• Korean Journal of Soil Science and Fertilizer
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• v.44 no.4
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• pp.662-666
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• 2011

In this study, distribution characteristics of dioxins in soils in Busan, Korea were investigated regarding different land use types. Soil sampling sites that distributed through the Busan city showed dioxin concentration ranging from 0.489 to $322.736pg-TEQ\;g^{-1}$ dry weight with a mean value of $26.257pg-TEQ\;g^{-1}$ dry weight. The mean dioxin concentrations of investigated soils ranged from 1.554 to $50.357pg-TEQ\;g^{-1}$ dry weight in consideration of each land use type. That in metal refinery sites with $50.357pg-TEQ\;g^{-1}$ dry weight was higher than any other sites, followed by waste incinerator sites with $44.285pg-TEQ\;g^{-1}$ dry weight. The majority of soil samples had the same dioxin congener profiling despite the different range of dioxin concentration. Octa-CDD was the major contributor among seventeen dioxin congeners with the range from 29.5 to 70.1% in real values. In contrast to real values, dioxin congener profiles in TEQ values were dominated by 2,3,4,7,8-PeCDF which contributed about 35.3~43.8% to the total dioxin concentrations. It was judged by these results that penta-CDF was the major contributor of soil samples in Busan city. The mean ratio of PCDFs/PCDDs in real values was about 0.71, but that in TEQ values was, in contrast to it, approximately 3.03.

• Journal of the Korean GEO-environmental Society
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• v.6 no.1
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• pp.23-31
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• 2005

The "Silt Pond" is 180 hectares in size and contained ultra soft slurry-like soil varying between 3 to 20 meters in thickness. Reclamation works in the Silt Pond commenced in the mid of 1990s. A considerable amount of subsurface investigation inclusive of sampling, field vane and density logging tests were carried out prior to the reclamation of the Silt Pond. Since material in the Silt Pond is extremely soft, filling was done by spreading sand with high water content in thin and equal thickness lifts, allowing the stability of the slurry-like foundation. Despite the extreme care taken, failures occurred during the sand spreading phase. A large piece of high strength geotextile measuring $900m{\times}700m$ was placed to strengthen the slurry like soil foundation at locations where the ultra-soft soil was found to be exposed. Following the remedial works, the Silt Pond was again reclaimed by sand spreading up to +4.0m CD. The success of the reclamation was confirmed by marine CPT profiling.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5C
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• pp.293-301
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• 2008

Soil profiling is one of the most important work among geotehnical engineering practice. Generally, soil profile is estimated from the observation of soil samples during subsurface exploration but such estimation also includes some experiencing aspects such as flushed water from the borehole, slime colour, boring speed and so on. In addition, since the capacity of hydraulic drill rig is significantly increased, thin layers might be easily missed. So, continuous soil profile is almost impossible over all depth to be bored from conventional subsurface exploration. While CPT or CPTu can serve continuous soil profile information over all depth generally in 5cm interval. Many charts or methods for soil profile from CPT result have been proposed during last several decades over the world. However they have not been verified in local ground condition in Korea. In this research, CPT results and soil classification results based on USCS were compiled from 17 sites over the Korea. Soil classification results by using 7 CPT soil classification charts were compared with those of USCS for the compiled database. Most proper CPT soil classification chart for Korean soil characteristics was evaluated and effective parameters for the soil classification from CPT were discussed. Finally interrelationship between CPT soil classification chart and USCS soil classification was evaluated.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.234-241
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• 2007

Biological amendments consisting of suspensions of selected microorganisms are often used in conjunction with various organic materials for amending soils to improve soil quality and plant growth. The effects of the biological amendment on chemical and biological properties of soil were investigated for a biological amendmentalone and when combined with different organic materials includingmunicipal compost (MC), poultry litter (PL), and cover crops (red clover (RC) and spring oats). A liquid preparation of a biological amendment called Effective Microorganisms was sprayed on the tested plots three times over a two-year period. Effective Microorganisms alone did not influence pH, K, or organic matter content in soil. However, increases in P in PL-treated soils in fall of both years andCa in MC-treated soil in fall 2001, and decreases in Ca, Mg, and cation exchange capacity (CEC) in RC-planted soil were associated with EM. Increased dehydrogenase(DH) activitiesassociated with Effective Microorganismswere only detected in July (P=0.0222) and October (P=0.0834) for RC-planted soils in the first year. Fluorescein diacetate (FDA) hydrolysisappeared to be enhanced by Effective Microorganisms in soils untreated or treated with MC and oatsbut only sporadically during the sampling period. FDA hydrolysis in both PL- and RC-treated soils as well as DH activity in PL-treated soils decreased with Effective Microorganisms treatment. Effective Microorganisms did not influence substrate utilization patterns expressed by the BIOLOG assay. We conclude that Effective Microorganisms effects on soil chemical and biological properties varied depending on the added organic materials. Effective Microorganisms periodically increased soil DH activity and FDA hydrolysis with RC and with MC plus oats, respectively.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.2
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• pp.96-106
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• 2003

134 Dutch cone (mechanical cone) and 9 piezocone (electronic cone) penetration tests have been performed in the southwestern part of Korea. In general, Dutch cone results may be different from that of piezocone due to the difference in structure of the cones. 6 Dutch cone and piezocone test data which were obtained at the same point respectively, were analyzed and plotted in soil classification chart proposed by Robertson et. al.(1986, 1990). Cone factors of Dutch cone and piezocone test empirically have been determined using laboratory and field vane test results. Using this cone factors, it was shown that there was good correlation between shear strength estimated using cone resistance and that of laboratory test and field vane tests. It was found that there was a good correlation between cone resistance from Dutch cone and that from piezocone. Relationship formula was also suggested. Dutch cone test provides a useful means for stratigraphic profiling in large project and has some advantage over piezocone in particular situations, such as very soft clay ground and dredged area.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.237-244
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• 2002

A comparative study of 134 mechanical (Dutch cone) and 9. electronic cone (Piezocone) penetration data from the southern part of Korea has been performed. In general, Dutch cone results may be different from piezocone results due to the difference in structure of the cones. Cone penetrometer test data were analyzed and plotted in soil classification chart proposed by Robertson et. al.(1986,1990) Cone factors of Dutch cone and piezocone test have empirically been determined using laboratory and field vane test results. Using this cone factors, it was shown that there was good correlation between shear strength estimated using cone resistance and that of laboratory test and field vane tests. It was found that there was a good correlation between cone resistance from Dutch cone and that from piezocone. Dutch cone test provides a useful means for stratigraphic profiling in large project and has some advantage over piezocone in particular situations, such as very soft clay ground and dredged area.

• Journal of the Korean Geophysical Society
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• v.2 no.3
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• pp.209-216
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• 1999

In order to get geologic information necessary for underground installation of water pipe, seismic refraction profiling was applied to the southwest side of the Seomjin River which flows between Namwon-gun, Cholabuk-do and Gokseong-gun, Cholanam-do. Before obtaining the in-line refraction data, walkaway data were recorded with 1 m geophone interval and -36∼+36 m offset range. From the walkaway data, it is interpreted that a dry soil layer with the average velocity of 585 m/s covers wet sediments with the average velocity of 1,326 m/s. The second layer overlies basements nearly horizontally with the average velocity of 4,218 m/s. Refraction profiling of 220 m long with the geophone interval of 2 m is interpreted with the Generalized Reciprocal Method (GRM). Three layers are identified with average velocities of 688 m/s, 1,473 m/s, and 3,776 m/s, respectively. The depth to the bedrock impossible for ripping ranges between two extremes, 1.51∼2.43 m and 2.25∼3.54 m, depending upon thickness of the hidden layer. A typical shortcoming of refraction method, the hidden layer problem, prevents accurate estimation in depth of the second layer.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.261-261
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• 2022

Cowpea [Vigna unguiculata (L.) Walp] is one of the most important grain legumes that enhance soil fertility and is well-adapted to various abiotic stress. Also, it is cultivated worldwide as a tropical annual crop, and the semi-arid regions are known as the main cowpea-produced regions. However, accumulation of soil salinity induced by low rainfall in these regions is reducing crop yields and quality. In general, plants exposed to soil salinity cause an accumulation of high ion chloride, which leads to the degradation of root and leaf proteins. In this study, we identified candidate genes associated with salinity tolerance through an analysis of differentially expressed genes (DEGs) in four cowpea germplasms with contrasting salinity tolerance. A total of 553,776,035 short reads were obtained using the Illumina Novaseq 6000 platform for RNA-Seq, which were subsequently aligned to the reference genome of cowpea Vunguiculata v1.2. A total of9,806 DEGs were identified between NaCl treatment and control of four cowpea germplasms. Among these DEGs, functions related to salt stress such as calcium transporter and cytochrome-450 family were associated with salt stress. In GO analysis and KEGG analysis, these DEGs were enriched in terms such as the "phosphorylation", ''extracellular region", and "ion binding". These RNA-seq results will improve the understanding of the salt tolerance of cowpea and can be used as useful basic data for molecular breeding technology in the future.

• Korean Journal of Environmental Agriculture
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• v.31 no.2
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• pp.192-199
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• 2012

BACKGROUND: Genetically modified (GM) crops must receive relevant regulator's authorization before they can be sold as seed or used food, feed and processing. Before approving any GM crop, the relevant government ministries are required to examine environmental risk assessment to make scientifically sound and socially acceptable decisions. But one of the least studied and understood areas in the environmental risk assessment of GM crops are their impact on soil microbial community. METHODS AND RESULTS: Recently, advanced methods have been developed to characterize the soil microbial community in various environments. In this study, the culture-dependent and culture-independent technical approaches for profiling soil microbial communities are summarized and their applicability to assess GM crops are discussed. CONCLUSION(S): We concluded that the effect of GM crops on soil microbial community need to be assessed on a case by case basis. The combination of culture-dependent and culture-independent method was necessary for reliable and detailed assessment of effect of GM crops on soil microbial community.

• Journal of Plant Biotechnology
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• v.8 no.1
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• pp.27-35
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• 2006

Plantlet regeneration in Asteracantha longifolia(L.) Nees (Acanthaceae), a medicinal herb has been achieved from seedling explants on basal MS medium. Three different seedling explants including node, internode and leaf segments on used. Of these three explant, leaf explants gave better response for both callus mediated organogenesis and direct multiple shoot induction. Number of explants showing differentiation of shout buds was higher on MS media supplemented with BA compared to kinetin. MS medium fortified with BA ($2.0mgl^{-1}$) and NAA ($0.5mgl^{-1}$) was found to be most suitable for both callus mediated organogenesis and elongation of shouts. The elongated shoots were successfully routed on MS medium fortified with NAA or IBA. Among them $0.1mgl^{-1}$ NAA or $0.2mgl^{-1}$ IBA provides better response for rhizogenesis. Regenerated plantlets were successfully established in soil where 85.4% or them developed into morphologically normal and fertile plants. RAPD profiling using four decamer primers confirmed the genetic uniformity of the regenerated plantlets and substantiated the efficacy and suitability of this protocol for in vitro propagation of A. longifolia.