• Korean Journal of Soil Science and Fertilizer
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• 제45권5호
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• pp.683-689
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• 2012

This research was carried out to investigate the effect of installation spacing of subsurface drip irrigation pipe on the mineral content, nutrient uptake, yield of lettuce, water requirement for irrigation, and soil chemical properties in greenhouse cultivation. Semi-forcing and retarding culture were implemented in this experiment, with four treatments containing overhead spray irrigation and three subsurface irrigation lateral spacing intervals of 30, 40, 50 cm at a depth of 30 cm from soil surface, respectively. Each mineral content of lettuce grown under subirrigation system did not show significant difference between treatments, however the uptake of nutrients was lower at 50 cm-distance. The yield was largest in 30 cm-subirrigation (SI), followed by 40 cm-SI, overhead spray, and 50 cm-treatment. Water requirement for irrigation was highest in overhead spray, and it was in reverse proportion to the distance of irrigation pipes. $NO_3$-N content in the soil, at a depth of 10 cm, showed a higher value in 50 cm-SI, followed by 40 cm-SI, overhead spray and 30 cm-SI. Exchangeable K content was highest in 50 cm-SI, Mg was highest in 40 cm-SI, and Ca was lowest in 30 cm-SI. In conclusion, the lettuce yield was not different between 30 and 40 cm-SI, but water requirement for irrigation was lower as the distance of irrigation pipes was further. And it seems to be needed more precise research on this theme, because crop yield and the dynamics of soil minerals in subsurface irrigation can vary with the depth and distance of irrigation pipes, dripper, water flow depending on the soil texture, and plant response to soil minerals.

• Korean Journal of Soil Science and Fertilizer
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• 제42권Spc호
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• pp.40-44
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• 2009

This study was carried for the understanding of infiltration and percolation characteristics of water in agricultural land filled with rock-dust (Technosols). The experiment was performed at two sites (A, B), and soil horizons of the sites were classified with 4 layers, respectively. The soil texture of all soil horizons was analyzed with silt loam (SiL) except for the soil texture, which was loamy sand (LS), at the lowest horizon of measurement site A. The bulk densities at each horizon of two soils were mostly over $1.49g{\cdot}cm^{-3}$, which is very higher than $1.25g{\cdot}cm^{-3}$ of typical medium-textured mineral soil, except for the surface of site A measured immediately after tillage. The concentrations of $P_2O_5$ at surface of two soils s were 1962 (A), 1613 (B) $mg{\cdot}kg^{-1}$, respectively. These concentrations are 3.2~6.5 times of $300{\sim}500mg{\cdot}kg^{-1}$, which is the optimum concentration for crop growth. Infiltration rates at surface of the soils were 3.54 (A), 2.85 (B) cm $hr^{-1}$, but percolation rates at soil horizons under the surface were below 0.3 (A), below 0.003 (B) cm $hr^{-1}$. These results would be because the surface soils were managed by tillage and crop planting etc., but soils under surface were formed with structural problems occurred at the formation time of agricultural land accumulated with rock-dust or a compaction by farm machines.

• Economic and Environmental Geology
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• 제44권3호
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• pp.203-215
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• 2011

Geochemical and mineralogical properties of a contamited soil should be taken into account to decide a remediation strategy for a given contaminant because development and optimization of soil remedial technologies are based on geochemical and mineralogical separation techniques. The objective of this study was to investigate the geochemical and mineralogical characteristics of arsenic-contaminated soils. The arsenic-contaminated soil samples were obtained from Chonam gold mine, Gwangyang, Chonnam, Particle size analysis, sequential extraction, and mineralogical analyses were used to characterize geochemical and mineralogical characteristics of the As-contaminated soils. Particle size analyses of the As-contaminated soils showed the soils contained 17-36% sand, 25-54% silt, 9-28% clay and the soil texture were sandy loam, loam, and silt loam. The soil pH ranged from 4.5 to 6.6. The amount of arsenic concentrations from the sequential soil leaching is mainly associated with iron oxides (1 to 75%) and residuals (12 to 91%). Major minerals of sand and silt fractions in the soils were feldspar, kaolinite, mica, and quartz and minor mineral of which is an iron oxide. Major minerals of clay fraction were composed of illite, kaolinite, quartz, and vermiculite. And minor minerals are iron oxide and rutile. The geochemical and mineralogical analyses indicated the arsenic is adsorbed or coprecipitated with iron oxides or phyllosilicate minerals. The results may provide understanding of geochemical and mineralogical characteristics for the site remediation of arsenic-contaminated soils.

• Journal of the Korean earth science society
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• 제25권8호
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• pp.754-763
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• 2004

This study was aimed to examine the Landsat Enhanced Thematic Mapper Plus (ETM+) index, which matches well with the field survey data in the wildfire area of Gangneung, Gangweon Province, Korea. In the wildfire area NDVI (Normalized Difference Vegetation Index), SAVI (Soil Adjusted Vegetation Index), and Tasseled Cap Transformation Index (Brightness, Wetness, Greenness) were compared with field survey data. NDVI and SAVI were very useful in detecting the difference between the wildfire and non-wildfire area, but not so in classify the soil types in the wildfire area. The soil plane based on the Tasseled Cap Transformation showed a better result in classifying the soil types in the wildfire areas than NDVI and SAVI, and corresponded well with field survey data. Using a linear function based on greenness and wetness in the Tasseled Cap Transformation is expected to provide a more efficient and quicker method to classify wildfire areas.

• Journal of Korea Soil Environment Society
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• 제2권3호
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• pp.49-57
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• 1997

Naturally-occurring iron minerals, goethite and magnetite, were used to catalyze hydrogen peroxide and initiate Fenton-like oxidation of silica sand contaminated with diesel, kerosene in batch systems. Reaction conditions were investigated by varying H$_2$0$_2$concentration(0%, 1%, 15%), initial contaminant concentration(0.2, 0.5, 1.0g diesel and kerosene/kg soil), and iron minerals(1, 5wt% magnetite or goethite). Contaminant degradations in silica sand-iron mineral-$H_2O$$_2$ systems were identified by determining total petroleum hydrocarbon(TPH) concentration. In case of silica sand contaminated with diesel(1g contaminan/kg soil with 5wt% magnetite) addition of 0%, 1%, 15% of $H_2O$$_2$showed 0%, 25%, and 60% of TPH reduction in 8 days, respectively When the mineral contents were varied from 1 to 5wt%, removal of contaminants increased by 16% for magnetite and 13.1% for goethite. The results from system contaminated by kerosene were similar to those of the diesel. Reaction of magnetite system was more aggressive than that of goethite system due to dissolution of iron and presence of iron(II) and iron(III); however, dissolved iron precipitated on the surface of iron mineral and seemed to cause reducing electron transfer activity on the surface and quenching $H_2$$O_2$. The system used goethite has better treatment efficiency due to less $H_2$$O_2$ consumption. Results of this study showed possible application of catalyzed $H_2$$O_2$ system to petroleum contaminated site without addition of iron source since natural soils generally contain iron minerals such as magnetite and goethite.

• Korean Journal of Soil Science and Fertilizer
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• 제33권6호
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• pp.377-383
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• 2000

The composition of primary minerals of sand fractions and secondary minerals of clay fractions were investigated on the polder soils developed from alluvio-marine deposits near to Sapgyo-lake, constructed a sea dike across river estuary located in the west coast. The effects of a topographical sequence on the physico-chemical properties and mineralogical characteristics were evaluated using XRD, DTA, and TG with the chemical composition of $H^+$ saturated clays. Soils located on the seashore side were more silt fraction, higher pH and exchangeable cations than the others. The dominant minerals of soil parent materials are in the order of quartz, feldspars, micas, chlorite and amphibole. According to the greater distance from the lake, the amount of 1:1 minerals increased, but 2:1 minerals decreased. The dominant clay minerals of polder soils are kaolinite, vermiculite and illite. Hydroxy interlayer minerals are abundant in the clay fractions derived from the soil parent materials which have relatively low soil pH.

• Korean Journal of Organic Agriculture
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• 제12권3호
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• pp.345-352
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• 2004

This study was carried out to investigate the effect of soil-born microorganism, vitabio on growth of leaf lettuce in the vinyl house. Total weights of leaf lettuce treated with vitabio showed difference compared with untreated leaf lettuce. Sugar content was also increased. Mineral contents of leaf lettuce showed no difference between treated with vitabio and untreated with vitabio. Exchange Capacity (EC) and Organic Matter (OM) in chemical properties of soil treated with vitabio showed higher than soil in untreated vitabio. Vitabio treated soil contained much more microorganisms such as Bacteria, Actinomycetes, Hyphomycetes, Bacillus sp. Pseudomonas sp. after harvest.

• Geomechanics and Engineering
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• 제15권6호
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• pp.1135-1141
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• 2018

Volume changes of soils induced by inorganic acids cause severe foundation and superstructure failures in industrial buildings. This study aimed to assess the potential of fly ash to control volume changes in soils under acidic environment. Two soils such as black cotton soil predominant with montmorillonite and kaolin clay predominant with kaolinite were used for the present investigation. Both soils exhibited an increase in swelling subjected to phosphoric acid contamination. Ion exchange reactions and mineralogical transformations lead to an increase in swelling and a decrease in compressibility in black cotton soil, whereas phosphate adsorption and mineral dissolution lead to an increase in swelling and compressibility in case of kaolin clay. Different percentages of Class F fly ash obtained from Ramagundam national thermal power station were used for soil treatment. Fly ash treatment leads to significant reduction in swelling and compressibility, which is attributed to the formation of aluminum phosphate cements in the presence of phosphoric acid.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.390-393
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• 2002

Many researchers have studied for the barrier liner in the landfill that is mixed with clay mineral, native soils and solidified agent. However, they have a littel but problems for safety construction and maintenance as a bottom liner systems in the landfill. In this paper the authors studied the effects on hydraulic conductivity by electric-chemical ion-exchange agent that is a soil stabilization agent(Sulphonated Oil), The application of the soil stabilization agent to meet the hydraulic conductivity of clay liner in landfill is possible if the additive quantity and a proper reaction time is determined relevantly in the laboratory test.

• Proceedings of the Korean Institute of Building Construction Conference
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• 한국건축시공학회 2016년도 추계 학술논문 발표대회
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• pp.91-92
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• 2016

Red mud is an inorganic by-product produced from the mineral processing of alumina from Bauxite ores. the development of alkali-activated slag-red mud cement can be a representative study aimed at recycling the strong alkali of the red mud as a construction material. This study is to investigate the pore characteristics of alkali-activated slag-red mud soil pavement according to the red mud content. The results showed that the porosity of alkali-activated slag-red mud soil pavement increased but the compressive strength of that decreased as the red mud content increased.