• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.2
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• pp.225-230
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• 2009

This study was conducted to response the growth, seed yield, nitrogen content and different cation content of two soybean, flooding-tolerant cv. Pungsannamulkong (PNSK) and flooding-sensitive cv. Tawonkong (TWK) when these were subjected to flooding stress at R1 stage for cultivation in paddy field. Flooding, underground water levels (UWL) of 0 cm, 10 cm and 40 cm, was experimented from flowering time to harvest time. The dry matter and seed yield of soybean with UWL of 0 or 10 cm declined in comparison with UWL of 40 cm and these were more reduction in TWK than in PNSK. The amount of nitrogen uptake decreased in higher UWL and there was a high significant relationship $(R^2=0.872)$ between nitrogen content and seed yield at flooding stress. K content of leaf and stem in soybean plants had a small change with UWL but Ca content had a decrease (leaf and stem) or increase (root). Mn and Fe content were increased at higher UWL and were more in TWK than in PNSK.

• Geomechanics and Engineering
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• v.19 no.5
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• pp.447-462
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• 2019

The vacuum preloading method has been used in many countries for ground improvement and land reclamation works. A sand cushion is required as a horizontal drainage channel for conventional vacuum preloading. In terms of the dredged-fill foundation soil, the treatment effect of the conventional vacuum preloading method is poor, particularly in Tianjin, China, where a shortage of sand exists. To solve this problem, straight-line vacuum preloading without sand is widely adopted in engineering practice to improve the foundation soil. Based on the engineering properties of dredged fill in Lingang City, Tianjin, this paper presents field instrumentation in five sections and analyzes the effect of a prefabricated vertical drain (PVD) layout and a vacuum pumping method on the soft soil ground treatment. Through the arrangement of pore water pressure gauges, settlement marks and vane shear tests, the settlement, pore water pressure and subsoil bearing capacity are analyzed to evaluate the effect of the ground treatment. This study demonstrates that straight-line vacuum preloading without sand can be suitable for areas with a high water content. Furthermore, the consolidation settlement and consolidation degree system is developed based on the grey model to predict the consolidation settlement and consolidation degree under vacuum preloading; the validity of the system is also verified.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.5
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• pp.107-115
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• 2002

This study was carried out to compare artificial soil formulated by blending calcined clay and coconut peat with perlite, then to evaluate this soil as a perlite substitute for use as an artificial planting medium. To achieve this, a determination of the physico-chemical properties and it's effect on plant growth were conducted by comparing those with large perlite grains and small grains. The results are summarized as follows: 1) The bulk density was 0.41g/㎤. This density was lower than that of field soil, but higher than that of large perlite grain(0.23g/㎤) and small grain(0.25g/㎤). The porosity, field capacity, and saturated hydraulic conductivity were 71.3%, 49.2%, and 3.8$\times$10-2cm/s, respectively. The air-permeability, water holding capacity, and drainage were better than or equal to that both large and small perlite grain. 2) It was near-neutral in reaction(pH=6.6). It had a high organic carbon content(65.8g/kg) and a low available phosphoric acid content(84.7mg/kg). It was similar to crop soil in cation exchange capacity(11.4cmol/kg). It had a low exchangeable calcium content(0.71cmol/kg), a low exchangeable magnesium content(0.68cmol/kg), a high exchangeable potassium content(2.54cmol/kg), and a high exchangeable sodium content(1.12cmol/kg). Except for the exchangeable potassium and sodium content, the chemical properties were better than or equal to both large and small grain perlite. The excessive exchangeable potassium or sodium content will inhibit plant growth. 3) In Experiment 1, the plant growth tended to be higher compared to that of large and small perlite gains. But in Experiment 2, it tended to be lower. This might be linked to the excessive exchangeable potassium or sodium content. 4) It could be considered as a renewable perlite substitute for greening of artificial soil. But, it would be necessary to leach the excessive exchangeable potassium or sodium to avoid the risk of inhibiting plant growth.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.9
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• pp.1351-1356
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• 2013

To enhance the utilization of Allium hookeri (AH) as a food, characteristics of AH roots and leaves cultivated under open field and greenhouse conditions were investigated. The moisture content of the roots and leaves were 81.05 to 84.18% and 88.85 to 90.12%, respectively. The moisture content of AH cultivated in the open field was 2 to 3% lower than the moisture content of AH cultivated in the greenhouse for both roots and leaves. The content of nitrogen-free extract, carbohydrates, was 13.49 to 16.20% in the roots and 7.08 to 7.79% in the leaves. The main mineral generated from both open field and greenhouse cultivation was potassium, at 503.98 to 512.08 mg% in leaves. The free sugar content of roots cultivated in the open field was four times higher than the content in the leaves, and roots cultivated in the greenhouse contained three times lower free sugar than the leaves. In particular, the fructose content of roots cultivated in the open field was about 12 times higher than roots cultivated in the greenhouse. The crude saponin and total polyphenol content was higher in leaves than roots, and was higher in the open field than the greenhouse. The $IC_{50}$ for DPPH radical scavenging activity was highest, 2.74 mg/mL, in 70% MeOH extracts of AH leaves cultivated in the greenhouse. Water and 70% MeOH extracts of AH leaves cultivated in the greenhouse showed no cytotoxicity to RAW 264.7 cells. Water extracts of AH leaves cultivated in the open field markedly inhibited the production of the inflammatory mediator nitric oxide. These results suggest that AH may be used as the material of health functional food.

• Korean Journal of Agricultural and Forest Meteorology
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• v.1 no.2
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• pp.110-118
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• 1999

This experiment was conducted to characterize the vertical transport trend of dissolved elements through throughfall, stemflow, effluent from Ao layer, and leachate out of soil profile on Pinus koraiensis stand in Experimental Forest of Kyunghee University, located in Kwangju, Kyunggi province for 12 months from July, 1998 to Jun, 1999. In addition, we investigated the content of dissolved elements and the factors influencing the water chemistry concentrations separately collected from the field. Water movement in the process of throughfall and stemflow from precipitation, and rainfall leached from Ao layer into soil water was governed by concentration of through fall, precipitation, rainfall intensity, seasonal variation, and other factors. Also, smaller changes of pH in soil water than that of dissolved elements in soil water could contribute buffer capacity, as well as balancing the concentration between cations and anions.

• Korean Journal of Remote Sensing
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• v.34 no.6_1
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• pp.1119-1130
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• 2018

Soyang Lake has been contributing to economic growth by preventing flood damage in the metropolitan area, the water level in the middle to upper flow of lake has been greatly decreased due to the drought in 2015. In order to restore the existing flow rate, Bupyungbo has been built in Bupyeong-ri, Shin Nam-myeon, Inje-gun to cause artificial changes on the sedimentary environment of Bupyeong freshwater region. Therefore, this study intends to confirm the changes of sedimentary environment since Bupyeongbo has been utilized. For this study, we used the Sentinel-2 satellite image data periodically to measure the dimension of water according to the volume of water kept near Bupyung district and analyzed the particle size and the percentage of water content of the sediments through field study. The Sentnel-2 satellite images showed us how the water surface has been changed and that during the period from September 2017 to October 2018, the minimum and maximum area of water surface was observed in June 2018 and in January 2018, respectively. In addition, we find that the smaller being the particle size, the higher having the water content and that there is higher the correlation between the water content and the grain size of the sediment layer. Hereafter, if we will acquire the drone images at Bupyung district, we expect that we will be able to measure the distribution of sediments in the same area according to different time periods and observe various kinds of sediment through field work.

• The Korean Journal of Soil Zoology
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• v.5 no.2
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• pp.165-168
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• 2000

The earthworm was investigated for knowing about that he inhabits in grassland, orchard field, organic farming land, greenhouse land, and ordinary farming land according to use of upland. The earthworm lives all in grassland and orchard field where was investigated, in 6 among 8 sites of organic farming land, in 5 among 12 sites of greenhouse land, in 5 among 25 sites of ordinary farming land. The earthworms that were shown are the Lumbricidae and the Megascolecidae. The number of the earthworm was 14 in orchard field, 12 in grassland, 10 in organic farming land, 7 in greenhouse land and 3 in ordinary farming land. The weight of the earthworms was declined in order of 12.3 g in orchard field, 11.6 g in organic farming land, 10.6 g in grassland, 4.2 g in greenhouse land and 2.9 g/0.25 m$^2$in ordinary farming land. If the water content of soil is not below 5% or over 35%, earthworm was no problem to live in. It was examined that the earthworm could live if pH values was not just strong acid or alkal. And if the organic matter is below 1%, the earthworm do not live but move another place.

• Journal of the Korean Geotechnical Society
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• v.33 no.4
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• pp.25-34
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• 2017

The soil-water characteristics is the most important state parameter for understanding changes in suction and water contents of unsaturated soil slopes. In the field, the hysteretic behaviors of drying and wetting soil-water characteristic curve are real and the adoption of path-dependent suction-water content is needed to predict the hydro-mechanical analysis of unsaturated soils. In this study, in-situ monitored hydraulic behavior of various soil slopes are compared with the data from numerical analysis with the laboratory soil water characteristic curve. Then, the verifications are performed based on the field monitored data respectively. Therefore, the use of path-dependent soil-water characteristic curves could be more rational for design and analysis of unsaturated soil slopes under rainfall conditions.

• Journal of the Korean Geosynthetics Society
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• v.14 no.4
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• pp.97-104
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• 2015

When carrying out design for soft ground improvement before reclamation of dredged soil, it is very important to appropriately evaluate design parameters such as compression index and undrained strength in order to estimate optimum construction cost. In this study, consolidation and strength parameters were estimated by the samples obtained from the similar reclaimed land. Water content and compression index of dredged soil reclaimed by hydraulic fill method were quite decreased in comparison with those of in-situ conditions at Incheon site. Relationships between compression index(Cc) and water content (wn), and between undrained strength (su) and water content (wn) for dredged soil were obtained by field vane test and oedometer test, respectively. Applicability of Schmertmann correction method (compression index) for low plasticity silty soil was discussed according to comparison with designed and measured settlements.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1C
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• pp.1-5
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• 2010

The river maintenance processing has revealed that the river beds in Korea have been significantly polluted in various ways for the last two decades. Thus, the dredging, transportation and landfilling of these contaminated materials are attracting public attention these days. In this study, electrokinetic method was applied in order to accelerate the settling processes of clay particles in suspension and evaluate the factors affecting the settling behaviour. It has been found from the testing results that the settling velocity under the influence of electrokinetics was much faster than the gravitational one, and the water content of slurry soil reduced significantly after the electrokinetic processing. The initial water content of slurry soil should be one of the important factors affecting the settling behaviour as well as variation of water content, and hence the electrokinetic processing would be the cost-effective method for the field application.