• Title/Summary/Keyword: field research station

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Effluent Characteristics of Nonpoint Source Pollutant Loads at Paddy Fields during Cropping Period (영농기 광역논으로부터 비점오염물질 유출 특성)

  • Han, Kuk-Heon;Kim, Jin-Ho;Yoon, Kwang-Sik;Cho, Jae-Young;Kim, Won-Il;Yun, Sun-Gang;Lee, Jeong-Taek
    • Korean Journal of Soil Science and Fertilizer
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    • v.40 no.1
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    • pp.18-24
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    • 2007
  • Paddy fields are apparently nonpoint source pollution and influence water environment. In order to improve water quality in rivers or lakes, to low nutrient load from paddy fields are required. To establish comprehensive plan to control agricultural non-point source pollution, it is imperative to get a quantitative evaluation on pollutants and pollution load from paddy fields. A field monitoring study was carried out to investigate the water balance and losses of nutrients from fields in Sumjin river basin. The size of paddy fields was 115 ha and the fields were irrigated from a pumping station. The observed total nitrogen loads from paddy fields were larger than those of the unit loads determined by Ministry of Environment data (MOE). It is because the nitrogen fertilization level at the studied field was higher than the recommended rate and the high irrigation and subsequent drainage amount. On the contrary, total phosphorus loads were less than those addressed by MOE since phosphorus fertilization level was lower than that of standard level. Therefore, it was found that fertilization, irrigation, and drainage management are key factors to determine nutrient losses from paddy fields. When the runoff losses of nutrients were compared to applied chemical fertilizer, it was found that 42 to 60% of nitrogen lost via runoff while runoff losses of phosphorus account for 1.3 to 7.6% of the total applied amount during the entire year.

A survey on the EMF Levels of Study and Electric Appliances in Korea (국내 전철 및 가전제품을 대상으로 한 전자장 수준 실태조사)

  • Jang, Seong Ki;Cho, Yong Sung;Lee, Seok Jo;Yoo, Seong Wha;Jung, Kyung Mi;Lim, Jun Ho
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.15 no.1
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    • pp.71-81
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    • 2005
  • The purposes of this study was to collect, analyze, and describe the MF exposure levels from subways in Korea and to measure and evaluate the MF levels generated from electric appliances used at general homes. The target subway lines were Seoul Metropolitan Line 1 to Line 8, Bundang Line, Incheon Line, Daegu Line, Gwangju Line, and Busan Line 1 and Line 2. We measured at each station in those subway lines and, all the train types (pantograph-equipped, motor-equipped, and common), and platform types(facing and isolating) were investigated by the distance(80, 200, 400 cm) from the train on 19 targeted subway lines using 3 magnetic field measuring devices (EMDEXII, Enertech Co.) during the survey from January till October, 2004. On the other hand, the levels of the 60Hz magnetic fields generated from 14 items of home electric appliances such as electric blankets, hair dryers, electric razors, etc. were measured at 10 general homes using 5 EMDEXII meters with a sampling interval of 1.5 second by the distance(surface, 30, 50, 100, 300cm ) from the target electric appliances. The survey results in the whole subway lines examined in this study were as follows; Seoul Metropolitan Line 4 using AC(alternating current) power source showed the highest mean value of $2.85{\mu}T$, followed by Seoul Metropolitan Line 1 running between Seoul and Incheon using AC($2.78{\mu}T$), Seoul Metropolitan Line 1 between Seoul and Uijongbu using AC($2.73{\mu}T$), Bundang Line using AC($1.79{\mu}T$), Seoul Metropolitan Line 1 connected from Yongsan using AC($1.67{\mu}T$), Seoul Metropolitan Line 1 between Seoul and Suwon using AC($0.79{\mu}T$), and so on. In general, the intensity of the magnetic field in the subway systems in Korea was significantly higher when using AC($2.14{\pm}0.91{\mu}T$) than when using DC($0.29{\pm}0.44{\mu}T$) power source. Among the home electric appliances examined, microwave ovens showed the highest mean value of $7.69{\mu}T$, followed by hair dryers($6.47{\mu}T$), vacuum cleaners($5.27{\mu}T$), televisions ($2.26{\mu}T$), electric blankets($1.38{\mu}T$), personal computers ($0.81{\mu}T$), and so on. Two items of electric appliances showed the excess value of $0.2{\mu}T$ at the distance of 30cm in the MF exposure level; electric razors $1.58{\pm}2.13{\mu}T$ and vacuum cleaners $0.48{\pm}0.44{\mu}T$. As a whole, this study showed a tendency that the shift of the MF levels according to the increase of distance from the electric appliances was lower than those of the results surveyed in UK and USA. As a result, this study is expected to suggest meaningful data for the future study in exposure assessment of magnetic fields and for the establishment of guidelines for subways and electric appliances in Korea. More detailed and large scaled exposure assessment studies should be performed continuously to get the various and useful information on health risk assessment of MFs in Korea.

Study on Corn Yield Enhancement by Plant-Growth Promoting Rhizobacterium (식물생장촉진 근권세균에 의한 옥수수(Zea may L.)의 생산성 향상에 관한 연구)

  • Choi, Ki Chun;Jeong, Kwang Hwa;Lee, Joung Kyong;Youn, Chang;An, Seung Hyun;Yook, Wan Hang
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.19 no.1
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    • pp.31-40
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    • 1999
  • This study was conducted to investigate the effects of rhizosphere bacterium and pathogenic fungi on the growth of corn(Zea may L.) in continuous corn cultivation soil(CCCS) and non-continuous cultivation soil(NCCS). Corn was established by seeding into pots of 30 cm in diameter and 50 cm in depth containing 1 : 1 mixture of soil and vermiculite. Rhizobacterium and pathogenic fungi were inoculated into the soils. The field experiment was carried out at the Animal Research Station, College of Agriculture, Chonnam National University. Sample of corn was taken from each pot at 50 days and 90 days after sowing. Corn was cultivated in a vinyl house with three replications under natural daylight conditions. The bacterium used in this study was Bacillus subtilis. B. subtilis was directly isolated and identified from forage rhizosphere soil. Dry matter(DM) of coron plant in treatment without B. subtilis was lower than that in treatment of B. subtilis. DM of corn plant inoculated with B. subtilis was higher than that of corn inoculated with pathogenic fungi in both CCCS and NCCS. DM of corn plant in NCCS was more increased than that in CCCS. The effect of B. subtilis inoculation on the growth of corn was better in NCCS than in CCCS. However, DM of corn plant was apparently decreased by the inoculation of the pathogenic fungi in both CCCS and NCCS.

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Estimation of Quantitative Source Contribution of VOCs in Seoul Area (서울지역에서의 VOCs 오염원 기여도 추정에 관한 연구)

  • 봉춘근;윤중섭;황인조;김창녕;김동술
    • Journal of Korean Society for Atmospheric Environment
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    • v.19 no.4
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    • pp.387-396
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    • 2003
  • A field study was conducted during the summer time of 2002 to determine compositions of volatile organic compounds (VOCs) emitted from vehicles and to develop source emission profiles that is applied to CMB model to estimate the source contribution of certain area. Source emission profile is widely used for the estimation of source contribution by the chemical mass balance model and have to be developed applicable for the target area of estimation. This study was aimed to develop source emission profile and estimation of source contribution of VOCs after application of the chemical mass balance (CMB) receptor model. After considering the emission inventory and other research results for the VOCs in Seoul, Korea, the sources like vehicle emission (tunnel), gas station (gasoline, diesel), solvent usage (painting operation, dry cleaning, graphic art), and gas fuels were selected for the major VOCs sources. Furthermore, ambient air samples were simultaneously collected from 09:00 to 11:00 for four days at eight different official air quality monitoring sites as receptors in Seoul during summer of 2001. Source samples were collected by canisters, and then about seventy volatile organic compounds were analyzed by gas chromatography with flame ionization detector (GC/FID). Based on both the developed source profiles and the database of the receptors, CMB model was intensively applied to estimate mass contribution of VOCs sources. Examining the source profile from the vehicle, the portion of alkanes of VOCs was highest, and then the portion of aromatics such toluene, m/p-xylene were followed. In case of gas fuel. they have their own components; the content of butane, propane, ethane was higher than any other component according to the fuel usage. The average of the source apportionment on VOCs for 8 sites showed that the major sources were vehicle emission and gas fuels. The vehicle emission source was revealed as having the highest contribution with an average of 49.6%, and followed by solvent with 21.3%, gas fuel with 16.1%, gasoline with 13.1%.

Phonotaxis of the African Mole Cricket, Gryllotalpa africana Palisot de Beauvois (땅강아지의 주음성에 관한 연구)

  • 김기황
    • Korean journal of applied entomology
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    • v.32 no.1
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    • pp.76-82
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    • 1993
  • Phonotaxis of the African mole cricket, Gryllotalpa africana palisot de Beauvois, was investigated in 1990 and 1992 at the agronomy Experiment Station of Korea Ginseng & Tobacco Research Institute in Hwaseong-gun, Kyonggi-do, Male adults produced calling sounds (calling songs) through the openings of subsurface burrows. Intensities of the sound were 77-80 dB at 15 cm above the openings. When tape recordings of male calling songs were broadcasted outdoors at 105-110 dB by two horn speakers installed at the center of a 1.4 m diameter-funnel, flying adults were attracted for 1.5 hours from about 30 minutes after sunset. Among attracted adults, 14.3-16.9% landed in the funnel, and 65.7-74.7% landed on the ground within 2m form the sound source. Females were 66.7-74.3%, which seemed to be due to the sex ratio of the population in the field. Adults landing in the funnel and at the distance of within 2m from the center of the funnel were tend to be a little more than those attracted to a blacklight trap.

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Root-zone Placement of Carbofuran for Control of Rice Insect Pests (Carbofuran 수도근계처리의 해충방제효과)

  • Ryu J. K.;Choi S. Y.;Lee H. R.;Song Y. H.
    • Korean journal of applied entomology
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    • v.16 no.4 s.33
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    • pp.217-220
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    • 1977
  • During 1976 the effects of carbofuran placement in the root zone of the rice plants, the varieties Palkweng and Yushin, were evaluated for control of common rice pests in the paddy field at the Honam Crops Experiment Station. The methods of insecticide placement included the use of capsule formulation and liquid injection by the root-zone liquid insecticide injector designed at the International Rice Research Institute. The single ro~t-zone application of carbofuran at 2 days after transplanting was compared with two and fcur broadcast applications of carbofuran and diazinon. Capsules were the most. effective in controlling the striped rice borer (Chilo suppressalis), small brown plant-hopper (Laodelphax striatellus), green rice leafhopper (Nephotettix cincticeps) and stripe virus disease which is transmitted by the small brown planthopper. However, one injector application of carbofuran was equal or better the broadcast applications. Their control effectiveness were more significant on Palkweng susceptible to common rice pests than on Yushin resistant to the stripe virus disease.

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Morphological Differences between Larvae of the Oriental Fruit Moth (Grapholita molesta Busck) and the Peach Fruit Moth (Carposina sasakii Matsumura) in Korea

  • Lee, Seung-Yeol;Choi, Kwang-Shik;Choi, Kyung-Hee;Yoon, Tae-Myung;Jung, Hee-Young
    • Applied Microscopy
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    • v.43 no.1
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    • pp.21-26
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    • 2013
  • The oriental fruit moth (Grapholita molesta Busck) and the peach fruit moth (Carposina sasakii Matsumura) are the most severe insect pests affecting apple orchards in Korea. To prevent an outbreak of these two species and to control these agricultural insect pests, it is important to identify them accurately. However, it is hard to classify them when they were in the larval stage since they tunnel into the apple fruit. In this study, surface structures of the two species of larvae were observed using stereo microscope and scanning electron microscope. Distinct differences between the two species of larvae were found. The prothorax spiracles of oriental fruit moth larvae were approximately twice as large as those of peach fruit moth larvae. The arrangements of subventral setae, located around the proleg, were different between oriental fruit moth and peach fruit moth larvae. Furthermore, subdorsal setae of oriental fruit moth were located next to the spiracle on the 8th abdominal segment, while that of peach fruit moth was located above the spiracle. The identification of the two species of larvae observed in this study was confirmed using polymerase chain reaction-restriction fragment length polymorphism method. Surface structural differences are intrinsic characteristics for each species of larvae and can easily be identified using stereo microscope. These specificities will be helpful where a large number of field-collected larvae need to be identified routinely in pest control research.

A Study on the Estimation of Soil Erosion Quantity Using USLE in the Upper Region of ManKyoung River Basin (USLE를 활용한 만경강 상류지역에서의 토양침식량 산정에 관한 연구)

  • Lee, Jae Hyug;Shim, Eun Jeung;Lee, Yeon Kil;Kim, Tae Woong
    • Journal of Wetlands Research
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    • v.14 no.3
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    • pp.317-328
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    • 2012
  • The objects of this study are to perform appropriateness analysis of USLE(universal soil loss equation) model and to accumulate the data measured in field. The basin area of Bongdong station is $342.27km^2$. This study simulated sediment outflows in the basin and performed a comparative analysis of simulated outputs with actual measurement values. Also annual rainfall was used to calculate rainfall-runoff erosivity factor which can influence soil erosion. The calculation of annual average soil erosion was made by soil erosion maps. The maps with a resolution of ($30m{\times}30m$) were created by multiplication of factors(R, LS, K, C, P) from ArcView Map Calculator. In this paper, it was shown that soil erosion was not occur in the most of basin.

Effect of Harvesting System on Labor-saving in Sweetpotato Cultivation (고구마 수확작업체계별 생력효과의 차이)

  • Kim, Hag-Sin;Lee, Joon-Seol;Chung, Mi-Nam
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.56 no.4
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    • pp.400-403
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    • 2011
  • This experiment was carried out to determine the effect of mechanization on lavor-saving in sweetpotato cultivation. The field experiment was conducted from 2005 to 2006 in Mokpo Experiment Station of the National Institute of Crop Science. In order to determine the efficiency of mechanical harvesting, different harvesting methods were compared. Mechanical harvesting method was done as follows: cutting of vines by machine, removal of plastic film mulching, and harvesting by two-row and one-row harvesting system. The result showed harvesting labor was decreased by 66.6% in two-row harvesting. The ratio of damaged sweetpotato by mechanical harvesting decreased by 49.4% in two-row and 38.4% in one-row harvesting compared to conventional method. The total labor cost was saved by 48.2% - 70.4% using mechanical method. In addition, the total income also increased by ca. 62.9% - 81.2%. Thus, it was concluded that mechanical harvesting is more efficient and economical method than conventional one.

Accuracy of Combined Block Adjustment with GPS-Permanentstation (GPS 연속관측점을 이용한 결합블럭조정의 정확도)

  • 박운용;이재원;신상철
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.17 no.1
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    • pp.21-32
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    • 1999
  • Mapping and precise point determination by photogrammetry have been shown to be an economic solution. But control points are necessary to determine the exterior orientation parameters. Although the number of required control points has been reduced based on extended bundle adjustment and reinforced cross-strip, the ground survey is a significant factor of whole expenses in photogrammetry. The status of GPS-photogrammetry with kinematic DGPS-positioning to overcome this disadvantages, is now steadly progressive since the first possibility has been proved. The completed satellite configuration, powerful receiver function and upgraded software for kinematic DGPS-positioning have extensively improved the accuracy of combined bundle adjustment. So the research for the operational use of GPS-photogrammetry is absolutely necessary. The presented test field was designed for identification of subsidences in a coal mining area, flown with 60% sidelap and cross strips. Just with 6 control points and combined block adjustment instead of the traditionally used 21 horizontal and 81 vertical control points the same ground accuracy has been reached. The accuracy of kinematic GPS-positioning and combined block adjustment was independent upon the distance of the ground reference station. It also has been showed that the special model for the systematic error correction in the combined block adjustment.

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