• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.2
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• pp.73-79
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• 2020

This study was conducted to develop a technique for the stable production of Italian ryegrass(IRG) seeds in reclamation sites. Harvesting 35 days after heading in Autumn resulted in the highest production, an average of 2,232kg/ha. The production yield decreased due to seed loss as harvesting was delayed to 45 and 55 days post-heading. For the harvested 35 days post-heading, under growing rice sowing resulted in 80% seed yield of after rice sowing's; spring sowing resulted in 40%. After rice sowing using the domestic IRG seeds of 30kg/ha produced the highest seed yield of 2,507kg/ha. The highest straw yield has resulted when using the imported IRG seeds of 20kg/ha for after rice sowing 35 days post-heading fresh weight 36,667kg/ha, dry weight 14,500kg/ha, and TDN weight 7,895kg/ha.

• Journal of the Korean GEO-environmental Society
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• v.14 no.10
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• pp.39-47
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• 2013

Recently, there have been various domestic construction activities related to the reclamation of the dredged soils to expand the land use. However, the reclaimed grounds made of the dredged soils cause various problems due to highly compressible and low shear strength nature. Particularly, this nature induces huge problems in case of the harbor facilities and road construction on the reclaimed sites. Furthermore, in the reclamation activities, the marine dredged soils are often used instead of the well sorted sand, which induces problems of compressibilities. Therefore, in this study, the mechanical characteristics of artificial soil mixture of kaolinite representing the marine dredged soils and the pond ash. A large consolidometer is designed and manufactured to produce the artificial soil mixture. To represent various mixing ratio between the fly ash and bottom ash in the pond ash, six samples with the same stress history are made with different mixing ratio among kaolinite, bottom ash and fly ash. Isotropically consolidated and undrained compression tests are performed to investigate the shear characteristics of soil mixtures. Based on the experimental results, as the components of mixed ash increase, the friction angle increase and the cohesion values decrease. Also, the porepressure parameters at failure, Af increase with the mixing components of the pond ash. The portion of bottom ash has more impact on the shear behavior than that of fly ash.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.3
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• pp.63-74
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• 2019

This study carried out a human risk assessment of Cu, Pb, Zn and Ni contained in soil contaminated by improperly buried heavy metal wastes in railway sites. The purpose of the human risk assessment is to derive the need for soil remediation and factors that should be considered during soil remediation. Risk assessment was performed in accordance with the Environment Ministry's Risk Assessment Guidelines. The results of the human risk assessment of contaminated heavy metal soil contaminated by improperly buried waste in the railway site were presented after the process of determining exposure concentration, calculating exposure, and determining carcinogenic hazards. The heavy metal content of soil is 621.3 Cu mg/kg, 2,824.5 Pb mg/kg, 1,559.1 Zn mg/kg and 45 Ni mg/kg, which is the exposure concentration of the target contaminant. The results of human exposure according to exposure pathways were high in the order of soil outdoor dust >soil ingestion >soil contact, and Pb >Zn >Cu >Ni were higher in order of contaminant. The carcinogenic and noncarcinogenic risks of soil contaminated with heavy metal waste were higher than the allowable carcinogenic risks (TCR> $10^{-6}$) and the risk index (Hi < 1.0) suggested by USEPA. Therefore, the site needs to be remediated.

• Korean Journal of Weed Science
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• v.32 no.1
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• pp.1-9
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• 2012

This study was conducted to survey vegetation changes and soil characteristics in Saemangeum new reclaimed tidal land. Soil salinity in border area to tidal land was 22.3 dS $m^{-1}$ but showed 1.1~3.44 dS $m^{-1}$ over the distance of 2 km from border line. The vascular plants in survey sites were recorded as total 26 taxa in 6 families. The frequency of species appearance of Aster tripolium, A. subulatus var. sandwicensis were highest by 61.5 and that of Phragmites communis, Puccinellia nipponica were 53.8. The almost vegetations occurred in the patch which range of soil salinity 14 dS $m^{-1}$ were halophytes as Salicornia europaea, Suaeda asparagoides, S. japonica. As lowed soil salinity as 6.7 dS $m^{-1}$, mixed vegetation of halophytes with P. communis, P. nipponica, Carex pumila were occurred. Dominant species in the range of 3.0 dS $m^{-1}$ area were A. subulatus var. sandwicensis, P. communis, Echinochloa spp., Zoysia sinica and Conyza canadensis. Biomass production was the highest in the area of dominant vegetation with P. communis, and mixed zone with P. communis and Aeschynomene indica are followed. The correlation between vegetation biomass and soil salinity, soil pH and dominance index of vegetation were negative. But that of vegetation biomass and soil organic content were positive.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.502-509
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• 2011

It is important to determine optimum soil covering depths for tree survival and growth because soil covering depths for establishing tree planting bases in coastal reclaimed lands are related to the costs for soil collection, transportation and land reclamation. The objectives of this study were carried out to determine optimum soil covering depths for the normal growth of planted trees in a coastal reclaimed land. The study sites were located in Asan National Industrial Complex in Pyeongtaek City, Gyeonggi-do. Four tree species (Pinus thunbergii, Chamaecyparis pisifera, Zelkova serrata, Quercus acutissima) with one hundred eighty trees of each species were planted in various depths of soil covering (no soil covering, 0.5 m, 1.5 m, 2.0 m soil covering treatments) on April 1998, and the tree growth patterns were measured on September 2000. The change of soil properties, tree mortality rate, root collar diameter and height growth were measured from each soil covering depth treatment on September 2000. Soil pH, EC, exchangeable cations ($K^+$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$), anion $Cl^-$, and base saturation increased with decreased soil covering depths. The mortality rates of tree species showed decreased with increased soil covering depths. The height growth of tree species increased with increased soil covering depths. Height growth of Pinus thunbergii was significantly different between the soil covering depth below 0.5m and other three covering depths, while the growth of other species (C. pisifera, Z. serrata, Q. acutissima) was significantly higher in soil covering depths below 1.5 m than in other soil covering depth treatments. The root collar diameter growth of all tree species showed increasing trends with increased soil covering depths. It is recommended to cover the soil depths above 1.5 m to decrease mortality and to stimulate the tree growth of C. pisifera, Z. serrata and Q. acutissima, while P. thunbergii which is a salt tolerate species could be planted in the 1.0 m soil covering depth.

• Korean Journal of Food Science and Technology
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• v.40 no.4
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• pp.365-374
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• 2008

Plastics are comparatively new polymeric materials that are manufactured by chemical synthesis, making them different from natural materials such as wood, paper, stone, metal, and glass. Due to a wide range of properties, including processing capabilities and duration, plastics have become rapidly ubiquitous, being used in all industries, and have improved our quality of life. However, it is true that plastics cause environmental contamination problems that have become important social issues, such as environmental hormone leakage due to incineration or reclamation, difficulty in securing reclamation sites, and deadly poisonous dioxin generated by the incomplete incineration of waste plastic materials. To solve these problems, it is urgent to develop and commercialize degradable plastics that can be stably and conveniently used just as general plastics, and that are easily decomposed by sunlight, soil microbes, and heat generated from reclaimed land after use. This review presents recent worldwide trends in the development and marketing of environmentally degradable plastics.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.3
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• pp.108-117
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• 2013

Among the byproducts from thermal power plant using coal combustion, fly ash as mineral admixture is widely utilized in concrete manufacturing for its engineering merits. However residuals including bottom ash are usually reclaimed. This study presents an evaluation of engineering properties in cement mortar with pond ash (PA). For this work, two types of pond ash (anthracite and bituminous coal) are selected from two reclamation sites. Cement mortar specimens considering two w/c (0.385 and 0.485) ratios and three replacement ratio of sand (0%, 30%, and 60%) are prepared and their workability, mechanical, and durability performance are evaluated. Anthracite pond ash has high absorption and smooth surface so that it shows reasonable workability, strength development, and durability performance since it has dense pore structure due to smooth surface and sufficient mixing water inside. Reuse of PA is expected to be feasible since PA cement mortar has reasonable engineering performance compared with normal cement mortar.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.1
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• pp.13-23
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• 2015

This study was performed to compare the effects of different drainage layers on tree growth at the exposed sites of Saemangeum sea dike. 4 types of drainage layers including control(dredged soil), specially prepared bark, gravel, and wood chip were set in 150~165cm depth of soil. Pinus thunbergii and Celtis sinensis were planted after 9 months of soil treatment. Electrical conductivity(EC) of soil in all treated plots were decreased under $4dS{\cdot}m^{-1}$, and NaCl(%) was decreased under 0.05% after 1 year from soil treatment. Soil moisture at the 120cm depth of the bark treated plot was higher than that of the 180cm soil depth, below the drainage layer. It is considered that vertical mobility of water was inhibited. Organic matter(OM) at the 120cm soil depth increased at bark and wood chip treated plots. Survival rates after 4 years of P. thunbergii and C. sinensis were 100% in all treatments. The height of P. thunbergii was not significantly different among the treatments while the height of C. sinensis was significantly different among the treatments and it was highest at the bark treated plot.

• Journal of the Korean Geosynthetics Society
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• v.11 no.1
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• pp.23-33
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• 2012

The stability of urban railway foundation can be a problem due to the excessive settlement. The settlement at the base of railway is monitored by the installed settlement gauges. The piezometer and pore water pressure measurement device are installed to measure the variation of pore water pressure and ground water table during the continuous pullout of sheet piles which were used for the braced cut. The settlement of railway is predicted with using the computer program CAIN RDA. The input data for the numerical analysis are obtained from the field soil exploration data and soil properties. The surcharged load from landscaping over the ground surface and the weight of train are taken into account for the estimation of settlement. As a result of numerical analysis, the range of settlement for six different Sites is from 5.94 cm to 12.77 cm. Thus, the settlement level at Site 2 is occurred 12.77 cm which is higher than the allowable settlement of 10 cm.

• Journal of Environmental Impact Assessment
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• v.19 no.6
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• pp.539-546
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• 2010

In nature, the overall effect of heavy metals on the biota can be influenced by a number of environmental factors like soil characteristics and air pollution by elevated $CO_2$. Pillbugs(Isopoda, Armadillium vulgare) take up heavy metals with their food and store them mainly in the vesicles of hepatopancreas. They accumulate certain metals, occuring in relatively large numbers, are easily collected and identified. Therefore, it has been suggested that total body concentration of metals in pillbugs could be positively correlated to the levels of environmental exposure and that pillbugs could be used as biological indicators of metal pollution and global change by $CO_2$. The aim of the study is to determine effects of heavy metal concentrations in soil and elevated $CO_2$ on pillbugs'body accumulation of heavy metal and growth rate. In this study, pillbugs were collected at five sites (N=287) May 2006. Cu and Zn concentrations in pillbugs were higher than in soils (1.39-41.70 times) than in control. The high bioconcentration of lead in Sangam may be partly associated with reclaimed land uses. Pillbugs in low $CO_2$ and Pb condition showed higher growth rate than in elevated $CO_2$ and Pb condition.