• 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.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.447-453
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• 1999

Salt accumulation is one of themajor problems in soils under protected cultivation . Since protected cultivation does not have rainfall or excessive irrigation, salt accumulaiton inthe soils is inevitable. In this study, characteristics of salt accumulation in soil column were ivestigated, and a salt-extracting method was tested to see its effectiveness. The results showed that the concentration of salt in top soil layers increased and electrical conductivity as thesalt concentration decreased especially in the top soil layer .When extraction medium was applied.

• Journal of Environmental Science International
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• v.31 no.3
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• pp.247-254
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• 2022

This study investigated the effect of vegetation mat on plant growth and salt reduction in the soil treated with high concentration deicing salt. In order to measure soil chemical characteristics and plant growth, three native groundcover plants (Dendranthema zawadskii var. latilobum, Dendranthema boreale, and Kalimeris yomena) were grown in each of the three plastic containers (50.0 cm width × 35.0 cm length × 8.5 cm deep) with a high concentration treatment of calcium chloride deicing salt. There were two treatments: control, and BVM that combines B (blanket) and VM (vegetation mat). 1,600 g of soil was placed on the top of the drainage layer with 290 g of perlite, 100 seeds each of the three native plants with three repetitions were sowed, and 10 g/L of calcium chloride deicing salt was added in the treatment. As a result of the chemical properties of soil, soil in control treatment was acidic and soil electrical conductivity in BVM was the lowest. Also, exchangeable cations (K⁺, Ca²⁺, Na⁺, and Mg²⁺) in soil and all the three plants were significantly decreased in the BVM treatment. Meanwhile, the germination rate of Dendranthema zawadskii var. latilobum was the highest under high concentration deicing salt in compared to the two plants. Overall, three native groundcover plant growth was higher in the BVM than control treatment significantly. These results suggest that the treatment of blanket vegetation mat has a positive effect on soil and plant growth in soil damaged by deicing salt.

• Korean Journal of Environmental Agriculture
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• v.32 no.4
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• pp.332-337
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• 2013

BACKGROUND: Newly reclaimed land has poor soil environment for crop growth since it is high in salt concentration but low in organic content compared with ordinary soil. It is known that whole-crop-barley can grow better in the soil of relatively high salt concentration than other crops but, the growth is poor at the concentration if higher than certain amount and it is a difficulty to secure productivity. Hence, the level of soil salt concentration suitable for the production of bulky feed in newly reclaimed land has been investigated. METHODS AND RESULTS: At Saemanguem reclaimed land, the land for the soil salt concentration electrical conductivity (EC) 0.8, 3.1, 6.5, 11.0 dS/m was selected; and chemical fertilizer $N-P_2O_5-K_2O$ (150-100-100kg/ha) was tested; and forage barley 220kg/ha were sown. The soil salt concentration during the cultivation period decreased in the order of harvest season>earing season>sowing season>wintering season, and the salt concentration in harvest season is 1.4-4.2 times higher than that of the sowing season. The higher the salt concentration, the poorer the over ground growth due to poor rooting; especially at EC 11.0 ds/m there was emergence but, it blighted after wintering. The Yield from the soil salt concentration 3.1dS/m and 6.5 dS/m was 68% and 35% from that of the soil salt concentration 0.8 dS/m (8.8 MT/ha) respectively. The proline content in early life stage was more than that of the harvest season, and it increased with salt concentration. The higher salt concentration, the more $Na_2O$ and MgO content in harvest season; but the higher the salt concentration, the less the content of N, $P_2O_5$, $K_2O$ and CaO. CONCLUSION(S): When the soil salt concentration becomes higher than 3.1 dS/m, the yield becomes poor because there is serious growth inhibition of forage barley both in root part and above aerial part that results in unbalanced absorption of nutrients. Therefore, it is recommended that the salt concentration should be lowered below 3.1 dS/m by underground drainage facilities or irrigating water for the stable production of whole-crop-barley.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.s02
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• pp.66-80
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• 1989

Salt injury in rice is caused mainly by the salinity in soil and in the irrigated water, and occasionaly by salinity delivered through typhoon from the sea. The salt concentration of rice plants increased with higher salinity in the soil of the rice growing. The climatic conditions, high temperature and solar radiation and dry conditions promote the salt absorption of rice plant in saline soil. The higher salt accumulation in the rice plant generally reduces the root activity and inhibits the absorption of minerals of rice plant, resulting the reduction of photosynthesis. The salt damages of rice plant, however, are different from different growth stage of rice plants as follows: 1. Germination of rice seed was slightly delayed up to 1.0％ of salt concentration and remarkably at 1. 5％, but none of rice seeds were germinated at 2.5％. This may be due to the delayed water uptake of rice seeds and the inhibition of enzyme activity, 2. It was enable to establish rice seedlings at seed bed by 0.2％ of salt concentration with some reduction of leaf elongation. The increasing of 0.3％ salt concentration caused to the seedling death with varietal differences, but most of seedlings were death at 0.4％ with no varietal differences. 3. Seedlings grown at the nursery over 0.1％ salt, gradually reduced in rooting activity after transplanting according to increasing the salt concentration from 0.1％ up to 0.3％ of paddy field. However, the seedlings grown in normal seed bed showed no difference in rooting between varieties up to 0.1％ but significantly different at 0.3％ between varieties, but greatly reduced at 0.5％ and died at last in paddy after transplanting. 4. At panicle initiation stage, rice plant delayed in heading by salt damage, at meiotic stage reduced in grains and its filling rate due to inhibition of glume and pollen developing, and salt damage at heading stage and till 3 weeks after heading caused to reduction of fertilization and ripening rate. In viewpoint of agricultural policy the overcoming strategy for salt injury is to secure sufficient water source. Irrigation and drainage systems as well as underground drainage is necessary to desalinize more effectively. This must be the most effective and positive way except cost. By cultural practice, growing the salt tolerant variety with high population could increase yield. The intermittent irrigation and fresh water flooding especially at transplanting and from panicle initiation to heading stage, the most sensitive to salt injury, is important to reduce the salt content in saline soil. During the off-cropping season, plough and rotavation with flooding followed by drainage, or submersion and drainage with groove could improve the desalinization. Increase of nitrogen fertilizer with more split application, and soil improvement by lime, organic matter and forign soil addition, could increase the rice yield. Shift of trans-planting is one of the way to escape from the salt injury.

• Journal of Electrochemical Science and Technology
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• v.14 no.3
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• pp.205-214
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• 2023

Soil salinity is becoming one of the most devastating environmental hazards over the years. Soil investigation involves fast, low cost and non disturbing methods to measure soil characteristics for both construction projects as well as for agricultural use. The electrical resistivity of saline soils is greatly governed by salt concentration and the presence of moisture in soil matrix. Experimental results of this investigation highlight that there is a significant relationship between the electrical resistivity of soil samples mixed with chloride solutions (NaCl, KCl, and MgCl₂) at various concentrations, and soil physical properties. Correlations represented by quadratic functions were obtained between electrical resistivity and soil characteristics, namely, water content, degree of saturation and salt concentration. This research reveals that the obtained correlations between electrical resistivity, salt concentration, water content and degree of saturation are effective for predicting the characteristics of salt affected soils in practice, which constitute a governing element in the assessment of saline lands sustaining infrastructure.

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.397-402
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• 2009

In Korea, salt stress is one of the major problems limiting crop production and eco-environmental quality in greenhouse soil. The objective of this study was to evaluate the effectiveness of organic residues (Chinese milk vetch, maize stalk, rice straw, and rye straw) for reducing salt activity in greenhouse soil. Organic residues was incorporated with salt-accumulated soil (EC, 3.0 dS $m^{-1}$) at the rate of 5% (wt $wt^{-1}$) and the changes of electrical conductivity (EC) was determined weekly for 8 weeks under incubation condition at $30^{\circ}C$. The EC, microbial biomass carbon (MBC), and water soluble ions in soil was strongly affected by C/N ratio of organic residues. After 8 weeks incubation, the concentration of water soluble $NO_3{^-},\;Ca^{2+}$, and $Mg^{2+}$ was significantly decreased in organic residues having high C/N ratio (maize stalk, rice straw, and rye straw) incorporated soil compared to organic residues having lower C/N ratio (Chinese milk vetch) incorporated soil. The EC value in Chinese milk vetch incorporated soil was higher than control treatment. In contrast, maize stalk, rice straw, and rye straw amended soil was highly decreased the EC value compared to control and Chinese milk vetch applied soil after 4 weeks incubation. Our results indicated that incorporation of organic residues having high C/N ratio (>30) could reduce salt activity resulting from reducing concentration of water soluble ions.

• Journal of the Korean Geotechnical Society
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• v.27 no.9
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• pp.47-53
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• 2011

Marine dredged soils taken from navigation channels or construction sites of coastal area usually have a lot of salt in pores of clayey soils. This paper investigates effect of salt on mechanical characteristics of non-salt and salt-rich stabilized dredged soil. The stabilized dredged soil (SDS) consisted of dredged soil and cement. Several pairs of SDS with non-salt and salt-rich dredged soils, noted as N-SDS and S-SDS, respectively, were prepared to compare their strengths and compressibility characteristics. The microstructures, strength and compressibility characteristics of N-SDS and S-SDS specimens at 7 and 28 days of curing time were evaluated using scanning electronic microscope (SEM), unconfined compression test, and oedometer test. It was found that salt concentration of clayey soil affected not only the formation of soil structure but also the strength development of mixture. The compression index and swelling index of S-SDS were also greater than those of N-SDS, which indicated that the compressibility of mixture increased due to salt concentration. Salinity in clayey soil had a negative effect on the strength development and compressibility characteristics of stabilized dredged soils.

• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.4
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• pp.85-93
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• 1988

This laboratory study was carried out in order to produce fundamental data for analyzing salt movement and desalinization effects, using samples of silt loam soil collected in Gyehwado and Daeho reclaimed tidelans, and samples of silty clay loam soil collected in Kimie tideland. Desalinization experiments with gypsum treatment were performed to analyze changes of the hydraulicc conductivity with changes of the soil property and the salt concentration during the desalinization of reclaimed tideland soils by leaching through the subsufface drainage, and correlations between factors infl uencing the reclamation of salt affected soils were analyzed by the statistical method. The results were summarized as follows: 1. The reclaimed tideland soils used in this study were saline-sodic soils with the high exchangeable sodium percentage and the high electrical conductivity. 2. Changes of the hydraulic conductivity with the amount of leaching water and the leaching time elapsed were affected by the amount of gypsum except exchangeable sodium and clay contents. The regression equation between the depth of water leached per unit depth of soil (Dw / Ds : X) or the square root of the leaching time elapsed (T $^1$ $^2$ : X) and the relative hydraulic conductivity (HCr:Y) could be expressed in Y=a . bx. 3. The more exchangeable sodium and clay contents regardless of the amount of gypsum, the more the leaching time was required until a given volume of water was leached through the soil profile. The regression analysis showed that the relationship between the depth of water leached per unit depth of soil(Dw /Ds:X) and the square root of the leaching time elapsed(T$^1$$^2$ :Y) could be described by Y=a . Xb. 4. The hydraulic conductivity was influenced to a major degree by the salt concentration provided that the electrical conductivity was below 10 mmhos / cm during the desalinization of reclaimed tideland soils. The regression equation between the relative electrical conductivity ( ECr : X) and the relative hydraulic conductivity (HCr:Y) could be expressed in Y=a + b . X-$^1$. 5. In conclusion, the hydraulic conductivity, leaching requirements and the leaching time elapsed can be estimated when the salt concentration decreases to a certain level during the desalinization of reclaimed tidelands, and the results may be applied to the analysis of salt movement and desalinization effects.

• Journal of Environmental Science International
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• v.30 no.10
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• pp.803-809
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• 2021

This study aimed to investigate the effects of soil amendment (heat-expanded clay and active carbon) and planting of Dendranthema zawadskii var. latilobum on the remediation of salt-affected soil and the plant growth under high calcium chloride (CaCl₂) concentration. The experimental group comprised treatments including Non treatment (Cont.), heat-expanded clay (H), active carbon (AC), planting (P), heat-expanded clay+planting (H+P), active carbon+planting (AC+P). A 200 mL solution of CaCl₂ at a concentration of 10 g·L^-1 was applied as irrigation once every 2 weeks. Compared to the Cont., the incorporation of the 'heat-expanded clay' amendment decreased electrical conductivity of the soil leachate and cation exchange capacity, whereas the growth of Dendranthema zawadskii var. latilobum was relatively increased. These results suggest that the combination of 'heat-expanded clay' amendment and planting will mitigate negative effect of de-icing salts and improve plant growth in salt-contaminated roadside soils.