• Proceedings of the KSRS Conference
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• v.1
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• pp.483-486
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• 2006

The study describes the monitoring of the Bay of Bengal as a ballast water exchangeable sea using MODIS/Aqua-derived diffuse attenuation coefficient (K(490)) synchronized with in situ ballast water sampling and analysis along the LNG carrier's route between Japan and Qatar from 2002 to 2005. Based on the relationship between K(490) and corresponding in situ plankton cell densities, the Bay of Bengal is recognized as a ballast water exchangeable sea to meet the regulation of ballast water performance standard of International Maritime Organization (IMO). Furthermore the Bay of Bengal with more than 200m depth and more than 200 nautical mile distance from shore is extracted based on the regulation of ballast water exchange area of IMO. However, an anomalously high K(490) area is found off the coast of Sri Lanka during the northeast monsoon in 2005, which corresponds higher cell densities than the criterion set by the regulation of IMO. The phenomenon of high cell density in the Bay of Bengal seems to be related with the phytoplankton bloom during the northeast monsoon. Seasonal and annual variability of phytoplankton bloom will be investigated to establish an early routing system for avoiding the high cell density area in advance.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.1
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• pp.96-105
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• 1989

This laboratory study was performed to produce basic data for the estimation of water requirements for desalinization, through analyzing changes of the electrical conductivity and the exchangeable sodium percentage during the desalinization of reclaimed tidelands. Desalinization experiments were carried out by two water management practices, namely, the leaching method by subsurface drainage and the rinsing method by surface drainage, using samples of silt loam soil and silty clay loam soil collected in reclaimed tidelands. The results obtained from this study were summarized as follows : 1. The sample soils used in this study were saline-sodic soils with the high electrical conductivity and the high exchangeable sodium percentage. 2. Changes of the electrical conductivity and the exchangeable sodium percentage with water requirements for desalinization showed a similar tendency in the desalinization experiment by the same water management practice. 3. The regression equation between the relative electrical conductivity(EC/EC) and water requirements for desalinization(Dw/Ds) could be described by Dw/Ds=O. 29x(EC/EC.) -0.982 (Leaching method), Dw/Ds=3. 678X0. 030(EC/EC ) (Rinsing method). 4. The regression equation between the relative exchangeable sodium percentage (ESP/ESP ) and water requirements for desalinization (Dw/Ds) could be expressed in Dw/Ds = 0.039 x (ESP/ESP. ) - 1. 134 (Leaching method), Dw/Ds=7. 197X0. 024(ESP/ESP ) (Rinsing method). 5. It was estimated that water requirements for the adequate desalinization would be Dw/Ds=0.3 (Leaching method) and Dw/Ds=3.0 (Rinsing method)

• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.4
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• pp.127-133
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• 1988

This study was performed to obtain the basic data analyzing salt movement and desalinization effects, and two different desalinization experiments through leaching and rinsing were carried out, using samples of silt loam soil and silty clay loam soil collected in reclaimed tidelands. The relationships between the electrical conductivity of saturation extract and the electrical conductivity at various dilutions, and the correlations between electrical conductivity, total salt concentration, exchangeable sodium percentage and pH during the desalinization of reclaimed tidelands, were analyzed by the statistical method. The results obtained from this study were summarized as follows: 1.The sample soils used in this study were saline-sodic soils in accordance with the USDA classi- fication system of salt affected soils. 2.The electrical conductivity of saturation extract could be estimated conveniently, using the electrical conductivity of extract from various different soil-water suspensions. 3.The total salt concentration could be expressed in the electrical conductivity, but there was a little difference by soil textures. 4.The regression analysis showed that the relationship between the electrical conductivity of saturation extract and the exchangeable sodium percentage during the desalinization of reclaimed lands could be described by a linear regression equation. 5.The value of pH showed a tendency to increase according as the exchangeable sodium percentage decreased during the desalinization of reclaimed tidelands.

• Journal of Plant Biology
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• v.7 no.2
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• pp.1-8
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• 1964

Cha, Jong Whan (Dept. of Biology, Graduate School, Dong Kuk Univ.) The changes of chemical properties of forest soils in dry and wet seasons. Kor. Jour. Bot. VII(2): 1-8, 1964. Soil selected for the present investigation was collected from a mountain of the Forestry Experiment Station of the vicinity of Seoul. The forest communities studied were three forest and a unplanted soils. The soil samples were obtained from each forest type during dry and wet seasons. And these samples were collected from four horizons of all communities respectively. It was showed that exchangeable hydrogen was increased by rainfall, and total exchangeable base decreased in the same way. The content of nitrogen is washed away by rainfall, especially ammonium nitrogen was highly significant between dry and wet season. On the contrary, organic matter and available phosphorus were of no significant difference between dry and wet seasons. The values of pH appeared a different response in dry and wet seasons according to the plant communities. The needle-leaved forest soils showed more acidity than the broad-leaved forest soils, and the least acidity in open places. All nutrients in soil studied gradually decreased down the profiles. According to statistical analyses of the soil components among all soil horizons, total exchangeable bases in wet season indicated only significant at 1%. Exchangeable hydrogen and organic matter of the soil in dry season was particularly very low with increased depth in the profile. The fertility level of most forested soils selected for the present investigation is low according to chemical tests for available nutrient elements.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.920-924
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• 2012

This study was performed to estimate total contents of arsenic (As) by stepwise multiple-regression analysis using chemical properties and extractable contents of metal in paddy soil adjacent to abandoned mines. The soil was collected from paddies near abandoned mines. Soil pH, electrical conductively (EC), organic mater (OM), available phosphorus ($P_2O_5$), and exchangeable cations (Ca, K, Mg, Na) were measured. Total contents of As and extractable contents of metals were analyzed by ICP-OES. From stepwise analysis, it was showed that the contents of extractable As, available phosphorus, extractable Cu, exchangeable K, exchangeable Na, and organic mater significantly influenced the total contents of As in soil (p<0.001). The multiple linear regression models have been established as Log (Total-As) = 0.741 + 0.716 Log (extractable-As) - 0.734 Log (avail-$P_2O_5$) + 0.334 Log (extractable-Cu) + 0.186 Log (exchangeable-K) - 0.593 Log (exchangeable-Na) + 0.558 Log (OM). The estimated value in total contents of As was significantly correlated with the measured value in soil ($R^2$=0.84196, p<0.0001). This predictive model for estimating total As contents in paddy soil will be properly applied to the numerous datasets which were surveyed with extractable heavy metal contents based on Soil Environmental Conservation Act before 2010.

• Journal of Korean Society of Forest Science
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• v.97 no.3
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• pp.296-304
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• 2008

This study was carried out to analyze vegetation and soil characteristic, and ordination of Stewartia koreana community. The Stewartia koreana community was classified into Acer mono subcommunity, Pinus densiflora subcommunity, Sapium japonicum subcommunity, and Stewartia koreana typical subcommunity. In the study sites, soil organic matter, nitrogen, available phosphorous, exchangeable K, exchangeable Ca, exchangeable Mg concentration, cation exchange capacity, and soil pH were ranged from 14.31~34.27%, 0.33~0.77%, 7.83~22.88(mg/kg), 0.23~1.07(me/100 g), 0.29~2.93(me/100 g), 0.33~1.49(me/100 g), 10.47~22.48(me/100 g), and 4.65~4.96, respectively. The area of the Acer mono subcommunity, found in highlands, showed that contained the highest organic substances, nitrogen, available phosphorous, and cation exchangeable capacity concentration among the communities. The low elevation regions where the Pinus densiflor subcommunity is formed, showed the lowest concentrations of exchangeable Ca, and Mg.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.1
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• pp.92-100
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• 2009

This study was carried out to investigate vegetation structure and soil properties of Angelica gigas population distributed in Jeombongsan, Bangtaesan, Odaesan, Gyebangsan and Jirisan. From August 2007 until September 2008, 5m${\times}$5m quadrat was established in native area of Angelica gigas in order to record a dominants and coverage, and soil factors at 20 sites. It was found that the altitude in the distributed areas for Angelica gigas population was 710m or more. Angelica gigas population was classified into Parasencio auriculata var. kamtschatical dominant population, Pseudostellaria palibiniana dominant population, Isodon excisus dominant population and typical dominant population. In the site of study, soil pH, electrical conductivity, soil organic matter, available phosphorous, and exchangeable potassium, exchangeable calcium, exchangeable magnesium, exchangeable natrium concentration and total nitrogen were ranged from 5.1~6.2, 0.1~0.79dS/m, 2.21~22.11%, 9.56~37.97mg/kg, 1.85~23.88cmol+/kg, 0.21~1.18cmol+/kg, 1.07~5.09cmol+/kg, 0.04~0.14cmol+/kg and 0.09~1.04% respectively. The Parasencio auriculata var. kamtschatical dominant population was found in area of high altitude and had high slope degree. But Pseudostellaria palibiniana dominant population was found in area of low altitude and low slope degree. Isodon excisus dominant population was found to have higher soil pH and exchangeable potassium concentration than the other dominant population.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.3
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• pp.63-72
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• 2014

The exchangeable battery electric bus is an eco-friendly public transportation vehicle. Due to the technological limitation, however, it should repeatedly change batteries with charged ones. The unmanned battery exchangeable electric bus being studied in Korea can exchange batteries automatically by using a battery swapping system. In this paper, we propose an unmanned battery exchangeable electric bus management system. The proposed system provides two services: the bus information service and the battery change scheduling service. The bus information service is the existing traditional metropolitan area bus information systems, which inform bus passengers how long they should wait for the buses. Our second service assigns a low-battery bus, which needs to change the batteries, to the battery swapping system, which stores fully-charged batteries. To validate the proposed system, we model the system by using the DEVS formalism. The simulation result shows that the proposed system provides the services properly.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.6
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• pp.378-382
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• 2004

Soil pH is an important indicator for soil reactions and crop growth. pH buffer capacity and lime requirements are necessary to comprehend and manage soils well. The characteristics related with soil pH were analyzed and 5 field trials were conducted to elucidate pH buffer capacity of soil and lime requirements and liming factor for Korean acid soils. Soil minerals were analyzed for the soil of 2 years after treating $CaCO_3$ using X-ray diffraction. The amount of neutralized $H^+$ was regarded as the exchangeable aluminium overcoming ${\Delta}pH$, because pH buffer capacity of soil depended on exchangeable aluminium. Lime requirement was somewhat similar to the KCl exchangeable aluminium and it was also affected by the exchangeable cation by added lime. X-ray diffraction analyses revealed that an aluminium dissociation from Korean acid soils was equilibrated with kaolin minerals and changed into anorthite ($CaAl_2Si_2O_8$) by neutralizing with $CaCO_3$. Neutralizing process was composed of changing process of $Al^{3+}$ into $H^+$ and $Al(OH)_4{^-}$ ionic species and of neutralizing $H^+$ by, the amount of which was lime requirement. The fact that anorthite dissociates an aluminium ion higher than kaolinite does enabled to consider a liming factor (LF) the content of exchangeable cation and ${\Delta}pH$, $LF=1.5+0.2{\times}{\sum} Cations{\times}{\Delta}pH$.

• Journal of Ginseng Research
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• v.39 no.1
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• pp.81-88
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• 2015

Background: In Changbai Mountains, Panax ginseng (ginseng) was cultivated in a mixture of the humus and albic horizons of albic luvisol in a raised garden with plastic shade. This study aimed to evaluate the impact of ginseng planting on soil characteristics. Methods: The mixed-bed soils were seasonally collected at intervals of 0-5 cm, 5-10 cm, and 10-15 cm for different-aged ginsengs. Soil physico-chemical characteristics were studied using general methods. Aluminum was extracted from the soil solids with $NH_4Cl $(exchangeable Al) and Na-pyrophosphate (organic Al) and was measured with an atomic absorption spectrophotometer. Results: A remarkable decrease in the pH, concentrations of exchangeable calcium, $NH_4^+$, total organic carbon (TOC), and organic Al, as well as a pronounced increase in the bulk density were observed in the different-aged ginseng soils from one spring to the next. The decrease in pH in the ginseng soils was positively correlated with the $NH_4^+$ (r=0.463, p<0.01), exchangeable calcium (r=0.325, p<0.01) and TOC (r= 0.292, p < 0.05) concentrations. The $NO_3^-$ showed remarkable surface accumulation (0-5 cm) in the summer and even more in the autumn but declined considerably the next spring. The exchangeable Al fluctuated from $0.10mg\;g^{-1}$ to $0.50mg\;g^{-1}$ for dry soils, which was positively correlated with the $NO_3^-$ (r=0.401, p < 0.01) and negatively correlated with the TOC (r=-0.329, p < 0.05). The Al saturation varied from 10% to 41% and was higher in the summer and autumn, especially in the 0-5 cmand 5-10 cm layers. Conclusion: Taken together, our study revealed a seasonal shift in soil characteristics in ginseng beds with plastic shade.