• Korean Journal of Environmental Agriculture
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• v.15 no.4
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• pp.488-493
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• 1996

This study was conducted to find out the residual aspect and the effect of quizalofop-ethyl on microorganisms used to control broad-leaf weeds at Yeongok soil series, the experiment field, Chonnam R.D.A. and Namwon soil series, the experiment field, Jeju R.D.A. More than 60 percent of quizalofop-ethyl treated in soil was degraded within 7 days. The degradation of quizalofop-ethyl in soil increased rapidly with incubation temperature. The half-life of quizalofop-ethyl in soil was 15 days(Yeongok series) and 16 days(Namwon series). The number of microorganisms in soil treated with quizalofop-ethyl decreased prominently with incubation time. But the number of Fusarium did not reduce in comparison with that of other soil microorganisms. Therefore, it was thought that the decomposition of quizalofop-ethyl in soil was affected by $Fusarium^2$.

• International Journal of Advanced Culture Technology
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• v.8 no.1
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• pp.182-187
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• 2020

Silver nanoparticles (AgNPs) have been manufactured in recent years and widely used in various fields. Reactive oxygen species (ROS), which occur in AgNPs, destroy cell membranes. It is widely accepted that ROS generated in this manner inhibit microorganisms growth and causes toxic effects, However, it does not affect cell membranes directly but positively affects growth in plants with cell walls. The nanoball used in this experiment is a new material that generates ROS stably and is used in aqueous solution. Results of this study indicate a 30% increase in yield of Ginseng mixed with culture soil. The analysis of soil condition after cultivation showed that the possibility of repetitive cultivation in soil mixed with Nanoball was high. This suggests that Nanoball is an antimicrobial active material due to the microbial / extermination effect of pathogenic microorganisms. Therefore, there may be potential applications in agricultural cultivation sites as a repetitive cultivation technology that reuses soil.

• Geomechanics and Engineering
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• v.4 no.2
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• pp.135-150
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• 2012

This paper presents the study of the effect of microorganism Bacillus pasteurii on the properties such as Atterbergs' limit and unconfined compressive strength of cohesive soils. The results of this study reveal that the liquid limit and plasticity index for all clay soils decreased and the unconfined compressive strength increased. Decrease in plasticity index is very high for Kuttanad clay followed by bentonite and laterite. The unconfined compressive strength increased for all the soils. The increase was high for Kuttanad soil and low for laterite soil. After 24 h of treatment the improvement in the soil properties is comparatively less. Besides the specific bacteria selected Bacillus pasteurii, other microorganisms may also be taking part in calcite precipitation thereby causing soil cementation. But the naturally present microorganisms alone cannot work on the calcite precipitation.

• Korean Journal of Environmental Agriculture
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• v.17 no.3
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• pp.279-285
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• 1998

Fenitrothion-degrading microorganisms were isolated from 124 sampling sites of paddy, upland, forest and polluted soil, and wastewater. A total of 1,071 strains were isolated from each selective medium supplemented with 50mg/l of fenitrothion - nutrient agar (NA) 601, potato dextrose agar (PDA) 201, Actinomycetes isolation agar (AIA) 168 and basal salt medium (BSM) 101, respectively. Twenty-eight effective strains of them, which showed more than 80% degradation of fenitrothion by the gasliquid chromatography(GLC) analysis. were successfully selected from each liquid culture supplemented with 50mg/l of fenitrothion - NB 12(upland soil 3, paddy soil 3, forest soil 2, polluted soil 4), PDB 8(upland soil 1, paddy soil 2, forest soil 2, polluted soil 3) and PSB 8(upland soil 1, forest soil 1, polluted soil 6), respectively. Four strains - NPal, NFol, PFol and BPol, which have the most powerful degradation activity were finally selected among 28 fenitrothion-degrading microorganisms based on the degradation rate at the concentration of 100mg/l fenitrothion in enrichment media.

• Korean Journal of Agricultural Science
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• v.49 no.3
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• pp.463-481
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• 2022

Phosphorous (P) is considered to be one of the key essential elements demanded by crop plants. Approximately 70 - 90% of phosphatic fertilizers applied to crops are fixed in soil as Ca, Fe, and Al metal cations, which are insoluble and thus not readily available for plant uptake. Therefore, most soils are deficient in plant available P. This is usually rectified by applying phosphate fertilizers continuously, although this is not economically viable or environmentally acceptable. The present paper reviews the mechanisms involved with phosphate solubilization and mineralization by phosphate solubilizing microorganisms (PSMs) with the associated factors that determine the success. PSMs are effectively involved in mediating the bioavailability of soil P. Their contribution includes mineralization of organic P solubilization of inorganic P minerals, and storing sizable amounts of P in biomass through different mechanisms such as the production of organic and inorganic acids, H₂S, siderophores, exopolysaccharides, and production of enzymes such as phosphatases, phytase, and phosphonatases/C-P lyases, which are capable of chelating the metal ions, forming complexes, and making plant available P. PSMs manifest a wide range of metabolic functions in different environments, resulting in significantly higher plant growth, enhanced soil properties, and increased biological activities. Therefore, development of bio-inoculants with efficient novel PSM strains and further investigations on exploring such strains from diverse ecological niches with multifunctional plant-growth-promoting traits are needed.

• Microbiology and Biotechnology Letters
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• v.21 no.5
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• pp.399-405
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• 1993

For screening of the antiviral agent from soil, about 520 strains of microorganisms were evaluated for their antiviral activity, About 6.9% of strains showed more than 95% antiviral activity against Herpes Simples Virus (HSV)-1. Two strains among 30 strains active against HSV-1 virus showed a quite strong activity against human immunodeficiency virus.

• YAKHAK HOEJI
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• v.28 no.2
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• pp.89-95
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• 1984

Microorganisms having beta-latamase inhibitory activity were selected from soil samples collected from 63 spots throughout the country. Screening procedures consist of two steps. Those are growth inhibition test of penicillinase-producing Staphylococcus aureus by double-layered agar plate containing penicillin G as a substrate, and that of penicillin sensitive Staphylococcus aureus ATCC 6538 in the similiar condition including penicillinase. Finally, a strain was selected from a soil sample of Pa-ju, Kyeong-gi Do. This strain was classified as a Streptomyces sp. by ISP(International Streptomycete Project) and Bergey's manual.

• International Journal of Railway
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• v.4 no.1
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• pp.1-4
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• 2011

In this study, the feasibility of using bioremediation to treat lubricant-contaminated soil around railroad turnouts was investigated. Lubricants used during the maintenance of railroad turnouts can drip onto the ground causing soil contamination. In the laboratory experiments, the residual TPH (Total Petroleum Hydrocarbons) concentration in soil gradually decreased after microorganisms degrading the lubricants were added. Generally, the soil around railroad turnouts is covered by a layer of ballasts. In the column experiments that were designed considering field sites, the removal efficiency of TPH was about 11% after 60 days of cultivation time. In the field experiments, microorganisms were added into the soil periodically, and finally the residual TPH concentrations were reduced to less than 1,700 mg/kg-soil on average. These results indicate that the lubricant in the contaminated soil around railroad turnouts could be efficiently removed through bioremediation method.

• The Microorganisms and Industry
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• v.19 no.2
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• pp.49-57
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• 1993

Chenges in respiration of the soils collected from the reclaimed tidal soil in Chogi-ri, Kanghwa Island and treated with organic matters are presented. The measurement of the respiration for the smaples, which were incubated for 0,2,4 and 5 weeks, were carried out by using Warburg's respirometer. While the respirations of the samples added by organic matters were increased 6.7 - 28.0 times compared with that 0 week during the incubation in case of 5-year soil, the respiration in case of 3-year soil were increased 3.3-11.8 times. Thus, the effect of adding organic matters on the respiration of the experimented soils, as this indicates, was much higher for the soil of 5-year area than that of 30-year area. And for the organic matters Salicornia was most effective and then Suaeda and Oryzae. The samples treated with Salicornia and Suaeda showed their highest respiration rate at the 4th week, but the one with Oryzae was measured to increase progressively during 5 weeks experimented. Regarding the salinity, content of organic matters and number of bacteria, in each intact soil experimented, 5-year soil samples had much poor habitat then 30-year soil for the activity of soil microorganisms, but according to the result mentioned above, it is firmly believed that the addition of organic matters on the saline soil is one of the best means to change the reclaimed tidal land into arable land with less time duration.

• Research in Plant Disease
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• v.8 no.1
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• pp.26-33
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• 2002