Causes of Soil Salinization, Sodification, and Alkalinization

2017 ◽  
Author(s):  
Elisabeth N. Bui
Keyword(s):  
Ion Exchange ◽  
Driving Forces ◽  
Water Movement ◽  
Soil Salinization ◽  
Natural Soil ◽  
Sodic Soils ◽  
Mineral Equilibria ◽  
Evaporative Concentration ◽  
Soluble Ions ◽  
Alkaline Conditions

Driving forces for natural soil salinity and alkalinity are climate, rock weathering, ion exchange, and mineral equilibria reactions that ultimately control the chemical composition of soil and water. The major weathering reactions that produce soluble ions are tabled. Where evapotranspiration is greater than precipitation, downward water movement is insufficient to leach solutes out of the soil profile and salts can precipitate. Microbes involved in organic matter mineralization and thus the carbon, nitrogen, and sulfur biogeochemical cycles are also implicated. Seasonal contrast and evaporative concentration during dry periods accelerate short-term oxidation-reduction reactions and local and regional accumulation of carbonate and sulfur minerals. The presence of salts and alkaline conditions, together with the occurrence of drought and seasonal waterlogging, creates some of the most extreme soil environments where only specially adapted organisms are able to survive. Sodic soils are alkaline, rich in sodium carbonates, with an exchange complex dominated by sodium ions. Such sodic soils, when low in other salts, exhibit dispersive behavior, and they are difficult to manage for cropping. Maintaining the productivity of sodic soils requires control of the flocculation-dispersion behavior of the soil. Poor land management can also lead to anthropogenically induced secondary salinity. New developments in physical chemistry are providing insights into ion exchange and how it controls flocculation-dispersion in soil. New water and solute transport models are enabling better options of remediation of saline and/or sodic soils.

scholarly journals Physiological and Biochemical Responses of Jerusalem Artichoke Seedlings to Mixed Salt-Alkali Stress Conditions

2015 ◽  
Vol 43 (2) ◽  
pp. 473-478 ◽  
Author(s):  
Shuai SHAO ◽  
Mingming QI ◽  
Shuang TAO ◽  
Jixiang LIN ◽  
Yingnan WANG ◽  
...  
Keyword(s):  
Seedling Growth ◽  
Jerusalem Artichoke ◽  
Soil Salinization ◽  
Stress Conditions ◽  
Energy Crop ◽  
Alkaline Stress ◽  
Alkali Stress ◽  
Mixed Salt ◽  
Effective Utilization ◽  
Alkaline Conditions

Soil salinization and alkalization frequently co-occur in the grassland, but little information exists concerning the mixed effects of salt-alkaline stress on plant. Jerusalem artichoke is an economically and ecologically important energy crop and also considered as a salt-tolerant species. In this study, we investigated the effects of 12 mixed salt-alkaline conditions on the seedling growth and responses of Jerusalem artichoke to such conditions. The results showed that the seedling growth decreased with the increasing salinity and pH, and the destructive effects were more markedly under the interactions of highest salinity and pH. The Na+, Mg2+ and Ca2+ concentrations were all increased with the increasing salinity and pH, but the K+ kept stable. The Cl- concentration increased when the treatment without alkali salts, and the NO3– and H2PO4- concentrations were decreased with the increasing salinity. Jerusalem artichoke seedlings enhanced organic acids and proline to supply the shortage of inorganic anions and cope with osmotic stress from the high Na+ concentration. Above results show that the toxicity effects of the interactions of salt stress and alkali stress on plant is much greater than that only salt or alkali stress. A better understanding of the seedlings of Jerusalem artichoke under mixed salt-alkali stress conditions should facilitate the effective utilization of this species under such complex environment in Northeast China.

scholarly journals Sources and controls of calcium and magnesium in storm runoff: the role of groundwater and ion exchange reactions along water flowpaths

1997 ◽  
Vol 1 (3) ◽  
pp. 671-685 ◽  
Author(s):  
P. J. Chapman ◽  
B. Reynolds ◽  
H. S. Wheater
Keyword(s):  
Ion Exchange ◽  
Overland Flow ◽  
Divalent Cations ◽  
Stream Water ◽  
Storm Runoff ◽  
Natural Soil ◽  
Exchange Reactions ◽  
Mineral Horizon ◽  
Relative Contribution ◽  
Pipe Water

Abstract. A combined hydrological and chemical investigation was undertaken in a small moorland catchment at Plynlimon to determine the processes controlling storm runoff chemistry. Flow from natural soil pipes, overland flow from peat soils, throughflow from a mineral horizon and streamflow were gauged and sampled intensively during seven storms. Stormflow Ca and Mg concentrations in stream water consistently exceeded those observed in overland flow, pipeflow and throughflow. The response of Ca and Mg to increases in streamflow varied between the storms and could not be explained readily by the mixing of the dominant source waters monitored within the catchment. Intensive sampling of pipe water along a major stormflow pathway revealed a large and consistent increase in the concentration of dissolved Ca and Mg accompanied by a corresponding decrease in acidity, the magnitude of which was strongly influenced by antecedent conditions. Analyses of soil exchangeable cations along the stormflow pathway revealed soils enriched in divalent cations probably derived from a groundwater source. Laboratory leaching experiments confirmed that rapid cation exchange reactions could explain the changes in pipe water chemistry along the stormflow pathway. The relative contribution of flow from pathways where these ion exchange reactions occur strongly influences the stormflow response of Ca and Mg in the stream. The results also highlight a potentially important, indirect role for base-rich groundwater in modifying storm runoff chemistry along water flowpaths.

scholarly journals Predicted Infiltration for Sodic/Saline Soils from Reclaimed Coastal Areas: Sensitivity to Model Parameters

2014 ◽  
Vol 2014 ◽  
pp. 1-12
Author(s):  
Dongdong Liu ◽  
Dongli She ◽  
Shuang’en Yu ◽  
Guangcheng Shao ◽  
Dan Chen
Keyword(s):  
Water Movement ◽  
Soil Surface ◽  
Coastal Areas ◽  
Model Parameters ◽  
Wetting Front ◽  
Sodic Soils ◽  
Infiltration Process ◽  
Infiltration Model ◽  
Soil Physical Quality ◽  
Cumulative Infiltration

This study was conducted to assess the influences of soil surface conditions and initial soil water content on water movement in unsaturated sodic soils of reclaimed coastal areas. Data was collected from column experiments in which two soils from a Chinese coastal area reclaimed in 2007 (Soil A, saline) and 1960 (Soil B, nonsaline) were used, with bulk densities of 1.4 or 1.5 g/cm3. A 1D-infiltration model was created using a finite difference method and its sensitivity to hydraulic related parameters was tested. The model well simulated the measured data. The results revealed that soil compaction notably affected the water retention of both soils. Model simulations showed that increasing the ponded water depth had little effect on the infiltration process, since the increases in cumulative infiltration and wetting front advancement rate were small. However, the wetting front advancement rate increased and the cumulative infiltration decreased to a greater extent whenθ0was increased. Soil physical quality was described better by theSparameter than by the saturated hydraulic conductivity since the latter was also affected by the physical chemical effects on clay swelling occurring in the presence of different levels of electrolytes in the soil solutions of the two soils.

Classification and Mitigation of Soil Salinization

2017 ◽  
Author(s):  
Tibor Tóth
Keyword(s):  
Soil Salinity ◽  
Soil Classification ◽  
Soil Salinization ◽  
Classification Systems ◽  
Salt Accumulation ◽  
Soil Taxonomy ◽  
Sodic Soils ◽  
Water Rates ◽  
Irrigated Lands ◽  
The Right

Soil salinity has been causing problems for agriculturists for millennia, primarily in irrigated lands. The importance of salinity issues is increasing, since large areas are affected by irrigation-induced salt accumulation. A wide knowledge base has been collected to better understand the major processes of salt accumulation and choose the right method of mitigation. There are two major types of soil salinity that are distinguished because of different properties and mitigation requirements. The first is caused mostly by the large salt concentration and is called saline soil, typically corresponding to Solonchak soils. The second is caused mainly by the dominance of sodium in the soil solution or on the soil exchange complex. This latter type is called “sodic” soil, corresponding to Solonetz soils. Saline soils have homogeneous soil profiles with relatively good soil structure, and their appropriate mitigation measure is leaching. Naturally sodic soils have markedly different horizons and unfavorable physical properties, such as low permeability, swelling, plasticity when wet, and hardness when dry, and their limitation for agriculture is mitigated typically by applying gypsum. Salinity and sodicity need to be chemically quantified before deciding on the proper management strategy. The most complex management and mitigation of salinized irrigated lands involves modern engineering including calculations of irrigation water rates and reclamation materials, provisions for drainage, and drainage disposal. Mapping-oriented soil classification was developed for naturally saline and sodic soils and inherited the first soil categories introduced more than a century ago, such as Solonchak and Solonetz in most of the total of 24 soil classification systems used currently. USDA Soil Taxonomy is one exception, which uses names composed of formative elements.

Driving forces for sodium removal during phytoremediation of calcareous sodic and saline-sodic soils: a review

2006 ◽  
Vol 21 (2) ◽  
pp. 173-180 ◽  
Author(s):  
M. Qadir ◽  
A.D. Noble ◽  
J.D. Oster ◽  
S. Schubert ◽  
A. Ghafoor
Keyword(s):  
Driving Forces ◽  
Sodic Soils ◽  
Sodium Removal

scholarly journals DESERTIFICATION AND LAND DEGRADATION IN KAZAKHSTAN

THE BULLETIN ◽  
2020 ◽  
Vol 5 (387) ◽  
pp. 95-102
Author(s):  
G. Issanova ◽  
◽  
A. Saduakhas ◽  
J. Abuduwaili ◽  
K. Tynybayeva ◽  
...  
Keyword(s):  
Land Degradation ◽  
Soil Degradation ◽  
Water Shortage ◽  
Significant Degree ◽  
Soil Salinization ◽  
Aral Sea ◽  
Current Status ◽  
Anthropogenic Factors ◽  
Natural Soil ◽  
Carbonate Content

Desertification and land degradation are common processes in arid and semi-arid regions of Kazakhstan, especially southern parts, where areas are covered by a great variety of desert types. In deserts, soil-forming processes take place in conditions of severe water shortage, and high level of soil degradation and desertification. The main natural factors for these processes are a flat terrain, a high degree of arid climate, soil salinity, carbonate content, a lack of structure and low natural soil fertility. However, the anthropogenic factors of desertification and soil degradation became dominant last decades. The study considers the actual problems of natural and anthropogenic factors of desertification and land degradation within Kazakhstan. The desertification of huge territories is accompanied by soil contamination, waterlogging by surface water and groundwater, soil salinization, erosion (water, wind), degradation of vegetation cover, dehumidification and a decrease in general regional biological capacity. Analysis of the current status of the soil cover has shown intensive land degradation 43 % of the territory of Kazakhstan is subjected to degradation in significant degree; over 14 % of pastures have reached an extreme degree of degradation or are completely degradated. The Aral Sea region, Northern Caspian Sea and Southern Balkhash deserts can be observed as areas of intensive soil desertification, salinization and deflation processes. As well as the desertification process are progressing in the irrigated soils of the deltas of Syrdarya, Shu, Ile and Karatal rivers.

scholarly journals Delineating reclamation zones for site-specific reclamation of saline-sodic soils in Dushak, Turkmenistan

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256355
Author(s):  
Elif Günal
Keyword(s):  
Soil Salinity ◽  
Land Development ◽  
Soil Salinization ◽  
Accurate Information ◽  
Soil Reaction ◽  
Target Area ◽  
Sodic Soils ◽  
Spatial Trend ◽  
Soil Layers ◽  
Best Management

Soil salinization is the widespread problem seriously affecting the agricultural sustainability and causing income losses in arid regions. The major objective of the study was to quantify and map the spatial variability of soil salinity and sodicity. Determining salinity and sodicity variability in different soil layers was the second objective. Finally, proposing an approach for delineating different salinity and sodicity zones was the third objective. The study was carried out in 871.1 ha farmland in Southeast of Dushak town of Ahal Province, Turkmenistan. Soil properties, including electrical conductivity (EC), soil reaction (pH), sodium adsorption ratio (SAR), calcium carbonate and particle size distribution (clay, silt and sand fractions) in 0–30, 30–60, 60–90 and 90–120 cm soil layers were recorded. The EC values in different soil layers indicated serious soil salinization problem in the study area. The mean EC values in 0–90 cm depth were high (8 dS m-1), classifying the soils as moderate to strongly saline. Spatial dependence calculated by the nugget to sill ratio indicated a strong spatial autocorrelation. The elevation was the primary factor affecting spatial variation of soil salinity in the study area. The reclamation of the field can be planned based on three distinct areas, i.e., high (≥12 dS m-1), moderate (12–8 dS m-1) and low (<8 dS m-1) EC values. The spatial trend analyses of SAR values revealed similar patterns for EC and pH; both of which gradually decreased from north to the south-west. The amount of water needed to leach down the salts from 60 cm of soil profile is between 56.4–150.0 ton ha-1 and the average leaching water was 89.8 tons ha-1. The application of leaching water based on the amount of average leaching water will result in higher or lower leaching water application to most locations and the efficiency of the reclamation efforts will be low. Similar results were recorded for sulfur, sulfuric acid and gypsum requirements to remediate sodicity. The results concluded that the best management strategy in planning land development and reclamation schemes for saline and sodic soils require accurate information about the spatial distribution of salinity and sodicity across the target area.

Relationships between Ion and Water Movement in the Human Jejunum, Ileum and Colon during Perfusion with Bile Acids

1973 ◽  
Vol 45 (5) ◽  
pp. 593-606 ◽  
Author(s):  
D. L. Wingate ◽  
E. Krag ◽  
H. S. Mekhjian ◽  
S. F. Phillips
Keyword(s):  
Ion Exchange ◽  
Bile Acids ◽  
Water Movement ◽  
Human Colon ◽  
Bulk Flow ◽  
Mucosal Cell ◽  
Slight Variation ◽  
Low Concentrations ◽  
Net Flux ◽  
Lower Magnitude

1. Perfusion of the human jejunum with low concentrations of glycine-conjugated bile acids in physiological solutions induced net fluid flow that varied between absorption and secretion, with only slight variation of the luminal osmotic and ionic milieu. 2. Transmucosal net flux rates for water and the principal ions were calculated. Regression analysis of the flux data was consistent with the concept of a ‘net transported fluid’ which was iso-osmotic with respect to the lumen, with a superimposed fixed net anion exchange unaffected by the rate or direction of bulk flow. 3. Recalculation of earlier data from comparable studies of the human colon showed similar relationships consistent with varying iso-osmotic bulk flow and fixed ion exchange, the latter differing from that found in the proximal bowel. 4. Studies were performed also in the human ileum. Variable iso-osmotic bulk flow was again encountered, but ion exchange was of a lower magnitude than in the jejunum or colon. Qualitatively, ion exchange in the ileum was intermediate between the jejunum and colon. 5. These analyses suggest that transmucosal bulk flow and ion exchange may be quantitatively and spatially independent processes. They provide support for the hypothesis that bulk flow may be intercellular (and hence extracellular), while ion exchange may take place across the luminal face of the mucosal cell. 6. Secretory agents, such as the dihydroxy bile acids, provide a useful means of analysing solute-solvent flow relationships in greatly differing bulk flow conditions with relatively stable physicochemical parameters.

scholarly journals Calculation of optimal flow of ionite during water treatment in the column of continuous action

2020 ◽  
Vol 161 ◽  
pp. 01084
Author(s):  
Alexander Golovanchikov ◽  
Olga Zalipaeva ◽  
Tatiana Sinenko ◽  
Natalia Shibitova ◽  
Natalia Prokhorenko ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Ion Exchange ◽  
Driving Forces ◽  
Working Capital ◽  
Longitudinal Diffusion ◽  
Capital Costs ◽  
Exchange Column ◽  
Displacement Mode ◽  
Sodium Cations ◽  
Ion Exchange Column

In the article an algorithm for calculating the continuous ion exchange column is proposed. By analogy with the calculation of the optimal phlegm number of the rectification column this algorithm takes into consideration depreciation charges for capital costs associated with the size of the column and working capital associated with the consumption of ionite and its regeneration. This algorithm can be used to calculate depreciation charges for capital costs related to column sizes and working capital regarded to ionite consumption and regeneration. Examples of ionite consumption calculation at typical and proposed algorithms of calculation and technological and geometric parameters used in column of water purification from sodium cations are given. Thus, in a typical calculation, when the water being purified from sodium cations moves in the ideal displacement mode and the excess of ionite is 1% of its minimum consumption. The optimal ionite consumption corresponding to the minimum of capital costs and working capital, which requires an increase in the ionite consumption by 5.6% of its minimum consumption. In this case the cost of ion exchange increases by 4.5%. It confirms the recommendations for industrial operation and design of ion exchange columns and increases the minimum ionite consumption by 1÷10%. The continuous ion exchange column was calculated including the longitudinal diffusion. Necessity of the further increase of the ionite consumption with regard to the longitudinal diffusion is shown. In the article an example of the ion exchange process calculation in comparison with the typical one, when the displacement mode for the treated water is ideal, is given. Similar equations for the dependences of the concentration of extracted ions in the purified solution and ionite granules are proposed if the equilibrium dependence is described by a linear equation. The working line is dependent on the concentration of the extracted ions in an ionite and on their concentration in the purified water, first, because of a jump in concentration at the inlet and a concave shape of the working line (the latter is usually a straight one in case of the mass-transfer processes) reduces the local and average driving forces of mass-transfer process significantly. It leads to increasing of the moving layer height of the ion exchanger in the column 2 times, and can lead to crossing the line of equilibrium by reducing the concentration jump at the entrance. Consequently, it is necessary to increase ionite consumption by more than 18% compared to its minimum consumption.

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