• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.6
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• pp.13-22
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• 2006

The purpose of this study is to propose rational methods in order to maintain vegetation condition and soil environment based on the analysis of tree growth in relation to the soil environment, which is one of the most significant environmental factors on vegetation condition in urban parks and open spaces. The result of the study can be described as below;The soil on every study site had strong acidity. In particular, study sites around industrial district and central business district showed extreme soil acidity. Therefore, soil management system is needed in urban parks and green spaces around those areas. Among Cambium Electric Resistance classified by locations of urban parks and open spaces, one in the costal area was the lowest. The Cambium Electric Resistance in the industrial area was the highest. Therefore, soil condition and locational environment in the industrial area are highly related to the Cambium Electric Resistance. Among the factors, which affect Cambium Electric Resistance in different locations, inorganic content was found to be the main factor in all of the study sites. Inorganic content was an important factor to the Cambium Electric Resistance in study sites located in industrial and central business districts. In the study sites located in costal area, Soil acidity was found to be other important factors that affect Cambium Electric Resistance. To improve the soil acidity, soil buffering ability should be improved from activating microorganisms in the soil by using lime and organic material, Since it takes a long time to make a change in the soil structure, well planed maintenance system is required by mid-term or long-term plans.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.4
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• pp.69-79
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• 1992

To estimate soil behavior and structural characteristics under the conditions of cyclic loading, freezing & thawing and initial state, several testing was performed and obtained following results. 1.After repeated freezing and thawing processes, original soil structure was destroyed and changed to globular structure from honeycomb or tube in its structure types. Also above processes resulted increasing the soil compression strain while decreasing the failure stress in stress-strain relationship and reached the soil structure into the mode of brittle fracture. Under cyclic loading conditions, soil cluster which was originally dispersed structure colloided with each other, seperated, and finally the soil failed due to the effect of overcompaction. 2.Through the stabilization processes seperated by four steps, the structure of soil skeleton was changed to quite different globular type. The degree of compressibility of soil was decreased in the normally consolidated zone, while the strength against external load increased due to soil particle stabilization. 3.Soil stress-strain chracteristics were largely influenced by repeated up and down processes of temperature. The maximum deformation was obtained in the case of temperature between 0 10˚C by the reseon of particle cluster reformation. 4.Soil compressibility was largely influenced by the optimum moisture content. Under freezing process, swelling could be found and its magnitude was proportional to the density of soil. 5.Density of soil was decreased as increasing the number or repeated freezing and thawing processes and the largest decreasing rate was found at the first turning point from freezing to thawing cycle.

• The Journal of Engineering Geology
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• v.12 no.4
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• pp.459-469
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• 2002

We have remolded marine clay sample collected along the vertical and horizontal directions and investigated the characteristics of the consolidation constants by SCT and CRSC methods. We have studied also on consolidation chracteristics and application for weathered granite soil using SCT and CRSC methods for undisturbed and disturbed samples. As the result, values of pre-consolidation stress, compression index, excessive pore pressure, pore water pressure ratio of the marine-clay were different due to different test methods(SCT and CRSC) and sampling directions(vortical and horizontal directions). Disturbed and undisturbed samples of the weathered granite soil have showed similar change aspect like marine clay during over-consolidatied and normally consolidatied stages.

• Journal of the Korean Geosynthetics Society
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• v.14 no.3
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• pp.43-51
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• 2015

In seasonal frozen areas which have a temperature difference in the winter and spring season like south korea, if stiffness reduction by repeated freezing and thawing occurs to slopes adjacent to private facilities or mountain slopes, safety factor is insufficient to design criteria and landslide could be occurs due to rainfall or snowfall. It can lead to large damage of human life and property. In this study, in order to examine the safety changes of mountain slopes by repeated freezing and thawing, soil samples series of SP and SM by USCS distributed in surface soil of mountain slopes were collected for specimens. Through the direct shear test, the characterestics of frozen soil shear strength were analyzed and by utilizing numerical methods, chracteristics of strength reduction of weathered granite soil according to repeated action of freezing and thawing, changes in the stability of the slopes when applying freezing and thawing of the soil samples were examined. As a result, the maximum shear stress decreased approximately 10%, and slope stability analysis confirmed that required safety factor is less than compare with the non-frozen samples.

• Korean Journal of Plant Resources
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• v.9 no.2
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• pp.177-181
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• 1996

This study was carried out to obtain basic data for technical inprovement about cultivation according to micrometerological changes under various mulching materials in Dendropanox morbifera LEV. The results are summarized as follows. Transparent polyethylene film and black polyethylene film mulching materials increased the soil porosity and reduced change of the soil moisture content. The rate of missing plant during overwinter increased in the control plot. Growth of Dendropanox morbifera LEV, was accelerated by transparent polyethylene film and black polyethylene film mulched.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.1
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• pp.24-29
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• 1995

This experiment was canied out to select the optimum utilization method by various pasture types at National Livestock Research Institute, Suwon in 1992 and 1993. Tne main plot was two pasture types. wfiich were mainly top-grass(orchardgrass dominated pasture) and mainly bottom-grass(perennial ryegrass dominated pasture), and the subplot was three pasture utilization methods (grazing, grazing after the 1st cutting, and alternate utilization of cutting and grazing). Average dry matter yields of pasture were not affected by pasture types, but there was significant difference(p <0.05) by pasture utilization methods. Daily DM production of pasture was increased with alternate utilization of cutting and grazing at two pasture types. Also, pasture availability is increased by mainly top grasses and alternate utilization of cutting and grazing. Soil phsical chracteristics are improved by alternate utilization of cutting and grazing. According to the results obtained from this experiment, it is suggested that alternate utilization of cutting and grazing is effective for dry matter yield, pasture availability and soil phsical characteristics regardless of pasture types in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.1
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• pp.12-17
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• 1989

Soil and water temperature were evaluated to relate rice growth to topographical chracteristics in paddy soils. Water temperature (WT) and so il temperature (ST) were measured under the various altitudes, slopes and irrigation methods. Temperature fluctuation and growth status in the same field were measured; 1. Air temperature (AT) and ST of 10cm soil depth were decreased with increasing altitude. Difference of its fluctuation in AT, WT and ST of 10cm soil depth in the lapse rate was 0.64, 0.84 and $0.82^{\circ}C$ per 100m elevation, respectively. 2. Maximum WT, in panicle initiation stage, was decreased slowly with increasing altitude whereas minimum WT fallen rapidly. It suggested that the lapse rate of WT was affected by minimum WT. 3. Source of irrigation water and irrigation method affected the WT. WT, ST and rice growth varied with the locations within the same field. 4. Pumping irrigation of artesian well resulted in more fluctuation of WT between irrigation intervals than did the conventional irrigation.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.158-161
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• 1998

The study was carried out to examine changes of ${\alpha}$-amylase activity and free proline contents during rice germination under low temperature($13^{\circ}C$). The plant height, root length, and germination rate were investigated during seed germination under the low temperature. Those growth chracteristics were the highest in Dongjin cultiver compared with other rice cultivars. The ${\alpha}$-amylase activity of the 9 days after germination was higher in Dongjin than those of Sangju and Koshihikari cultivars. The content of free proline was increased in all rice cultivars, when the germination of rice seeds was prolonged. As a result, it was concluded that ${\alpha}$-amylase activity and free proline content of Donjin cultivar were relatively increased higher under low temperature stress than those of other rice cultivars.

• Korean Journal of Medicinal Crop Science
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• v.15 no.5
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• pp.362-366
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• 2007

This study was conducted to evaluate the status of habitat distribution, environmental characteristics and plant species growing with Lonicera japonica in its habitats. In the distribution of plant coverage below 30%, it was 84.6% in the inland area and 80.7% in the seashore area. There was similar coverage in both inland and seashore areas. But the average relative coverage in the seashore area was 26.1%, which is a little higher than that of the inland area (22.5%). In the habitats, both inland and seashore areas showed a high distribution ratio below 10 degrees. But among them, inland areas showed a high distribution ratio (62.4%) below 10 degrees, which was about twice as much as the seashore areas (32.2%). Habitat distribution was most often found on the southern slopes in both inland and seashore areas. The average soil pH of Lonicera japonica habitat was 5.2 in the inland areas and 6.9 in the seashore areas. Also, the seashore areas showed little content of $P_2O_5$, but high content of K, Mg, Na on the other hand compared to the inland area. Miscanthus sinensis was the highest importance value (16.4) among plants growing with Lonicera japonica in their habitats in both inland and seashore areas. But in the inland areas, Artemisia princeps showed the highest importance value, and Miscanthus sinensis was the highest in the seashore areas.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.1-10
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• 2018

Although the soil nailing method is generally used as a gravity grouting, the development and application of pressurized grouting method has recently increased to address the problem of joint generation and filling due to grouting. Pressurized grouting of the soil nailing method is generally used in combination with ordinary portland cement and water. In the field, the cement is mixed with the rapid setting cement to reduce curing time because ordinary portland cement takes more than 10 days to satisfy the required strength. In this study, uniaxial compression tests and laboratory tests were carried out to confirm the efficiency of the grouting material according to the mixing ratio of rapid setting cement. The mixing ratio of 30% grouting satisfies the required strength within 7 days and satisfies the optimum gel time. As a result of the laboratory test with granite weathered soil, the reinforcing effect was confirmed to be 1.5 times as compared with the gravity type at an injection time of 10 seconds and a strain of 15%. The friction resistance increases linearly with the increase of the injection time, but it is confirmed that the friction resistance decreases due to the hydraulic fracturing effect at the injection time exceeding the limit injection pressure. Numerical analysis was performed to compare the stability of slopes not reinforced with slopes reinforced with gravity and pressurized soil nailing.