• Bulletin of Korea Environmental Preservation Association
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• v.19 no.10
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• pp.50-51
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• 1997

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.2
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• pp.113-119
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• 2014

Arsenic and its compounds which is one of the most toxic elements that can be found naturally on earth in small concentrations are used in the production of pesticides, herbicides, and insecticides. Most arsenic that cannot be mobilized easily when it is immobile is also found in conjunction with sulfur in minerals such as arsenopyrite (AsFeS), realgar, orpiment and enargite. In this investigation we observed the leaching of arsenic in soils amended with several levels of gravel size of arsenopyrite collected from a road construction site. Soil and gravel size of arsenopyrite were characterized by chemical and mineralogical analyses. Results of XRF analysis of arsenopyrite indicated that the proportion of arsenate was 0.075% (wt $wt^{-1}$) while the maximum amount of arsenic in soil samples was 251.3 mg $kg^{-1}$. Cumulative amounts of effluent collected from the bottom of the soil column for different mixing rate of the gravel were gradually increased where proportion of the gravel mixed was greater than 70% whereas the effluent was stabilized to the maximum after approximately 45 pore volumes of effluent or greater were collected. The arsenic in the effluent was recovered from the soil columns in which the proportion of arsenopyrite gravel was 60% or greater. The total amount of arsenic recovered as effluent was increased with increasing proportion of gravel in a soil, indicating that the arsenic in the effluent was closely related with gravel fraction of arsenopyrite.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.2
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• pp.73-80
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• 2015

Arsenic which is found in several different chemical forms and oxidation states and causes acute and chronic adverse health effects is a toxic trace element widely distributed in soils and aquifers from both geologic and anthropogenic sources. Arsenic which has a mysterious ability to change color, behavior, reactivity, and toxicity has diverse chemical behavior in the natural environment. Arsenic which has stronger ability to readily change oxidation state than nitrogen and phosphorus due to a consequence of the electronic configuration of its valence orbitals with partially filled states capable of both electron donation and acceptance although the electronegativity of arsenic is greater than that of nitrogen and similar to that of phosphorus. Arsenate (V) is the thermodynamically stable form of As under aerobic condition and interacts strongly with solid matrix. However, it has been known that adsorption and oxidation reactions of arsenite (III) which is more soluble and mobile than As(V) in soils are two important factors affecting the fate and transport of arsenic in the environment. That is, the movement of As in soils and aquifers is highly dependent on the adsorption-desorption reactions in the solid phase. This article, however, focuses primarily on understanding the fate and speciation of As in soils and what fate arsenic will have after it is incorporated into soils.

• Korean Journal of Agricultural Science
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• v.46 no.1
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• pp.205-217
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• 2019

The aim of this study was to identify land resources because food production and supply in North Korea have been at risk due to variations in its seasonal climate. More than three-fifths of the soils are locally derived from the weathering of granitic rocks or various kinds of schists developed from crystalline rocks. Well-developed reddish brown soils derived from limestone are found in the North Hwanghae province and in the southern part of the South Pyeongan province. Additionally, a narrow strip of similarly fertile land runs through the eastern seaboard of the Hamgyong and Kangwon Provinces. The loss of clay particles and organic matter are major causes of degradation in the soil physical and chemical properties in North Korea. 75% of the areas converted from forests became croplands, and 69% of the land converted to croplands came from forests. The net forest loss was quite small from the 1990s to the 2000s. However, deforestation in areas with a slightly lower elevation and gentler slope between 1997 and 2014 led to severe soil erosion resulting in a drastic change in the physical and chemical properties of the soil which influenced cropland stability and productivity. Therefore, the drastic changes in land cover as well as in the physical and chemical properties of the soil caused by various geographical features have seriously influenced the productivity of crops in North Korea.

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.843-853
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• 2021

The objectives of this paper were to simply estimate soil loss levels as caused by wind in reclaimed tidal flat land (RTFL) and the threshold wind velocity in the RTFL. For this experiment, RTFL located at Haenam Bay was selected and a total of 150 soil samples were collected at the Ap horizon from the five soil series. The particle distribution curves, including the limit of the non-erodible particle size (D > 0.84 mm) for each Ap horizon soil, show that the proportions of non-erodible particle sizes that exceeded 0.84 mm were 4.3% (Taehan, TH), 8.9% (Geangpo, GP), 0.5% (Bokchun, BC), 1.6% (Poseung, PS) and 1.4% (Junbook, JB), indicating that the amount of non-erodible soil particles increased with an increase in the sand content. The average monthly, daily and instantaneous wind velocities were higher than the threshold friction velocity (TFV) calculated according to the dynamic velocity (V_d) by Bagnold, while the average monthly wind velocity was lower than those of the TFV suggested by the revised wind erosion equation (RWEQ) and wind erosion prediction system (WEPS). The susceptible proportions of erodible soil particles from the Ap horizon soil samples from each soil series could be significantly influenced by the proportion of sand particles between 0.025 and 0.5 mm (or 0.84 mm) in diameter regardless of the threshold wind velocity. Thus, further investigations are needed to estimate more precisely soil erosion in RTFL, which shows various soil characteristics, as these estimations of soil loss in the five soil series were obtained only when considering wind velocities and soil textures.

• Asian Journal of Turfgrass Science
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• v.24 no.1
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• pp.36-44
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• 2010

We were investigated turf color and Normalized Difference Vegetation Index (NDVI) to affect greenup promotion of 38 cultivar in 5 species for spring season, most popularly used in Korea golf courses. Kentucky bluegrass (Poa pratensis L.), tall fescue (Festuca arundinacea Schreb), creeping bentrgass (Agrostis palustris Huds), perennial ryegrass (Lolium parenne L.) and zoysiagrass (Zoysia spp.) cultivar had higher leaf color for greenup promotion in Ami, Amx and Oligo than Con treatment and there were also significantly difference among treatments. Turfgrass NDVI also showed significant difference among cultivars in species. Spray of Ami, Amx and Oligo has the higher value of turf NDVI than Con. Based on our results, green up fast during spring season may affected much more with application of Ami, Amx and Oligo than Con.

• Asian Journal of Turfgrass Science
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• v.24 no.1
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• pp.50-55
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• 2010

Five turfgrass species and 46 cultivars were investigated for difference of spring greenup and living ground cover. Turf color and Normalized Difference Vegetation Index (NDVI) for greenup were investigated between species and cultivars. Turf color and NDVI were showed significantly different among species and cultivars. Turf color was showed significantly different among 20 cultivars of kentucky bluegrass (Poa pratensis L.). NDVI was significantly difference among 20 cultivars of kentucky bluegrass and 6 cultivars of tall fescue (Festuca arundinacea Schreb). The percentage living ground cover was showed significantly different among creeping bentgrass (Agrostis palustris Huds) cultivars and fineleaf fescue cultivars in spring.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1188-1194
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• 2008

As computation technologies has developed, the analysis using load transfer is mainly performed. But most of the functions used in the above program has been developed in foreign countries. Also in our nation, lots of studies concerning load transfer are being researched. The investigation of suitability about the piles installed in our grounds, however, is required as functions acquired experientially, basing on the piles installed in foreign grounds. In this background, the load transfer curve required to use load transfer method on its design through the analysis of field tests inside our nation intends to be made, on which this research focuses.

• Korean Journal of Human Ecology
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• v.11 no.3
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• pp.223-235
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• 2002

The purpose of this study was to examine the influences of the materialism of university students. The data were collected for 331 university students. The data were analyzed by the package of SPSS program. The methods of analyses included basic descriptive categorical analysis (frequencies, means, percentages) as well as t-test, one way ANOVA, and multiple regressions. To summarize major findings from the analysis: (1) A significant difference was found in the materialism of university students by the socio-economic variables such as the amount of pocket money. (2) A significant difference was found in the materialism of university students by more self-esteem than life satisfaction. (3) A significant difference was found in the materialism of university students by parent's materialism and competitive achievement pressure. (4) According to the multiple regression analysis, it was found that the materialism of university students was influenced by the order of self-esteem, parent's materialism and competitive achievement pressure.

• 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.