• Environmental Engineering Research
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• v.10 no.4
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• pp.199-204
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• 2005

Experiments were performed to estimate the organic release from the aquifer soil in riverbank and/or riverbed filtration via a kinetic approach. Organic release was assumed as a reaction of first order regarding concentrations in both soil and water phases. The reaction rate constants were obtained by comparing the model predictions with the experimental data of organic release reaction and the equilibrium distribution of organic matter between water and soil phases. Results show that the organic release from the aquifer soil was not negligible under normal conditions in Korea reaching 4.7mg-COD/L-day. This indicates that manganese and iron start to be released from aquifer soil in the riverbank filtration in the middle reach of the Nakdong river if the travel time of the filtrate exceeds about 5 days. It was also seen that the COD of the soil organic matter was 0.89mg-COD/mg-OM and that 65% of the COD was BOD5.

• The Korean Journal of Ecology
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• v.21 no.4
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• pp.321-328
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• 1998

To describe the major environmental factors operating in coastal wetland and to characterize the distribution of the plant species over the wetland in relation to the major environmental gradients, 12 soil physical and chemical properties were determined. The gradient of water and osmotic potential of soil, electrical conductivity, sodium and chloride content and soil texture alsong the three habitat types of salt marshes, salt swamp and sand dune were occurred. The 24 coastal plant communities from principal component analysis (PCA) on the 12 variables were at designated as a gradient for soil texture and water potential related with salinity by Axis I and as a gradient for soil moisture and total nitrogen gradient by Axis II On Axis I were divided into 3 groups (1) 9 salt marsh communities including Salicornia herbacea communities (2) 5 salt swamp communities including Scirpus fluviatilis communities and (3) 10 sand dune communities including Jmperata cylindrica communities on Axis II were divided into 2 groups (1) salt marsh and sand dune communities, and (2) 3 salt swamp communities. The results could account for the zonation of plant communities on coastal wetland observed alsong envionmental gradients.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.223-223
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• 2017

This study aimed to determine the effect of organic matter content and water condition in soil on yield, carbohydrate, and inulin contents of two varieties of Jerusalem artichoke. The plants were grown with high and low organic soil either under irrigation or no irrigation in a randomized complete block design (RCBD) with three replications. In result, the yield of Jerusalem artichoke was higher about 7 kg in soil with high organic matter than in soil with low organic matter, while it was higher about 11 kg under the irrigation than under no irrigation. The yield of white variety was higher about 9 kg than that of purple variety. Under the irrigation, a 12 kg and 9 kg of higher yields were observed in the soil with high and low organic matter content, respectively, than under no irrigation.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.17-19
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• 2004

Recently, we have recognized that ‘Soil Environmental Prevention Act’could not provide perfect solutions on many complicated problems which are now emerging and/or can be solved by adopting comprehensive policies. In this study, some suggestions were made to solve a few tangled problems such as conducting the Land Partnership Plan(LPP) project, investigating soil and ground water contamination of the industrial area, building a integrated information system for soil and ground water, establishing detailed guidelines for remediation and verification, and re-constructing the legal and institutional framework for integrated management of soil and ground water. These suggestions may help policy makers to build conceptual frameworks for solving these problems.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.966-972
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• 2009

Soil-aggregate system in pavement foundations exist in unsaturated conditions. However, change in water content on foundation layers due to joint and structural cracks during rainfall may cause problems like layer deformations or partial settlements. Therefore, a need exist to evaluate the infiltration and drainage capacity of soil-aggregate foundation system under both saturated and unsaturated conditions. To do that, a laboratory soil-water characteristic curve and permeability under unsaturated conditions are assessed to establish hydraulic properties of geomaterials and limited numerical analysis are performed respectively. As a result, it was found that suction profiles and drainage process was greatly influenced by the initial suction of soil-aggregate system at the time of infiltration, soil water characteristics curves, and hysteresis effects.

• Asian Journal of Turfgrass Science
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• v.10 no.3
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• pp.177-186
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• 1996

The effects of salt are studied on control of weeds and growth of Korean turfgrass(Zoysia japon-ica Steud.). And the mobility of salt were determined in a lawn field. At post-emergence stage, the growth of the 13 weeds such as Trifolium repens, Erigeron canadensis, Artemisia prieceps, Equi-setum arvense, etc were controlled by treatment of salt and salt water, Pea-annua and Equisetum arvense were tolerant to salt compared with the other 11 weeds. At pre-emergence stage, the salt controlled the germination of the weeds in soil. 300~500 kg /10a salt and 20~30 % salt waterwere enough for the control of weeds, However, salt water injuried the lawngrass except the dormancy stage. The mobility of salt in soil was increased by rainfall. After 160mm of rainfall, the salinity in the soil treated with salt 500kg /l0a was below 0.3 ms/cm in surface soil and about 0.1 ms /cm in soil 30 cm depth. Key words: Soil environmental survey, Korean turfgrass, Salt, Salt water.

• Water Engineering Research
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• v.7 no.1
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• pp.29-41
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• 2006

The Imha watershed is vulnerable to severe erosion due to the topographical characteristics such as mountainous steep slopes. Sediment inflow from upland area has also deteriorated the water quality and caused negative effects on the aquatic ecosystem of the Imha reservoir. The Imha reservoir was affected by sediment-laden density currents during the typhoon 'Maemi' in 2003. The RUSLE model was combined with GIS techniques to analyze the mean annual erosion losses and the soil losses caused by typhoon 'Maemi'. The model is used to evaluate the spatial distribution of soil loss rates under different land uses. The mean annual soil loss rate and soil losses caused by typhoon 'Maemi' were predicted as 3,450 tons/km2/year and 2,920 ton/km2/'Maemi', respectively. The sediment delivery ratio was determined to be about 25% from the mean annual soil loss rate and the surveyed sediment deposits in the Imha reservoir in 1997. The trap efficiency of the Imha reservoir was calculated using the methods of Julien, Brown, Brune, and Churchill and ranges from 96% to 99%.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.349-352
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• 1998

In many circumstances, it is infeasible to simulate the daily water yield in every land use or soil type of the watershed or river basin. These situations can be simulated in“Soil and Water Assessment Tool”(SWAT) using a concept called“hydrologic response units”(HRU's) within a topographically-defined subbasin. Soil water balance, crop growth, nutrient cycling management, etc., are simulated for each HRU For the watershed of Bok-ha river, the effect of HRU's in SWAT has been studied in respect to water yield. The optimum number of HRU's was 23 based in data capacity and correlation coefficient.

• Water Engineering Research
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• v.5 no.3
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• pp.133-146
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• 2004

Soil and water assessment tool (SWAT) was simulated based on the default parameters and a priori soil parameter estimation method in Bocheong watershed of Korea. The performance of the model was tested against the measured daily runoff data for 5 years between 1993 and 1997. The sensitivity analysis of SWAT model parameters was conducted to identify the most sensitive model parameters affecting the model output. The results of SWAT simulation indicate that the overall performance of SWAT in calculating daily runoff is reasonably acceptable. However, there is a problem in estimating the low flow components of streamflow since the low flow components simulated by SWAT are significantly different from the measured low flow. The sensitivity analysis with SWAT points out that soil related parameters are the most sensitive parameters affecting surface and ground water balance components and groundwater flow related parameters exhibit negligible sensitivity.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.1
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• pp.63-73
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• 2003

The settling of the dredged soil may vary with mineral composition, grain size distribution, initial water content and salt concentration of suspension of the site. A series of settling column test was performed to investigate the behaviour of solid suspension material from dredging and reclamation. Settling mode was divided into four types from the observation of interface and settling curves of clay minerals and marine clay samples, and the relationship charts of salt concentration and the initial water content were established to use in the dredging operation with any salt concentration. The critical initial water content which was defined as a threshold of zone settling and the consolidation settling was varied with salt concentration of water and was proportional to the plasticity of soil in sea water.