• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.1-9
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• 2008

The main purpose of this study is to accumulate the fundamental data representing groundwater of plastic film houses by means of water quality and its multivariate statistical analysis. Groundwater samples were collected in every two years since 2000 to 2004 from total 211 sites. According to the result of water quality analysis, ground water quality was suitable for irrigation purpose averagely. Correlation analysis showed that EC was highest positively correlated with $Mg^{2+}$ to 0.810(p<0.01), 0.776(p<0.01) in April and July, respectively. $NO_3-N$ was highest positively correlated with T-N to 0.794(p<0.01) in October. This result shows that it can lead to a different result even in similar case sometimes. Four factors were extracted through factor analysis in April and July, but five factors were extracted in October. The proportions of cumulative variance by the factor were 64.9, 60.2, and 70.7 in April, July, and October, respectively. The first factor was highly related to anions and cations such as $Ca^{2+},\;Mg^{2+},\;Cl^-,\;{SO_4}^{2-}$, and EC in contrast to that of stream water. According to the cluster analysis, 211 sites are classified into four groups. Common type of ground water quality was shown in group A. The pH and $PO_4-P$ were highest in Group B. The anions and cations were highest in Group C. $COD_{Cr}$ was highest in Group D.

• Journal of Bio-Environment Control
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• v.14 no.2
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• pp.89-94
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• 2005

This study was conducted to investigate the effect of nonwoven fabrics weight(Ounce) on growth, quality and yield of oriental melon (Cucumis melo L. var. makwa Mak.). Seedling of 'Gumssaragi-Eunchun' was grafted on 'Shinthozoa' root stock. In this study, The minimum air temperature in 6 ounce at night was $4.8^{\circ}C,\;6.9^{\circ}C$ in 9 ounce, $7.9^{\circ}C$ in 12 ounce and $8.0^{\circ}C$ in 15 ounce, respectively. Leaf length, stem diameter, leaf numbers, leaf area, fresh weight and dry weight for 30 days after planting were better in high minimum air temperature at night than in low minimum air temperature, particularly leaf areas of the plant in 9 ounce was $370cm^2$ at 30 days after planting, $116\%$ in 12 ounce, $129\%$ in 15 ounce. The xylem exudates amount in 9 ounce for 24 hours just after basal stem abscission was 10.1mg. It was 1.2 times much in 12 ounce and 1.9times much in 15 ounce than in 9 ounce at 30 days after planting. The blooming of female was faster by 6 days in 15 and 12 ounce but was delayed by 3 days in 6 ounce than 9 ounce, and the days of blooming to harvesting were shorter by 3 days in 15 ounce and 4 days in 12 ounce but was delayed by 3 days in 6 ounce than in 9 ounce. Fruit weight, fruit length, fruit diameter, flesh thickness, soluble solids, and total yield was the highest in 15 ounce followed by 12 ounce,9 ounce and 6 ounce. Fermented fruit rate was the highest in 6 ounce followed by 9 ounce, 12 ounce and 15 ounce, and marketable fruit rates were 15, 12, 9 and 6 ounce in order. Compared to 1,781kg yield per 10a of 9 ounce, $19\%\;and\;49\%$ was increased under 12 ounce and 15 ounce but $47\%$ were decreased 6 ounce.

• The Korean Journal of Petroleum Geology
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• v.3 no.1 s.4
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• pp.1-15
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• 1995

Seismic reflection profiles and exploratory drilling well samples from the southern marginal-continental shelf basin of Korea delineate that the Tertiary sedimentary sequences can be grouped into five sequences (Sequence A, Sequence B, Sequence C, Sequence D and Sequence E, in descending order). Paleontologic data, K-Ar age datings, correlation with tuff layers and sequence stratigraphic analysis reveal that the sequences A, B, C, D and E can be considered as the deposits of Holocene $\~$ Pleistocene, Pliocene, Late Miocene, Early $\~$ Middle Miocene and Oligocene, respectively. The sequence stratigraphic and structural analyses suggest that the southern part of the Cheju Basin had experienced severe folding and faulting. NE-SW trending strike-slip movement is responsible for the deformation. The sinistral movement of strike-slip fault ceased before the deposition of Sequence B. Age dating and rare-earth elements analysis of volvanic rocks reveal+ that the Sequence D was deposited during the Early $\~$ Middle Miocene and the Sequence I was deposited earlier than the deposition of the Green Tuff Formation. Sedimentary petrological studies indicate that sediments of the Sequence I came from the continental block provenance. After the deposition of the Sequence E, uplift of the source area resulted in increase of sediment supply, subsidence and volcanic activities. The Sequence D show these factors and the sediments of the Sequence D are considered to be transported from the recycled orogenic belt.

• Journal of Animal Environmental Science
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• v.15 no.2
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• pp.171-182
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• 2009

Conventionally, many pig producers have utilized a continual sow managements system that the matings, farrowings and weanings are done weekly basis. But this transitional method is not able to cut the cycle of diseases and fully apply all-in/all-out system because of the continuous flow of sows and pigs. Conventional weekly management system is currently limiting in small farm to work efficiently both for workers and pigs. Therefore, pig producers have found novel management methods for applying all-in/all-out system, improving pig health, leading to better growth, lowering mortality and reducing medication costs nowadays. Moreover, all-in/all-out pig management system has known as a strategy for improving productivity in swine farm. The batch system is one of the best management methods to adopt all-in/all-out pig management system that prevent spreading diseases in pig and remove cycle of diseases. Batch farrowing system is a concept for providing a group of sows that delivery within a specific farrowing interval and inducing a large enough scale of piglets to fill the weaner facilities. There are different types of batch farrowing system with batch size and interval of farrowing when several factors at the swine farm are considered such as total number of sows, available facilities in the farm, and the efficiency of workforce. Sow managements such as farrowing, weaning and breeding, every 3 weeks rather than weekly, 2 or 5-week interval have advantages for workers and reproductive cycle of sows as well as pig flow. Because there are several pros and cons both in weekly and batch management system, various factors should be considered to apply the most suitable management system in each individual farm. To improve poor swine productivity in Korea compared to ED, batch system for sows will be an alternative choice which is able to prevent high incidence of diseases in swine farm such as PMWS, PRRS, PRDC and PED because all-in/all-out pig management can be also applied automatically by using this management system.

• Journal of fish pathology
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• v.25 no.3
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• pp.263-270
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• 2012

This study surveyed for the prevalence of parasites, bacteria and viruses in four fish species, olive flounder (Paralichthys olivaceus), red sea bream (Pagrus major), black sea bream (Acathopagrus schlegeli) and black rockfish (Sebastes schlegeli) in 2010. The survey was aimed to compare the pathogens detected from wild and cultured fish for an epidemiological study. Anisakis sp. was predominantly detected from wild olive flounder and red sea bream (58.6% and 41.7% respectively), but not from the cultured fishes, suggesting anisakid infection is rare in cultured fish. The wild fish get in contact with the anisakids through their prey such as small fishes or crustaceans which carry the anisakids; whereas the cultured fish are fed with formulated feed, free of anisakids. Bacterial detection rates from the wild fishes examined in the study were lower than those of cultured fishes. Vibrio sp. dominated among detected bacterial population in cultured olive flounder (18%). Since vibriosis is known as a secondary infection caused by other stressful factors such as parasitic infections, handling and chemical treatment, it seems that cultured olive flounder are exposed to stressful environment. Viruses diagnosed in the study showed difference in distribution between wild and cultured fishes; hirame rhabdovirus (HRV) (0.1%) and lymphocystis disease virus (LCDV) (3.9%) were detected in the cultured olive flounder, but not in the wild fish, and marine birnavirus (MBV) (1.7%) and red sea bream iridovirus (RSIV) (3.2%) were detected from the wild and cultured red sea bream, respectively. From the survey conducted, it can be concluded that even though some pathogens (Trichodina sp., Microcotyle sp., etc.) are detected from both the wild and cultured fish, pathogens such as Anisakis sp., Vibrio sp. and LCDV showed difference in distribution in the wild and cultured host of same fish species and this can be attributed to their environmental condition and feeding.

• Journal of Korean Society of Forest Science
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• v.22 no.1
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• pp.49-62
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• 1974

1. In the comparison of survival ratio among three different methods(bark graft, veneer graft, root graft), bark graft showed the highest survival ratio and root graft was the lowest. It was shown to be significant at the level of 5% in the analysis of variance for the results. It was able to be supposed that one of the main causes for the results was the different amounts of ferric tannic acid which was formated owing to the reaction of grafting knife with tannic acid oozing from cutting faces of the tree. In juvenile tissue graft, the survival ratio of inverted radicle graft was a little higher than that of juvenile stem graft, but there was no significant difference between two methods in analysis of variance. 2. The most hairs of chestnut tree leaves were recognized as stellates on the most part of leaves except for venation. The number of rays in the stellates was ranged from 4 to 8 generally. It was shown to be highly significant differences at the level of 1% among the each race growing at the similar environmental condition in the length of ray and the distributed ratio of the stellates having different ray number. 3. Excepting for the basal width of serration there were no significant differences between $Imakita_1$, $Imakita_2$ as well as between $Teteuchi_1$, $Teteuchi_2$ at the each point of experimental items in this study. Such results made this study more useful. 4. Among the races that were growing in the similar environmental condition, there were highly significant differences at the level of 1% in the length and the width of serration. 5. The rolling of hair, the angle of serration from the leaf margin, the existence of lateral vein in the serration, the intrusion of main vein into the serration and the width of main vein were observed to be somewhat useful as the subsidiary methods for the identification of chestnut races.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.1
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• pp.123-130
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• 2011

Objectives of this study were to compare the environmental effects of digestates produced in bioenergy village on the rice paddy field for recycling. Digestates were applied to the soils and the soil properties and the crop responses were analyzed according to the standard methods of soil evaluation. Plant height and the number of tiller showed similar results in both the conventional and digestate treated field, and the yield of rough rice was higher in the field treated with digestates than that with chemical fertilizer. The amounts of nitrogen absorbed in straw and grain were larger in the digestates-treated field than chemical fertilizer-treated one, and efficiency of nitrogen applied was shown to be the highest in 100% treated digestate of the pig manure. Exchangeable cation and pH increased in the soil treated with digestate after harvesting, but salt was not accumulated. With these results, it was concluded that resource recycling in green town can be facilitated through the securement of arable lands for the application of digestates and the proper use of these fertilizers. Long-term effects of digestate application on the soil environment should be sustainingly studied.

• Journal of Wetlands Research
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• v.23 no.4
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• pp.317-326
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• 2021

The present study was carried out with a view to understand the distribution and ecology of Clihton retropictus (Martens, 1879), a class II endangered wildlife designated and protected by the Ministry of Environment, Republic of Korea, and to suggest the effective conservation and management measures for this species and its habit. First, the distribution of Clihton retropictus was investigated nationwide, and environmental factors such as salinity and substratum were analyzed in consideration of the ecological characteristics of this species. In addition, the individual size, density, and movement of Clihton retropictus per each district surveyed were analyzed. Due to its nature of inhabiting in the brackish water zone, the analysis showed that the salinity of this species was 0.7 ~ 16.6‰ at low tide and 1.0 ~ 17.3% at high tide. It was learned from the analysis of substratum that its composition in each river under investigation was slightly different, but most of substratum had a higher composition ratio than gravel (pebble, 16 ~ 64 mm). On the other hand, the size of each individual was checked by measuring the length of its diameter, and there was almost no change in the individual when the inhabited range of Clihton retropictus was short. However, there was tendency that the longer the habitat range, the bigger the individual size. From surveying the population density by season, it was made clear that, during the summer (July to August) and fall (September to October), the density was relatively higher while the number of individuals decreased significantly during winter (November to December) when the water temperature was lowered. In an effort to effectively establish conservation and management measures, the moving distance was measured, and it became known that, during the surveys in summer and fall when the individuals were active, the individuals moved in more distances than during the winter survey. The results of this study are expected to be utilized as basic data for establishing effective management plans such as creation of habitats for Clihton retropictus, its migration projects and selection of migration destinations which get unavoidable due to development projects.

• Journal of the Korean earth science society
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• v.42 no.2
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• pp.201-220
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• 2021

The objective of this study is to increase awareness and interest regarding polar science and thereby aid in establishing the concept and future direction of polar literacy. To analyze the current status, textbooks based on the common school curriculum pertaining to polar topics were reviewed. Six countries that actively conduct polar science, namely Korea, France, Japan, Germany, the United States, and the United Kingdom, were chosen. Subsequently, 402 cases in 110 science and social studies (geography) textbooks of these countries were analyzed through both quantitative and qualitative methods. Based on the obtained results, the importance of polar research in geoscience education and the need for spreading awareness regarding polar research as an indicator of global environmental changes were examined. It was found that the primary polar topics described in the textbooks are polar glaciers, polar volcanism, solid geophysics, polar infrastructure, and preservation of geological resources and heritage. This demonstrates that the polar region is a field of research with important clues to Earth's past, present, and future environments and is also a good teaching subject for geological education. However, an educational approach is needed for systematically laying emphasis on polar research. The implications of this study are manifold, such as the establishment of a cooperative system between polar scientists and educators, extraction of core concepts for polar literacy and content reconstruction, discovery of new polar topics associated with the curriculum, diversification of forms of presentation in textbooks, and development of an affective image that is based on correct cognitive understanding. Furthermore, through the continuance of polar topics in textbooks, students can improve their awareness regarding polar literacy and polar science culture, which in turn will serve as the driving force for sustainable polar research in the future.

• Korean Journal of Breeding Science
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• v.43 no.1
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• pp.68-80
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• 2011

This study was conducted to investigate characteristics and variations of rice panicle traits for breeding temperate japonica varieties adapted to tropical environment. Eleven panicle traits were investigated from nine Korean rice varieties cultivated in Korea and wet season of the Philippines. Tested cultivars were composed of six temperate japonica varieties, three Tongil-type varieties, and one indica variety bred in the Philippines. The number of spikelets on secondary rachis branches (SRBs) was the most variable trait in both environments, while the mean number of spikelets on a primary rachis branch (PRB) was the least variable. Compared with PRB-related traits, SRB traits showed higher correlation with the number of spikelets per panicle. Compared with the plants grown in Korea, the number of spikelets on SRBs, the number of SRBs, spikelets, and rachis branches per panicle were decreased more than other traits in the Philippines. According to path analysis, the number of spikelets on SRBs per panicle affects the number of spikelets per panicle more than the number of spikelets on PRBs per panicle. Climatic factors such as growth duration, cumulative mean temperature, and integrated solar radiation were highly correlated with the relative rate of number of spikelets per panicle. To breed temperate japonica rice varieties adapted to tropical environment, it would be important to select lines which maintain proper growth duration and spikelets on SRBs in target region.