• Korean Journal of Environmental Agriculture
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• v.39 no.4
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• pp.327-333
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• 2020

BACKGROUND: Through Saemangeum development project, 283 ㎢ of new land is planned to be created and the reclaimed land of 89.7 ㎢ will be used as agricultural land. Therefore, monitoring of soil salinity is required to evaluate the suitability of the land for agricultural purposes. METHODS AND RESULTS: We investigated changes of soil physico-chemical properties, including electric conductivity (EC), of the Saemangeum reclaimed tidal land (1,195 ha) from 2008 to 2017 to obtain basic data for suitable soil management of the Saemangeum reclaimed tidal land. Soil samples were collected from the sites spaced 200 meters apart from each other. Soil analysis results showed that average soil EC was 14.5 dS m-1 in 2008, and decreased to 6.5 dS m-1 in 2014 and to 0.9 dS m-1 in 2017. Accordingly, the soil area below soil EC 4.7 dS m-1 (accepted as farmable soil salinity) increased; 25.0% in 2008, 54.3% in 2014, and 96.9% in 2017. The annual decrease in soil EC was described as y = -1.5756x + 14.6 (R2= 0.96), where y = soil EC and x = elapsed years since 2008. CONCLUSION: The soil salinity have decreased to a level for cultivation of most edible crops. However, since the soil chemical properties, such as soil organic matter were inadequate for the cultivation of crops, it was suggested that management of soil fertility would be important for efficient agricultural use of Saemangeum reclaimed land.

• Earthquakes and Structures
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• v.25 no.3
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• pp.199-208
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• 2023

Seismic performance analysis is one of the fundamental steps in the design of new or retrofitting buildings. In the seismic performance analysis, the adapted spectral acceleration curve for a given site mainly governs the seismic behavior of buildings. Since every soil site (class) has a different impact on the spectral accelerations of input motions, different spectral acceleration curves have to be involved for every soil class that the building is located on top of. Modern seismic design codes (e.g., Eurocode 8, EC8, or Turkish Building Earthquake Code, TBEC) provide design response spectra for all the soil classes to be used in the building design or retrofitting. This research aims to evaluate the EC8 and TBEC based design response spectra using the spectra of real earthquake input motions that occurred (and were recorded at only soil classes A, B and C, no recording is available at soil class D) in a specific area in Turkey. It also conducts response spectrum analyses of 5, 10 and 13 floor reinforced concrete building models under EC8, TBEC and actual spectral response curves. The results indicate that the EC8 and especially TBEC given design response spectra cannot be able to represent the mean actual spectral acceleration curves at soil classes A, B and C. This is particularly observed at periods higher than 0.3 s, 0.42 s and 0.55 s for the TBEC design response spectra, 0.54 s, 0.65 s and 0.84 s for the EC8 design response spectra at soil classes A, B and C, respectively. This is also reflected to the shear forces of three building models, as actual spectral acceleration curves lead to the highest shear forces, followed by the shear forces obtained from EC8 and, then, the TBEC design response spectra.

• 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.

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.2
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• pp.128-134
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• 1990

Croping pattern, fertilizer application, Soil chemical characteristics, plant nutritional condition and growth status were investigated in three major vinyl house farms near Yesan. Croping pattern changed from tomato to pumpkin due to tomato diseases such as wilting and blossom-end rot. Wilting seemed to be closely related with high EC, nitrogen and root cyst nematodes. Calcium deficiency seemed to be due to high potassium, EC in soil and high uptake of iron. Chinese cabbages in summer showed poor growth (80% inhibition) due to high EC(1.8mmho/cm) and easily got wenny root disease that might due to high phosphorus (1055ppm) in soil. Summer radish showed poor growth (50% inhibition) due to high EC(1.6mmho/cm), K and Mg resulting in base imbalance. Farmers used 5 kinds of compound fertilizer as basal application and one without P for top dressing. Urea and KCL were used for top dressing. Heavy application of livestock manure and chemical fertilizer for every crop made eutrophic even in subsoil.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.501-504
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• 2001

The effect of soil EC on tissue morphology of leaf and shoot tip in cucumber (Cucumis sativus L. cv. Euinchim-baekdadagi) seedlings was investigated. Number of trichomes on leaf upper epidermis increased with the increase in soil EC from 1.0 to $3.0dS{\cdot}m^{-1}$, but the shape and number of stomata on lower epidermis remained unchanged. Epidermal cells of cucumbers grown in EC $1.5dS{\cdot}m^{-1}$ soil was occupied mostly by large vacuole whereas those grown in EC $3.0dS{\cdot}m^{-1}$ soil were filled with a nucleus, mitochondria, chloroplast and other micro-organelles. Sponge parenchima cells were also larger and contained fewer chloroplasts at EC $1.5dS{\cdot}m^{-1}$ than those grown at EC $3.0dS{\cdot}m^{-1}$. Leaf thickness decreased at high EC and the color of epidermal cells became significantly darker on the photograph of optical microscope. Normal tissue differentiation was greatly suppressed in plants grown in soils with $3.5dS{\cdot}m^{-1}$ or higher EC.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1065-1072
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• 2012

Crop productivity decreases globally as a result of salinization. However, salinity impact on greenhouse-grown crops is much higher than on field-grown crops due to the overall concentrations of nutrients in greenhouse soils. Therefore, this study was performed to determine the short-term changes in growth, photosynthesis, and metabolites of tomato plants grown in greenhouse under heavily input of fertilizers evaluated by microbial activity and chemical properties of soils. The soils (< 3, 3.01~6, 6.01~10 and > 10.01 dS $m^{-1}$) from farmer's greenhouse fields having different fertilization practices were used. Results showed that the salt-accumulated soil affected adversely the growth of tomato plants. Tomato plants were seldom to complete their growth against > 10.0 dS $m^{-1}$ level of EC. The assimilation rate of $CO_2$ from the upper fully expanded leaves of tomato plants is reduced under increasing soil EC levels at 14 days, however; it was the highest in moderate or high EC-subjected (3.0 ~ 10.0 dS $m^{-1}$) at 28 days. In our experiment, soluble sugars and starch were sensitive markers for salt stress and thus might assume the status of crops against various salt conditions. Taken together, tomato plants found to have tolerance against moderate soil EC stress. Various EC levels (< 3.0 ~ 10.0 dS $m^{-1}$) led to a slight decrease in organic matter (OM) contents in soils at 28 days. Salinity stress led to higher microbial activity in soils, followed by a decomposition of OM in soils as indicated by the changes in soil chemical properties.

• The Korean Journal of Ecology
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• v.20 no.2
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• pp.133-143
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• 1997

From 1984 to 1989 reclaimed coastal lands in Choongnam Province of the western coast of Korea were studied for soil texture at three sites(Daeho, Hyundai A and Hyundai B) and for desalination one site(Hyundai B). The soil textures of varied sites in Hyundai A were horizontally similar and composed of 39-40% clay, 40-49% silt and 8-14% sand. But those in Da돼 and Hyundai B differed horizontally in the same area and vertically at the same site. Soil texures of Da돼 were composed of 15-17% clay, 30-45% silt and 40-55% sand and those of Hyundai B were composed of 22-45% clay, 26-49% silt and 17-31% sand. The measured electrical conductivity(EC), which represents whole salt content of the reclaimed soil, decreased year by year. The vertical distribution of the EC changed temporally and spatially in the upper zone above a 50 cm depth but not in The lower zone below a 50 cm depth. The EC valus of the soil were inversely proportional to the magnitued of annual precipitation, evaporation and the numbers of rainy days with r equalling -0.97. But the annual decrease of the EC was directly proportional to climatic factors with r=0.7. Salt in the reclaimed land was leached out by the percolative action of surplus rain water, or moved up by evaporation and carried away by running rain water. The running out of the salt on the soil surface was most efficiently carried out over 10 mm precipitation per day.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.5
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• pp.247-252
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• 2005

Soil pH is an intensity factor of releasing hydrogen ion which is buffered by aluminum. It depends on pH buffer capacity of Al whether soil pH is governed directly by cations or not. A study was conducted to elucidate the pattern of pH changes by soil EC. Fertilizer and three kinds of organic manures composed of cow and pig and fowl dropping and one kind of rice straw compost were added independently into upland sandy loam soil. This treated soils and four upland soils under plastic film house having different levels in electrical conductivity (EC) were incubated with field capacity at $30^{\circ}C$ for 5, 10, 20 and 40 days. Soil pH varied directly as the cations contained in organic materials according to degree of saturating pH buffer capacity (pBC) of sandy loam soil. pH of the soils under plastic film house was lowered by soil EC due to governing by overplus of cation beyond pBC.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.3
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• pp.37-50
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• 2019

In this study, we analyzed the soil salinity of Saemangeum agricultural land using GIS spatial interpolation method. Dominant soils series of experimental sites were Munpo (coarseloamy, mixed, non-acid, mesic, typically fluvaquents), which was based on the fluvio-marine deposit. Soil samples were periodically collected at 0~20cm and 20~40cm layer from each site. First, the distribution characteristics of EC, ESP, and SAR according to spatial interpolation were analyzed using 142 sample points. Through the error analysis of 143 validation points, the IDW method for EC and SAR, and the Kriging interpolation method for ESP were selected as the optimal interpolation method. Using the optimal interpolation method, the characteristics of EC, ESP, and SAR were analyzed for the change of soil salinity from 2014 to 2016. As a result, EC, ESP and SAR were decreased by 0.26mg/L, 5.97mg/L and 0.73mg/L respectively due to the dilution effect caused by rainfall.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.411-419
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• 2019

The purpose of this study was to analyze the growth and functional differences between C. rotundus and G. littoralis according to different electrical conductivity (EC) conditions in reclaimed soil conditions. C. rotundus and G. littoralis seeds were sown in a tray and managed for seedlings stage for eight weeks. They were transplanted in the pots containing reclaimed soils sampled in the Saemangum region. The plants were grown in the reclaimed land soil for 12 weeks under the control, 1, 2, 4, and $8dS{\cdot}m^{-1}$ conditions and in horticultural soils with EC $1.0dS{\cdot}m^{-1}$. Plant height, leaf length and width of C. rotundus were the highest in EC $1dS{\cdot}m^{-1}$. Leaf, flower and tuber numbers of C. rotundus were the highest in EC $2dS{\cdot}m^{-1}$ and the lowest in EC $8dS{\cdot}m^{-1}$, and SPAD was the highest in EC 2 and $4dS{\cdot}m^{-1}$ and the lowest in EC $8dS{\cdot}m^{-1}$. The fresh weights of shoot and root of C. rotundus grown under EC $2dS{\cdot}m^{-1}$ increased and then decreased as the concentration increased. When compared plant growth between reclaimed soil and horticulture soil with EC $1dS{\cdot}m^{-1}$, the fresh weights of shoot and root, SPAD, leaf number, flower number, and tuber number were higher in horticultural soils. Although G. littoralis grown under EC $8dS{\cdot}m^{-1}$ was the lowest in all growth parameters, there were no significant differences among other EC treatments. C. rotundus had the highest p-coumaric acid content in EC $1dS{\cdot}m^{-1}$. And the catechin content in shoot of G. littoralis was the highest in the control, and root of Glehnia littoralis had the highest benzoic acid contents in EC $1dS{\cdot}m^{-1}$. If the soil EC is well managed within $4.0dS{\cdot}m^{-1}$, two plants would be cultivated in reclaimed land.