• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.294-297
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• 2000

Heavy metals are extracted from Chonju stream sediment, roadside soils and sediments along Honam expressway, soils and tailings from mining area using partial ectraction in Standard Method, partial ectraction method with maintaining 0.1N of extraction solution and acid digestion. In samples having buffer capacity against acid, 0.1N of extraction solution can not be maintained and pH of extraction solution increases up to 8.0 when partial extraction in Standard Method is used. The averages and ranges of (heavy metals extracted using partial extraction in standard method, HPE)/(heavy metals extracted using partial extraction method with maintaining 0.1N of extraction solution, HPEM) values are 0.506 and 0.145~1.126 in Cd, 0.534~ and 0.078~0.928 in Zn, 0.461 and 0.041~1.715 in Mn, 0.359 and 0.011~0.874 in Cu, 0.195 and 0.018~1.785 in Cr, 0.710 and 0.003~3.075 in Pb, and 0.088 and 1.73$\times$10$^{-5}$ ~0.303 in Fe. These data indicate that the difference between HPE and HPEM is big in the order of Fe, Cr, Cu, Mn, Cd, Zn and Pb. It is quite possible that the partial extraction method in Standard Method of soil in Korea is not adequate for an assessment of contamination in area where buffer capacity of soil will be decreased or lost after a long term exposure of soils to environmental damage.

• Journal of Applied Biological Chemistry
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• v.65 no.1
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• pp.1-6
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• 2022

Urea is one of the most common nitrogen fertilizer, but nitrogen use efficiency by crop is low because of rapid hydrolysis of urea and loss of nitrogen in environments. Therefore, it is important to control the nitrogen release from nitrogen fertilizers. In this study, pyroligneous acid (PA) was used as a mean to inhibit urease in soil and prevent excessive nitrogen release from urea. Active ingredient in PA (AI) inhibited ammonification of urea in soil by reducing extracted ammonium nitrogen at 79.7% compared to the soil without PA. In order to evaluate the effect of PA on fertilization efficiency of urea, Chinese cabbage (Brassica campestris var. Pekinensis) was cultivated in soil treated with urea and PA both in pot and field. For PA treatment, half amount of urea was used compared to the amount of urea conventionally applied to Chinese cabbage. The PA treatment with half amount of urea resulted in similar Chinese cabbage biomass to the conventional urea application. Nitrogen concentration in Chinese cabbage was less in PA treatment indicating that Chinse cabbage effectively used nitrogen. Consequently, fertilization of urea with PA will reduce amount of fertilizer and frequency of application.

• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.217-221
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• 2001

Pseudomonas sp. PA09 was isolated from farm soil and used for the optical resolution of D-pipecolic acid from DL-popecolic acid. The strain PA09 consumed L-pipecolic acid preferentially as the sole carbon and energy source, thus accumulating D-pipecolic acid in the culture broth. Optimization to improve the enantiomeric excess and yield was performed. The time course experiment showed that the strain OP09 consumed L-pipecolic acid almost to completion after 35h of cultivation, and the enantiomeric excess and the yield (% of residual D-pipecolic acid) were 99.8 and 96.0%, respectively.

• Journal of Plant Biotechnology
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• v.44 no.2
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• pp.156-163
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• 2017

A greenhouse experiment was conducted for evaluation of ecological effects of transgenic melon plants in the rhizospheric soil in terms of soil properties, enzyme activities and microbial communities. Organic matter content of soil under transgenic melon plants was significantly higher than that of soil with non-transgenic melon plants. Significant variations were observed in organic matter, total P and K in soil cultivation with transgenic melon plants. There were also significant variations in the total numbers of colony forming units of fungi, actinomycetes and bacteria between soils treated with transgenic and non-transgenic melon plants. Transgenic and non-transgenic melon significantly enhanced several enzymes activities including urease, acid phosphatase, alkalin phosphatase, arysulphtase, ${\beta}$ glucosidase, dehydrogenase, protease and catalase. Soil polyphenoloxidase activity of $T_1$ transgenic melon was lower than that of $T_0$ transgenic melon and a non-melon plant during the same period. The first generation transgenic melon plants ($T_0$) showed significantly greater (p<0.05) effect on the activitiy of arylsulfatase, which increased from $2.540{\times}10^6CFU\;g^{-1}$ (control) to $19.860{\times}10^6CFU\;g^{-1}$ ($T_0$). These results clearly indicated that transgenic melon might change microbial communities, enzyme activities and soil chemical properties.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.2
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• pp.93-99
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• 2017

Analysis of mineral nutrients in plant is required for evaluating diagnosis of plant nutritional status. Pretreatment procedure for the analysis of plant can be varied depending on elements to be analyzed. Wet-digestion is suitable for total nitrogen, phosphate and cations, however, digestion solution including nitric acid is not suitable for nitrogen analysis. Incineration procedure is required to analyze chloride, silicate and total sulfur. After digestion, total nitrogen is analyzed by Kjeldahl method, and phosphate is detected at 470nm by colorimetric analysis with ammonium meta vanadate. Cations and micro elements are determined by titration or colorimetry, also, these elements can be measured by Atomic absorption spectrometer (AAS) or Inductively coupled plasma spectrometer (ICP).

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.2
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• pp.146-152
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• 2015

Heavy metal pollution has been a critical problem in agricultural field near at the abandoned metal mines and chemical amendments are applied for remediation purpose. However, biological activity can be changed depending on chemical amendments affecting crop productivity. Main purpose of this research was to evaluate biological parameters after applying chemical amendments in heavy metal polluted agricultural field. Result showed that soil respiration (SR) and microbial biomass carbon (MBC) were changed after chemical amendments were applied. Among three different amendments, lime stone (LS), steel slag (SS), and acid mine drainage sludge(AMDS), AMDS had an effect to increase SR in paddy soil. Comparing to control ($93.98-170.33mg\;kg^{-1}day^{-1}$), average of 30% increased SR was observed. In terms of MBC, SS had an increased effect in paddy soil. However, no significant difference of SR and MBC was observed in upland soil after chemical amendment application. Overall, SR can be used as an indicator of heavy metal remediation in paddy soil.

• Korean Journal of Environmental Agriculture
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• v.26 no.4
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• pp.294-299
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• 2007

Natural gypsum has been used as a soil amendment in the United States. However, flue gas desulfurization (FGD)-gypsum has not traditionally been used for agricultural purpose although it has potential benefit as a soil amendment. To expand use of FGD-gypsum for agricultural purpose, the effect of FGD-gypsum on soil chemical properties was investigated in the field scales. Application rates for this study were 0 (control), 1.1, and 2.2 Mg ha-1 of FGD-gypsum. After two year application, the soil samples were taken to 110 cm depth and sub-sampled at 10 cm intervals. The heavy metal contents in FGD-gypsum were lower than ceiling levels allowed by regulations for land-applied biosolids. Soil pH was not largely affected by FGD-gypsum application. Although degree of calcium (Ca) saturation in surface horizons increases only slightly with respect to the control, there is a clear decrease in exchangeable aluminum (Al). FGD-gypsum clearly increases the soil electrical conductivity (EC) with increasing application rate. Water-soluble Ca and sulfate is increased with FGD-gypsum application and these ions moved to a depth of at least 80 cm after only 2 years. We conclude that surface application of FGD-gypsum can mitigate toxicity of Al and deficiency of Ca in subsoil of acid soil.

• Advances in environmental research
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• v.1 no.3
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• pp.211-221
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• 2012

Bromadiolone (BRD), a second generation anticoagulant often applied to the living environment to control rodents, is usually considered to have low environmental toxicity due to its poor solubility in water. In this study of the effect of humic acid (HA) on BRD using electronic absorption spectroscopy, it has been observed that BRD is appreciably solubilized even in low concentrations of aqueous HA solutions. The BRD solubilization efficiency of aqueous HA was found to be $2.39{\pm}0.14$ ($4.53{\pm}0.26{\mu}M\;ppm^{-1}$). It was also seen that BRD is reasonably solubilized in aqueous extract of farm soil.

• Journal of Plant Biology
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• v.3 no.2
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• pp.1-5
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• 1960

Azotobacter is isolated from soil and its purified species is identified as A. chroococcum. The survival rate of Azotobacter irradiated with UV light is measured, and the reproductive rates of the survivals are calculated. In general, not only the survival rate, but also the length of the generation time of the survival progeny is inversely proportional to the irradiated dose of UV light. The reproduvtive rate of Azotobacter is increased with the exogeneous treatment of nucleic acid derivatives.

• Journal of Soil and Groundwater Environment
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• v.8 no.3
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• pp.30-36
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• 2003

The effect of humic acid on the simultaneous removal of nitrate and phosphate was investigated in a micellar-enhanced ultrafiltration (MEUF). At the low molar ratio of cetylpyridinium chloride (CPC) to contaminants, the removal of nitrate was lower to 50％ by 100 ppm of humic acid due to the competition for binding on micelles. At the molar ratio higher than 3, however, the removal of nitrate was over 80％. Phosphate was removed over 80% at the molar ratio higher than 1. The CPC and humic acid were rejected over 99 ％ by UF membrane. The flux did not decrease by 100 ppm of humic acid but rather slightly increased since the humic acid adsorbed on the membrane made the membrane more hydrophilic. As a result, humic acid did not diminish the performance of MEUF in the simultaneous removal of nitrate and phosphate.