• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.74-77
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• 2001

In order to investigate the effect of salinity level on tracking characteristics of polymer insulators for distribution power systems, tracking tests were performed by tracking wheel tester under different salt concentration. In this study, 6 kinds of polymer insulators were tested under 2200 ${\mu}\textrm{s}$/cm and 4000${\mu}\textrm{s}$/cm salinity. The salinity level has a significant effect on the tracking characteristics. Namely, most polymer insulators showed the good tracking resistance in case of low salinity level. But, in case of high salinity level some polymer insulators showed the excessive erosion and tracking. These phenomena may come from the different aging mechanism. It can be concluded that too high salinity level is not desirable in aging test of polymer insulators.

• Korean Journal of Soil Science and Fertilizer
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• v.51 no.1
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• pp.50-60
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• 2018

This study was to evaluate the effect of organic amendments incorporation on soil properties and plant growth under two different soil salinity levels and various cultivated crops at Saemangeum reclaimed tidal land for three years from 2012 to 2014. The soil texture of the experimental site was sandy loam. Four different crops, sesbania (Sesbania grandiflora), sorghum-sudangrass hybrid (Sorghum bicolor-Sorghum sudanense), rice (Oryza sativa L.) and barley (Hordeum vulgare) were cultivated at low (< $1dS\;m^{-1}$) and high (> $4dS\;m^{-1}$) soil salinity levels. The soil salinity was significantly lowered at the rice cultivation site compared to continuous upland crops cultivation site in high soil salinity level. But the soil salinity was increased as cultivating sesbania coutinuously in low soil salinity level. The soil organic matter content was increased with the incorporation of straw at the continuous site of rice and barley, and the average of soil organic matter was increased by $0.9g\;kg^{-1}$ per year which was effective in soil aggregate formation. The highest biomass yield plot was found in barley (high salinity level) and sesbania (low salinity level) cultivation site, respectively. Our research indicates that rice cultivation in paddy field with high salinity level was effective in lowering soil salinity and sesbania cultivation was useful to biomass production at upland with low salinity. In conclusion, soil salinity and organic matter content should be considered for multiple land use in newly reclaimed tidal land.

• Journal of Environmental Science International
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• v.23 no.5
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• pp.801-806
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• 2014

Long-term change in sea level along the eastern coast of Korea was illustrated using four tide-gauge station (Pohang, Mukho, Sokcho, Ulleung) data, water temperature and salinity. Seasonal variation in the sea level change was dominant. The sea level change by steric height derived from water temperature and salinity was relatively lower than that measured from the tide-gauge stations. Sea level rising rate per year by steric height increased with latitude. The effect of salinity(water temperature) on the sea level change is greater in winter(in summer).

• Journal of the Institute of Convergence Signal Processing
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• v.21 no.1
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• pp.1-6
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• 2020

To make an automated system for a salt field, it is necessary to measure the salinity and water level of the evaporation site. In this paper, a method to simultaneously measure the salinity and water level by measuring the buoyancy forces of two fixed buoyancy bodies is proposed. The proposed measurement method measures the buoyancy of the main part and reference part when the measuring device is immersed in the salty water, and simultaneously measures the salinity and water level through the sum and difference of the two buoyancy forces. Since there is no mechanical movement in the measurement of buoyancy, measurement errors and maintenance needs can be reduced in the mudy environment of salt field. By applying the proposed method, we developed a system that can simultaneously measure salinity and water level remotely at the evaporation site of a salt field. Through a measurement experiment using a reference salty water having various levels of salinity, the results of a salinity error of 0% and a water level error of 2mm were obtained, and the effectiveness of the proposed salinity and water level measuring device was verified. When an automated system is constructed using the developed salinity and water level measuring device, labor reduction, work environment improvement, and productivity improvement are expected.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.6
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• pp.139-147
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• 2014

Forecasting salinity in an estuary reservoir is essential to promise irrigation water for the reclaimed land. The objective of the research was to assess salinity balance and its temporal and spatial variations in the Iwon estuary reservoir which has been issued by its high contents of salinity in spite of desalination process for four years. Seepage flows through the see dikes which could be one of possible reason of high salinity level of the reservoir was calculated based on the salinity balance in the reservoir, and used as input data for salinity modeling. A three-dimensional hydrodynamic model, Environmental Fluid Dynamics Code (EFDC), was used to simulate salinity level in the reservoir. The model was calibrated and validated based on weekly or biweekly observed salinity data from 2006 to 2010 in four different locations in the reservoir. The values of $R^2$, RMSE and RMAE between simulated and observed salinity were calculated as 0.70, 2.16 dS/m, and 1.72 dS/m for calibration period, and 0.89, 1.15 dS/m, and 0.89 dS/m for validation period, respectively, showing that simulation results was generally consistent with the observation data.

• Journal of Korean Society on Water Environment
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• v.18 no.3
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• pp.237-243
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• 2002

The effect of a salinity on the performance of a biological nutrient removal system was investigated using a model SBR(Sequencing Bach Reactor) system. The system was operated at a 12hr, 18hr, 24hr, and 36hr HRT with a salinity level of 20,000mg/L and compared with a system similarly operated with fresh water. The influent salinity level of 8,000 mg/L does not have a significant effect on BOD removal efficiency, there is a noticeable decrease in BOD removal rate from 10,000 mg Cl-/L. The Nitrogen could be removed from the saline wastewater with the same efficiency as for the fresh water because of low C/N ratio in anoxic period. The excess biological phosphorous removal is highly affected by the increase in the influent salinity. The efficiency is decreased from 96.6% to 43.4% when the influent salinity is increased from 0 to 20,000mg/L.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.4
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• pp.113-120
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• 2015

The objectives of this study were to monitor and assess the effects of saline irrigation water on lettuce and carrot growth in protected cultivation. One control and 4 treatments with three replications, which were differentiated according to the level of salinity in irrigated water, were employed for each vegetable to assess the effects of the irrigation with saline water. Monitoring results showed that the use of irrigation water containing above a certain level of salinity was found to cause excessive accumulation of salts in the soil as saline irrigation water increased electrical conductivity (EC) and sodium ($Na^+$) content in both lettuce and carrot soil samples, while tap water irrigation used as control decreased the salinity in the samples. The salinity higher than the threshold level of irrigation water was found to reduce the yields of lettuce and carrot, while in less than the threshold level the higher the salinity of the irrigation water increased the yields. The salinity of the irrigation water also appeared to increase the internal salinity of the plant as the $Na^+$ content in plant increased as the salinity of irrigation water increase. Increased $Na^+$ content was analyzed to be able to increase the sugar content in carrot. This study could contribute to suggest water quality criteria for safe use of saline water in protected cultivation, although long-term monitoring is needed to get more representative results.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.5
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• pp.365-372
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• 2013

Crop development and nutrient availability are strongly influenced by soil salinity levels. This study was conducted to investigate the effect of rice straw and nitrogen (N) fertilizer for silage barley under various soil salinity levels at Saemangeum reclaimed tidal land. Three levels of rice straw (0, 2.5, 5.0 ton rice straw $ha^{-1}$) and N (0, 150, 225 kg N $ha^{-1}$) were applied at 0.04, 0.23, 0.35% soil salinity levels. Biomass yield of silage barley was influenced by the interactions between rice straw application and N fertilization. Although there was no single effect of rice straw application on biomass yield, it was significantly increased with N application and a rice straw application of 5.0 ton $ha^{-1}$. Sodium content in silage barley was significantly lower at 0.04% salinity level, and but it was statistically increased with increasing soil salinity levels. Forage qualities such as total digestible nutrients and relative feed value of silage barley were significantly higher with N application at 0.04% salinity level, but there was no effect of rice straw application. Soil organic matter content was increased with N and rice straw application regardless of soil salinity level. The results of this study showed that the effect of rice straw and N fertilization on silage barley was influenced by soil salinity levels, which indicates that the management practice of silage barley at Saemangeum reclaimed tidal land should consider soil salinity levels.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.194-198
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• 2004

This study was conducted to identify the appropriate nitrogen fertilizer application rate for improving rice quality in tidal reclaimed area, at the Gyehwado substation of the Honam Agricultural Research Institute during 2002-2(103. The experimental fields contained 0.1% (low salinity) and 0.3-0.4% (medium salinity) Nacl in soil solution. Plant height at panicle formation stage was tall ay heavy nitrogen level and the effect of heavy nitrogen was higher in low than in high soil salinity condition. Heading date was not affected by applied nitrogen levels from 8 to 16 kg/10a in low soil salinity condition but it was one day later in 24 kg/10a nitrogen level when compared with the standard nitrogen level,20 kg/10a. In middle soil salinity condition, the heading date was one day earlier in 8 to 16 kg/10a and similar in 24 kg/10a, when compared with 20 kg/10a nitrogen level. And also it was four days later in middle than in low soil salinity condition. In low soil salinity condition, grain number $\textrm{m}^2$ increased but ripened grain ratio decreased as the nitrogen application increased and finally, milled rice yield was not different among heavy nitrogen application levels compared with 12 kg/10a. Head rice ratio was high and protein content was low in 12 kg/10a or lower nitrogen level. In middle soil salinity condition, grain number $\textrm{m}^2$ increased and ripened grain ratio was not affected as the nitrogen application increased. And finally, milled rice yield increased with increasing nitrogen application levels, Head rice ratio was high and protein content was not affected by nitrogen application levels. Therefore, on the basis of milled rice yield and rice grain quality inreclaimed land, the appropriate nitrogen application level would be 12 kg/10a in low soil salinity condition and 20 kg/10a in middle soil salinity condition.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.364-364
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• 2017

Saemangeum reclaimed land is a part of Saemangeum Development Project. Most of the persistent problems of Saemangeum reclaimed land remain to be related to soil salinity. Soil salinity is a major abiotic factor related to microbial community structure and also fungi have been reported to be more sensitive to salinity stress than bacteria. The aim of this study was conducted to investigate the effect of soil salinity levels on the microbial communities in Saemangeum reclaimed land using 454 pyrosequencing analysis. Soil samples was collected from 12 sites of in Saemangeum reclaimed land. For pyrosequencing, 27F/518R (bacteria) and ITS3/ITS4 (fungi) primers were used containing the Roche 454 pyrosequencing adaptor-key-linker (underlined) and unique barcodes (X). Pyrosequencing was performed by Chun's Lab (Seoul, Korea) using the standard shotgun sequencing reagents and a 454 GS FLX Titanium sequencing System (Roche, Inc.). In the soil samples, Proteobacteria (bacteria) and Ascomycota (fungi) shows the highest relative abundance in all the soil sample sites. Proteobacteria, Bacteroidetes, Plantomycetes, Gemmatimonadetes and Parcubacteria were shown to have significantly higher abundance in high salinity level soils than low salinity level soils, while Acidobacteria and Nitrospirae has significantly higher relative abundance in low salinity level soils. The abundance of fungal, Ascomycota has the highest relative abundance in soil samples, followed by Basidiomycota, Chlorophyta, Zygomycota and Chytridiomycota. Basidiomycota, Zygomycota, Glomeromycota and Cerozoa were show significantly higher relative abundance in low salinity level soils. The principal coordinate analysis (PCoA) and correlation analysis shown to salinity-related soil parameters such as ECe, Na+, SAR and EPS were affected to bacterial and fungal community structure. Proteobacteria, Bacteroidetes, Plantomycetes exhibited significantly positive correlation with soil salinity, while Acidobacteria exhibited significantly negative correlation. In the case of fungal community, Basidiomycota and Zygomycota were seen show significantly negative correlation with salinity related soil parameters. These results suggest that provide understanding effect of soil salinity on microbial community structure and correlation of microbial community with soil parameters in Saemangeum reclaimed land.