• Journal of Korea Water Resources Association
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• v.36 no.4
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• pp.691-703
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• 2003

In this paper, a new and integrated approach easily used to calculate the pollutant loads from agricultural watersheds is suggested. Basic concepts of this empirical tool are based on the hypotheses that variations in event mean concentrations(EMCs) of the pollutants from a given agricultural watershed during rainstorms are only due to the rainfall pattern. This assumption would be feasible to agricultural watersheds whose land uses does not change during the cultivation period overlapped by rainy season and also in which point-sources of the pollutants are rare. Therefore, if EMC data sets through extensive sampling from various rural areas are available, it is possible to establish relationships between EMCs, shapes and land uses of the watersheds, and rainfall events. For this purpose, fifty one sets of EMC values were obtained from nine different watersheds, and those data were used to develop predictive tools for the EMCs of 55, COD, TN and TP in rainfall runoff. The results of the statistical tests for those formulas show that they are not only fairly good in predicting actual EMC values of some parameters, but also useful in terms of calculating pollutant loads on any time-spans such as the day of rainfall event or weekly, monthly, and yearly. Their applicability was briefly demonstrated and discussed. Also, the unit loads calculated from EMCs based on different land uses and real rainfall data over one of the watershed used for this study. were provided, and they are compared with other well-known unit loads.

• Journal of Applied Biological Chemistry
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• v.52 no.3
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• pp.121-125
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• 2009

We measured the influence of antifungal antagonists Bacillus subtilis AH18 and Bacillus licheniformis K11 on soil microbial community in microcosms. Both antifungal antagonists were confirmed to suppress hot pepper phytophthora blight. Phospholipid fatty acids (PLFA) were analyzed to investigate the soil microbial community. B. subtilis AH18 changed the total PLFA composition and bio-indicators of PLFA, compared with other treatments. B. subtilis AH18 decreased the proportion of bacteria and gram negative/gram positive bacteria, and increased the fungi/bacteria and anaerobic/aerobic microorganisms. In addition cy19:0/18:$1{\omega}7c$, which means adaptation to unfavorable environmental conditions, was increased by the application of B. subtilis AH18. On the other hand the inoculation of B. licheniformis K11 or combined inoculation of both antifungal strains did not affect soil microbial community. The suppression of phytophthora blight and preservation of indigenous soil microbial community may be achieved by the combined application of B. subtilis AH18 and B. licheniformis K11.

• Korean Journal of Plant Resources
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• v.8 no.2
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• pp.189-193
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• 1995

A new paeony variety 'Euiseongjakyak' was developed by Gyeongbug Provincial Rural Development Administration in 1993. This variety was selected from pure lint selection. It is characterized by red flower of single type, deep white flesh colour, straight and big radixs. When compared with 'Punggi jerye' a check variety, it is more resistant to lodging, disease and insect injury, and outyielded by 32% in total radix and 17% in marketable radix during 3 years regional performance trials. In the radix, the content of starch and sugar was higher by $9.8\sim12.22%$, crude protein and ash was similar and fiber was lower by 1.17% compared to 'Punggi jerye'.

• Journal of Environmental Impact Assessment
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• v.24 no.1
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• pp.78-86
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• 2015

Water plays the fundamental role in sustaining the living system. Water scarcity is mostly experienced dramatically by people living in poverty, most of them in rural areas and often in the poorest countries. Burundi has been identified as one of those countries. This study aimed to analyze and estimate the current and future water demands in the seven communes surrounding Kibira National Park (KNP) in Burundi. Sectors such as households, livestock, agricultural production and industry as the key water users in the study area were considered. The results showed an alarming increase in future water demand. Water demand by food crops increased to $288,779,060m^3/yr$ in 2020 and $306,018,348m^3/yr$ in 2050. Agricultural sector will be demanding the major available water in the seven communes surrounding Kibira National Park except Muruta and Bukeye which showed that water demand for tea industry was the highest in 2050. The water resources could be the greatest challenges for the overall development of the communities surrounding Kibira National Park. The current water resources may not be enough and therefore may not be able to meet the needs of those seven communities around KNP.

• Korean Journal of Plant Resources
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• v.21 no.4
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• pp.260-264
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• 2008

For the resistance test for Phytophthora blight of $T_1$ and $T_2$ transformants in pepper, Phytophthora blight fungus was inoculated to seedlings of the $T_1$ and $T_2$ transformants by concentration (density: zoospore $10^3/ml$). Occurrence rate of blight at 5days after inoculation was 4.0 % in T1-1 line and 10.0% in $T_1-2$ line, and its rate for 12 days after inoculation was 52.0% in $T_1-1$ line, 64.0% in $T_1-2$ line, respectively. Therefore, the lower occurrence rate to blight was enable to select resistant transformants in the some inoculation density (zoospore $10^3/ml$), meanwhile 'Kumtap' and 'Subicho' were 100% in highest occurrence rate to blight. For field test, in which blight was commonly occurred, of the Youngyang Pepper Experiment Station, the acquired transformant resisting to blight was similar to characteristics of domestic varieties, 'Subic ho' for fruit shape, but there are some differences in growth, days to flowering, fruit characteristics. Occurrence of blight in $T_2-1-6$, and $T_2-4-9$ lines was smaller approxmately 30% than commercial varieties, 'Kumtap', although occurrence of blight in field was showed higher difference among tested lines. In this study, we concluded that the transformants showing blight resistance selected from habitual field could be fixed at every generation, and the developed transformation system was also considered to develop transformants in pepper.

• Journal of Korean Society of Forest Science
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• v.86 no.1
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• pp.87-97
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• 1997

In this research, photo images of uncultivated marginal lands were simulated to visualize alternative land use patterns using image capture technology. Based on an original photos, 3 simulated images were created ; barren condition, aforested condition and shrub-covered condition. The simulated images were then used to evaluate respondents' visual preference(SBE value) and willingness to pay for the agricultural development tax as a hypothetical payment vehicle. The SBE values for barren condition are the lowest, as expected. When original condition is changed to forested or shrubbed, the SBE values are increased significantly. The logistic models for the willingness to pay for the various alternative land uses performed significantly, ${\rho}$ statistics for 6 models ranges from 0.3 to 0.4 and correct percentage for predicted probability are about 75%. Among independent variables, the amount of tax offered is the most influencing factor to predict the probability. Income also shows some relationship with no statistical significance. Other variables behave inconsistently in the model. When SBE and WTP are correlated, rather consistent trends can be observed. With the increase of SBE, WTP predicted by the model increases accordingly. It can be concluded that enhancement of scenic quality of the agricultural lands leads to increase of people's willingness to pay to support the rural environmental conservation.

• Korean Journal of Plant Resources
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• v.35 no.5
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• pp.675-685
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• 2022

A comparative analysis was performed on the soil chemical properties of greenhouse or open field where flower crops were grown from 2018 to 2020. The pH of greenhouse soils was kept slightly higher than the optimum range suggested by Rural Development Administration and that of open field soils was maintained within the optimum range for three years. The contents of organic matter (OM) were within the optimum range without significant change every year in both soils. Available phosphate (Av. P₂O₅) of greenhouse soils was the highest at 560 mg/kg in 2018, but it decreased every year and fell within the appropriate range in 2020. The concentration of Av. P₂O₅ in open field soils have fluctuated for three years, not showing a significant difference. Electrical conductivity (EC) of greenhouse soils was higher every year than the standard, 2.0 dS/m, but EC of open field soils remained below the standard. The contents of exchangeable cations were higher than the standard, showing significant differences among the years in greenhouse soils. In open field soils, other cations except exchangeable K⁺ were maintained higher than the optimal level and only Ca²⁺ showed a significant difference among the years. In Pearson correlation matrices, the value of exchangeable Ca²⁺ had a significantly positive correlation with exchangeable Mg²⁺ content at both greenhouse and open field soils. Based on principal component analysis, the soils of greenhouse were distributed within the range of high concentrations of Av. P₂O₅, EC and exchangeable cations, while the soils of open field were characterized by low contents of OM and exchangeable cations. Therefore, it is essential to lower the concentration of exchangeable cations in greenhouse soils. It is common for the soils of open field to have a low OM content, so that organic fertilizers should be more actively applied to the soils in open field.

• Korean Journal of Plant Resources
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• v.37 no.1
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• pp.62-70
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• 2024

Fruit thinning rate and characteristics were investigated for three years on seven promising pear (Pyrus pyrifolia Nakai) cultivars, which were treated by lime-sulfur as an eco-chemical thinning substance. Lime-sulfur was treated twice at the second and third days after full bloom by cultivar. Most of pear cultivars were significantly thinned by lime-sulfur compounds. Especially 'Whangkeumbae', 'Supergold' and 'Hanareum' exhibited high flower thinning rates, 41.5%, 40.1% and 39.9%, respectively. As weather conditions at the lime-sulfur treatment, insolation and cloud amount were correlated with flower thinning rate but not significant (r = 0.49 and r = -0.45, respectively). These results suggest that lime-sulfur is suitable for reducing labor force for flower thinning of Korean pears but flower thinning effects of lime-sulfur can vary depending on other factors such as environmental conditions. This information will provide useful data for low labor force cultivation of Korean pear cultivars.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.2
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• pp.128-136
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• 2014

It is known that the best way to recycle fly ash is to use in concrete. It is impossible to bury in the ground this fly ash recently, so it is trying to use high volume fly ash concrete. Nevertheless, recent main research topics are focused in the part of material only. However, it is necessary to perform the researches about elasticity modulus, stress-strain relationship and structural behavior. Therefore, in this paper, 18 test members were manufactured with 3 test variables, namely fly ash replacement ratio 0, 35, 50%, concrete compressive strength 20, 40, 60MPa and 2 tensile steel ratio. 18 test members were tested for flexural behavior. From the test results, there were no differences between 35, 50% high volume fly ash cement concrete and ordinary concrete without fly ash (FA=0%). In order to evaluate the HVFAC flexural behavior, Analytical model was proposed and the computer program was developed. There were no differences between test results and analysis results. So, the proposed analytical model was reasonable.

• Korean Journal of Plant Resources
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• v.33 no.5
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• pp.467-475
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• 2020

The purpose of this study is to investigate the vasodilatation effect of kirenol isolated from Sigesbeckia pubescens on the rabbit basilar artery. In this study, to determine the vasodilatation effect of kirenol on the rabbit basilar artery, arterial rings with intact or damaged endothelium were used for the experiment. And used an organ bath and force transducer were contracted by endothelin. Kirenol, major active constituents of S. pubescens, showed a moderate vasodilatation effect on the basilar arteries of rabbits. Therefore, treatment with kirenol may selectively accelerate cerebral blood flow through dilatation of the basilar artery. This result suggests a potential role of kirenol isolated from S. pubescens as a source of vasodilatation agent.