• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.614-625
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• 2008

The project of Construction of Siem Reap bypass road in Cambodia consists of alignment improvement of existing route, extension of width of road and laterite paving. This project is carried out by fast-track method on the design and construction for bypass road of 15.2 km length and 8m width for five months. Though some difficulties for the construction works such as the location of borrow pit and rock source, rainy seasons etc, the construction could be completed successfully owing to the cooperation of related authorities, company and residents. This 2 way Angkor detouring road will function as industrial roads in Siemreap region. These new two roads will not only bring better logistics requirements and safety, but also impact to poverty alleviation and preservation the beauty of the ecological environment of Angkor region. The basic information related to geotechnical engineering of this project is introduced.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.12
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• pp.1681-1689
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• 2011

The beneficial effects of tea catechins (TCs) are related not only to their antioxidant potential but also to the improvement of animal meat quality. In this study, we assessed the effects of dietary TC supplementation on plasma biochemical parameters, hormone responses, and glutathione redox status in goats. Forty Liuyang goats were randomly divided into four equal groups (10 animals/group) that were assigned to four experimental diets with TC supplementation at 4 levels (0, 2,000, 3,000 or 4,000 mg TC/kg DM feed). After a 60-day feeding trial, all goats were slaughtered and sampled. Dietary TC treatment had no significant effect on blood biochemical parameters, however, low-density lipoprotein cholesterol (p<0.001), triglyceride (p<0.01), plasma urea nitrogen (p<0.01), and glucose (p<0.001) decreased and total protein (p<0.01) and albumin (p<0.05) increased with the feeding time extension, and day 20 was the turning point for most of changes. Interactions were found in glutathione (p<0.001) and the ratio of reduced and oxidized glutathione (p<0.05) in whole blood between treatment and feeding time. Oxidized glutathione in blood was reduced (p<0.05) by 2,000 mg TC/kg feed supplementation, and a similar result was observed in longissimus dorsi muscle. Though plasma glutathione peroxidase (p<0.01) and glutathione reductase (p<0.05) activities were affected by treatment and feeding time interactions, and glutathione S-transferases activity increased with feeding day extension, no changed values appeared in longissimus dorsi muscle. In conclusion, dietary TC supplementation affected the concentrations of some blood metabolites and accelerated GSH depletion in the blood of goats. In terms of less high-density lipoprotein cholesterol, the highest insulin and IGF-I concentrations, the highest ratio of reduced and oxidized glutathione in plasma, the dosage of 2,000 mg TC/kg feed might be desirable for growing goats to prevent glutathione depletion and keep normal physiological metabolism.

• Research in Plant Disease
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• v.22 no.4
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• pp.289-292
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• 2016

We surveyed the occurrence of Japanese yam mosaic virus (JYMV) on Yam in Gyeongsangbukdo pronvince from 2013 to 2015. The symptoms of JYMV were yellow stripes and chlorosis in yam leaves and the infection rate was ranged from 33.6% to 40.8%. We determined nucleotide sequence encoding the polyprotein of JYMV isolate BRI from yam leaves using next-generation sequencing (NGS) method. The partial nucleotide portion (7,736 nucleotides) of the genomic RNA of the JYMV isolate BRI has been sequenced (accession No. KU309315). The region sequenced includes a single open reading frame (ORF) encoding a polyprotein composed of 2,497 amino acids containing the coat protein (CP) and 3' untranslated region (UTR). The genomic organization of this isolate shows almost the same to that of other members of JYMV. The JYMV isolate BRI showed 77% to 79% nucleotide identity with the Japanese and Chinese strains and isolates. This is the first report of the genome nucleotide sequence of JYMV from Dioscorea opposita in Korea.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.267-267
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• 2017

In Korea, the average air temperature has been elevated twice faster than the average global warming. And the climate warming is characterized by the smaller rise of air temperature in summer and the greater rise of air temperature in spring and winter. Therefore, the number of frost-free days to determine the cultivation ability of crops has increased by more than 15 days in 10 years according to climate warming. This climate warming trend has extended and is projected to extend not only the sweet potato growing season but also the sweet potato early cultivating area to higher altitude and latitude region. This study was carried out to evaluate the possibility of sweet potato double cropping in the southern island area of Korea by assessing the growth and yield performance of sweet potato cultivated at extremely-early and -late time. We had performed at Yokji Island Yokji Island($E128^{\circ}$ 18' $N34^{\circ}$ 36'), a representative specified complex area of sweet potato cultivation in southern Korea. As the test varieties, the major cultivars of the this region, Shinyulmi and early hypertrophic cultivars, Dahomi were used. The prior cropping were planted with PE film mulching on March 30 and April 10, and harvested after 110 days. So the succeeding cropping were planted without PE film mulching on July 25 and August 5 according to the harvesting time of the prior sweet potato and harvested after 120 days. As a control, it was harvested on September 15, 120 days after planted on May 15. Each experimental plot had an area of 12 square meters consisting of 4 beds, and was planted one at a time at intervals of 25cm. We had investigated growth characteristics - main vine length, node number, branch number, total vine yield, and tuberous root characteristics - tuberous root number, average weight, starch value, and etc. After harvesting, we analyzed the economic effects by examining the postharvest quantity, the input labor, the management cost, and the income. The total yield of marketable products in prior and succeeding cropping was 46~70% higher than that of control. The average unit price of sweet potato was 36% higher than the conventional culture, and the gross income increased by 98%, but the operating cost increased by 83%, and the farm income increased by 103%. There are considerations such as the difficulty of enlargement of cultivation area due to lack of labor in limited space and the need for watering measures due to spring drought. However, if the area of application for sweet potatoes double system is increased by 10%, it can be used as a new cropping system.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.280-280
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• 2017

In Korea, the average air temperature has been elevated twice faster than the average global warming. And the climate warming is characterized by the smaller rise of air temperature in summer and the greater rise of air temperature in spring and winter. Therefore, the number of frost-free days to determine the cultivation ability of crops has increased by more than 15 days in 10 years according to climate warming. This climate warming trend has extended and is projected to extend not only the sweet potato growing season but also the sweet potato early cultivating area to higher altitude and latitude region. This study was carried out to evaluate the possibility of sweet potato double cropping in the southern island area of Korea by assessing the growth and yield performance of sweet potato cultivated at extremely-early and -late time. We had performed at Yokji Island Yokji Island($E128^{\circ}$ 18' $N34^{\circ}$ 36'), a representative specified complex area of sweet potato cultivation in southern Korea. As the test varieties, the major cultivars of the this region, Shinyulmi and early hypertrophic cultivars, Dahomi were used. The prior cropping were planted with PE film mulching on March 30 and April 10, and harvested after 110 days. So the succeeding cropping were planted without PE film mulching on July 25 and August 5 according to the harvesting time of the prior sweet potato and harvested after 120 days. As a control, it was harvested on September 15, 120 days after planted on May 15. Each experimental plot had an area of 12 square meters consisting of 4 beds, and was planted one at a time at intervals of 25cm. We had investigated growth characteristics - main vine length, node number, branch number, total vine yield, and tuberous root characteristics - tuberous root number, average weight, starch value, and etc. After harvesting, we analyzed the economic effects by examining the postharvest quantity, the input labor, the management cost, and the income. The total yield of marketable products in prior and succeeding cropping was 46~70% higher than that of control. The average unit price of sweet potato was 36% higher than the conventional culture, and the gross income increased by 98%, but the operating cost increased by 83%, and the farm income increased by 103%. There are considerations such as the difficulty of enlargement of cultivation area due to lack of labor in limited space and the need for watering measures due to spring drought. However, if the area of application for sweet potatoes double system is increased by 10%, it can be used as a new cropping system.

• Korean Journal of Environmental Agriculture
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• v.31 no.3
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• pp.205-211
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• 2012

BACKGROUND: Generally, nitrogen (N) fertilization higher than the recommended dose is applied during vegetable cultivation to increase productivity. But higher N fertilization also increases the concentrations of nitrate ions and nitrous oxide in soil. In this experiment, the impact of N fertilization was studied on nitrous oxide ($N_2O$) emission to standardize the optimum fertilization level for minimizing $N_2O$ emission as well as increasing crop productivity. Herein, we developed $N_2O$ emission inventory for upland soil region during red pepper and Chinese milk vetch cultivation. METHODS AND RESULTS: Nitrogen fertilizers were applied at different rates to study their effect on $N_2O$ emission during red pepper and Chinese milk vetch cultivation. The gas samples were collected by static closed chamber method and $N_2O$ concentration was measured by gas chromatography. The total $N_2O$ flux was steadily increased due to increasing N fertilization level, though the overall pattern of $N_2O$ emission dynamics was same. Application of N fertilization higher than the recommended dose increased the values of both seasonal $N_2O$ flux (94.5% for Chinese cabbage and 30.7% for red pepper) and $N_2O$ emission per unit crop yield (77.9% for Chinese cabbage and 23.2% for red pepper). Nitrous oxide inventory revealed that the $N_2O$ emission due to unit amount of N application from short-duration vegetable field in fall (autumn) season (6.36 kg/ha) was almost 70% higher than that during summer season. CONCLUSION: Application of excess N-fertilizers increased seasonal $N_2O$ flux especially the $N_2O$ flux per unit yield during both Chinese cabbage and red pepper cultivation. This suggested that the higher N fertilization than the recommended dose actually facilitates $N_2O$ emission than boosting plant productivity. The $N_2O$ inventory for upland farming in temperate region like Korea revealed that $N_2O$ flux due to unit amount of N-fertilizer application for Chinese cabbage in fall (autumn) season was comparatively higher than that of summer vegetables like red pepper. Therefore, the judicious N fertilization following recommended dose is required to suppress $N_2O$ emission with high vegetable productivity in upland soils.

• Research in Plant Disease
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• v.25 no.1
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• pp.16-21
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• 2019

Botrytis cinerea is the pathogen for a gray mold generating problems during the cultivation and transportation of roses. But there is little information about the difference of the symptom severity caused by gray mold on rose varieties and pathogen strains. 16 strains were collected from the rose cultivation area to confirm the degree of disease occurrence against strains and each variety. Collected 16 strains were identified based on the sequences analysis of ITS region of ribosomal DNA by using specific primers. The sequence analysis was performed by comparing the sequences to find a difference. To confirm the difference in disease occurrence for each strains, the difference was classified from 0 to 5 stages using charmant variety as a control. The data was confirmed through Kruskal-Wallis ANOVA. The result showed the significant difference in the pathogenicity caused by strains. WNG6_5 showed the lowest pathogenicity with 0.24 and WNG6_3 showed the highest with 3.20. The difference between two strains were almost 3.0. In addition, nine varieties of roses were more investigated with three strains such as the strains of WNG6_5, Hwa_1, and WNG6_3. The result showed that the Love Letter variety showed resistance and the Ice Bear variety was sensitive to three strains. Taken together, this study showed the significant difference by the interactions of rose varieties and gray mold strains.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.1
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• pp.59-69
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• 2013

Temporal and spatial variation in the freshwater region, created by river runoff, of a small bay, caused by the passage of typhoons was examined using a three-dimensional primitive equation model (the Princeton Ocean Model, POM). Numerical experiments were implemented focusing on temporal evolution in the freshwater region in association with typhoon tracks. The model domain covered most of the estuary around the Nakdong River, including Noksan Bay, where river water is periodically released from upstream (Noksan dam). The model showed that the extension of the freshwater region outside of the bay depended strongly on the tracks of typhoons, specifically the associated wind directions and inner flow fields that are accompanied by new clockwise eddies. The model also showed that entrainment from typhoon passage frequently creates salt wedges in the estuary, indicating that organisms in the bay are biologically and chemically influenced with variation in the freshwater region.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.2
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• pp.168-172
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• 2006

In this study. the transcriptional features of a 2.8 kb region spanning the sigH and rplA genes of Bacillus subtilis were clarified using synthetic oligonucleotides complementary to the transcripts of the rpmG, secE, nusG, and rplK genes. The 5' ends of three transcripts corresponding to this region were located and mapped on the chromosome via primer extension analysis. Three regions, designated Prg, Pn, and Prk, which partially share the consensus sequence recognized by ${\sigma}^A$ RNA polymerase, were theorized to function as promoter elements. The rpmG and secE genes of B. subtilis were cotranscribed from the designated prg promoter, whereas the nusG and rplK genes were transcribed separately from the Pn and Prk promoters, respectively. Accordingly, the transcriptional features, as well as the gene organization, of the region encompassing the sigH and rplA genes of B. subtilis, including the rpmG-secE-nusG-rplK genes, were determined to be distinct from those of Escherichia coli. Divergences in terms of gene organization and transcriptional features within the relevant region would serve as excellent criteria for the delineation of phylogenetic relationships among bacteria.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.477-484
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• 2020

This study was conducted to investigate the effects of slow-releasing fertilizer and sowing date on waxy corn propagated through double cropping without tillage. "Mibaek 2" was sown for first cropping on March 25^th, April 5^th, and April 15^th, and for second cropping on July 5^th, July 15^th, and July 25^th in 2018-2019. In order to save labor, slow-releasing fertilizer was utilized only one time before sowing. The accumulated temperature from sowing to silking was about 590-700℃. It took 65-77 days when "Mibaek 2" was sown in early April, but the one sown in early July took 42-52 days. In the first cropping, the culm length and ear length caused by the sowing date had no statistical significance, but the kernel set length was the highest at 123 cm in the sowing district on April 5^th. The weight of marketable ears was the highest at 100%, in addition to soil testing-based recommended fertilization. Meanwhile, in the second cropping, culm length, ear length, and yield were less compared to the first cropping. The culm length, kernel set length, ear length, and seed set length decreased as sowing date was delayed. The number and yield of marketable ears were the highest at 100%, in addition to soil testing-based recommended fertilization like in the first cropping. It has been found that securing yield by July 15^th to finish the second seeding of the crop in the central part of Korea is advantageous. These results of this study will be helpful to farmers for the double cropping of waxy corn cultivation and management.