• Title/Summary/Keyword: Exchangeable sodium percentage

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Experimental Studies for Analyzing Salt Movement and Desalinization Effects on Reclaiming New Manguem Tideland (새만금지구 간석지토양의 염분거동해석 및 제염효과분석을 위한 실험적연구)

  • 구자웅;한강완;서승덕
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.31 no.2
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    • pp.92-103
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    • 1989
  • This study was performed in order to produce the basic data for devising irrigation project and desalinization countermeasure through analyzing salt movement and desalinzation effects. The Desalinization experiments with water management practices were carried out, using the soil samples collected in New Manguem tideland. The changes of electrical conductivity, exchangeable sodium percentage, pH and hydraulic conductivity during the desalinization experiments, and the correlations between various factors influencing desalinization, 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 salin-sotlic soils with the high electrical conductivity and the high exchangeable sodium percentage, and the soil texture was silt loam. 2. A large amount of the soluble salts was removed in the begining of desalinization experiments. The initial electrical conductivity and the initial exchangeable sodium percentage decreased considerably in the beginning, and were gradually slow in the rate of decrease 3. The value of pH showed a tendency to increase during the desalinization and were little by little slow in the rate of increase, and could be estimated by the regression equation. 4. The initial hydraulic conductivity were raised greatly with gypsum treatment and the penmeability was maintained adequately, The hydraulic conductivity and the leaching time elapsed during the desalinization could be estimated by the regression equation. 5. The water requirement for desalinization with various water management practices could be estimated for a given electrical conductivity, exchangeable sodium percentage, and pH reading respectively.

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A Laboratory Study on the Estimation of Water Requirements for the Desalinization of Reclaimed Tidelands (간척지토양의 제염용수량산정에 관한 실험연구)

  • 구자웅;한강원;은종호
    • 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)

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Relationship Between Electrical Conductivity, Exchangeable Sodium Percentage and pH During Desalinization of Reclaimed Tidelands (간척지토양의 제염과정중 전기전도도와 치환성 나트륨 백분율 및 pH 사이의 관계)

  • 구자웅;은종호
    • 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.

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Salt Removal in a Reclaimed Tidal Land Soil with Gypsum, Compost, and Phosphate Amendment

  • Lee, Jeong-Eun;Seo, Dong-Hyuk;Yun, Seok-In
    • Korean Journal of Soil Science and Fertilizer
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    • v.48 no.5
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    • pp.326-331
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    • 2015
  • High salinity and sodicity of soils play a negative role in producing crops in reclaimed tidal lands. To evaluate the effects of soil ameliorants on salt removal in a highly saline and sodic soil of reclaimed tidal land, we conducted a column experiment with treating gypsum, compost, and phosphate at 0-2 cm depth and measured the salt concentration of leachate and soil. Electrical conductivity of leachate was $45-48dSm^{-1}$ at 1 pore volume (PV) of water and decreased to less than $3dSm^{-1}$ at 3 PV of water. Gypsum significantly decreased SAR (sodium adsorption ratio) of leachate below 3 at 3 PV of water and soil ESP (exchangeable sodium percentage) below 3% for the whole profile of soil column. Compost significantly decreased ESP of soil at 0-5 cm depth to 5% compared with the control (20%). However, compost affected little the composition of cations below a depth of 5 cm and in leachate compared with control treatment. It was concluded that gypsum was effective in ameliorating reclaimed tidal lands at and below a soil layer receiving gypsum while compost worked only at a soil layer where compost was treated.

Water-dispersible Clay Content in Summer Rainy Season for Korean Irrigated Rice Paddy Fields as Affected by Cultivated Years Using Heavy Agro-machinery and Soil Properties (우리나라 관개논에서 토양특성과 대형농기계를 사용한 경작년수에 따른 여름 강우기 분산성 점토의 함량)

  • Han, Kyung Hwa
    • Korean Journal of Environmental Agriculture
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    • v.37 no.4
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    • pp.317-323
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    • 2018
  • BACKGROUND: This study was conducted to evaluate the water-dispersible clay content of paddy soils over the country in the summer rainy season as affected by cultivated years using heavy agro-machinery and soil properties such as texture and exchangeable sodium percentage. METHODS AND RESULTS: Water-dispersible clay content of 16 soil series of Korean paddy soils over the country were investigated in summer rainy season from July to August, 2006 by Middleton's method. Water-dispersible clay content ranged from non-detected to 4.8%, showing maximum value from the fine textured soils and high clay dispersibility in average from the coarse textured soils. Longer cultivated years using agro-machinery more than 40 hp result in higer water-dispersible clay content for 60% of studied paddy soils with less than 5% of exchangeable sodium percentage (ESP). Exceptionally, soils with relatively big difference of ESP at about 10 percent showed higher water-dispersible clay content with higher ESP. CONCLUSION: Long years of cultivation using agro-machinery with more than 40 hp enhanced water-dispersiblility of clay in approximately 60% of the studied paddy fields except for salt-affected soils.

Influence of Varying Degree of Salinity-Sodicity Stress on Enzyme Activities and Bacterial Populations of Coastal Soils of Yellow Sea, South Korea

  • Siddikee, Md. Ashaduzzaman;Tipayno, Sherlyn C.;Kim, Ki-Yoon;Chung, Jong-Bae;Sa, Tong-Min
    • Journal of Microbiology and Biotechnology
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    • v.21 no.4
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    • pp.341-346
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    • 2011
  • To study the effects of salinity-sodicity on bacterial population and enzyme activities, soil samples were collected from the Bay of Yellow Sea, Incheon, South Korea. In the soils nearest to the coastline, pH, electrical conductivity ($EC_e$), sodium adsorption ratio (SAR), and exchangeable sodium percentage (ESP) were greater than the criteria of saline-sodic soil, and soils collected from sites 1.5-2 km away from the coastline were not substantially affected by the intrusion and spray of seawater. Halotolerant bacteria showed similar trends, whereas non-tolerant bacteria and enzymatic activities had opposite trends. Significant positive correlations were found between EC, exchangeable $Na^+$, and pH with SAR and ESP. In contrast, $EC_e$, SAR, ESP, and exchangeable $Na^+$ exhibited significant negative correlations with bacterial populations and enzyme activities. The results of this study indicate that the soil chemical variables related with salinity-sodicity are significantly related with the sampling distance from the coastline and are the key stress factors, which greatly affect microbial and biochemical properties.

Soil Properties of Reclaimed Tidel Lands and Tidelands of Western Sea Coast in Korea (우리나라 서해안 간척지 및 간석지 토양의 이화학적 특성)

  • Koo, Ja-Woong;Choi, Jin-Kyu;Son, Jae-Gwon
    • 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.

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Vegetation and Soil Properties of Scrophularia takesimensis Population in Ulleung Island (울릉도 섬현삼(Scrophularia takesimensis Nakai) 개체군의 식생과 토양특성)

  • Han, Kyeong-Suk;Kim, Mu-Yeol;Suh, Gang-Uk;Kwon, Hye-Jin;Song, Ho-Kyung
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.13 no.1
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    • pp.24-31
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    • 2010
  • This study was carried out to analyze vegetation and soil characteristic, and ordination of Scrophularia takesimensis population, Ulleung Island. The Scrophularia takesimensis population was classified into Aster spathulifolius for. oharai dominant population, Vitis amurensis dominant population and Scrophularia takesimensis typical population. The Scrophularia takesimensis population was located in elevation of 1m to 6m, in Ulleung Island. In the study sites, soil organic matter, nitrogen, available phosphorous, exchangeable potassium, exchangeable calcium, exchangeable magnesium and exchangeable sodium concentration, and cation exchange capacity, and soil pH were 9.1~19.1%, 0.19~0.52%, 87.1~196.7mg/kg, 2.0~2.8cmol+/kg, 5.4~5.9cmol+/kg, 5.9~8.8cmol+/kg, 4.4~4.8cmol+/kg, 20.3~26.7cmol+/kg, and 6.8~8.0, respectively. The Vitis amurensis dominant population was mainly found in the high percentage of total nitrogen, organic matter, CEC in comparison with Aster spathulifolius for. oharai dominant population.

Changes of Hydraulic Conductivity During Desalmization of Reclaimed Tidelands (간척지 토양의 제염과정중 수리전도도의 변화)

  • 구자웅;은종호
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.30 no.4
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    • pp.85-93
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    • 1988
  • This laboratory study was carried out in order to produce fundamental data for analyzing salt movement and desalinization effects, using samples of silt loam soil collected in Gyehwado and Daeho reclaimed tidelans, and samples of silty clay loam soil collected in Kimie tideland. Desalinization experiments with gypsum treatment were performed to analyze changes of the hydraulicc conductivity with changes of the soil property and the salt concentration during the desalinization of reclaimed tideland soils by leaching through the subsufface drainage, and correlations between factors infl uencing the reclamation of salt affected soils were analyzed by the statistical method. The results were summarized as follows: 1. The reclaimed tideland soils used in this study were saline-sodic soils with the high exchangeable sodium percentage and the high electrical conductivity. 2. Changes of the hydraulic conductivity with the amount of leaching water and the leaching time elapsed were affected by the amount of gypsum except exchangeable sodium and clay contents. The regression equation between the depth of water leached per unit depth of soil (Dw / Ds : X) or the square root of the leaching time elapsed (T $^1$ $^2$ : X) and the relative hydraulic conductivity (HCr:Y) could be expressed in Y=a . bx. 3. The more exchangeable sodium and clay contents regardless of the amount of gypsum, the more the leaching time was required until a given volume of water was leached through the soil profile. The regression analysis showed that the relationship between the depth of water leached per unit depth of soil(Dw /Ds:X) and the square root of the leaching time elapsed(T$^1$$^2$ :Y) could be described by Y=a . Xb. 4. The hydraulic conductivity was influenced to a major degree by the salt concentration provided that the electrical conductivity was below 10 mmhos / cm during the desalinization of reclaimed tideland soils. The regression equation between the relative electrical conductivity ( ECr : X) and the relative hydraulic conductivity (HCr:Y) could be expressed in Y=a + b . X-$^1$. 5. In conclusion, the hydraulic conductivity, leaching requirements and the leaching time elapsed can be estimated when the salt concentration decreases to a certain level during the desalinization of reclaimed tidelands, and the results may be applied to the analysis of salt movement and desalinization effects.

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Analysis of Exchangeable Sodium Percentage During Desalinization of Reclaimed Tidal Lands (간척지 토양의 제염과정 중 교환성 나트륨 백분율 분석)

  • Koo Ja Woong;Choi Jin Kyu;Son Jae Gwon
    • KCID journal
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    • v.8 no.1
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    • pp.48-60
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    • 2001
  • This study was performed in order to produce the basic data for the estimation of water requirements for desalinization and developing prediction techniques of desalinization to be applicable in the beginning of tidal land reclamation through analyzing ch

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