• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.258-262
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• 2003

연안지역에서 해수침투대의 평가를 위하여 다양한 물리검층을 수행하였다. 특히, 해수침투대의 정량적인 평가에 활용될 수 있는 지층의 공극측정은 매우 어려운 문제중의 하나이다. 연안지역의 경우, 미고결지층에 대한 불교란 시료 채취가 어렵고 대부분의 관측정은 시추공 붕락방지를 위하여 내경 50mm 의 PVC 케이싱을 설치하는 경우가 많기 때문에 공극의 측정은 현실적으로 많은 어려움이 따른다. 본 연구에서는 전남 영광지역에서 각종 조사목적으로 굴착한 시추공에서 다양한 물리검층을 수행하여 공내수의 높은 전기전도도가 기원하는 지층을 확인하고자 하였다. 전자유도검층과 공극검층을 수행한 시추공(YK-4호공)에 대한 해석결과, 공내수의 높은 전기전도도는 물리검층법으로 추정한 사질층 공극수와 비슷한 범위를 보였다. 물리검층법으로 추정한 공극이나 높은 염수를 보이는 구간에 대한 해석결과는 보완해야할 많은 부분이 있지만 제한된 현장 상황에서 조사결과의 불화실성을 줄이는데 많은 기여를 할 것으로 기대된다.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.1
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• pp.1-7
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• 2003

Time domain reflectometry (TDR) is a newly developed method for measuring simultaneously solute concentrations and volumetric water content of soil. Bulk electrical conductivity ($EC_a$) of soil is obtained from TDR signal using several equations proposed, and electrical conductivity of soil solution ($EC_w$) can be calculated using the linear relationship $EC_a=EC_w\theta(a\theta+b)+EC_s$ between $EC_a$ and $EC_w$ at constant soil water content. The objectives of this study were to evaluate $EC_a$ proposed by several workers and to obtain the empirical constants (a, b, and $EC_s$) for $EC_w$ of the soils from A, Bl, and B2 horizon of an agricultural field (Coarse loamy, Fluvaquentic Eutrudepts). The $EC_a$ proposed by Yanuka et al. responded most sensitively to the KCl solute concentrations. The empirical constants of a, b, and $EC_s$ for $EC_w$ were -0.249, 1.358, and 0.054 for A horizon, -2.518, 2.708, and 0.097 for Bl horizon, and 2.490, -0.250, and 0.103 for B2 horizon, respectively. Therefore, the results of this study showed that Yanuka et al. equation was most useful one in determining $EC_a$, from TDR signal for agricultural soil with low salinity and that the empirical constants for the calculation of $EC_w$, from $EC_a$ can be obtained through a simple calibration experiment.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.1
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• pp.71-75
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• 2001

Linear regression analyses between the electrical conductivity of the saturation-paste extract. ECe, and the electrical conductivity of the 1:5 soil extract, EC1:5, for different soils yielded different dilution factors, or slopes with significant $r^2$ values from 0.842 to 0.905. The dilution factor was inversely proportional to the cation exchange capacity of soil which reflected textural difference. The dilution factors recommended for different textural classes ranged from 6.44 for clay soil to 12.29 for sandy soil based on the CEC's of the textural classes among 350 surface soils recorded in the Taxonomical Classification of Korean Soils except volcanic ash derived soils. Though saturation percentage of the saturation-paste of the soils in this study, CEC should be taken into account for dilution factor between ECe and EC1:5, and the suggested dilution factors might be reasonable estimate for the soil textural classes.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1295-1299
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• 2011

This study was conducted at the organic farming fields which garlics were planted. The treatments were as follows; water of $3,850L\;ha^{-1}$ (Control), plots applied 1 time, 2 times and 3 times with sea water of $3,850L\;ha^{-1}$. In 3 times sea water treatment plot, the level of EC, Exch. Na and $Cl^-$ were 1.1, 2.1, and 3.3 times higher than control plot, respectively. Due to seawater application, the contents of inorganic elements such as T-N, Ca, Mg, Na, Fe, Mn, and Zn in garlic were generally lower than Control, but not significant.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.120-127
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• 1998

This study was performed to produce basic data for developing prediction techniques of desalinization through analyzing soil properties of reclaimed tidal lands, using soil samples collected in 11 units of tidal land reclamation projects. The average apparent specific gravity (bulk density), real specific gravity (particle density), porosity, and saturation percentage were measured to be 1.33, 2.64, 49.6%, and 56.3%, respectively. It was estimated that the soil texture class of reclaimed tidal lands would be silt or silt loam. The electrical conductivity and exchangeable sodium percentage were estimated to be $20{\sim}40dS\;m^{-1}$ and 30~50% in the beginning of tidal land reclamation, and the value of pH was measured to be 6.5~7.9. In conclusion, the soil properties of reclaimed tidal lands could be descrived to be saline-sodic soils with the high electrical conductivity and exchangeable sodium percentage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.3
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• pp.334-339
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• 1985

A sweet corn hybrid, Honey Bantam, was planted on 24 May, 1984 in a silty clay loam soil to investigate the effects of polyethylene(P.E.) mulch and different levels and placements of Nitrogen(N) on soil properties and sweet corn growth. A split-split plot design with three replications was employed; P.E. mulch and bare soil were main plot, N levele of 8, 12, 16, and 20 kg/10a were subplot, and band and broadcast of fertilizers were sub-subplots. At early growth stage soil temperature under P.E. mulch was higher than that in bare soil by 5-10$^{\circ}C$, but the differences decreased as plant growth advanced. Soil hardness increased with soil depth while P.E. mulch reduced soil hardness probably by holding high soil moisture. Soil pH decreased up to the 6th week after planting and then increased in bare soil, but it contineously decreased up to the 8th weeks under P.E. mulch regardless N levels and placements. Electrical conductivity(EC) of soil increased up to the 6th weeks after planting and then decreased in all treatments except broadcast of fertilizers under P.E. mulch where EC increased contineously. Generally, soil EC under P.E. mulch was higher than that in broadcast. Broadcast of fertilizers did not affect emergence of seedlings in all N levels under P.E. mulch and bare soil, but band of fertilizers at all N levels under P.E. mulch and higher levels of N in bare soil reduced emergence rate significantly. Percent stand was possitively correlated with soil EC and it strongly influenced the number of marketable ears. Plant growth was enhanced and silking date was earlier by 14-19 days under P.E. mulch compared to bare soil probably due to increased soil moisture, reduced soil hardness and higher soil temperature.

• Journal of Korean Society of Forest Science
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• v.86 no.4
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• pp.489-501
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• 1997

This research was conducted to analyze the influence of the environmental factors on water quality such as pH, dissolved oxygen, and electrical conductivity of rainfall, throughfall, soil water(A and B layer), and stream water quality at a small forested watershed. Rainfall, throughfall, soil water(A and B layer), and stream water were sampled at the study sites in Kwanak Arboretum, Seoul National University in Mt. Kwanak for 14 months(Jul. 1, 1996~Aug. 31, 1997). Average rainfall pH value was 6.06(ranged from 5.02 to 6.60). Acid rain frequency(less than pH 5.6) was 16.7%. The lowest rainfall pH value was 5.02. Average of pH values in hydrological processes were decreasing in the following order, stream water>soil water [Prunus serrulata var, spontanea(B layer>A layer)]>throughfall(Prunus serrulata var. spontanea)>soil water [Carpinus laxiflora(B layer >A layer)]>throughfall(Carpinus laxiflora)>rainfall>soil water [Pinus rigida(B layer>A layer)]>throughfall(Pinus rigida). pH values of throughfall in Prunes serrulata var. spontanea and Carpinus laxiflora were higher in Pines rigida. Average of dissolved oxygen values in hydrological processes were decreasing in the order, stream water>throughfall(Carpinus laxiflora>Prunus serrulata var, spontanea>Pines rigida)>rainfall>soil water [Prunes serrulata var. spontanea(A layer)>Pines rigida(A layer)>Carpinus laxiflora(A layer)>Prunes serrulata var. spontanea(B layer)>Pines rigida(B layer)>Carpinus laxiflora(B layer)]. And average electrical conductivity values in hydrological processes were decreasing in the order, soil water (B layer>A layer)>throughfall(Pinus rigida>Prunes serrulata var, spontanea>Carpinus laxiflora)>stream water>rainfall. Multiple regression equations of electrical conductivity and $Mg^{2+}$, $Na^+$, total amount of cation, total amount of ion, and no. of before non-rain days in rainfall, throughfall, soil and stream water shows high significance(Multi R; 0.84).

• KCID journal
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• v.8 no.1
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• pp.70-79
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• 2001

This study was Performed to analyze desalinization effects of gypsum treatments in reclaimed tidal lands and to obtain the basic data for developing prediction techniques of desalinization to be applicable to reclaimed tidal lands at the beginning stage.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.4
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• pp.193-199
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• 2003

Electrical conductivity (EC) is a major indicator of soil salinity. Measurement of EC in saturation-paste extract of soil (ECe) is a standard way to evaluate soil salinity. However, many of the data on soil salinity have been obtained by measuring the EC of 1:5 soil-water extract (EC1:5) or salt percentage which is calculated from EC1:5 by multiplying a conversion factor. We analyzed 90 soil samples collected from 9 reclaimed tidelands in Korea, and derived relationships between ECe and dilution factors (DF1:5) which can convert EC1:5 to ECe in 2 soil textural groups at 5 salinity levels. Regression equations between ECe and DF1:5 were DF1:5 = 1.3624In(ECe) + 5.1386($r^2=0.37^{***}$) for soils of more than 50% silt content, DF1:5 = 1.9505In(ECe) + 5.3679($r^2=0.66^{***}$) for soils of less than 50% silt content. And the relationship for all soils investigated was DF1:5 = 1.4001In(ECe) + 5.4865($r^2=0.51^{***}$). From the relationships, conversion factors for calculation of ECe from EC1:5 of salt percentage data were estimated for soils of different textures and salinity levels.

• FLOWER RESEARCH JOURNAL
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• v.19 no.3
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• pp.144-150
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• 2011

This study was carried out to develop the soil amendment practice by phosphate solubilizing bacteria application in greenhouse chrysanthemum cultivation area with high salt accumulation. The experimental site (ShinWoo Flower, GwangJu) has been cultivated chrysanthemum for 15 years and showed significant salt accumulation. The phosphate solubilizing bacteria, Pseudomonas putida (KSJ11), Acinetobacter calcoaceticus (KSJ3) and Acinetobacter calcoaceticus (WP20) formulated on vermiculite for easy use, were applicated. Each 250L of phosphate solubilizing bacteria was applied for $82m^2$ before planting. Acinetobacter calcoaceticus (KSJ3; WP20) increased the amount of soluble phosphorus in an effective level. Particularly, Acinetobacter calcoaceticus (WP20) increased not only the level of soluble phosphorus but also potassium, calcium and magnesium resulting in the increase of EC in the soil. The level of nematode was also decreased with the non-treated increased. As a result, we suggest that selected phosphate solubilizing bacteria (WP20) could be a useful practice for soil amendment in chrysanthemum plantation soil and provided an opportunity to reduce the use of the fertilizer during the cultivation period.