• Journal of Korean Society of Forest Science
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• v.97 no.3
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• pp.266-273
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• 2008

The effects of soil acidification on the seedling growth and nutrition of Pinus densiflora and Quercus acutissima were investigated. The relationship between the seedling growth and molar (Ca+Mg+K)/Al ratio of in soil solution was examined. The results suggested that growth inhibition of seedling Pinus densiflora and Quercus acutissima was due to the low pH of soil solution, which was followed by leach of Al into soil solution, and decrease of essential elements, such as Ca in aerial pant of the seeding caused by the increase of Al concentration in subterranean pant of the seedlings. The level of growth inhibition was determined not only by Al concentration, but also by the balance of inorganic elements, Al, Ca, Mg and K. The growths of two species in total dry weight were clearly inhibited when molar (Ca+Mg+K)/Al ratio of the soil was lower than 6.0. The growth in dry weight, in the condition of the molar ratio was 0.8, was decreased 60% or 50% for the seedling of Pinus densiflora or Quercus acutissima respectively. It was concluded that the molar (Ca+Mg+K)/ Al ratio could be an important index for evaluation of the effects of soil acidification, due to acid deposition such as acid rain, on growth of trees and nutrition. And it might be a more useful indicator for evaluation of critical load of acid deposition on forest ecosystems.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.6
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• pp.398-404
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• 2000

We examined the effect of soil:water ratio on the equivalent concentration of individual electrolyte species and the electrical conductivities (EC) of the diluted extracts of 24 soil samples (loam or silt loam) collected from rose-cultivated plastic houses to estimate the EC of saturated soil-paste extracts (ECe) from diluted soil extracts. With increasing volume ratio of water (higher dilution), the equivalent concentrations of each electrolyte species and their sum increased. The relative contribution to the EC, however, was highest for $NO_3{^-}$, irrespective of soil:water ratio. The measured ECe was 6.36 for loam and $8.09dS\;m^{-1}$ for silt loam soils and the corresponding soil:water ratio was 0.38 and 0.50, respectively. The EC_e estimated from the EC of diluted extracts at 1:1, 1:2, or 1:5 soil:water ratios using their corresponding uniform diluted factors was lower than the measured EC_e and this difference was greater with higher dilution and EC values. Therefore, the alternative diluted factors (y) for each soil: water ratio were obtained following the definition of diluted factor and were correlated significantly with volume ratios of added water (x): y=1.55x+0.5 for loam and y=1.21x+0.48 for silt loam soils. On the other hand, correlation analyses of the EC of soil extracts (y) to the volume ratio of added water (x) on log-log scale yielded linear models: logy = -0.805logx + logb, SD of slope=0.05, b=sample specific constant, n=24). With known saturation percentage of a sample representing a group and and the EC of diluted extract of a given soil, the EC_e could be predicted using the proposed logarithmic equation.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.06a
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• pp.3-7
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• 1998

본 연구에서는 광산 인근 토양에서 산성비를 비롯한 침출수에 의한 지하 환경 오염 메카니즘을 검토하고, 오염 방지 및 교정과 대안의 효과를 정량화 하기 위한 방안을 고찰하였다. 이를 위하여 중금속인 비소의 오염도가 높은 토양을 대상으로 인위적 산성용액에 의한 비소의 용출을 실험적으로 검토하였다. 한편, 산성 침출오염수에 의한 지하 환경의 오염을 방지하기 위하여 석회석을 활용한 토양의 안정화방법의 효과를 살펴보았다. 오염된 시료토양에 포함된 비소는 pH 1 이하의 강산성 용액일수록 격렬히 용출되었으며, pH 값이 낮아질 수록 최대 용출량은 증가되는 것으로 나타났다. 석회석에 의한 토양 안정화방안은 매우 효과적이었으며, 석회석에 의한 산성용액의 중화반응 특성식은 미반응 핵 모델중에서 화학반응이 속도지배인 특성식에 잘 부합되는 것으로 보여진다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.198-201
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• 2001

In-situ flushing의 적용에 따른 농도 저감이 생물학적 분해에 미치는 영향을 알아보기 위하여, 초기농도 13mg/kg dry soil과 3mg/kg dry soil인 토양을 생물학적으로 처리한 결과 제거효율은 각각 86% 및 81%였으며, 두 가지 토양 모두 24시간 이후에는 미생물에 의한 작용이 크지 않은 것으로 나타났다. 이것은 토양상에서 용액상으로의 미생물에 의한 작용이 크지 않은 것으로 나타났다. 이것은 토양상에서 용액상으로의 물질전이 속도가 율속 단계로 작용하고 있기 때문이라 생각된다. 토양에 잔류하는 계면활성제가 생물학적 분해에 미치는 영향을 본 결과, 잔류하는 계면활성제에 의해 물질전이 속도가 향상되어 생분해가 지속적으로 일어났으며 초기농도 3mg/kg dry soil인 경우 120시간이 경과한 후 89%의 제거효율을 나타내었다. 계면활성제와 보조용매가 동시에 잔류하는 경우에는 계면활성제에 대한 순응기간이 보다 길어지는 것을 알 수 있었으며, 메탄올과 에탄올의 경우 각각 84%의 제거효율을 나타내었다.

• Journal of Soil and Groundwater Environment
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• v.7 no.3
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• pp.85-94
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• 2002

Overall objective of this study was to evaluate the electrochemical characteristics of fine soils during the electrokinetic(EK) remediation. Zeta potential of kaolinite as a function of solution pH and surfactant concentration was investigated to make a relationship with electroosmotic flow direction and rate. During the EK experiments, pH of pore solution, electroosmotic permeability($k_e$), electric conductivity($\delta_e$) and voltage distribution was measured, respectively, The point of zero charge(PZC) of kaolinite was estimated to be about 4.2 and the zeta potential of kaolinite above PZC was more negative as solution pH increased. Sorption of surfactants on the kaolinite altered the zeta potential of kaolinite. resulting from the variation of electrochemical characteristics of kaolinite surface. hs the EK experiment progressed, low pH was predominant over most of the kaolinite specimen and thus resulted in very low mass and charge flow. The $k_e$ and $\delta_e$ was also affected by the variation of voltage drop across the EK column with time. Results from this study implied that zeta potential of kaolinite affected by the pH variation of pore solution and voltage distribution in soil column played important role in the determination of mass and charge flow during EK process. It was also suggested that pH adjustment or addition of suitable sorbates could alter the electrochemical characteristics of soil surface and thus maintain high mass and charge flow rate with time.

• Journal of Korean Society of Forest Science
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• v.87 no.4
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• pp.611-619
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• 1998

This study was carried out to examine the effects of soil acidification on growth and nutrient status of 2 - year - old Pious densiflora Sieb. et Zucc. seedlings grown for 120 days in brown forest soils acidified with $H_2SO_4$ solution with or without leaching rations from the soil. The concentrations of A1 in the acidified soils increased with increasing amount of $H^+$ added to the soil. The total dry weight of the seedlings was decreased by the addition of the $H_2SO_4$ solution. The increase of Al concentration in the belowground part resulted from the decreased concentration of essential mineral elements such as Ca and Mg in the aboveground part. In addition, a strong positive correlation(r=0.96, p<0.001) was observed between the dry weight of the seedlings and the molar (Ca+Mg+K)/A1 ratio of the soil solution. When the molar (Ca+Mg+K)/Al ratio was approximately 7.0, the dry weight of the seedlings began to decrease compared with that of the seedlings in the control treatment. The seedlings with the molar (Ca+Mg+K)/Al ratio of 1.0 resulted from approximately 40% growth reduction compared with the control value. The results suggest that the molar (Ca+Mg+K)/Al ratio of the soil solution may be a useful indicator for assessing the critical load of acid deposition.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.5
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• pp.316-325
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• 2001

To develope a technique for efficiently managing fertilizer for cucumber, a quick test method to quantify nitrate content in soil solution and leaf petiole juice using a simple instrument was investigated. Among the nitrate analyzing instruments such as compact ion meter, nitrate ion meter, and test strip with reflectometer, the paper test-strip used in conjunction with a hand-held reflectometer was most closely correlated with ion chromatography method in nitrate content, and then it would be suggested with a tool that a farmer can use rapidly, conveniently and accurately for nitrate analysis in a field. Nitrate content in soil solution collected by porous cup was very variable on the lapsed time after drip irrigation and the sampling positions such as soil depth and the distance from dripper. As a result, a significant correlation between nitrate contents of soil solutions and 2M KCl soil extract was not found. However, nitrate content in soil solution extracted with a volume basis (soil:water=1:2) showed the highly significant correlation with that in 2M KCl extract. Nitrate contents of cucumber leaf petiole juices was greatly different between upper and lower leaves. Eleven to sixteen positioned-leaf would be a proper sampling position to determine nitrate content in leaf petiole for evaluating nutrient state by plant tissue analysis. From the secondary regression equations between nitrate contents of soil and petiole juice and the yield of cucumber, nitrate levels for real time diagnosis were estimated as $400mg\;l^{-1}$ soil solution by porous cup. $300mg\;l^{-1}$ in a soil volume extraction, and $1400mg\;l^{-1}$ in petiole juice from spring to summer season. In addition, the maximum yield of cucumber fruit in pot test was obtained in nitrate $1500mg\;l^{-1}$ level of petiole juice, which was similar to nitrate $1400mg\;l^{-1}$ in greenhouse trial.

• Journal of Korea Soil Environment Society
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• v.3 no.3
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• pp.109-116
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• 1998

Treatability tests of a soil washing device were performed for the remediation of eil-contaminated soil. The contaminant-containing soil with water was first fed into a oc-current screw conveyor and then into a counter-current washer. Surfactant was introduced into the washer and feeding soil was continuously separated on the basis of #40 mesh at the same time. A washing efficiency of 97.9% was achieved by the the soil washing device optimized.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.4
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• pp.303-308
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• 1994

We have obtained following results by executing this experiment to define effects of organic substances applied and temperature on fungistatic effect which is regarded as basic factor of inhibition against hot-pepper blight affection : 1. Fungistatic effect of soil on Phytophthora capsici is enlarged by application of organic material such as rice straw rather than matured composts. Morever, it is confirmed that fungistatic efect is more eminent at the temperature of $15^{\circ}C$ and $5^{\circ}C$ than at $30^{\circ}C$, Degree of fungistatic effect of soil tends to decrease as the goe on from the moment of using organic substance generally, in soil applied as the goes on from the moment of using organic substance generally, in soil applied rice straw it is prove that fungistatic effect is maintained stably in a long term. 2. Effect of applicating organic substances and treating by temperature on production of zoosporangium of Phytophthra capsici is reviewed. In case that sterilized soil solution is added on cultured hypae of Phytophthra capsici, increase in the production of zoosporangium is found which is statistically significant(at degree of 1%), while decrease effect statistically significant is found in case of adding soil solution used for applying bark compost. However, defferences between treatments of temperature is not found. On the other hand, when nonsterilized soil solution is added, significant defference between types of organic substance is not found, while significant difference is found between treatments of temperature, therefore formation of zoosporangium is increased at the condition of $5^{\circ}C$ comparing to that of $30^{\circ}C$. 3. Putting above result of examination concerning to composition of soil microrganisms in each treated soil and to fungistatic effect of them, it seems that fungi and bacteria in soil is mostly related to fungistatic activity of soil.

• Journal of Soil and Groundwater Environment
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• v.11 no.6
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• pp.8-17
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• 2006

Laboratory scale experiments were performed to investigate the removal efficiency of the in-situ chemical oxidation method and the air-sparging method for diesel contaminated soil and groundwater. Two kinds of diesel contaminated soils (TPH concentration : 2,401 mg/kg and 9,551 mg/kg) and groundwater sampled at Busan railroad station were used for the experiments. For batch experiments of chemical oxidation by using 50% hydrogen peroxide solution, TPH concentration of soil decreased to 18% and 15% of initial TPH concentration. For continuous column experiments, more than 70% of initial TPH in soil was removed by using soil flushing with 20% hydrogen peroxide solution, suggesting that most of diesel in soil reacted with hydrogen peroxide and degraded into $CO_2$ or $H_2O$ gases. Batch experiment for the air-sparging method with artificially contaminated groundwater (TPH concentration : 810 mg/L) was performed to evaluate the removal efficiency of the air-sparging method and TPH concentration of groundwater decreased to lower than 5 mg/L (waste water discharge tolerance limit) within 72 hours of air-sparging. For box experiment with diesel contaminated real soil and groundwater, the removal efficiency of air-sparging was very low because of the residual diesel phase existed in soil medium, suggesting that the air-sparging method should be applied to remediate groundwater after the free phase of diesel in soil medium was removed. For the last time, the in-situ box experiment for a unit process mixed the chemical oxidation process with the air-sparging process was performed to remove diesel from soil and groundwater at a time. Soil flushing with 20% hydrogen peroxide solution was applied to diesel contaminated soils in box, and subsequently contaminated groundwater was purified by the air-sparging method. With 23 L of 20% hydrogen peroxide solution and 2,160 L of air-sparging, TPH concentration of soil decreased from 9,551 mg/kg to 390 mg/kg and TPH concentration of groundwater reduced to lower than 5 mg/L. Results suggested that the combination process of the in-situ hydrogen peroxide flushing and the air-sparging has a great possibility to simultaneously remediate fuel contaminated soil and groundwater.