• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.65-69
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• 1998

In order to evaluate the utility of bituminous coal fly ash, gypsum, oyster shell as soil amendments, aadic clayloam paddy soils with low calaum content were amended in the upper 15㎝ with amendments, and then Chinese cabbage was cultivated under plastic film house. Amendments treated were, in metric tons per hectare, i) none(Check) ; ii) 80 fly ash(FA) ; iii) 4 shell(SH) ; iv) 56 fly ash+24 gypsum (FG) ; v) 40 fly ash+24 gypsum+0.8 shell(FGS). On the whole, soil chemical properties were improved by amendments treatments. Amongst treatments, FA prominently neutralized soil pH and increased contents of Av. $P_2O_5$, Ex. K, and Av. B in soils. Besides, it showed the highest ratio in bacteria/fungi and (bacteria+actinomycetes)/fungi. FGS also affected the neutralization of soil pH and the increment of Ex. Mg. Amendments plants appeared alkaline damages only at early growing stage, but showed positive responses in fresh weight yields : 23% for FGS : 21% for FG : 19 18% for SH. At harvesting, leaves both of FA and FGS plants had higher values in contents of N, P, K, Ca, Mg, Fe, Mn, Zn, B, reduang-sugar, and vitamin-C than of others. In especial, Check plants appeared the heart rot symptoms owing to calaum defiaency differently from amendments plants. Taken together, FGS was an effective combination enable to maximize the utility of fly ash, gypsum, shell as soil amendments, espeaally in cabbage yield and quality.

• Journal of the Korean Geotechnical Society
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• v.20 no.2
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• pp.27-36
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• 2004

The corrosion rate measurement procedure for the permanent ground anchors using polarization resistance measurements and electrochemical impedance spectroscopy is presented in this paper. The polarization resistance measurements were used to determine the correlation between corrosion rate in the steel and soil characteristics. The electrochemical impedance spectroscopy was used to predict the time dependent corrosion reaction and evaluate the different type of coating systems and the effect of cement grouting on the corrosion attack under various conditions. The results indicate that a low pH soil is a good indicator of a corrosive soil. The low pH soil condition (<5) in both clay and sand has a significant effect on the corrosion reaction of steel members in permanent found anchors. In the case of neutral and alkaline conditions beyond pH 6 in clay and sand, no consistent acceleration of corrosion was measured and the corrosion rate was constant regardless of variations of soil pH levels. Laboratory test data for porcelain clay indicate that the change of soil pH level has a small influence on the corrosion reaction in the steel member. The use of cement footing in the bonded length is sufficient to decrease the corrosion rate to a level close to 0.003∼0.01mm/y at the end of the given period. With epoxy and fusion bonded epoxy coating, the steel specimens remained unaffected and retained the original condition. It is suggested that epoxy and fusion bonded epoxy coating can provide effective protection against corrosion for a long time even in aggressive environment.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.E1
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• pp.29-39
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• 2003

The 10-day interval basis measurements of precipitation samples at Yangyang, the rural and coastal area on the eastern coast of the Korea peninsula were accomplished for understanding the precipitation chemistry and the temporal variations of major ions September 1991 to February 1997. The precipitation was slightly acidic, and 37% of the samples in winter were pH less than 4.5. The concentrations of cations were found on the order $Na^+\;>\;{NH_4}^+\;>\;Ca^{2+}\;>\;Mg^{2+}\;>\;K^+$ and those of anions followed the pattern $Cl^-\;>\;{SO_4}^{2-}\;>\;{NO_3}^-$. Neglecting sea salt components, the major ions controlling precipitation chemistry were nss-${SO_4}^{2-}$ and ${NO_3}^-$ in anion and ${NH_4}^+$ and nss-$Ca^{2+}$ in cation. Concentrations of these ions were lower than those measured at urban sites in Korea, but were higher than those measured in Japan. Most of nss-${SO_4}^{2-}$ and ${NO_3}^-$ were neutralized by ammonia and calcium species, especially alkaline soil particles in spring and ammonia gas in other seasons. Considering also the annual value of ［nss -${SO_4}^{2-}$］/［${NO_3}^-$］ ratio of 2.62 and the neutralizing factors, ammonium sulphate compounds were dominant. Annual mean concentrations of these ions showed relatively small fluctuations, while larger seasonal variations were observed with higher levels in spring and winter. Precipitation amount, influence extent of acidic gases and alkaline particles long-range transported from China continent, and energy consumption pattern in each season might be able to explain this seasonal trend.sonal trend.

• Journal of Applied Biological Chemistry
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• v.59 no.1
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• pp.83-90
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• 2016

The aim of the present study was to evaluate the degree of metal contamination of the Turag River water and its suitability for irrigation. Twenty water samples were analyzed for physicochemical parameters and metals viz., calcium, magnesium, potassium (K), sodium, copper (Cu), zinc (Zn), iron (Fe), manganese (Mn), lead (Pb), cadmium (Cd), chromium (Cr), and nickel (Ni). All water samples were slightly alkaline to alkaline. Regarding electrical conductivity (EC), all samples were suitable for crop in soils with moderate permeability and leaching. Water samples were medium salinity and low alkalinity hazard classes. In terms of total dissolved solids (TDS), all samples were classified as freshwater. As per sodium adsorption ratio (SAR) and soluble sodium percentage (SSP), all samples were classified as excellent. No residual sodium carbonate (RSC) was detected in any of the samples, indicating suitability for irrigation; and all samples were considered very hard. Cr and Mn contents in all samples were above FAO guideline values and, therefore, these metals were considered toxic. Zn, Cu, Pb, Cd, and Ni concentrations were below acceptable limit for irrigation and do not pose a threat to soil environment. Significant relationships were found between EC and TDS, SAR and SSP, SAR and RSC, and SSP and RSC. The combinations of ions such as K-Zn, K-Fe, K-Cu, K-Mn, K-Pb, Zn-Fe, Zn-Cu, Zn-Mn, Fe-Mn, Cu-Mn, Cu-Pb and Mn-Pb exhibited significant correlation. This study revealed that Turag River water samples are contaminated with Cr and Mn. This fact should not be ignored because water contamination by metals may pose a threat to human health through food chain.

• Korean Journal of Agricultural Science
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• v.25 no.1
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• pp.124-130
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• 1998

An alkalophilic bacterium, the strain AC-711 as a potent producer of alkaline cellulase, was selected among many isolates from soil environments. Morphological, physiological and chemical characteristics of the strain AC-711 suggested that it belongs to the genus Pseudomonas according to the Bergey's Manual of Systematic Bacteriology, however the G+C mol% (54.43) of its chromosomal DNA is lower than the normal values of the genus. The major cell wall fatty acids were determined as 15:0 and 17:0 anteiso. The production of alkaline CMCase by the strain was maximal when grown on the mediun containing 1% carboxymethyl cellulose, 0.1% $KH_2PO_4$, 0.02% $CoCl_2$, 0.02% Tween 80, 0.5% $Na_2CO_3$, 0.8% yeast extract, pH 10.3 at $30^{\circ}C$ for 3 days, and the most of enzyme was excreted into culture mediun.

• Microbiology and Biotechnology Letters
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• v.14 no.3
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• pp.239-244
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• 1986

To develop the potential use as new host strain for gene cloning, alkaline-tolerant isolates from soil were examined for amylase activity, protease activity, antimicrobial activity and transformability by using plasmid pUB 110. Of these strains, one was selected and identified as Bacillus sp. YA-14. in the enzymatic properties of Bacillus sp. YA-14 the optimal conditions for the reaction of amylase and protease were at pH 0.8 and pH 7.5 respectively. The antimicrobial activity of Bacillus sp. YA-14 was also found. For the transformation, Bacillus sp. YA-14 was cultured to late logarithmic growth phase ai 37$^{\circ}C$ in modified SPI medium (pH 8.0) containing 0.4% MgSO$_4$. The presence of pUB 110 plasmid DNA in transformants was confirmed by electrophoresis and stably maintained in the new host.

• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.289-294
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• 1992

Twenty-four bacterial strains among alkalophillic bacteria isolated from soil samples were examined for the presence of type II restriction endonuclease in aerobic culture. One strain was found to contain specific enzyme to cleave lambda DNA. The characteristics of this microorganism is the ability to grow well in alkalophilic and high temperature condition, that is at pH 10.3 and $50^{\circ}C$. This strain was tentatively identified to Bacillus alkaloPhilus subsp. halodurans when morphological, physiological and biochemical characteristics were examined. The enzyme was purified from crude extract by streptomycin sulfate, ammonium sulfate precipitation, which was followed by DEAE-cellulose and phosphocellulose ion exchange column chromatography, and the subunit molecular weight was about, 32,000 daltons by polyacrylamide gel electrophoresis containing 0.1% SDS.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.473-476
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• 2004

In this study, hydrochemical studies of thermal waters in the Bugok and Magumsan areas showing geothermal anomalies were carried, and the applicability of ion seothermometers and multiple mineral equilibrium approach was examined to estimate their potential deep reservoir temperatures. Typical thermal waters of the two areas are clearly grouped into two major types, according to water chemistry: Na-Cl type (group A) and Na-SO4 type (group D). Compared to group A, group B and C waters show some modifications in chemistry. Group E waters show the modified chemistry from group D. Geothermal waters from the two areas showed some different chemical characteristics. The thermal waters of group A and B in Magumsan area are typically neutral to alkaline (pH=6.7 to 8.1) and Cl-rich (up to 446.1 mg/L), while the waters of group D and E in Bugok area are alkaline (pH=7.6 to 10.0) and SO$_4$-rich (up to 188.0 mg/L). The group A (Na-Cl type) and group D (Na-SO$_4$ type) waters correspond to mature or partially immature water, whereas the other types are immature water. The genesis of geothermal waters are considered as follows: group A and B waters were formed by seawater infiltration into reservoir rocks along faults and fracture zones and possibly affected by fossil connate waters in lithologic units through which deep hot waters circulate; on the other hand, group D and E waters were formed by the oxidation of sulfide minerals (mainly pyrite) in surrounding sedimentary rocks and/or hydrothermal veins occurring along restricted fracture channels and were possibly affected by the input and subsequent oxidation of S-bearing gases (e.g. H2S) from deep thermal reservoir (probably, cooling pluton). The application of quartz, Na-K, K-Mg geothermometers to the chemistry of representative group A and D waters yielded a reasonable temperature estimate (99-147$^{\circ}C$ and 90-142$^{\circ}C$) for deep geothermal reservoir. Aqueous liquid-rich fluid inclusions in fracture calcites obtained from drillcores in Bugok area have an average homogenization temperature of 128$^{\circ}C$, which corresponds to the results from ion geothermometers. The multiple mineral equilibrium approach yielded a similar temperature estimate (105-135$^{\circ}C$ and 100-14$0^{\circ}C$). We consider that deep reservoir temperatures of thermal waters in the Magumsan and Bugok areas can be estimated by the chemistry of typical Na-Cl and Na-SO$_4$ type waters and possibly approach 105-135$^{\circ}C$ and 100-14$0^{\circ}C$.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.403-412
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• 2021

This study aimed to identify plant growth-promoting activity, phytopathogenic fungi growth inhibitory activity, mineral solubilization ability, and extracellular enzyme activity of the genus Bacillus in soil and the rhizosphere. With regards to antifungal activity against phytopathogenic fungi, DDP257 showed antifungal activity against all 10 pathogenic fungi tested. ANG20 showed the highest ability to produce indole-3-acetic acid, a plant growth-promoting factor (70.97 ㎍/ml). In addition, 10 species were identified to have 1-aminocyclopropane-1-carboxylate deaminase production ability, and most isolates showed nitrogen fixation and siderophore production abilities. Thereafter, the isolated strains' ability to solubilize minerals such as phosphate, calcite, and zinc was identified. With extracellular enzyme activity, the activity appeared in most enzymes. In particular, all the strains showed similar abilities for alkaline phosphatase, esterase (C4), acid phosphatase, and naphtol-AS-BI-phosphohydrolase production. This result was observed because the genus Bacillus secreted various organic substances, antibiotics, and extracellular enzymes. Therefore, through the results of this study, we suggest the possibility of using strains contributing to the improvement of the soil environment as microbial agents.

• Applied Biological Chemistry
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• v.43 no.4
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• pp.291-297
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• 2000

This study was conducted to find out the environmental factors affecting the differences in the half-life of the insecticide cyfluthrin in soil between field and laboratory tests carried out in 1998. Degradation and leaching of cyfluthrin in soil were examined under various environmental conditions that were considered to affect the residuality. Cyfluthrin was degraded 1.9 times faster in non-sterilized soil than in sterilized soil and 1.2 times at $25^{\circ}C$ than at $15^{\circ}C$. The half-lives of cyfluthrin were 61.4 days under the dark condition and 4.5 days under sunlight, and those were 11.8 days under the open condition and 23.8 days under the closed condition. The half-lives of the authentic compound and the commercial product of cyfluthrin were 15 and 1 day in the field test and 26 and 3 days in the laboratory test, respectively. Cyfluthrin was rapidly degraded with an increase in soil moisture content and decomposed faster in the alkaline solution of pH 12 than in the acidic solution of pH 3, but the half-life of cyfluthrin did not make any difference between pH 6.4 of the field test soil and pH 5.6 of the laboratory test soil. Cyfluthrin was immobile in soil from the results that $81{\sim}94%$ of the initial amount remained in the $0{\sim}2\;cm$ layer of the soil column regardless of the amount and time of rainfall after the chemical treatments. From viewing the abovementioned results, soil moisture content, sunlight and formulation type affected greatly soil microbes and volatilization affected slightly, and temperature, pH and rainfall did not affect the big difference in the half-life of cyfluthrin in soil between the field and laboratory tests in the year of 1998.