• 한국환경농학회지
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• 제5권2호
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• pp.135-140
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• 1986

K-bentonite를 K포화용액에서 이온교환법에 의해 제조했다. 모래땅, 황토, 산흙에서 K-bentonite 완효성의 효과를 비교 시험했는데, 특히 모래땅에서 그 효과가 컸다. 알타리무우 및 상치를 이용한 모래땅 재배에서 KCl시용구. 보다 K-bentonite구는 상치의 지상부의 생육과 알타리무우의 근부신장을 월등히 촉진 시켰다. 그러나 적정량을 관수하면서 모래, 산흙, 황토를 이용한 온실내 pot시험에서는 생육차를 발견할 수 없었다. K-bentonite는 무우 및 상치의 Vitamin C, Nitrate, Thiocyanate, Dry wt 등의 함량변화에 영향을 미치지 않았다. K-bentonite 실제 생산에 있어 문제점에 대해 논의하였다.

• 한국환경과학회지
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• 제4권5호
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• pp.41-41
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• 1995

In order to discuss the differences among the SMP(Surface Moisture Availability Parameter), by previous researchers on the basis of their own theoretical and empirical background, we assessed the SMP according to the soil types and volumetric soil water contents. The results are as follows. There are differences among all the five SMAPs. There''s a tendency that the larger grain size, the higher value of parameters. And they divided into two groups for their value: one group has parameters with exponential function and the other with cosine and linear function. The maximum difference between the two groups appears when the volumetric soil water contents are 0.07$m^3m^{-3}$ for sand, 0.l1$m^3m^{-3}$ for loam, 0.12 for clay, and 0.13$m^3m^{-3}$ for silt loam. So, these differences must be considered when we estimate the surface evaporation rate. From field data, the paddy field soil around Junam reservoir is classified as a silt has high wetness, 0.56. So, the parameter obtained from the field measurement is much higher than that of Clapp and Hornberger(1978)''s Table. This study treated the SMP for a certain point of time in winter season. But if we measured the soil water contents continuously, we could obtain better time-dependent parameter.

• 한국환경과학회지
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• 제4권5호
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• pp.427-435
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• 1995

In order to discuss the differences among the SMP(Surface Moisture Availability Parameter), by previous researchers on the basis of their own theoretical and empirical background, we assessed the SMP according to the soil types and volumetric soil water contents. The results are as follows. There are differences among all the five SMAPs. There's a tendency that the larger grain size, the higher value of parameters. And they divided into two groups for their value: one group has parameters with exponential function and the other with cosine and linear function. The maximum difference between the two groups appears when the volumetric soil water contents are 0.07m3m-3 for sand, 0.l1m3m-3 for loam, 0.12 for clay, and 0.13m3m-3 for silt loam. So, these differences must be considered when we estimate the surface evaporation rate. From field data, the paddy field soil around Junam reservoir is classified as a silt has high wetness, 0.56. So, the parameter obtained from the field measurement is much higher than that of Clapp and Hornberger(1978)'s Table. This study treated the SMP for a certain point of time in winter season. But if we measured the soil water contents continuously, we could obtain better time-dependent parameter. Key words : SMAP(Surface Moisture Availability Parameter), Paddy field, Volumetric soil water content, Evaporation, Capillary potential.

• 한국농공학회지
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• 제31권1호
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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)

• Applied Biological Chemistry
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• 제25권3호
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• pp.126-134
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• 1982

$^{14}C-2$, 6-Diethylaniline을 토양중에서 호기적으로 21 주간 배양시 발생된 $^{14}CO_2$는 살균하지 않은 A토양(clay loam)과 B토양(coarse sandy loam)에서 각각 6.5%와 10.1%이었다. Methanol로 토양을 추출시 A토양에서는 3.1%, B토양에서는 13.5%의 토양방사능이 추출되었다. 토양중에서의 분해산물은 2, 6-diethylacetanilide 이었으며 Chaetomium globosum은 순수배양시 분해산물로 2, 6-diethyl-p-benzoquinone을 생성하였고 이의 생성경로는 2, 6-DEA의 p-hydroxylation, quinoneimine의 형성 그리고 암모니아 발생을 수반하는 가수분해 등으로 제안하였다.

• 한국농공학회지
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• 제30권4호
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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 Forest and Environmental Science
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• 제35권1호
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• pp.31-40
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• 2019

Daphne pseudomezereum var. koreana is an endangered deciduous shrub distributed in mountain areas that is vulnerable to climate change. The purpose of this study was to provide foundational data on the physical characteristics, soil environment, and vegetation structure of habitats of Daphne pseudomezereum var. koreana habitat in Korea in order to help with management decisions on ecosystem restoration. Rock exposure was 15 to 35%, with an average of 24%. The native habitat of D. pseudomezereum included 129 taxa consisting of 46 families and 95 genera. Two-way cluster analysis divided the habitat into three plant communities: Community I (dominaterd by Tilia amurensis and Quercus mongolica), Community II (dominaterd by Fraxinus rhynchophylla and Acer pseudosieboldianum), and Community III (dominaterd by Ulmus davidiana var. japonica). The diversity indices for Communities I, II, and III were 1.124, 1.047 and 0.932, respectively. The soils were loam or clay loam. Soil pH, organic matter content, and available phosphoric acid were 5.40, 14.38%, and 31.08 ppm, respectively. Ordination analysis resulted that most significant factors influencing D. pseudomezereum distribution were magnesium content of soil, shrub layer, and altitude.

• Journal of Forest and Environmental Science
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• 제37권1호
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• pp.25-34
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• 2021

This study was conducted at Sitakunda coastal afforestation range, comprised of four beats- Bansbaria, Bakkhali, Baterkhil and Bogachattar, in Chittagong. Afforestation effects on soil physicochemical properties in comparison to adjacent barren land were analysed. In the study area, an area of 3277.33 ha was planted with Sonneratia apetala, Avecinnia officinalis, Excoecaria agallocha, Bruguiera sexangula, Ceriops decandra from 1968 to 2011. We found positive soil physicochemical changes in plantations in comparison to adjacent barren land. Soil bulk density of plantation was lower than the adjacent barren land. Soil pH and soil salinity were significantly higher in barren land whereas soil organic matter, organic carbon, nitrogen, phosphorus, potassium of plantations were higher in afforested land. Soil texture ranged from clay loam to sandy loam in different depth of these two types of land. However, this study concludes that there is clear evidence that afforestation has positive impacts on all soil properties in different location and soil depths in the study area.

• 한국약용작물학회지
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• 제2권3호
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• pp.193-197
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• 1994

토성(土性)에 따른 시호(柴胡)의 생육특성(生育特性)과 saikosaponin 함량(含量) 변이(變異)를 조사(調査)하여 시호(柴胡) 재배(栽培)에 있어서 토성(土性)이 미치는 영향(影響)을 알아보고자 본(本) 실험(實驗)을 수행(遂行)하여 다음과 같은 결과(結果)를 얻었다. 1. 토성(土性)에 따른 시호(柴胡)의 생육량(生育量)은 사양토(砂壤土)와 양토(壤土)에서 양호(良好)하였고 근수량(根數量)은 사양토(砂壤土)에서 가장 좋았다. 2. 시호근(柴胡根)의 총(總) saikosaponin 과 엑스함량(合量)은 식양토(埴壤土)에서 가장 높았다. 3. 1년생(年生)과 2년생(年生) 모두 토성(土性)에 따른 생욱특성(生育特性)과 성분함양(成分含量)은 동일(同一)한 경향(傾向)을 보였으며, 2년생(年生)의 생육(生育) 및 근수량(根收量)이 1년생(年生) 보다 높았으나 엑스 및 saikosaponin 함량(含量)은 낮았다. 4. 각(各) 생육요소(生育要素)와 엑스 및 saikosaponin 함량(含量)과의 교관분석(橋關分析) 결과(結果) 고도(高度)로 유의(有意)한 부(負)의 상관(相關)을 나타냈다.

• 한국토양비료학회지
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• 제49권4호
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• pp.327-334
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• 2016

In order to compare phosphorus (P) behavior of livestock manure compost (LMC) and chemical fertilizer (CF) applied to the sea-reclaimed land soils, incubation experiments were conducted for five weeks. Four soils differing textural classes, sandy loam and clay loam, and electric conductivity (EC) value, high and low, were applied with CF and LMC. LMC was applied at the level of 0, 1, 2, and 3% on the soil weight basis and CF was applied at the same levels of P as LMC. The results showed that increase of P application rate of CF and LMC led to linearly increase available $P_2O_5$ and $0.01M\;CaCl_2$ extractable P contents regardless of soil texture and EC. However, 0.01M $CaCl_2$ extractable P from soil applied with CF was significantly higher than with LMC. Correlation analysis between $0.01M-CaCl_2$ extractable P and fractionated P by different extraction methods showed that $0.01M-CaCl_2$ extractable P positively correlated with KCl-P (soluble and exchangeable P) and HCl-P (Ca and Mg bound P). However, NaOH-P (Fe and Al bound P and organic P) and residual P was adverse. The amount of NaOH-P significantly influenced to the amount of 0.01M $CaCl_2$ extractable P of CF and LMC in the soils. The application of LMC at sandy loam soil could be carried out in the consideration of nutrient leaching and crop uptake.