• Journal of the Korean Geotechnical Society
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• v.28 no.11
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• pp.69-78
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• 2012

Conventional numerical analysis for rainfall-induced slope stability has been estimated by separating seepage and stress-strain behavior, respectively. Many researchers' models from commercial softwares and literatures define that partially saturated permeability is the only function of degree of saturation (or matrix suction) and then they do not consider hydraulic-mechanical characteristics for the analysis. However, in practice, the water flow processes in a deformable soil are influenced by soil skeleton movement and the pore water pressure changed due to seepage will lead to changes in stress and to deformation of a soil. The relationship between seepage and soil behavior causes a change of partially saturated permeability as well as saturated permeability with the lapse of time. Instability of partially saturated soil slopes due to infiltration would be analyzed from reduction of negative pore water pressure calculating the process of water flow based on predicted partially saturated permeability. Therefore, partially saturated permeability should be defined by the function of degree of saturation (or matric suction) and porosity. The paper presents the comparison between staggered and monolithic coupled analysis regarding seepage and stress deformation problems. As a result, the decrease in matric suction on soil slope from monolithic analysis is slower than that from staggered analysis.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.1
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• pp.65-73
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• 1994

Earthworm cast was investigated in this study in order to domestically develop inexpensive and safe plug nursery soil. 20,30,40 and 50% of earthworm cast were added to the nursery soil as vegetable plant growth media, in which peatmoss and vermiculite constituted the rest of the soil. The effects of earthworm cast on the growth of pepper (Capsicum annuum L.) seedling were obtained as follows. 1. According to the growth stages, significant differences(p=0.001) were recorded in number of leaves, leaf area and biological dry matter yield per plant(shoor or root dry matter yield per plant). In view of mixing ratios in the nursery soil, number of leaves, leaf area and stem weight per plant showed differences significantly at 1% level and leaf weight, root weight and biological dry weight per plant at 5% level, respectively. 2. The nursery soil with earthworm cast showed increased number of leaves and leaf area per plant compared to the commercial nursery soil particularly in the later stage of this study than in the earlier stage 3. Through the total period of seedling growth, leaf weight, stem weight and root weight per plant in the nursery soil with earthworm cast were genrally higher than those in the control and this trend was apparant in the treatment of more than 40% of mixing ratio with earthworm cast. 4. Although leaf weight per plant was higher than stem weight per plant till the 3rd week, from the 4th week stem weight per plant was getting higher. In the later stage of seedling growth, the stem weight was higher in the earthworm cast mixed treatment than that in the control. 5. There was no significant difference on biological dry matter yield in the earlier stage of this study, however in the later stage, it was higher in the earthworm cast mixed treatment than that in the control.

• Horticultural Science & Technology
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• v.16 no.2
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• pp.222-225
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• 1998

The objective of this study was to observe the effects of potassium-carboxymethyl cellulose (K-CMC), which is a natural polymer derivative, and polyacrylamide (PAM), which is a commercial synthetic polymer, on soil physicochemical properties and yields of the cabbage. To increase water absorbing capacity (WAC), hydrophilic carboxymethyl group was introduced to cellulose chain and it was confirmed by FT-IR. WAC was tested by tea-bag method in distilled water and 3% NaCl solution. PAM is slightly more absorptive than K-CMC in distilled water, but in NaCl solution, K-CMC is more absorptive than PAM. Soil particle sizes above $1_{mm}$ were immediately increased from 9.6 to approximately 16.6% by the application of K-CMC and PAM, respectively. Infiltration rates of soil were approximately twice as great as those of the control when conditioned with the K-CMC and PAM treatment. K content of soil treated with K-CMC was significantly higher than those of PAM and control, but the other components of soil chemical properties were not different. The early growth and vegetative production of cabbage in the K-CMC and PAM treatments were significantly higher than the control. The contents of vitamin C were increased with the treatment of K-CMC. It was proposed that K-CMC treatment influence K component of the soil and vitamin C content of the cabbage, therefore, it improved the yields as well as crop quality.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.2
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• pp.119-123
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• 2011

To use barley as a green manure crop, this study has been conducted in Suwon, Gyeonggi-do to establish the barley green manure (BGM)-rice cropping system with emphasis on soil incorporation date and BGM density. The nitrogen (N) contents of rye and barley, grass green manure crops, were 1.4~2.4% at early growth stage and decreased rapidly to 0.6~1.0% at late growth stage. The biomass of barley was 449 kg/l0a at heading stage (HS) and increased to 421 kg/10a at 10 days after heading stage (DAH), 473 kg/10a at 20 DAH. C/N ratio of BGM was the lowest 26.3 at HS. The N contents of BGM was in the range of 0.9~1.5%, the highest at HS and gradually decreased, and the output of N were 4.3-6.3 kg/10a. The total amount of nitrogen, phosphorous and potassium of BGM showed the highest level at 10 DAH. Culm length of rice was relatively longer as the BGM application time was delayed. The application of BGM into soil increased plant height of rice by 7.2~7.7 em as compared to the plants treated with commercial fertilizer at recommended rate. but panicle length of rice showed a similar tendency in both the soil-applied of BGM and commercial fertilizer. N contents of unhulled rice was the highest at HS of BGM and followed by 10 DAH of BGM and 20 DAH of BGM. This trend could also be seen in rice straw. The yield of rice in the soil-applied of BGM was 10~15% lower than in the soil-applied of commercial fertilizer. Based on this study, application of BGM made it possible to save 30~50% of application amount of nitrogen fertilizer for following crops.

• Journal of Environmental Science International
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• v.24 no.10
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• pp.1253-1264
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• 2015

This study assessed the fertilizing value of struvite deposit recovered from swine wastewater in cultivating Chinese cabbage. Struvite deposit was compared with commercial fertilizers: complex, organic and compost to evaluate the fertilizing effect of struvite deposit. Laboratory pot test obviously presented that the struvite deposit more facilitated the growth of Chinese cabbage than organic and compost fertilizers even though complex fertilizer was the most effective in growing Chinese cabbage. It was revealed that the growth rate of Chinese cabbage was simultaneously controlled by phosphorus (P) and potassium (K). Also, the nutrients such as nitrogen (N), P, K, calcium (Ca) and magnesium (Mg) were abundantly observed in the vegetable tissue of struvite pot. Specifically, P was the most abundant component in the vegetable tissue of struvite pot. Meanwhile, the utilization of struvite as a fertilizer led to the lower accumulation of chromium ($Cr^{6+}$) than other pots, except for compost fertilizer pots, and no detection of cadmium (Cd), arsenic (As) and nickel (Ni) in the Chinese cabbage. The experimental results proved that the optimum struvite dosage for the cultivation of Chinese cabbage was 2.0 g struvite/kg soil. On the basis of these findings, it was concluded that the struvite deposits recovered from swine wastewater were effective as a multi-nutrient fertilizer for Chinese cabbage cultivation.

• Journal of Korean Society for Atmospheric Environment
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• v.5 no.2
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• pp.12-20
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• 1989

Distribution of benzo(a)pyrene (BaP) in Seoul surface soils was investigated with a simple micro-analytical method consisting of ultrasonic extraction, one-dimensional dual band thin-layer chromatographic separation (TLC) and spectrofluorometric determination. The TLC was done in the following condition: thin-layer plate; Kieselguhr G/Acetylated cellulose, Developer; 1st; ether, 2nd; methanol-ether-water (4:4:1, V/V). The results thus obtained were as follows; 1. All the samples collected from various areas were contained detectable amount of benzo(a)pyrene. The range and average of benzo(a)pyrene contents in Seoul areas are 0.20 $\sim$5.90ppm and 1.01 ppm, respectively. 2. Benzo(a)pyrene contents in soils obtained from commercial areas were much higher than those in industrial and residential areas. The contents range in commercial, industrial, and residential areas are 0.31 $\sim$ 5.90 ppm, 0.36 $\sim$ 1.22 ppm and 0.20 $\sim$ 0.67 ppm, respectively. 3. Benzo(a)pyrene contents in soils from major roads were far higher than those from side or park roads. The ranges of benzo(a)pyrene contents in major, park and side road are 0.40 $\sim$ 5.9 ppm, 0.20 $\sim$ 0.70 ppm, 0.31 $\sim$ 1.30 ppm, respectively. These findings suggest strongly that surface soils in Seoul city are polluted by benzo(a)pyrene probably emitted automobiles.

• Journal of Applied Biological Chemistry
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• v.49 no.4
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• pp.135-139
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• 2006

A alkalophilic strain, Bacillus licheniformis MH31 producing an alkaline protease was isolated from mine soil of Boryeong in Korea. Production of a high level of alkaline protease was achieved 42 h after incubation when the bacterium was grown at pH 9.0 and $35^{\circ}C$ in Horikoshi medium supplemented with 0.5%(w/v) starch and 1%(w/v) skim milk as carbon and nitrogen source, respectively. The molecular weight of partially purified enzyme was estimated to be 30 kDa by SDS-PAGE and its optimum pH was pH 10. The enzyme showed optimum temperature at $50^{\circ}C$, and was stable up to $60^{\circ}C$ after 1 h incubation. The protease was strongly inhibited by 1 mM of PMSF which was known well as strong inhibitor of serine proteases, but almost not inhibited by 5 mM of EDTA and 1,10-phenanthroline. When the protein hydrolysis products of 1% skim milk by partially purified protease was compared with available commercial proteases using HPLC analysis, most of hydrolysis products were detected below molecular weight of 10,000 and the hydrolysis ratio of purified enzyme was 24.8% lower than those(above 32%) of commercial proteases.

• Journal of Environmental Science International
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• v.5 no.6
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• pp.771-778
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• 1996

The sediment in the highly contaminated Gamjeon brook was collected, mixed with the raw material of the tile, and then the commercial tile was produced using the mixture. The concentrations of the heavy metals in the mixture-before and after the tile was produced-were analyzed and the effects of the acid solution on the produced tile were examined. The production of the tiles was successful and the result of heavy metal analysis showed that the concentration of Fe was the highest and that of Cd was the lowest The amount of heavy metal in the sediment - the raw material of the tile mixture was more than that of the produced tile. The elution concentration of the heavy metal by the acid solution(pH : 4 - 7) was low and the quality of the produced tile was better than the commercial tile. The result of this study suggested that the contaminated sediment was removed to produce good tiles, therefore the water pollution and soil pollution were reduced.

• Environmental Engineering Research
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• v.21 no.1
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• pp.29-35
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• 2016

This study evaluated the fertilizing value of struvite deposit recovered from swine wastewater in cultivating lettuce. Struvite deposit was compared to complex fertilizer, organic fertilizer and compost to evaluate the fertilizing effect of struvite deposit. Laboratory pot test showed that the struvite deposit better enhanced lettuce growth in comparison to commercial fertilizers. It was revealed that the growth rate of lettuce was simultaneously controlled by phosphorus (P) and magnesium (Mg). Moreover, nutrients such as nitrogen (N), P, K, calcium (Ca) and magnesium (Mg) were abundantly observed in the vegetable tissue of struvite pot. Meanwhile, struvite application led to the lower accumulation of mercury (Hg), lead (Pb), chromium ($Cr^{6+}$) and nickel (Ni). In addition, no detection of cadmium (Cd), arsenic (As) and nickel (Ni) in the lettuce tissue was observed in struvite application pots. The experimental results proved that the optimum struvite dosage for lettuce cultivation was 0.5 g struvite/kg soil. The column experiments clearly showed that ammonia nitrogen was more slowly released from struvite deposit than from complex fertilizer. Consequently, it was concluded that the struvite deposits recovered from swine wastewater were effective as a multi-nutrient fertilizer for lettuce cultivation.

• Microbiology and Biotechnology Letters
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• v.23 no.3
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• pp.263-268
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• 1995

A screening was performed to isolate exoploysaccharide-producing microorganisms, which synthesized specific exopolysaccharide for the substitutive of commercial polysaccharides, from natural sources. Soil bacterium, one of 378 mucoid isolates, was finally selected as potential producer of polysaccharides which made the culture broth very viscous and thus examined in detail for optimal medium composition. Isolated strain was identified as Xanthomonas sp. EPS- 1 from the results of morphological and biochemical characteristics. The composition of optimal medium for exopolysaccharide production was as follows: 50 g sucrose, 1.5 g peptone, 2 g KH$_{2}$PO$_{4}$, 2 g MgSO$_{4}$, -7H$_{2}$O, 3 g NaCl, 0.05 g CaCO$_{3}$, 0.07 g FeSO$_{4}$-7H$_{2}$O and 0.05 g MnSO$_{4}$-7H$_{2}$O in 1 liter of distilled water. From the experiments of temperature and pH dependence, the optimal conditions for exopolysaccharide biosynthesis seemed to be 30$\circ$C and 8.0, respectively. About 14.9 gram of maximum exopolysaccharide per liter was obtained at the initial pH 8.0, 30$\circ$C and 250 rpm in a flask culture. The exopolysaccharide EPS-1 had such potential as an emulsifying agent and a gelling agent in comparision with commercial exopolysaccharide.