infiltrometer method was used to measure the vertical hydraulic conductivity of three soils under different soil planar surface treatments. Seven selected pedotransfer functions were used to estimate percentile diameters and the reduction in infiltration caused by compaction was misconstrued as caused by changes in percentile diameter. Results showed that compaction on the sandy loamy foot paths reduced the hydraulic conductivity by about 50%. The study showed that perceptual models of infiltration processes and appreciation of scale problems in modeling are far more sophisticated than normally presented in texts. Hydraulic measurement methods are still relevant and will provide significant information of grain size of the soils.

• Journal of Agricultural Extension & Community Development
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• v.11 no.1
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• pp.111-123
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• 2004

The directions and tasks of rural planning system can be accessed by the three view points of planning theory that are value formation, mean identification and effectuation. The concept of rural planning in Korea have been confronted with many problems and need to make new paradigm being able to develop depressed rural area. The highest valve in rural planning have been changed from economic development oriented to environmentally sound and sustainable development oriented. Also, the strategy of rural development have been changed rapidly. The growth pole theory and agricultural economic development strategy have been replaced by the urban-rural linkage theory and multi-sectoral development strategy including economic. social and spatial development. In recent, The implementation instruments for rural development focus on the participation of residence in rural area.

• Journal of the Korean Society of Safety
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• v.33 no.6
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• pp.8-14
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• 2018

Recently, serious problems occurred such as insecticide eggs, sanitary pads with carcinogens, radon(Rn) emitting beds in domestic. It had not been establishing the inspection system to evaluate safety and human harmfulness before occurring real accidents. This research was conducted to test preliminary experimental inspection for consideration of safety insensibility. The influence of corrosion of metals and plants was studied through aerosol type spraying of agricultural pesticide products coming into the market. These products contain primary three insecticide ingredients(Flufenoxuron, Etoxazole, Fipronil) in recent accidents. Visual examination, SEM-EDS and optical microscope were used for the analysis for corrosion effect. Results show that a lot of ingredients contain in the crop protection products, and various type of corrosion exist in the surface of metals and plants. Therefore, it is necessary to provide health warning and accurate range of use for crop protection products containing insecticide ingredients.

• The Plant Pathology Journal
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• v.25 no.3
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• pp.263-269
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• 2009

Bacterial wilt, Fusarium wilt and Foot rot caused by Ralstonia solanacearum, Fusarium oxysporum, and Phytophthora capsici respectively, continue to be severe problems to tomato, potato and black pepper growers in Vietnam. Three bio-products, Bacillus vallismortis EXTN-1 (EXTN-1), Bacillus sp. and Paenibacillus sp. (ESSC) and Bacillus substilis (MFMF) were examined in greenhouse bioassay for the ability to reduce bacterial wilt, fusarium wilt and foot rot disease severity. While these bio-products significantly reduced disease severities, EXTN-1 was the most effective, providing a mean level of disease reduction 80.0 to 90.0% against bacterial wilt, fusarium wilt and foot rot diseases under greenhouse conditions. ESSC and MFMF also significantly reduced fusarium wilt, bacterial wilt and foot rot severity under greenhouse conditions. Bio-product, EXTN-1 with the greatest efficacy under greenhouse condition was tested for the ability to reduce bacterial wilt, fusarium wilt and foot rot under field condition at Song Phuong and Thuong Tin locations in Ha Tay province, Vietnam. Under field condition, EXTN-1 provided a mean level of disease reduction more than 45.0% against all three diseases compared to water treated control. Besides, EXTN-1 treatment increased the yield in tomato fruits 17.3% than water treated control plants.

• Journal of Korean Society of Rural Planning
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• v.20 no.1
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• pp.1-12
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• 2014

Living environments in rural area have become deteriorated rapidly. Increase of aging population, decline in agricultural income, polarization of wealth in rural community due to rural returners have caused severe decline and imbalance of living environments in rural area. Responding to this circumstances, governments currently develop projects for improving living environments focusing on individual housing which were excluded from governmental supports because those had been regarded as private property. Nevertheless, there are still some gaps and problems in evaluating the quality of living environment and suggesting effective solutions. It would be because standards and guidelines of the projects have been based on urban housing system. In order to support the implementation of the projects, this research has developed an index for evaluating and monitoring the quality of living environments in rural area. By applying Delphi method, the index has been created in four categories of 'security', 'convenience', 'comfortability', and 'durability' 'Security' consists of structural safety, crime, disaster, accident prevention. 'Convenience' includes three divisions of living, traffic, farm working. 'Comfortability' is divided into sanitation, indoor environments, and aesthetic appreciation. Lastly, 'durability' has four divisions of energy conservation, environmental friendliness, efficiency, and economics. Each sub-division also has different items from three to twelves. In the case of an index for performance evaluation, items have been derived from energy conservation(6-items), and environmental friendliness(7-items). Items developed as an index for evaluating rural living environments in this research might be good background information for remodeling project in rural housing development.