• 한국토양비료학회지
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• 제42권4호
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• pp.280-288
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• 2009

간척지에서 식생의 공간적 분포 변이에 영향을 주는 요인을 알아내기 위하여, 중서부 해안 경기만의 신간척지와 간척연대가 다른 간척지 세 곳, 그리고 이들의 인근 비간척 간석지에서 식생 분포를 조사하였다. 토양 염도의 지표로 포화침출액의 전기전도도를 조사하였다. 토양염도에 따라 식생 분포가 확연이 달랐다. 토양 염도에 따라 각 식생의 최적 서식지가 존재하며, 이는 저염도 지점에는 중성 식물이, 고염도 지점에는 염생식물이 분포함을 의미하고 있다. 서식 식물 군집에 따른 토양 염도의 순서는 다음과 같다. 즉, 토양 염도는 식생 위조지>선구 염생식물지> 혼합선구염생식물지> 선구염생식물지> 선구염생식물 및 통성 염생식물 혼합지> 혼합 통성염색식물지> 통성염생식물 및 중성식물 혼합지>혼합 중성식물지의 순이었다. 이 결과는 토양 염도의 공간적 토양 구배에 따라 식물 종의 분포가 이루어짐을 보여 주고 있으며, 이에 따라 식물종의 분포에 따라 토양 염도의 차이를 판단할 수 있음을 시사하고 있다. 토양 염도와 식물종의 분포양상 관계는 여러 간척지간에 큰 차이를 보이지 않았고, 식물 군락 밀집도가 간척 이후 식생이 어떤 방향으로 천이되는지의 지표를 제시하여주고 있다.

• Journal of Plant Biotechnology
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• 제38권3호
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• pp.203-208
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• 2011

We transferred Dhn5 (dehydrin5) gene from barley to poplar to determine the effect of its expression on the transgenic poplars. The results from northern blot analysis showed that the expression level of gene varied among the transgenic lines. During their culture on tissue culture media, the transgenic poplars formed vigorous growing callus in the presence of 5% PEG. When the transgenic poplars were growing in pots and witheld watering, they stayed much healthier than nontransgenic poplars. The transgenic poplars showed higher rates of photosynthetic rates, stomatal conductance and evaporation rates under the drought stress, although there was no significant difference in soil water content within the treatments. The relative electrical conductivity of the transgenic poplars after 20% PEG treatment was lower than that of nontransgenic poplars. The results provide evidence that the expression of hvDhn5 gene conferred drought tolerance in the transgenic poplars.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기설비전문위원
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• pp.169-172
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• 2004

The tower footing resistance is an extremely important parameter in the determination of lightning flashover. For the reduction of back flashover faults, power utility companies have had a concern to decrease the footing resistance. There are two manufactures of the conductivity concrete materials in Korea. In this paper, we investigated possibility of soil pollution due to the conductivity concrete materials. Also, we analyzed on the reduction characteristics of footing resistance of those.

• 한국지하수토양환경학회지:지하수토양환경
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• 제28권5호
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• pp.25-35
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• 2023

This study aimed to classify spring types based on the hydrogeological characteristics of springs in Yongsu-ri~Hamo-ri coastal area in western part of Jeju Island. The springs in study area can be broadly categorized into three groups: perched groundwatrer springs (soil type), perched groundwater springs (sediment type), and basal groundwater springs. The perched groundwater springs of soil type correspond to springs where groundwater seeps out from the perched aquifer formed in the soil layer due to the development of clayey Kosan Formation beneath the surface. Because of the low hydraulic conductivity of soil layer, the average of spring discharge is less than 1 m³/day. The quality of spring water is significantly influenced by agricultural activities, resulting in high nitrate nitrogen concentrations and electrical conductivity. While the perched groundwater springs (sediment type) of the Suwolbong Tuff, which are located in the upper part of Kosan Formation, exhibited relatively higher discharge rates, their water quality was similar to soil-type springs. Basal groundwater springs are located in the zone of basal groundwater, mostly near the coastline. This type of spring appears to discharge of up to 3,707 m³, and the salinity content varies with the tidal fluctuations, especially increasing significantly during dry seasons.

• Environmental Engineering Research
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• 제25권3호
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• pp.409-417
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• 2020

Investigation was carried out to assess the effect of cement dust deposition on the physico-chemical properties of soil near some cement plants in Jaintia Hills, Meghalaya. Soil samples were collected and analysed and compared with the control site. Comparison of various soil physico-chemical parameters revealed that cement dust emanating from cement plants has changed the soil quality in the surrounding areas of cement plants. The normal soil pH in the area is generally acidic. However, due to the continuous deposition of cement dust soil pH was found slightly alkaline near the cement plants. The higher values of soil parameters such as electrical conductivity and bulk density were also noticed near the cement plants. However, lower values of water holding capacity, soil moisture content, soil organic carbon and total nitrogen content were found compared to the control sites. The effect of cement dust deposition on soil is more in areas nearer to the cement plants. At present the changes may not be so serious but if this trend continues, soil properties of a vast area around the cement plants are likely to change leading to multiple effects on flora, fauna and socio-economy of the area.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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• pp.432-435
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• 2006

To evaluate geology and extent of leachate migration around the landfills, electrical resistivity survey were conducted in area of uncontrolled landfills in Cheonan and Wonju. The Cheonan landfill is located above the paddy fields and the resistivity survey lines were crossed to confirm possible pollution of the paddy fields by leakage of the landfill leachate. In Wonju, the landfill and the downgradient paddy fields are divided by a concrete barrier wall. At the bottom of the landfill, there is a leachate settlement system but has not been in operation. And a total of 4 survey line installed (1 parallel and 3 perpendicular to mean groundwater flow direction). According to the resistivity survey results, the landfill leachate in Cheonan appeared to be restricted only within the interior of the landfill, not to migrate into the subsurface of the paddy fields. These results are well consistent with electrical conductivity values of groundwaters obtained from a periodic analysis of water qualities. In Wonju, however, it was inferred that the leachate emanating from the landfill migrated beneath the abandoned leachate settlement system and it would reach the downgradient paddy field.

• 한국토양비료학회지
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• 제41권5호
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• pp.310-317
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• 2008

포화추출액중 전기전도도는 $1.0\sim28.4dS\;m^{-1}$의 범위로 평균 $4.8dS\;m^{-1}$를 나타내어 매우 높은 농도로 염류가 집적되고 있었다. 전기전도도 $4dS\;m^{-1}$ (포화추출액 조건으로 환산)를 초과한 경우가 전체의 55%를 차지하고 있었다. 복분자 비가림하우스 재배토양 중 전기전도도와 각각의 무기이온과의 단순상관관계를 조사한 결과, 전기전도도와 염소 ($r=0.85^{**}$), 질산 ($r=0.94^{**}$), 인산 ($r=0.88^{**}$), 황산 ($r=0.84^{**}$) 이온과 같은 음이온과 고도의 유의성 있는 정(+)의 상관관계를 나타내었고, 마그네슘 ($r=0.41^*$), 칼슘 ($r=0.38^*$), 칼리 ($r=0.47^*$) 이온과 같은 양이온과는 유의성 있는 정(+)의 상관관계를 나타내었다. 비가림 하우스형 복분자 재배토양 중에 함유되어 있는 염류집적 유발물질을 제거하는데 있어 작업의 편이성, 농업용수의 절감 및 처리시간 등을 고려하였을 때 용탈법보다 수세법이 더 효과적인 것으로 나타났다.

• 한국토양비료학회지
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• 제44권6호
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• pp.1035-1041
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• 2011

Salinity of soil under the plastic film houses in Korea is known as a significant factor to lower the crop production and to hamper the sustainable agricultural land management. In this study we propose a field monitoring technique to examine the methods applied to minimize the adverse effect of salts in soil based on the relationship between soil electrical characteristics and soil properties. Field experiments for 4 different treatments (water only, fertilizer only, DTPA only, and DTPA and fertilizer together) were conducted on soils at the plastic film house built for cultivating a cucumber plant located at Chunan-si, Chungchungnam-do in Korea. The electrical resistivity was measured by both a dipole-dipole and wenner multi-electrodes array method. After the electrical resistivity measurement we also measured the soil water content, temperature, and electrical conductivity on surface soil. The resulted image of the interpreted resistivity by the inversion technique presented a unique spatial distribution depending on the treatment, implying the effect of the different chemical components. It was also highly suspected that resistivity response changed with the nutrients level, suggesting that our proposed technique could be the effective tool for the monitoring soil water as well as nutrient during the cropping period. Especially, subsoils under DTPA treatment at 40 to 60 cm depth typically presented lower soil water accumulation comparing to subsoils under non-DTPA treatment. It is considered that DTPA resulted in increase of a root water uptake. However, our demonstrated results were mainly based on qualitative comparison. Further experiments need to be conducted to monitor temporal changes of electrical resistivity using time lapse analysis, providing that a plant root activity difference based on changes of soil water and nutrients level in time.

• 한국토양비료학회지
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• 제38권5호
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• pp.247-252
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• 2005

토양 pH는 토양화학반응의 결과로 토양용액으로 해리하는 수소이온을 나타내는 intensity factor이고 토양의 알루미늄에 의하여 수소이온이 완충되고 있다. 토양 양이온에 의하여 알루미늄의 수소이온 완충기능이 저하되면 토양 pH 양상이 달라지므로 토양 EC에 따른 토양 pH 양상은 토양의 pH 완충력 등 토양관리를 위한 중요한 정보를 담고 있다. 토양에 투입되는 양분에 의하여 토양 pH가 달라지는 현상을 구명하고 시설재배지 토양의 EC에 따른 토양 pH 양상을 파악하기 위하여 사양토에는 가축분과 퇴비 및 비료를 넣고 시설재배지 토양은 무처리 상태로 $30^{\circ}C$에서 5, 10, 20, 40일간 호기항온 후 토양과 토양용액의 화학적 특성을 분석하였다. 가축분을 첨가한 사양토의 pH 양상은 토양에 첨가된 양이온 함량에 비례하여 pH가 올라갔으며 양분이 축적된 시설토양의 pH 양상은 양분함량이 많을수록 pH가 낮아졌다. 따라서 토양 EC가 높아질 때 토양 알루미늄의 수소이온 완충력이 높은 상태에서는 토양의 pH는 양이온의 양에 비례하여 올라가지만 토양 알루미늄의 수소이온 완충력이 저하된 상태에서는 토양의 음이온의 양에 비례하여 pH가 낮아지는 것으로 나타났다.

• 한국토양비료학회지
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• 제48권5호
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• pp.326-331
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• 2015

High salinity and sodicity of soils play a negative role in producing crops in reclaimed tidal lands. To evaluate the effects of soil ameliorants on salt removal in a highly saline and sodic soil of reclaimed tidal land, we conducted a column experiment with treating gypsum, compost, and phosphate at 0-2 cm depth and measured the salt concentration of leachate and soil. Electrical conductivity of leachate was $45-48dSm^{-1}$ at 1 pore volume (PV) of water and decreased to less than $3dSm^{-1}$ at 3 PV of water. Gypsum significantly decreased SAR (sodium adsorption ratio) of leachate below 3 at 3 PV of water and soil ESP (exchangeable sodium percentage) below 3% for the whole profile of soil column. Compost significantly decreased ESP of soil at 0-5 cm depth to 5% compared with the control (20%). However, compost affected little the composition of cations below a depth of 5 cm and in leachate compared with control treatment. It was concluded that gypsum was effective in ameliorating reclaimed tidal lands at and below a soil layer receiving gypsum while compost worked only at a soil layer where compost was treated.