• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.667-671
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• 2004

The purpose of this paper is to study on the construction of environmentally friendly roadbed by reinforcing type soil solidification agent. The soil amendment agent used in this study is friendly to the environment, and has a function of soil-cement-agent solidification. The soil amendment agent was admixed with reinforced fiber material for enhancement of strength and durability of roadbed. The project of trial field test of roadbed construction with special reinforcing soil treatment agent was performed in Gyunggido on December 2003. A series of field and laboratory experiments including unconfined compressive strength, permeability were carried out to investigate the physical and mechanical characteristics of solidified roadbed treated by this reinforced solidifying agent. The results of this research showed that the roadbed using normal and poor soil could be efficiently constructed by treatment of this reinforcing type solidification agent admixed with fiber material.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.83-86
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• 2003

Soil Aquifer Treatment (SAT) is a technique in which secondary- or tertiary-treated wastewater is infiltrated through unsaturated soil and stored in the saturated zone. In SAT, contaminants are removed by physical and biochemical reactions taking place in soils. In this study, a numerical model was developed to predict changes in water quality during SAT operations. The contaminant species considered in the model were ammonium, nitrate, dissolved organic carbon, and dissolved oxygen. The model was calibrated against experimental data obtained from one dimensional soil column tests conducted for 84 days. The calibrated model will be used to find out optimum conditions for the pilot- and regional-scale SAT operations to be scheduled for the next phase of this project.

• Journal of the Korean Society of Tobacco Science
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• v.8 no.2
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• pp.43-49
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• 1986

Field experiment was conducted to investigate the effect of vinyl mulch on phosphate availability of soil and fertilizer in 1982. Growth of tobacco was more vigorous at each level of phosphate treatment in vinyl mulched than in bare soil. There was significant culture x Phosphorus treatment interaction for the yields of cured tobacco leaves. These results indicated that vinyl mulch was effective to improve phosphate availability of soil and fertilizer. Increase in soil temperature and maintenance of bulk density suitable for Phosphorus diffusion by vinyl mulch were likely to Play major roles on Phosphate availability, but other unknown factors appeared to be involved.

• Korean Journal of Agricultural Science
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• v.42 no.4
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• pp.423-429
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• 2015

This study was conducted to evaluate the effects of reduced nitrogen (N) and potassium (K) fertigation as additional fertilizer on tomato yield and nutrient contents in excessively nutrients-accumulated soil. Shoot and root dry weights (DW), dry matter rate for shoot, root and fruit and number of fruit in both AF50 and AF100 (50 and 100% levels of additional fertilizer) treatments were increased in comparison with those in AF0 (0% level of additional fertilizer) treatment. In case of nutrient uptake by tomato, nitrogen, phosphorous (P) and potassium contents in all tomato parts (leaf, stem, root and fruit) in AF50 and AF100 treatment were lower than those in AF0 treatment. On the contrary, soluble sugar and starch contents in all tomato parts in AF50 and AF100 were higher than those in AF0 treatment. There were differences between AF0 and AF50 or AF100 in tomato growth, yield, nutrient level and contents of soluble sugar and starch. In contrast, the level and initiation point of fertigation did not significantly affect the parameters. Based on our results, the application of properly reduced level of additional fertilizer is possible to maintain the productivity of tomato and alleviate the nutrient accumulation in plastic film house soils.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.3
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• pp.341-347
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• 2007

Chinese milk vetch (CMV) is a winter legume that is commonly used as cover crop in Korea. Kill date of cover crop for addition into soil affects N content in cover crop and N availability in soil. This study was conducted to evaluate the effect of CMV as green manure cover crop according to kill dates before growing corn without artificial fertilizer. Top of CMV cut three times on 13 April, 27 April, and 11 May were added into soil at a rate of 600 kg per 10a. Sugar content in CMV litter was persistently decreased from mid-April to late-May. The decrease of sugar content might be due to the transformation into starch and/or other storage or structural constituents. The decreased amount of sugars was greater than 12% and the increased amount of starch was less than 0.2%. Concentration of $NH_4^+$ in soil treated by CMV litter cut on May 11 was slightly higher than that in the treatment with early-cut (April 13) CMV, the concentration at 28 and 49 DAT (days after treatment) was higher in the treatment with late-cut CMV litter. Regardless of cut (kill) date of CMV, the phosphatase activity in the treatment of CMV litter was higher compared to the untreated control. Soil dehydrogenase activity was increased steadily by addition of CMV litter implying total microbial activities in the soil were increased. Our results demonstrate that the status of cover crop species at kill date is an important factor influencing soil enzyme activities derived from microorganisms. Therefore, the optimal kill date of cover crop should be examined to improve the efficiency of cover crop as green manure crop regarding the practical sequence in cropping system.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.1
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• pp.47-59
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• 2019

This study was composed of four treatments [no treatment, phosphate + limestone layer treatment, phosphate + sodium bicarbonate + cement layer treatment, and phosphate + sodium bicarbonate + limestone layer treatment] for figuring out vegetation effects on the acid drainage slope. Treated acid neutralizing techniques were effective for neutralizing acidity and vegetative growth in order of [first: phosphate + sodium bicarbonate + limestone layer treatment, second: phosphate + sodium bicarbonate+cement layer treatment, third: phosphate + limestone layer treatment and fourth: no treatment] on the acid drainage slope. We found out that sodium bicarbonate treatment was additory effect on neutralizing acidity and increasing vegetaive growth besides phosphate and neutralizing layer treatments. In neutralizing layer treatments, Limestone layer was more effective for vegetation and acidity compared to cement layer treatment. Cement layer showed negative initial vegetative growth probably due to high soil hardness and toxicity in spite of acid neutralizing effect. Concerning plants growth characteristics, The surface coverage rates of herbaceous plants, namely as Lotus corniculatus var. japonicus and Coreopsis drummondii L were high in the phosphate + sodium bicarbonate + limestone layer treatment while Festuca arundinacea was high in the phosphate + sodium bicarbonate + cement layer treatment. We also figured out that soil acidity affected more on root than top vegetative growth.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.4
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• pp.373-377
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• 1985

This experiment was designed to find out the soil properties to control the soil erodibility. Two kinds of soil conditioners, hydrophilic Uresol and hydrophobic Bitumen were treated to sandy loam and silt loam. Soil erodibility was tested during a simulated rainfall in a soil pan which was covered with a 2cm layer of treated and untreated aggregates (< 5.36mm) on a soil layer. The runoff starting time was delayed 8-20 minutes by Uresol treatment and it was hasten 1-21 minutes by Bitumen treatment. Runoff rates were reduced by Uresol to 62.5% in sandy loam and 93.7% in silt loam, but it was increased by Bitumen treatment. Erosion from the Uresol treated soil was remarkably reduced to 1.7-23.6% of that in the untreated soil. In case of the Bitumen treatment, the soil loss from silt loam was reduced to 55.5% of the control, but it was increased in sandy loam soil by 52% over the control. The ratio of soil loss and runoff, sediment concentration in runoff, was noticeably increased when the soil structure was unstable. There was significant correlation between soil loss and logarithm of wetting angle-stability index. Soil loss was greatly increased when the index was less than 0.2.

• Geomechanics and Engineering
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• v.15 no.4
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• pp.957-964
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• 2018

In this study, a method of electrochemical consolidation is applied. This method utilizes electro-osmosis, which is an effective ground improvement technique for soft clays, and soil treatment using lime, which is the oldest traditional soil stabilizer. The mechanism of lime treatment for soil involves cation exchange, which leads to the flocculation and agglomeration. Five representative laboratory tests-an electro-osmotic test and four electrochemical tests with various proportions of lime-were performed on dredged marine clay. The objectives of this study are to investigate the effect of electrochemical treatment and to determine the optimum dose for optimal consolidation performance of dredged marine clay. The results show that a better consolidation effect was achieved in terms of current, temperature, and vane shear strength by using electrochemical treatment. The best results were observed for the electrochemical test using 4% lime content.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.4
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• pp.413-416
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• 2008

The cultivation of green manure crop is considered as a good management practice by increasing soil organic matter and fertility levels. This experiment was conducted to improve the soil environment under rice-based cropping system at paddy soil (fine loamy, mixed, nonacid, mesic, family of Aeric Fluventic Haplaquepts) in National Institute of Crop Science (NICS), Korea in 2006 to 2007. The variation of soil temperature in green manure plots was lower than without green manure (control) during spring season (April to May). The temperature variation of no tillage plot (broadcast before rice harvest) was the lowest among treatments. After green manure cropping, the soil bulk density and porosity ratio were improved at the top soil. The production of green manure was the highest athairy vetch and barley mixture plot by partial tillage. However, mixture treatment had no improvement on soil organic matter. After rice cropping with green manure application, soil quality was improved such as soil physical properties except mixture treatment. Therefore, we suggest that soil quality should be improved by green manure cultivation under rice-based cropping system.

• Journal of Soil and Groundwater Environment
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• v.6 no.4
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• pp.13-23
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• 2001

In this study, the characteristics of pH variations and contaminant distribution in soil are investigated during electrokinetic treatment for the purpose of restoring contaminated soil with heavy metal. For these objects, laboratory test for the kaolin contaminated by lead was performed. During electrokinetic treatment, lead was transported from anode to cathode. And 75% of lead removed within 80% region of the specimen. Most lead, however, that transported from anode to cathode precipitated in the vicinity of cathode compartment, thus the amount of lead removed by electroosmosis was little. Electrokinetic treatment satisfied regulation criteria of Korean Soil Environment Conservation Law within almost region of the specimen. But enhancement methods can be regarded as inevitable requisite for the cathode region.