• Journal of The Korean Society of Agricultural Engineers
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• v.66 no.2
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• pp.53-62
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• 2024

This study assessed the efficiency of reducing soil erosion and suspended sediment through the restoration of alpine unauthorized and illegally cultivated fields, using the SWAT (Soil and Water Assessment Tool) model in the Mandae District. The results showed that in Scenario 5, which involved restoring unauthorized and illegal fields within forests, along rivers (banks), and in ditch areas were restored to their original land categories, achieved the highest efficiency in reducing average annual soil erosion and suspended sediment, with reductions of 8.1% and 4.5%, respectively. In particular, it was confirmed that the restoration of unauthorized and illegal fields within forested areas has a significant impact. This demonstrated that the restoration of unauthorized and illegal agricultural fields can substantially reduce the soil erosion and suspended sediment attributable to non-point source pollution. Our findings highlight the importance of managing these unauthorized and illegal agricultural activities in developing sustainable strategies within non-point source pollution management areas. This study is expected to provide important basic data to effectively establish water quality improvement strategies in the region of non-point source pollution management.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.315-322
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• 2001

Underground flexible pipes for electric cables are subject to external loads and surrounding soil pressure. Particularly, strain of flexible pipes is of great concern in terms of safety and maintenance for electric cables. In this paper, stress and strain of flexible pipes with various depth are calculated using traditional formula and FEM analysis. The results show that theoretical values are more conservative in strain whereas FEM analysis gives larger stress. Considering the strain criteria - 3.5 %, maximum, flexible pipes can be buried at the range of 50cm to 5m in depth without additional soil improvement.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.5
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• pp.543-550
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• 2015

In this study, using soil brick with combined effective microorganisms and emergent plants was identified which it can increase the effect of conservation and improvement of water. Lab-test was consist of four kind of reactors and each of reactors were A(rawwater), B(soil brick), C(emergent plant) and D(soil brick+emergent plant). Iris pseudoacorus, Phargmites australis, Typha angustifolia and Zizania latifolia were used for emergent plant. Evaluation of application on various environment were performed on agricultural waterway and pond. The pH measurement test of soil brick was performed due to evaluate whether a strong alkaline water flows out of the soil brick. Result of lab-test, removal efficiency of D was better than removal efficiency of A presenting 20.9%, 27.9% 21.5%, 33.8% and 58.4% for $COD_{Cr}$, $BOD_5$, TN, TP and TSS respectively. Removal efficiency of soil brick on agricultural waterway was revealed to be 49.5%, 45.0%, 43.7%, 37.3% and 28.6% for $COD_{Cr}$, $BOD_5$, TN, TP and TSS respectively. And removal efficiency of soil brick on the pond was revealed to be 12.7%, 10.5%, 9.32%, 10.4% and 36.3% for $COD_{Cr}$, $BOD_5$, TN, TP and TSS respectively. Result of pH measurement test of soil brick was neutral which was about 6 to 8.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.4
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• pp.181-190
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• 2001

This study was conducted to investigate the effect of swine liquid manure(SLM) and phosphorus fertilizer from September, 1998 to July, 1999 on the soil fertility on Italian ryegrass field, Cheju volcanic ash soil. pH(lst investigated), Mg (2nd investigated) and Cu content (2nd investigated) on soil grown by Italian ryegrass were significantly increased by an increase of fertilizer P(P

• Journal of Plant Biology
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• v.12 no.4
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• pp.9-18
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• 1969

In the previous paper(part III), a certian relationships between the changes of chlorinity and organic acid released from organic material were seemed to be concened to each other in saline soil suspension. Such a possibility had been a cause to take this experiments and this experiment was carried out under the treatment of organic acid crystal, oxalic acid and succinic acid, to the soil suspension(soil: water=20g:40cc) directly. The amount of organic acid treated to the suspension were related to the contents of organic material, as amount of organic acid per gram of organic material(391.76mg). The saline soil suspension were grouped and treated with the acids in order of 78.35mg(Group 1), 391.76mg(Group 2) 979.4mg(Group 3), and 1958.8mg(Group 4), respectively. Treated suspension had been incubated at room temperature and extract from suspension was used for analysis. Followings are summary of this report. 1) Changes of pH in soil suspension appeared a little increase after the treatment of organic acid until 168 hours. 2) Total acidity of soil suspension showed a variation, however, the values of total acidity appeared not to be increased or decreased during the period of experiment. 3) Sugar contents of soil suspension was increased until 168 hours after treatment. These results are similar tendency to the previous paper. 4) Addition of organic acid to soil suspension was confirmed not to be effective method for desalination from saline soil. Chlorinity of group 3 and 4 which were treated with high concentration of organic acid showed a decrease comparing to control group.

• Journal of Plant Biology
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• v.12 no.1
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• pp.7-14
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• 1969

Korea has a lots of margin for security of farm land from her coastal region. The area of saline soil may be reached about 10% of present farm land if the reclamation works are finished. This paper was conducted as a part of studying the possibilities of desalination of saline soil through the experiment of some halophytes. The halophytes in this works were Salicornia herbacea L., Suaeda glauca Bunge, chenopodium acuminatum Willd, and Scirpus triquerter L. Of the above halophytes, Salicornia was proved the most effective plant for desalination of saline soil referring to the following results; 1) The seasonal uptake of chloride by Salicornia was the highest of all. However, the general tendencies of all plants showed a decrease on August. 2) Salinity of soil showed the lowest value on the site where Salicornia was grwon densely. Comparing the other sites grouped by age of saline soil with the above site, the salinity of rice-paddy (10 years after reclamation) is similar to those of the site wehre Salicornia were as well as the 50 cm below the surface soil. 3) The maximum water holding capacity of surface soil appeared in the site of Salicornia, but in 50 cm below the surface, the maximum water holding capacity are almost on equat terms having no connection with the age of saline soil. Soil pH, other chemical compositions such as organic matter, magnesium, potassium, phosphorous, and nitrate were determined to elucidate the relationship between the changes of soil properties and chemical uptakes by certain halophytes. It is assumed that the above chemical compositions are frequently affected by the factors such as coastal circulation of salts, exchangeable base, microbial growth, climatic conditions, and irrigation of water.

• Journal of the Korean Geosynthetics Society
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• v.9 no.2
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• pp.1-9
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• 2010

At present, the sand mat method is actively used for improvement of soft ground. But, there are some problems related with sand mat which has been used as a way to accelerate consolidation settlement. First of all, insufficiency of sand due to imbalances in market supply and demand is the one of the biggest problems, which makes price high of sand and delays a term of total construction work. Moreover, it is necessary to preserve integrity of environment from natural disruption caused by indiscreet quarrying and dredging operation to supply sand for soil improvement construction site. This paper presents the feasibility study to use of Precious Slag Ball instead of sand mat as the replacing material through the basic soil property tests, the medium of discharge capacity test and analysis of settlement property. It is also evaluates the performance of Precious Slag Ball as a sand mat in terms of discharge capacity, ground settlement by the K-Embank program based on field experimental work.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1132-1135
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• 2008

In this study, a circular and indoor soil tank foundation was manufactured to study the improvement according to the degree of turbulence arising from PBD penetration, using the existing plate-type shoe and improved V-type shoe to change the degree of turbulence. Furthermore, to study the foundation improvement effect, the strength, settlement speed in the turbulence area were compared according to the shoe penetration. The results of the study showed that the V-type shoe reduced the strength coefficient decrease effect, and the foundation improvement effect according to the degree of turbulence was identified.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.3
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• pp.207-211
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• 1984

A series of soil surveys was conducted in 102 high yielding paddies randomly selected. Each paddy field was the contest winner's in a county, a province or the nationwide during 1976 to 1979. The data on soils and yields of the paddies were evaluated to find out the better practices. Cultivation practices such as intermittent irrigation, deep ploughing and application of soil improvement materials were intensively carried out with the increasing rates of yield. But, the yield of rice in the high yielding paddies was not significantly different according to the paddy soil type or the suitability calss. About 70% of the high yielding paddies were distributed in loam and silty clay loam. The properties of top soil in the high yielding paddies were more improved as compared with the common paddies. The cultivated soil depth and nutrient holding capacity were thought of as the important soil factors for high yield.

• Geomechanics and Engineering
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• v.10 no.5
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• pp.677-687
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• 2016

Industrialization and urbanization are the two phenomena that are going relentless all over the world. The consequence of this economic success has been a massive increase in waste on one hand and increasing demand for suitable sites for construction on the other. Owing to the surplus raw materials and energy requirement needed for manufacturing synthetic fibers, applications of waste fibers for reinforcing soils evidenced to offer economic and environmental benefits. The main objective of the proposed work is to explore the possibilities of improving the strength of soil using fly ash waste as an admixture and Human Hair Fiber (HHF) as reinforcement such that they can be used for construction of embankments and land reclamation projects. The effect of fiber content on soil - fly ash mixture was observed through a series of laboratory tests such as compaction tests, CBR and unconfined compression tests. From the stress - strain curves, it was observed that the UCC strength for the optimised soil - flyash mixture reinforced with 0.75% human hair fibers is nearly 2.85 times higher than that of the untreated soil. Further, it has been noticed that there is about 7.73 times increase in CBR for the reinforced soil compared to untreated soil. This drastic increase in strength may be due to the fact that HHF offer more pull-out resistance which makes the fibers act like a bridge to prevent further cracking and thereby it improves the toughness which in turn prevent the brittle failure of soil-flyash specimen. Hence, the test results reveal that the inclusion of randomly distributed HHF in soil significantly improves the engineering properties of soil and can be effectively utilized in pavements. SEM analysis explained the change of microstructures and the formation of hydration products that offered increase in strength and it was found to be in accordance with strength tests.