• Journal of Korean Society of Forest Science
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• v.95 no.2
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• pp.177-182
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• 2006

Little information is available on soil $CO_2$ efflux and crop yield under agroforestry systems. Soil $CO_2$ efflux, microbial biomass C, live fine root biomass, and cotton yield were measured under a pecan (Carya illinoinensis K. Koch)-cotton (Gossypium hirsutum L.) alley cropping system in southern USA. A belowground polyethylene root barrier was used to isolate tree roots from cotton which is to provide barrier and non-barrier treatments. The barrier and non-barrier treatment was randomly divided into three plots for conventional inorganic fertilizer application and the other three plots for organic poultry litter application. The rate of soil $CO_2$ efflux and the soil microbial biomass C were affected significantly (P < 0.05) by the fertilizer treatment while no significant effect of the barrier treatment was occurred. Cotton lint yield was significantly (P < 0.0 I) affected by the root barrier treatment while no effect was occurred by the fertilizer treatment with the yields being greatest ($521.2kg\;ha^{-1}$) in the root barrier ${\times}$ inorganic fertilizer treatment and lowest ($159.8kg\;ha^{-1}$) in the non-barrier ${\times}$ inorganic fertilizer treatment. The results suggest that the separation of tree-crop root systems with the application of inorganic fertilizer influence the soil moisture and soil N availability, which in tum will affect the magnitude of crop yield.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.1
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• pp.158-168
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• 2007

This study analyzed the reduction efficiency to a debris barrier planed with the Office of Forestry and local provinces among diverse measurements for the diminution of high-density turbid water and soil erosion of Soyang reservoir. As the analysis of soil erosion of Soyang river basin applying rainfall data (2005) and GIS database, soil erosion is estimated as 4,819,494 ton. Also, in the analysis of unit soil erosion, Chugok-, Jaun-, and Ohang stream shows high value comparing with other watersheds. Debris barrier watersheds are extracted as the center of 94 debris barrier points using GIS spatial analysis. As the analysis of soil erosion and sediment delivery ratio (SDR) of debris barrier watershed, the reduction efficiency of soil erosion of debris barrier of 2005 is analyzed as 6.8%, that is 330,203 ton. Also, the reduction efficiency of soil erosion of debris barrier of 2005 increases as 10.5%, that is 506,783 ton, when the locations of debris barrier are changed into the high soil erosion area over 5,000 ton.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.398-405
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• 2014

Salt accumulation at soil surface is one of the most detrimental factors for crop production in reclaimed tidal land. This study was conducted to investigate the effect of capillary barriers beneath the soil surface on dynamics of soil salts at coarse-textured reclaimed tidal land. A field experiment was conducted at Saemangeum reclaimed tidal land for two years (2012-2013). Capillary barriers ($3.5{\times}12m$) were treated with crushed-stone, oyster shell waste, coal briquette ash, coal bottom ash, rice hull and woodchip at 40-60 cm depth from soil surface. Silage corn (Zea mays) was cultivated during the experimental period and soil salinity was monitored periodically. Soil salinity was significantly reduced with capillary barrier compared to that of control. Oyster shell waste was one of the most effective capillary barrier materials to control soil salinity at Saemangeum reclaimed tidal land. At the first growing season capillary barrier did not influence on corn growth regardless of types of the material, but plant biomass and withering rate of corn were significantly improved with capillary barrier at the second growing season. The results of this study showed that capillary barrier was effective on the control of soil salinity and improvement of corn growth, which indicated that capillary barrier treatment can be considered one of the best management practices for stable crop production at Saemangeum reclaimed tidal land.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.98-101
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• 2002

Numerical experiments were performed to investigate horizontal barrier formation in unsaturated soils by permeation grouting through multiple vertical injection pipes. The results were compared with the horizontal barrier formation achieved by using multiple horizontal injection pipes. It was observed that tile point injection of the vertical pipe system generates a gel barrier that has a less lateral area than the injection through the horizontal pipe.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.189-196
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• 2003

Soil-cement column is often used as a contaminant barrier. This study presents the results of experimental study performed to investigate the changes of properties of soil-cement column under the attack of acids. Sulfuric nitric, and ascetic acid were used as contaminants. Specimen were made of clayey and sandy soils with addition of cement and water Permeability of soil-cement decreased with time during permeability test. When significant amount of acid percolated the specimen, permeability increased and compressive strength decreased due to the dissolution and leaching of cement and its chemical reaction compounds. Sulfuric and nitric acid were more effective than ascetic acid in deteriorating soil-cement column. Amount of acid required to lower the pH of soil cement below 12 was calculated from the results of permeability tests. This leads to a conclusion that, under the conditions employed in this study, the chemical stability of soil-cement column could be maintained against acid attack for longer than generally accepted lifetime of contaminant barriers.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.122-122
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• 2005

The remediation for contaminated soil and groundwater in contaminated site and waste site has to be compact and economic in maintaining and operating the system. In this study, the atomized slag was tested if they are an effective reactive material in permeable reactive barrier This novel reactive system technology was applied to the treatment of leachate from unplanned waste landfill. The system was optimized and developed to be commercialized.

• Journal of the Korean Geosynthetics Society
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• v.10 no.2
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• pp.29-34
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• 2011

The purpose of this study was to prevent spreading of contaminants from movement of underground water by creating a barrier using artificial freezing method on a soil contaminated by oils and various DNAPLs. Specimens with 80% and 90% degrees of saturation were prepared to form freezing barrier using artificial freezing method. As the results of freezing specimen within soil bin with artificial ground freezing system, artificial contaminated soil cut off wall formed the thinnest wall after 12 hours. It is judged that this cut off wall will control the second soil pollution by intercepting expansion and movement of pollutants and DNAPLs within artificial contaminated soil cut off wall by underground water, intercepting inflow or outflow of underground water. Cut off walls formed by artificial ground freezing system had each other freezing speed according to degree of saturation.

• Computers and Concrete
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• v.6 no.1
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• pp.79-93
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• 2009

In the present paper, a methodology has been presented for the reliability assessment of concrete barriers that lie at a certain depth in the soil, and a missile (a rigid projectile) impacts the top of the soil cover normally, and subsequently after penetrating the soil cover completely it hits the barrier with certain striking velocity. For this purpose, using expressions available in the literature, striking velocity of missile at any depth of soil has been derived and then expressions for the depths of penetration in crater and tunnel region of concrete barrier have been deduced. These depths of penetration have been employed for the derivation of limit state functions. Using the derived limit state functions reliability assessment of underground concrete barrier has then been carried out through First Order Reliability Method (FORM). To study the influence of various random variables on barrier reliability, sensitivity analysis has also been carried out. In addition, a number of parametric studies is conducted to obtain the results of practical interest.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.927-938
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• 2000

When microorganism is injected into porous medium such as soils along with appropriate substrate and nutrients, biomass retained in the soil pore. Soil pore size and shape are varied from the initial condition as a result of biofilm formation, which make hydraulic conductivity reduced. In this research, hydraulic conductivity reduction was measured after microorganism are inoculated and cultured with synthetic substrates and nutrients. Biomass-soil mixture was evaluated its applicability to the field condition as an alternative liner material in landfill by measuring hydraulic conductivity change after repetitive freeze-thaw cycles. Resistance of biofilm to chemical solution and degree of biodegradation were measured through column test.

• Journal of Soil and Groundwater Environment
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• v.21 no.1
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• pp.1-5
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• 2016

Capillary barriers, consisting of relatively fine-over-coarse materials, have been suggested as an alternative to traditional compacted soil covers. So, We were analysed to capillary barrier effect according to five cases of multi-layer cover systems. Water balance simulation was conducted with unsaturated flow model HELP to assess unsaturated hydraulic parameters such as hydraulic conductivity, climate affecting the performance of capillary barriers. Simulation were conducted for 5 Cases in the Ulsan area. Result of simulation indicated that three cases was formed unsaturated condition and capillary barrier effect.