• 한국환경생태학회지
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• 제27권1호
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• pp.71-84
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• 2013

본 연구에서는 비자림의 생태적 특성을 파악하고 건강진단을 통해 나주 불회사 비자림 산림유전자원보호구역의 관리방안을 도출하였다. A유형은 현 수준을 유지하면서 경쟁목이나 피해목이 발생할 경우에 이를 제거하거나 치료하는 소극적인 관리, B유형은 토양의 산성화를 개선하고 조릿대, 왕대와 굴참나무, 개서어나무 등의 낙엽활엽수들을 제거하여 비자림을 확대 육성하는 적극적인 관리, C유형은 편백림 안에서 토양의 산성화 개선과 기존 비자림 중심의 소극적 관리, D유형은 토양산성화 개선과 비자 치수를 보호 육성하기 위하여 경쟁관계에 있는 식생을 제거하는 적극적 관리를 도출하였다. 마지막으로 해당 산림유전자원보호구역은 IUCN 보호지역관리 카테고리에 따라 카테고리 III(자연기념물) 또는 IV(종서식지 보호구역)로 등록 관리되어야 함을 제안하였다.

• Journal of Forest and Environmental Science
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• 제37권4호
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• pp.292-303
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• 2021

Studies that relate the structure of tropical regrowth vegetation to soil properties are generally lacking in the literature. This study proposes three indices for assessing the structural regeneration of secondary forests. They are: (1) the tree diameter class, (2) the plant life form and (3) the woody/herbaceous plants ratio indices. They were applied to assess the regeneration status of forest regrowth vegetation (aged 1-10 years), derived savanna regrowth vegetation in south western Nigeria, and to secondary forests in different stages of succession in Columbia and Venezuela, Bolivia, Mexico in South and Central America and semi-arid savanna in Ethiopia and seasonal deciduous forest successional stages in India. In all the cases, the indices increased with increasing age of regrowth vegetation and hence, with increasing structural complexity of regenerating vegetation. The tree diameter class index increased from 32.1% in a 9-year secondary forest to 69.0% in an 80-year-old secondary forest in Columbia and Venezuela and from 0.4% in a 1-year fallow to 20.9% in 10-year regrowth vegetation in southwestern Nigeria. In semi-arid savanna in northern Ethiopia, the woody/herbaceous plants ratio index increased from 18.1% in a 5-year protected grazing enclosure to 75.1% in 15-year protected enclosure, relative to the status of 20-year enclosure. The indices generally had correlations of 0.6-0.90 with species richness and Simpson's/Margalef's species diversity, implying that they are appropriate measures of ecosystem development over time. The proposed indices also had strong and positive correlations with soil organic carbon and nutrients. They are therefore, significant indicators of fertility status.

• Journal of Ginseng Research
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• 제13권1호
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• pp.114-118
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• 1989

Tolclofos-methyl applied as seed dipping at 1,000 ppm for 3 hrs before sowing and soil drenching at the rate of 300 g ai./10 a in the middle of April protected emerging seedlings of Panax ginseng from damping-off caused by Rhiiutonia solani(AG2-1) in Yangjik Soil artificially infested with the pathogen. Germination rates with tolclofos-methyl, pencycuron, and control were 53.7%, 45.8%, and 7.5%, respectively, while the rate of the seeds at non-infested soil was 62.6%. The effectiveness of Tolclofos-methyl against the pathogen in the soil lasted upto 32 days in vitro. However, the transpiratio of ginseng seedlings increased greatly with chemical treatment, showing 0.02, 0.12, and 0.24 m1/cm2 leaf area/day at 0, 1,2, and 4 ppm a.i. of the fungicide, respectively.

• Journal of Biosystems Engineering
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• 제32권1호
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• pp.30-36
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• 2007

Geothermal heat pump systems use the earth as a heat source in heating mode and a heat sink in cooling mode. These systems can be used for heating or cooling systems in farm facilities such as greenhouses for protected horticulture, cattle sheds, mushroom house, etc. A horizontal type means that a geothermal heat exchanger is laid in the trench buried in 1.2 to 1.8 m depth. Because a horizontal type has advantages of low installation, operation and maintenance costs compared to a vertical type, it is easy to be adopted to agriculture. In this study, to heat and cool farm facilities and obtain basic data for practical application of horizontal geothermal heat pump systems in agriculture, a horizontal geothermal heat pump system of 10 RT scale was installed in greenhouse. Heating performance of this system was estimated. The horizontal geothermal heat pump used in this study had heating COP of 4.57 at soil temperature of 14$^{\circ}C$ for depth of 1.75m and heating COP of 3.75 at soil temperature of 7$^{\circ}C$ for the same depth. The stratification of water temperature in heat tank appeared during the whole heat rejection period.

• 한국전통조경학회지
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• 제28권2호
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• pp.67-74
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• 2010

보호수는 역사와 전통을 간직한 자원으로 우리의 소중한 자산이자 보호관리하여 대대로 물려주어야 할 자연유산이다. 보호수는 수목으로 육종학적, 유전학적인 의미를 가짐과 동시에 환경적, 정서적 의미를 가지며, 그 가치를 높게 평가할 수 있다. 본 연구는 제천시 보호수의 생육환경 및 관리현황을 조사하여 개선방안을 모색하고자 식물학적 특성, 입지현황, 건강도, 토양특성, 근원부 성상, 관리현황 등을 조사하였다. 제천시 보호수는 300 이상의 수령이 가장 많았으며, 평탄지에 주로 위치하였다. 입지유형은 마을형, 동산형, 도로형의 순이었으며, 개발 정도는 건물지가 가장 많았다. 형성층 전기저항 측정치는 평균 $8.4k{\Omega}$로 나타났으며, 4그루에서 수피이탈 현상이 있었다. 대부분의 보호수에서는 외과수술이 실시되어 있었고, 근원부성상에서 완전 나지화가 된 곳은 1그루로, 근원부위에 콘크리트로 포장된 곳은 2곳으로 조사되었다. 토양산도는 5.0~8.4의 범위로 평균 7.1로, 전기전도도 EC는 0.5dS/m 이하로 측정되었다. 보호책은 총 48그루 중에서 16그루만 설치되어 있었으며, 석축이 설치된 곳은 3곳이었다. 외과수술이 시행된 곳은 총 33그루로 대부분이 공동의 부패부위방지 및 치료인 것으로 추측되며, 안내판은 23그루에 설치된 것으로 조사되었다.

• 생물환경조절학회지
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• 제16권4호
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• pp.328-332
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• 2007

본 연구는 토양 염도(EC)에 따른 토마토의 생육효과를 검토코자 토양 중 염류농도(EC)를 각각 1.0, 2.5, 5.0 및 $7.5dS{\cdot}m^{-1}$로 두어 폿트 실험을 수행하였다. 토마토의 초장, 생체중, 건물중 등 생육은 토양 중 염류농도가 높을수록 억제되었으며 특히 EC $5.0dS{\cdot}m^{-1}$ 이상의 염류농도에서 큰 차이를 나타내었다. 지상부의 생체중과 건물중은 초장과는 달리 EC $7.5dS{\cdot}m^{-1}$에서 감소하였다. 반면 뿌리의 생체중과 건물중은 지상부와는 달리 EC $5.0dS{\cdot}m^{-1}$까지는 차이가 없었으나 EC $7.5dS{\cdot}m^{-1}$서는 매우 감소하였다. 평균과중은 EC $5.0dS{\cdot}m^{-1}$에서 92g으로 EC $1.0dS{\cdot}m^{-1}$ 129g보다 37g이나 가벼웠고 착과수는 평균과중과는 달리 EC $7.5dS{\cdot}m^{-1}$에서는 매우 감소하였다. 수량은 EC 5.0, EC $7.5dS{\cdot}m^{-1}$에서 각각 3,810, 3,216kg/10a로 EC $1.0dS{\cdot}m^{-1}$의 5,488kg/10a보다 각각 31%, 41% 감소하였다. 토마토 과실의 당도와 산도는 염류농도가 높을수록 증가하는 경향이었으며 토양 중 EC $5.0dS{\cdot}m^{-1}$ 이상에서 과실당도가 5.2% 이상 증가하였다. 잎의 수분퍼텐셜 및 엽록소, 기공전도도 및 광합성 함량은 염류농도가 높을수록 억제되었다. 총 T-N, P 및 Na 함량은 염 농도가 높아질수록 증가하는 경향이었으나, Ca, Mg 및 K 함량은 염류농도가 높을수록 감소하였다. Na 함량은 증가하였으며 다른 성분은 처리간에 차이가 없었다.

• 생물환경조절학회지
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• 제22권2호
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• pp.162-166
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• 2013

토양검정 후 시비수준이 멜론의 생육과 품질에 미치는 영향을 분석한 결과, 추천 시비량을 줄이면 엽면적과 과실 무게는 크게 감소하는 경향을 보였다. 엽면적은 추천시비량의 100% 시비구에 비해 0%와 50% 시비구에서 각각 54.1%와 24.5% 감소하였다. 과실무게는 추천 시비량의 100% 시비구에서 2670g인데 비해 0과 50% 시비구에서 각각 1650g과 2140g으로 38.2%와 19.9% 감소 하였다. 그러나 가용성 고형물과 자당 함량은 100% 시비구에 비해 50% 시비구에서는 각각 1.8%와 23.3% 증가하였다. 따라서 멜론 재배시 토양검정 후 추천 시비량의 50%만 시비하여도 엽수, 초장 및 엽면적 등의 생육과 평균과중에 감소가 없어 당도가 높은 멜론을 생산할 수 있을 뿐만 아니라 시비량을 줄임으로써 염류집적도 방지할 수 있을 것으로 판단되었다.

• Corrosion Science and Technology
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• 제21권1호
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• pp.1-8
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• 2022

The use of cathodic protection for metals can be achieved by sacrificial anode CP or impressed current CP, or a combination of both. Cathodic protection is a highly effective anti-corrosion technique for submerged metals or metals in soil. But because the non-immersion atmospheric automobile environment is a high resistance environment, it is limited by fundamental cathodic protection. However, the application of cathodic protection to automobiles is attractive because of the possibility of maintaining corrosion resistance while using lower-cost materials. A commercially available product for automobiles that uses both sacrificial anode CP and impressed current CP was tested in a periodic salt spray environment to investigate the performance of the devices. Experimental results show that the metal to be protected has different anti-corrosion effects depending on the distance from the anode of the device, but it is effective for the entire 120 cm long specimen exposed with one anode. The cathodic protection is effective because the conductive tape attached to the anode of the structure to be protected acts as a constant electrolyte in wet and dry conditions. The results show that the entire standard passenger car can be protected by cathodic protection with 4 anodes.

• 한국토양비료학회지
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• 제48권1호
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• pp.50-56
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• 2015

This research was performed to test the hypothesis that the optimal fertilization rate for lettuce is various with soil moisture conditions. The experiment was conducted under a rainfall-intercepted facility in Suwon, South Korea from 2002 to 2003. Soil was irrigated at 30, 50, or 80 kPa of soil moisture tension at 15 cm soil depth in 2002 spring and fall and 20, 30, 50, or 80 kPa in 2003 spring. Fertilization was performed with four levels in spring for both years: none, 0.5, 1.0, and 1.5 times of the recommended N, P, and K fertilization rate. The irrigation amount increased with decreased irrigation starting point as soil moisture tension. The maximum yield was found at the lowest soil moisture tension in spring while irrigation at 50 kPa resulted in the greatest yield in fall. The yield responses of lettuce to fertilization rates were various with soil moisture condition. In spring, maximum yield was found at 1.0 or 1.5 times of the recommended fertilization rate at 20, 30, and 50 kPa irrigation while 0.5 or 1.0 times of fertilization rate resulted in the maximum yield in fall. Especially for 80 kPa irrigation in 2003 spring, yield was decreased by fertilization. It suggested that the optimum fertilization rate for lettuce is affected by soil moisture condition and that lower fertilization rate should be suggested when soil is managed in drier condition.

• Corrosion Science and Technology
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• 제4권1호
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• pp.1-7
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• 2005

An alternating current (AC) corrosion on buried pipeline has been studied using coupon and ER probe. Coupons and ER probes were applied to the sites from high value of AC voltage to low value based on the survey of AC voltages on buried gas transmission pipeline over the country. Parameters such as AC current density of coupon, AC voltage, cathodic protection potential, soil resistivity and frequency were monitored continually. Corrosion induced by AC was observed even under cathodically protected condition that met cathodic protection criterion (; below -850 mV vs. CSE). Corrosion rate was affected mainly not by AC voltage but by both of frequency and AC current density. An experimental corrosion rate relation could be obtained according to effective AC current density, in which AC corrosion rate increased linearly with effective AC current density, and its slope was 0.619 in coupon method and 0.885 in ER probes.