• Journal of Bio-Environment Control
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• v.24 no.4
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• pp.333-340
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• 2015

Because soils in reclaimed lands nearby coastal areas have much higher salinity and moisture content than soils in inland area, parts of greenhouses embedded in such soils are exposed to highly corrosive environments. Owing to the accelerated corrosion of galvanized steel pipes for substrucrture and structure of greenhouses in saline environments, repair and reinforcement technologies and efficient maintenance and management for the construction materials in such facilities are required. In this study, we measured the corrosion rates of the parts used for greenhouse construction that are exposed to the saline environment to obtain a basic database for the establishment of maintenance and reinforcement standards for greenhouse construction in reclaimed lands with soils with high salinity. All the test pipes were exposed to soil and water environments with 0, 0.1, 0.3, and 0.5% salinity during the observation period of 480 days. At the end of the observation period, salinity-dependent differences of corrosion rate between black-surface corrosion and relatively regular corrosion were clearly manifested in a visual assessment. For the soils in rice paddies, the corrosion growth rate increased with salinity (0.008, 0.027, 0.036, and $0.043mm{\cdot}yr^{-1}$ at 0, 0.1, 0.3, and 0.5% salinity, respectively). The results for the soils in agricultural fields are 0.0002, 0.039, 0.040, and $0.039mm{\cdot}yr^{-1}$ at 0, 0.1, 0.3, and 0.5% salinity, respectively. The higher corrosion rate of rice-paddy soil was associated with the relatively high proportion of fine particles in it, reflecting the general tendency of soils with evenly distributed fine particles. Hence, it was concluded that thorough measures should be taken to counteract pipe corrosion, given that besides high salinity, the soils in reclaimed lands are expected to have a higher proportion of fine particles than those in inland rice paddies and agricultural fields.

• The Korean Journal of Ecology
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• v.23 no.5
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• pp.397-406
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• 2000

In order to clarify the ecophysiological characteristics of Chenopodiaceae which widely distribute on saline and arid habitats, we collected 10 chenopodiaceous plant species, examined their inorganic and organic solute patterns, and confirmed several common physiological characteristics. In spite of high soil Ca/sup 2＋/ contents, chenopodiaceous plants had a little water-soluble Ca within cells, but contained high contents of acid-soluble Ca particularly as a result of Ca-oxalate formation. These plant species also showed accumulation of inorganic ions such as K/sup ＋/, NO₃/sup －/ and Cl/sup －/, and Na/sup ＋/especially in saline habitats instead of K/sup ＋/ Meanwhile, with respect to nitrogen metabolism they retained high N contents in leaves, but showed very low amino acid contents. Additionally, they contained very little proline known to act as a cytoplasmic osmolyte. To ascertain whether this physiological characteristics in the field also can be found under controlled conditions, 7 chenopodiaceous plants (Atriplex gmelini, Corispermum stauntonii, Salicornia herbacea, Suaeda aspayagoides, Suaeda japonica, Chenopodium album var. centrorubrum, C. serotinum) were selected and cultivated under salt treatments. As well as field-grown plants, selected plant species showed similar solute pattern in growth experiment. In summary, the family of Chenopodiaceae represents the following physiological properties; high storage capacity for inorganic ions (especially alkali cations, nitrate and chloride), oxalate synthesis to maintain lower soluble Ca contents within cytoplasm, and low contents of amino acids. In addition to some characteristics mentioned above, the physiological plasticities of Chenopodiaceae which can properly regulate their ion and solute pattern according to soil conditions may enable its representative to grow in dry sand dune and salt marsh habitats.

• Korean Journal of Weed Science
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• v.12 no.1
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• pp.46-51
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• 1992

The survey of weed population in paddy field was carried out to invegstigate the weed group on 340 fields in Kyonggi Area in 1991. The weed species observed include 4 species of grasses, 7 species of sedges, and 14 species of broadleaf weeds, and the ratio of annual weed vs perennial weed was 25 : 75. Major dominant weed species were Eleocharis kuroguwai, Sagitaria trifolia, Echinochloa crusgalli and Cyperus serotinus. The dominant weed species in South Plain Region were Echinochloa crusgalli, Eleocharis kuroguwai, Sagitariu trifolia, Cyperus strotinus, in West Coast Region were Eleocharis kuroguwai, Sagitaria trifolia, Echinochloa crusgalli, Cyperus serotinus, in East Interior Region were Eleocharis kuroguwai, Sagitaria trifolia, Echinochloa crusgalli, Cyperus difformis and were Sagitaria trifolia, Eleocharis kuroguwai, Echinochloa crusgalli and Monochoria vaginalis in North Region. The dominant weed species in Normal and Poorly drained soil were Eleocharis kuroguwdi, Sagitaria trifolia, Echinochloa crusgalli and Cyperus serotinus and were Scirpus maritinus, Cyperus serotinus, Echinochlod crusgalli and Myriophyllum verticillatum in Saline Soil. More and many weeds were growing in single cropped field than double cropped field.

• Asian Journal of Turfgrass Science
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• v.23 no.1
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• pp.35-44
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• 2009

This study was carried out to examine the growth performance of 4 species of cool-season grasses and 4 species of zoysiagrasses under salt injury in Seo-san reclaimed area. Grasses were grown on the plots with capillary water interruption layer (WCWIL) and without capillary water interruption layer (WOCWIL) soil systems. Cool-season grass and seeding-type zoysiagrass plots were seeded on 6 Jun, 2006. Vegetative zoysiagrass 'Junggi' was established by sprigging and 'Senock' and 'Millock' were plugged. Electric conductivities of irrigation water (ECw) ranged from 0.28 to $3.3\;dS{\cdot}m^{-1}$. Electric conductivities (ECe) of the soil with capillary water interruption layer and without capillary water interruption layer ranged from 0.55 to $9.4\;dS{\cdot}m^{-1}$ and from 1.84 to $9.4\;dS{\cdot}m^{-1}$ respectively. Leaf color, turf quality, coverage rates, and growth rates were rated visually for 2 years. Zoysiagrass 'Junggi', creeping bentgrass, zoysiagrass 'Senock' and 'Millock' showed acceptable growth at salty fairway condition, while Kentucky bluegrass, perennial ryegrass, Kentucky bluegrass mixed with perennial ryegrass, and seeded zoysiagrass 'Zenith' showed establishment rates below 70%. These results will be useful when choosing turf grass species and cultivars for the golf courses in reclaimed land area.

• Geophysics and Geophysical Exploration
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• v.8 no.1
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• pp.78-85
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• 2005

This study, combining geophysical and environmental approaches, was undertaken to investigate the causes of secondary salinity in the Goondoola basin, in southwestern Queensland. Airborne radiometric, electromagnetic and ground electromagnetic datasets were acquired, along with data on soils and subsurface materials and groundwater. Relationships established between radiometric, elevation data, and measured material properties allowed us to generate predictive maps of surface materials and recharge potential. Greatest recharge to the groundwater is predicted to occur on the weathered bedrock rises surrounding the basin. Electromagnetic data (airborne, ground, and downhote), used in conjunction with soil and drillhole measurements, were used to quantify regolith salt store and to define the subsurface architecture. Conductivity measurements reflect soil salt distribution. However, deeper in the regolith, where the salt content is relatively constant, the AEM signal is influenced by changes in porosity or material type. This allowed the lateral distribution of bedrock weathering zones to be mapped. Salinisation in this area occurs because of local-andintermediate-scale processes, controlled strongly by regolith architecture. The present surface outbreak is the result of evaporative concentration above shallow saline groundwater, discharging at break of slope. The integration of surficial and subsurface datasets allowed the identification of similar landscape settings that are most at risk of developing salinity with groundwater rise. This information is now being used by local land managers to refine management choices that prevent excess recharge and further salt mobilisation.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.1
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• pp.70-75
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• 1986

The population and kinds of algae causing the waterbloom on the rice seedling bed and the damage of young rice plant by the nuisance green phytoplanktonic algae in rice field were studied to find out the efficiency of fertilizers and the effect of methods of fertilizers application in the rice field, laboratory, pot and green house. pot and green house. The results obtained were summarized as follows; 1. In the rice seedling bed, the kinds of algae causing waterblooms were identified mainly photosynthetic bluegreen algae as the Anabaena, Ulothrix and Oscillatoria spp. in reclaimed saline soil. Micromonospora, Oscillatoria, and Chlamydomonas spp. were habitated mainly in plain. Whereas, Spyrogyra, Oscillatoria and Navicula spp. were identified mainly in mauntainous area. 2. In the rice field, the nuisance phytoplanktonic green algae were identified mainly Scenedesmus, Chlamidospora, and Micromonospora spp. in Gimjae plain, in Namweon mountainous area and Gangjin costal plain, respectively. 3. The algal biomass has been havily habitated in which rice field were constituted with high pH value and high concentration of $NH^+_4-N$ and $NO^-_3-N$ in surface water and in soil with the optimum temperature for the algal growth ($22-30^{\circ}C$). 4. In the laboratory experiment, maximum algal biomass were obtained at levels of 80 ppm for the nitrogen and 20 ppm for the phosphorus. And were obtained of the levels of 40 ppm in the case of joint application of N and $P_2O_5$. 5. From the pot experiment, compare of the control plot, an addition of nitrogen alone or nitrogen+phosphorus enhanced algal biomass while the phosphorus alone did not. 6. Surface application of fertilizer was remarkably increased of algal biomass than did the whole layer or deep layer application.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.1
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• pp.133-149
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• 2022

Existing domestic studies on estimating rice yield were mainly implemented at the level of cities and counties in the entire nation using MODIS satellite images with low spatial resolution. Unlike previous studies, this study tried to estimate rice yield at the level of eup-myon-dong in Gimje-si, Jeollabuk-do using Sentinel-2 satellite images with medium spatial resolution, rainfall and soil data, and then to evaluate its accuracy. Five vegetation indices such as NDVI, LAI, EVI2, MCARI1 and MCARI2 derived from Sentinel-2 images of August 1, 2018 for Gimje-si, Jeollabuk-do, rainfall and paddy soil-type data were aggregated by the level of eup-myon-dong and then rice yield was estimated with gamma generalized linear model, an expanded variant of multi-variate regression analysis to solve the non-normality problem of dependent variable. In the rice yield model finally developed, EVI2, rainfall days in September, and saline soils ratio were used as significant independent variables. The coefficient of determination representing the model fit was 0.68 and the RMSE for showing the model accuracy was 62.29kg/10a. This model estimated the total rice production in Gimje-si in 2018 to be 96,914.6M/T, which was very close to 94,470.3M/T the actual amount specified in the Statistical Yearbook with an error of 0.46%. Also, the rice production per unit area of Gimje-si was amounted to 552kg/10a, which was almost consistent with 550kg/10a of the statistical data. This result is similar to that of the previous studies and it demonstrated that the rice yield can be estimated using Sentinel-2 satellite images at the level of cities and counties or smaller districts in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.4
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• pp.299-307
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• 2011

This study was carried out to obtain the basic data for selecting the cultivatable bioenergy crops through application of solidified sewage sludge in reclaimed lands. The experimental plots consisted of the mixing with solidified sewage sludge plot (SS50), the covering with solidified sewage sludge plot (SS100), and the original reclaimed land plot (ORL) on reclaimed land for the intended landfill in Sudokwon Landfill Site Management Corporation (SLC). The growth of energy crops (Geodae-Uksae 1, Miscanthus sacchariflorus, and Phragmites australis) were investigated from May to October, 2010 in each experimental plot. The soil from ORL showed higher salinity with high contents of exchangeable $Na^+$ cation than that of SS50 and SS100. Soil properties on reclaimed land used in this study must be improved by increasing the buffering capacity of saline with the treatment of solidified sewage sludge due to the fact that the contents of organic matter (OM) in both of SS50 and SS100 were higher than that of the ORL. Thus the growth of energy crops cultivated in the solidified sewage sludge plots were better than in ORL. Geodae-Uksae 1 which showed an excellent adaptability on reclaimed land treated with the solidified sewage sludge has considerably higher biomass than those of other energy crops (M. sacchariflorus and P. australis). This study suggested that Geodae-Uksae 1 is the most suitable biomass feedstock crop for bioenergy productions, and the solidified sewage sludge may be possible to utilize as a soil cover materials for cultivation of bioenergy crops in reclaimed land.

• Korean Journal of Weed Science
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• v.14 no.4
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• pp.239-244
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• 1994

As a fundamental study to control Alopeuclus aequalis Sobol. var. amurensis(Kom.) Ohwi., on dominant weed in barley and dry seeded rice cultivation on paddy fields, several factors which would have closer relations to its germination and emergence, were examined. The results are as follows. The dormancy of seeds were broken at dry-heat treatment of $30^{\circ}C$. The germination rate of the seeds was high in order of 15>10>20> $5^{\circ}C$ and was very low at more than $25^{\circ}C$. The emergence of A. aequalis was influenced little for the light, but had a tendency to be good on the dark condition. The seeds dried on room temperature germinated few but them treated on $30^{\circ}C$ for 24 hours were germinated over 80%. The A. aequalis occured few in the saline soil of salt concentration of more than 0.25% and the germination rate of seeds was very low on the over 0.5% solution of NaCl. On the solution of pH 6.0~12.0, the germination was not effected for pH but was very few on pH 2.0. At the paddy-lowland which have cultivated the soybean for three years A. aequalis emerged a few.

• Journal of the Korean Society of Groundwater Environment
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• v.1 no.1
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• pp.51-58
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• 1994

Electrical soundings and mappings were conducted to elucidate the geoelectrical structures of the local area of Cheju Island. The areas of the electrical surveys are coastal areas of Cheju Island, Gwagji, Sinpung-Sincheon. Generally, the geoelectrical structures of these areas are closely related with hydrogeological structures and it is very important to elucidate the geoelectrical structures for the water supply problems. Even though the results of electrical surveys in coastal areas of Cheju Island differ from place to place, there exists a general tendency of resistivity decrease with depth and the zone in the vicinity of mean sea level has low resistivity value. Also, there is good correlation between the low resistivity zone and the ground water distribution in the survey areas. A careful examination of the results of this study enabled resistivities of the rocks in Cheju Island to be divided in some categories. The resistivities of rocks unsaturated with ground water are greater than about 1000 ohm-m. The rocks saturated with fresh water have the resistivity value of about few hundreds ohm-m. Last, the rocks saturated with saline and/or brackish water have the resistivity value of about few tens ohm-m. The subsurface resistivity distribution of Cheju Island seems to be strongly dependent on the hydraulic characteristics of the rocks, and the amount and the salinity of the ground water in the rocks rather than the surface geology of the area.