• Korean Journal of Ecology and Environment
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• v.44 no.3
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• pp.253-263
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• 2011

This study was conducted to gain preliminary data for restoration and management of constructed small-scale ponds in paddy fields through analysis of their physicochemical and biological properties. A field survey was performed at 13 small-scale ponds located in paddy fields from August 2009 to October 2010. Structural properties, water quality, soil characteristics and fish fauna were measured. Results showed that small-scale ponds without frames might lose their function over time because of crumbling walls. Therefore, it is necessary for these ponds to have frames for soil protection and sustainable maintenance. Chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) concentration were higher than the water quality standard for agricultural water in small-scale ponds. In particular, TN concentration was 8.03 mg $L^{-1}$ and over 8 times the water quality standard because of the presence of livestock such as cows and pigs in the study areas. Sand, organic matter and available phosphorus contents of soil in small-scale ponds was 53.4${\pm}$16.6%, 21.8${\pm}$9.74 g $kg^{-1}$ and 12.8${\pm}$7.59 mg $kg^{-1}$, respectively indicating that sand and available phosphorus contents were suitable for plants in small-scale ponds, but organic matter contents was somewhat low in newly constructed small-scale ponds, and would take some time to stabilize for plant growing. Fish fauna was not diverse with only 4 species at all sites surveyed. Collected fishes share a common feature that they all inhabit paddy fields or canals with shallow water depth. In this study, all ponds were not linked to the streams and canals around them. It appears that connection to adjacent streams was the major factor controlling fish fauna in small-scale ponds. The results of statistical analysis were classified into three groups. Factor 1 was 26.3%, which shows a structural properties such as area and depth of small-scale pond. As for factor 2, it appears on 20.1%, showing water quality like a TP, suspended solids (SS) and COD. Small-scale ponds were classified into three groups by factor scores. Group I consisted of 6 small-scale ponds, which were larger than the others. Group III had higher water quality than the others. We conclude that the most important points to be considered for restoration and management of small-scale ponds is connection with adjacent streams or ditches and depth and size of the small-scale pond.

• Korean Journal of Ecology and Environment
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• v.45 no.4
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• pp.378-391
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• 2012

The objective of this study was to determine temporal patterns and longitudinal gradients of water chemistry at eight artificial reservoirs and ten streams within the Han-River watershed along the main axis of the headwaters to the downstreams during 2009~2010. Also, we evaluated chemical relations and their variations among major trophic variables such as total nitrogen (TN), total phosphorus (TP), and chlorophyll-a (CHL-a) and determined intense summer monsoon and annual precipitation effects on algal growth using empirical regression model. Stream water quality of TN, TP, and other parameters degradated toward the downstreams, and especially was largely impacted by point-sources of wastewater disposal plants near Jungrang Stream. In contrast, summer river runoff and rainwater improved the stream water quality of TP, TN, and ionic contents, measured as conductivity (EC) in the downstream reach. Empirical linear regression models of log-transformed CHL-a against log-transformed TN, TP, and TN : TP mass ratios in five reservoirs indicated that the variation of TP accounted 33.8% ($R^2$=0.338, p<0.001, slope=0.710) in the variation of CHL and the variation of TN accounted only 21.4% ($R^2$=0.214, p<0.001) in the CHL-a. Overall, our study suggests that, primary productions, estimated as CHL-a, were more determined by ambient phosphorus loading rather than nitrogen in the lentic systems of artificial reservoirs, and the stream water quality as lotic ecosystems were more influenced by a point-source locations of tributary streams and intense seasonal rainfall rather than a presence of artificial dam reservoirs along the main axis of the watershed.

• Journal of Life Science
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• v.27 no.1
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• pp.57-66
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• 2017

Traditional Korean fermented herbal plants are potential sources of new food that promote health, but they are still produced by yeast, fungi or bacteria fermentation. In the present work, mushroom (Paecilomyces tenuipes and Cordyceps militaris) fungal dongchunghacho were used to fermented Glycyrrhiza uralensis Fischer (licorice) or mixed with pupa. The pupa were tested as solid substrates for the production of corcycepin, liquiritin, and liquiritigenin. The fermented substrates were analyzed the content of cordycepin, liquiritin, liquiritigenin, and glycirrhizin productivity and inhibitory activity of NO. The cordycepin content of 70% EtOH extract from the fermented mixture of licorice and 50% pupa with C. militaris increased maximum at 33 times. Pupa was very excellent for the production of cordycepin. The liquiritin content was decreased in all the assays inoculated with P. tenuipes and C. militaris dongchunghachos. The liquiritigenin content was higher when fermented with P. tenuipes than C. militaris. The addition of pupa significantly reduced the liquiritin content and glycyrrhizin production. As a result, the liquiritigenin content increased in fermented P. tenuipes and C. militaris, and liquiritin and glycyrrhizin decreased. The inhibition of NO production in the different ethanolic extracts fermented with licorice and pupa was also significantly increased and higher than that of a nonfermented extract in higher polar solvent extracts. The contents of cordycepin and biological active compounds were altered in accordance with the concentration of pupa and fungi. This study provides basic data for use in developing dongchunghacho fungi as a functional food resource.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.2
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• pp.129-136
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• 1991

Dry matter productivity at silage stage of two corn hybrids varying resistance to rice blackstreaked dwarf virus(RBSDV) and two sorghum hybrids varying growth duration was evaluated at six planting dates (Apr. 1, Apr. 15, Apr. 29, May 13, May 27, and June 10) in Kyongsan where RBSDV is prevalent.Corn was harvested 38-40 days after silking. For sorghum 1st-cut was made 19-22 days after heading and some regrowth (2nd-cut) on October 13. 1. Percent stand of both corn hybrids was over 91% at all planting dates, but that of sorghum ranged 37.2-80.3% depending on hybrids and planting dates. 2. The number of days from planting to emergence decreased as planting date delayed in both crops. The number of days from emergence to silking of both corn hybrids and a sorghum hybrid(P 956) decreased as planting date delayed, but that of the other sorghum hybrid(P 931) increased significantly after May 13 planting. 3. RBSDV infection rate of corn hybrids was highest at April 1 planting (Kwanganok 24.896, Jinjuok 63.0%) and decreased up to April 29 planting and then increased as planting date delayed. Sorghum was not infected by RBSDV at all. 4. EarfTotal dry matter ratio of corn ranged 30.6-47.9% and that of sorghum 3.1-30.7% depending on hybrids and planting dates. All the hybrids developed grain normally at all planting dates except a sorghum hybrid (P 931) which developed few grains after May 13 planting. 5. Crude (C) protein and C. fat contents were similar among all treatments. C. fiber content of P 931 was higher than that of both corn hybrids and P 956, but nitrogen free extract (NFE) was lower. C. fiber and NFE of both corn hybrids and 1st-cut sorghum were similar among the planting dates, but C. fiber and NFE of 2nd-cut of sorghum decreased and C. protein increased as planting date delayed due to plants were younger. 6. Dry matter (DM) yield of all hybrids decreased as planting date delayed except Jinjuok of which yield was highest at April 29 planting. DM yield of corn was similar to 1st-cut sorghum, but lower than total DM yield of sorghum at April 1 and 15 plantings where regrowth yield was high.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.5
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• pp.477-482
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• 2006

Viral diseases, especially Barley yellow mosaic virus (BaYMV) and Barley mud mosaic virus (BaMMV), have been most serious in barley fields. In this study, we investigated the effect of different level of resistance to viral diseases on the plant growth and yield in barley. Various viral disease symptoms on leaves of overwintered plants were similar between medial-resistant and susceptible varieties of Saessalbori and Baegdong. In diagnosis of virus infection, BaYMV and BaMMV were detected in Saessalbori and Baegdong, but not in the resistant variety, Naehanssalbori. Plant height was restrained about $11{\sim}12cm$ prior to heading in Saessalbori and Baegdong comparing to Naehanssalbori. Even if both varieties were medial resistant to virus diseases, Saessalbori was different from Baegdong in heading date and culm length due to its recovery from viral damages prior to heading. Both medial-resistant and susceptible varieties were quite different from the resistant variety in yield components such as heading date, number of spikes and culm length when evaluated in the virus-infected or non-infected field. Baegdong delayed 7 days in heading date and reduced by more than 50% in culm length and spike numbers as compared to Naehanssalbori. On the other hand, Saessalbori showed similar heading date, but was shorter by 20% in culm length than Naehanssalbori. Three varieties tested in the non-infected field over two years were not significantly different for yield potential with ranges of $340{\sim}405kg/10a$. However, significant yield reduction (P<0.01) was observed in Saessalbori and Baegdong with ranges of $108{\sim}288kg/10a$ as compared to Naehanssalbori (391 kg/10a) when tested in the virus-infected field. Yield potentials of Saessalbori and Baegdong reduced by 35 and 63%, respectively in the virus-infected field as compared to those in the non-infected field. Our results showed that damages from virus diseases were significant on the early plant growth to yield and its components in barley.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.2
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• pp.155-163
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• 1999

Nutrient balance during rice cultivation in the paddy of a local area under the environmental protection for drinking water supply was investigated. To compare nutrient balance in the paddy soil applied with different types of fertilization, 7 treatments were selected as followings : Recommended level of chemical fertilizers(R), Conventional fertilization(CF), Fresh cow manure(FCM), Cow manure compost(CMC), Straw compost+reduced chemical fertilizer(SCF), Fresh straw+recommended level of fertilizers(FSC), and no fertilization as control(C). Here, FCM, CMC and SCF were applied at the same level of total nitrogen as recommended in R. Rice yield was the highest in the recommendation(R) and fresh cow manure (FCM) treatments with $6,730kg\;ha^{-1}$(index 100), and followed by SCF (index 98), FSC (index 98), CMC(index 94), and CF(index 94). But statistically significant difference was not recognized among treatments except the control. Nitrogen infiltration loss was high in the simple chemical fertilizer treatments with $63kg\;ha^{-1}$ in CF and $58kg\;ha^{-1}$ in R during rice cultivation, respectively. Nitrogen infiltration loss was decreased below half level of chemical fertilizer treatments with cow manure treatments ($23kg\;ha^{-1}$ in FCM and $27kg\;ha^{-1}$ in CMC) and with reducing chemical fertilizer treatment by adding straw compost ($25kg\;ha^{-1}$). Phosphate was not leached during rice cultivation in paddy soil of a fluvial deposit type, in which oxidation horizon was developed broadly under around 15 cm depth of surface soil. Phosphate balance (A-B) was closed to 0 in all treatments except cow manure treatment (CMC), in which it was $+30kg\;ha^{-1}$ and show the possibility of over accumulation of phosphate by continuously replicated application of cow manure compost. Potassium balance was negative value in all but straw recycling treatment (FSC). It means that potassium was continuously supplied from soil minerals, uptaken by plants or eluted out of soil. In conclusion, by substituting inorganic fertilizer for organic fertilizer or reducing application rate of chemical fertilizer through mixing organic fertilizer, it would be possible to achieve the same rice yield as in the recommendation treatment and to decrease nutrient leaching below half level in rice paddy soil.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.3
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• pp.239-253
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• 1999

The objective of this study was to determine the effects of various kinds of composts on the change of soil chemical properties in upland soils. Field experiments were conducted in the loam and sandy loam soils. Various kinds of composts such as poultry manure compost(PMC), cow manure compost(CMC), human excrement sludge(HES), and food industrial sludge compost(FISC) were applied annually at rates of 0, 40, and $80Mg\;ha^{-1}$ to soils grown with soybean and maize plants for 4 years during 1994 to 1997. The results of this study were as follows : The continuous application of human excrement sludge decreased soil pH up to 4.4~5.0, while other compost treatments increased soil pH compared with control plot. The EC increased initially and showed their maximum values at 20days after compost application, and then decreased up to 40 days, thereafter kept a certain level. The available phosphorous accumulated at 0~20cm depth in loam soil, and 0~50cm in sandy loam soil. Annual accumulation rates were 17% higher in sandy loam soil than loam soil. The more compost application rates and times, the higher base saturation percentage increased in upland soils. Four year's application at a rate of $80Mg\;ha^{-1}$ per year increased the base saturation percentage to 87~91% compared with 45% at control plot in the loam soil. While in sandy loam soil only three year's application of same rate increased the base saturation percentage to 81~92% compared with 30.4% at control plot. The average annual increasing rate of base saturation percentage at the same application rates of composts were higher in sandy loam soil by 2.0~3.7 times than in loam soil. The application of compost increased the exchangeable Ca, Mg, and K contents of soils by 2, 2~3, and 3~5 times, respectively, compared with the control. The contents of exchangeable canons were high in surface soil. and decreased with increase of soil depths. In the case of heavy metal content, there were no difference at the application of PMC and CMC but Ni. Fe, Zn, Cu was increased a little when the HES applied, and Ni and Cr was increased application with FISC.

• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.833-847
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• 2016

Drought stress is a major agricultural limitation to crop productivity worldwide, especially by which leafy vegetables, plant leaves eaten as vegetable, could be more lethal. The study was carried out to know the effect of drought tolerance plant growth promoting bacteria (PGPB) on water stress of kale seedlings. A total of 146 morphologically distinct bacterial colonies were isolated from bulk soil and rhizosphere soil of leafy vegetables and screened for plant growth promoting microbioassay in greenhouse. Out of them the isolate SB19 significantly promoted the growth of kale seedlings in increasement of about 42% of plant height (14.1 cm), 148% of leaf area ($19.0cm^2$) and 138% of shoot fresh weight (1662.5 mg) attained by the bacterially treated plants compared to distilled water treated control (9.9 cm, $7.7cm^2$, 698.8 mg). Shoot water content of SB19 treated kale seedlings (1393.8 mg) was also increased about 152% compared with control (552.5 mg). The SB19 isolated from bulk soil of kale plant in Iksan, Korea, was identified as species of Bacillus based on 16S rRNA gene sequencing analysis. We evaluated the effect of drought tolerance by the Bacillus sp. SB19 on kale seedlings at 7th and 14th days following the onset of the water stress and watering was only at 7th day in the middle of test. In the survey of 7th and 14th day, there were mitigation effect of drought stress in kale seedlings treated with $10^6$ and $10^7cell\;mL^{-1}$ of SB19 compared to distilled water treated control. Especially, there were more effective mitigation of drought damage in kale seedlings treated with $10^7cell\;mL^{-1}$ than $10^6cell\;mL^{-1}$. Further, although drought injury of bacterially treated kale seedlings were not improved at 14th day compared with 7th day, drought injury of $10^7cell\;mL^{-1}$ of SB19 treated kale seedlings were not happen rapidly but developed over a longer period of time than $10^6cell\;mL^{-1}$ of SB19 or control. The diffidence of results might be caused by the concentration of bacterial suspension. This study suggests that beneficial plant-microbe interaction could be a important role of enhancement of water availability and also provide a good method for improving quality of leafy vegetables under water stress conditions.

• Journal of Plant Biotechnology
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• v.43 no.4
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• pp.450-456
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• 2016

Rhizoctonia leaf blight (large patch) has become a serious problem in Korean lawn grass, which is extremely hard to treat and develops mostly from the roots of lawn grass to wither it away. Rhizoctonia leaf blight (large patch) is caused by Rhizoctonia solani AG2-2 (IV). To develop zoysia japonica with strong disease tolerance against this pathogenic bacterium, ${\beta}-1,3-glucanase$ was cloned from zoysia japonica, which is one of the PR-Proteins known to play a critical role in plant defense reaction. ${\beta}-1,3-glucanase$ is known to be generated within the cells when plant tissues have a hypersensitive reaction due to virus or bacterium infection and secreted outside the cells to play mainly the function of resistance against pathogenic bacteria in the space between the cells. This study utilized the commonly preserved part in the sequence of corn, wheat, barley, and rice which had been researched for their disease tolerance among the ${\beta}-1,3-glucanase$ monocotyledonous plants. Based on the part, degenerate PCR was performed to find out the sequence and full-length cDNA was cloned. E.coli over-expression was conducted in this study to mass purify target protein and implement in vitro activation measurement and antibacterial test. In addition, to interpret the functions of ZjGlu1 gene, each gene-incorporating plant transformation vectors were produced to make lawn grass transformant. Based on ZjGlu1 protein, antibacterial activity test was conducted on 9 strains. As a result, R. cerealis, F. culmorum, R.solani AG-1 (1B), and T. atroviride were found to have antibacterial activity. The gene-specific expression amount in each organ showed no huge difference in the organs based upon the transformant and against 18s gene expression amount.

• Korean Security Journal
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• no.41
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• pp.37-66
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• 2014

In recent years, with the development of computers and electronics, electronics and communication technology in a growing and each part is dependent on the cross-referencing makes all electronic equipment is obsolete due to direct or indirect damage EMP. Korea and the impending standoff North Korea has a considerable level of technologies related to the EMP, EMP weapons you already have or in a few years, the development of EMP weapons will complete. North Korea launched a long-range missile and conducted a nuclear test on several occasions immediately after, when I saw the high-altitude nuclear blackmail has been strengthening the outright offensive nuclear EMP attacks at any time and practical significance for the EMP will need offensive skills would improve. At this point you can predict the damage situation of Korea's security reality that satisfy the need, more than anything else to build a protective system of the EMP. The scale of the damage that unforeseen but significant military damage and socio-economic damage and fatalities when I looked into the situation which started out as a satellite communications systems and equipment to attack military and security systems and transportation, finance, national emergency system, such as the damage elsewhere. In General, there is no direct casualties reported, but EMP medical devices that rely on lethal damage to people who can show up. In addition, the State power system failure due to a power supply interruption would not have thought the damage would bring State highly dependent on domestic power generation of nuclear plants is a serious nuclear power plant accident in the event of a blackout phenomenon can lead to the plant's internal problems should see a forecast. First of all, a special expert Committee of the EMP, the demand for protective facilities and equipment and conduct an investigation, he takes fits into your budget is under strict criteria by configuring the contractors should be sifting through. He then created the Agency for verification of performance EMP protection after you have verified the performance of maintenance, maintenance, safety and security management, design and construction company organized and systematic process Guard facilities or secret communications equipment and perfect for the EMP, such as protective equipment maneuver system should take.