Soil Salinization

12 Key excerpts on "Soil Salinization"

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  eBook - ePub

  Soils as a Key Component of the Critical Zone 5

  Degradation and Rehabilitation

  • Christian Valentin(Author)
  • 2018(Publication Date)
  • Wiley-ISTE

    (Publisher)

  5 Soil Salinization and Management of Salty Soils

  5.1. Introduction

  The term salinization defines a process of accumulation or enrichment of salts (from the Latin sal), which is expressed in all terrestrial, aquatic and atmospheric environments, especially in the soil, a very particular three-phase (solid–aqueous–gaseous) natural object. Salinization occurs either naturally in surface waters (rivers, lakes), groundwater, dry environments, soils and wetlands, or artificially in soils and waters during anthropogenic activities (irrigation and soil fertilization, domestic and industrial waste, etc.).

  5.2. Natural salty environments

  5.2.1. Salts, dissolved particulate entities

  Salts are defined in several ways depending on the chosen context. For a chemist, salt is essentially the product of the action of a strong acid and a strong base (neutralization) or a strong acid and a non-noble metal. For a geoscientist, salts define all minerals that can be formed by the concentration and combination of major ions (chloride, sulfate and carbonate for anions; calcium, magnesium, sodium and potassium for cations). Minor or trace ions may be associated (borate, nitrate, phosphate, heavy metals). The pedologist specialized in salty soil will only consider salts that are more soluble than hydrated calcium sulfate (gypsum in gypsum soils) and calcium and/or magnesium carbonates (calcite, dolomite in calcareous soils). These include sodium chloride (halite), better known to humans as “table salt”. It is ingested daily to satisfy their physiological needs in the same way as other living beings, whether it be animals or plants [FLO 05, PAY 16].

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  Agroecological Approaches for Sustainable Soil Management

  • Majeti Narasimha Vara Prasad, Chitranjan Kumar(Authors)
  • 2023(Publication Date)
  • Wiley

    (Publisher)

  2020 ). Meanwhile, degraded soils stretch up to 6 billion ha worldwide (Ayub et al. 2020). The countries affected by salinization are in the arid and semi‐arid regions of North Africa, the Near East, the former Soviet Union, and Central Asia. They are also widespread in India, Iran, Iraq, Australia, and the Americas. Arid and semi‐arid areas cover approximately 46% of the terrestrial area in the world. In these climatic regions, approximately 50% of the irrigated areas have salinity problems at different levels. In the next 75 years, it is estimated that agricultural land will increase by only 10%, while the world population will double, and most of this increase will be in semi‐arid and arid regions of the world where salinity is very common. In response to the increasing population in the world, the area of agricultural lands is decreasing every year due to urbanization and industrialization. In addition, the increase in irrigated areas also increases the risk of salinization of soils in arid and semi‐arid areas. Salinization develops without feeling the salinity in over‐irrigated lands and is understood by the decrease in plant yield after certain stages. For this reason, the World Food and Agriculture Organization (FAO) has defined salinization as the “Silent Enemy.”

  There are three main sources of salts in soils. These are the salts produced by the disintegration of the minerals in the soil, the salts transferred from the atmosphere to the soil by precipitation, and the salts entering the soil from the ancient fossil‐based salt deposits in salty seas, lakes, and similar places. Soil salinity problems are further complicated where the groundwater is highly saline, especially near coastal region. The coastal region is likely to face severe challenges in the future due to rise in sea level resulting from global warming. Irrigation in arid and semi‐arid regions also causes salinization. With irrigation, the salt in the lower layers of the soil is carried up by capillarity during evaporation and accumulates in the root zone of the plant. Excessive irrigation, use of poor‐quality irrigation water, inadequate drainage systems, accumulation of soluble salts in soil water and especially in the upper soil layers in contact with the sun are among the other causes of salinization (Epstein et al. 1980 ). Natural or anthropogenic factors leading to salinity in soil are given in Figure 14.1 .

  Figure 14.1

  Salinization factors.

  The most influential human‐induced factors are land use, farming systems, land management, and land degradation. Inappropriate irrigation practices (such as the use of salt‐rich irrigation water) and insufficient drainage both cause salinization. Due to the close relationship between climate and agriculture, climate change also has an impact on the salinization of soils. Both precipitation and temperature will change as a result of climate change and affect agriculture soils. Coastal agriculture will also face added impacts from sea‐level rise, inundation, seawater intrusion, rising salinity, storm surges, tropical cyclones, and flooding (Gopalakrishnan et al. 2019

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  Climate Change and Soil Interactions

  • Majeti Narasimha Var Prasad, Marcin Pietrzykowski, Majeti Narasimha Vara Prasad(Authors)
  • 2020(Publication Date)
  • Elsevier

    (Publisher)

  Climate is one of the most important factors affecting the formation of soil with important implications for their development, use, and management. The principal climatic elements, which influence the soil formation are temperature, precipitation, and wind. Soils in warmer or wetter climates are more developed than soils in cooler or drier climates. There are feedback relationships between soils and climate. Soil biological processes affect the concentration of greenhouse gases in the atmosphere while greenhouse gases represent a significant regulator of the climate. In the last 150–200 years, the changing temperature regime resulted in considerable changes in the precipitation pattern. A changing climate also caused considerable changes in natural vegetation, soil properties, and land-use practices. The affecting soil properties depending on changing climate conditions are the soil temperature, the composition of soil gases, the biological parameters of the soil, the character of litter horizon, the intensity of cryoturbation phenomena, the salt content, the soil organic matter content, etc. These soil properties may change significantly within the time span from several years to several decades. Changing climate conditions determined by global warming and an increase in aridity will contribute to the salinization of the hydromorphic soils. The areas most prone to soil desertification and salinization are arid regions. Salinization is the accumulation of water-soluble salts in the soil solum. In the early stages, salinity affects the metabolism of soil organisms and reduces soil productivity, but in advanced stages it destroys all vegetation and other organisms living in the soil, consequently transforming fertile and productive land into barren and desertified lands. Water and soil salinity is likely to be increased in parallel with the temperatures; consequently, irrigation demand will be increased dramatically.

  Keywords

  Soil properties; soil gases; biological parameters; land-use practices

  Chapter Outline

  Outline

  • 12.1 The Formation and Importance of Soil 331
  • 12.2 The Impact of Agricultural Activities on Climate Change 333
  • 12.3 Climate Change and Its Effects on Salinization 335
  • 12.4 Salinization and Alkalization 337
  • 12.5 Salinity and Alkalinity Problem in the World 339
  • 12.6 Salinity and Alkalinity in Turkey 340
  • 12.7 What are the Risks of Soil Salinity and Alkalinity? 342
  • 12.8 Management of Saline and Alkaline Soils and Plant Production in These Soils 343
  • 12.9 Conclusion 348
  • References 349

  12.1 The Formation and Importance of Soil

  The earth, one of our most important natural resources, consists of minerals, air, water, organic matter, and countless creatures and is formed at the intersection of atmosphere, hydrosphere, biosphere, and lithosphere, which are the four layers surrounding our blue planet. The soil that covers the earth like a crust is an absolutely necessary ingredient for life that cannot be substituted. Human beings are dependent on soil for their survival. Although the relationship between men and soil has become more visible since human beings formed permanent settlements, it has actually started from the moment human beings started to exist. Soil is an object explored by other branches of science as well as being the focus of many areas such as art, economics, philosophy, health, industry, law, and literature, and it has always been discussed. Soil is an environment with a multifaceted perspective, and it responds to the needs of different professions.

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  Geospatial Technologies for Land Degradation Assessment and Management

  • R. S. Dwivedi(Author)
  • 2018(Publication Date)
  • CRC Press

    (Publisher)

  8

  Soil Salinization and Alkalinization

  Coauthored by Dr. Jamshid Fareftih Faculty of Bioscience Engineering, Department of Biosystems, Katholieke Universiteit Leuven, Heverlee, Belgium

  8.1 Introduction

  Soil Salinization/alkalinization is one of the major factors affecting biomass production (Csillag et al., 1993). Salt-affected soils (saline/alkali) occur mostly in arid and semiarid regions, but may also be found in subhumid and coastal zones. Salt-affected soils are highly erosive, and have poor structure, low fertility, low microbial activity, which are not conducive for plant growth. Salt concentration in the soil environment has a strong impact on crop yield and agricultural production due to poor land and water management and expansion of agricultural frontiers into marginal dry lands. Crop productivity and production losses have considerable impact on-farm and agricultural economies. For instance, the economic damage caused by secondary salinization was estimated at US$750 million per year for the Colorado River Basin in the United States of America, US$300 million per year for Punjab, and Northwest Frontier Provinces in Pakistan, and US$208 million per year for the Murray–Darling Basin in Australia (Ghassemi et al., 1995).

  Salt-affected soils contain excessive concentrations of either soluble salts or exchangeable sodium, or both. The process by which soluble salts are accumulated at the surface or near-surface of soil horizon is called salinization (Szabolcs, 1974). The build-up soluble salts in soils produce harmful effects to plants by increasing the salt content of the soil solution and by increasing the degree of saturation of the exchange materials in the soil with exchangeable sodium (US Salinity Laboratory Staff, 1954). The dominant salts in salt-affected soils consist of chlorides and sulfates of Na, Ca, and Mg. In terms of agricultural consequences, excessive salts in soil accelerate land degradation processes and increase the impact on crop yields and agricultural production. Additionally, the increase of salts in soil also affects other major soil degradation phenomena (Figure 8.1

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  Soil Health and Land Use Management

  • Maria C. Hernandez-Soriano(Author)
  • 2012(Publication Date)
  • IntechOpen

    (Publisher)

  The most affected soils are situated in Hungary, Romania, Greece, Italy and the Iberian Peninsula (Agricultura…., 2011). About 8.1 million hectares are salinized in India, of which 3.1 million are in coastal regions (Triphati et al., 2007). In Nordic countries, the use of salt to remove ice from highways produces localized salinization phenomena (Agricultura…., 2011). Considering the increasing temperatures and decrease in pluviosity which have characterized climates in recent years, the salinization problem has increased. Salinization results from natural or anthropogenic factors, constituting a process of soil degradation which, in some cases, is responsible for irreparable losses in their productive capacity, with great extensions of arable land becoming sterile. 2.1 Natural Soil Salinization and sodification factors The natural factors influencing soil salinity are: • geological phenomena which increase the salts concentration in groundwater and consequently in the soil; • natural factors capable of bringing groundwater containing elevated salt contents to the surface; • infiltration of groundwater in below sea-level zones (micro-depressions with reduced or absent drainage); • drainage of waters from zones with geological substrates capable of liberating large amounts of salts; • action of winds, which, in coastal zones, can transport moderate amounts of salts to the interior. The weathering of primary minerals (which make up the rocks or the original soil material) is the indirect source of nearly all the salts present in soils, although there are only a few cases in which this results in sufficient accumulation of salt (primary or pedogenetic salinization) to form saline soils.

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  Soil

  Fragile Interface

  • P Stengel, Sandrine Gelin(Authors)
  • 2003(Publication Date)
  • CRC Press

    (Publisher)

  Salinisation is therefore one of the most significant indicators of poor management in rural areas by human beings. Alkalinisation Salinisation Sodisation Glossary Increase in pH level of a soil subsequent to accumulation in it of salts such as sodium carbonate. Accumulation in soils of highly soluble salts, chlorides and sulphates of sodium or, in particular, of magnesium. This accumulation hampers development of plants that find it more difficult to draw the water they need because of a change in osmotic potential of the soil water. Fixation of sodium on the adsorption complex of soils. Sodisation is often observed by a degradation in the physical properties of particular soils (for example, tendency of the soil to become impermeable). R eferences A1 Droubi A. 1976. Geochimie des sels et des solutions concentrees par evaporation. Modele thermodynamique de simulation. Application aux sols sales du Tchad. Sciences Geologiques, Memoire, 46. Strasbourg, 177 pp. A1 Droubi A, Cheverry C, Fritz B, Tardy Y. 1976. Geochimie des eaux et des sels dans les sols des polders du lac Tchad: application d'un modele thermodynamique de simulation de l'evaporation. Chemical Geology 17: 165-177. 148 Consequences of Exploitation of Soils by Man AJ Droubi A, Fritz B, Gac JY, Tardy Y. 1980. G eneralized residual alkalinity concept; application to prediction of the chem ical evolution of natural w aters by evaporation. Airier. J. Sci., 280: 560-572. Bernstein L. 1975. Effects of salinity and sodicity on plant grow th. Annu. Rev. Phytopathol. 13:295-312. Bertrand R, N 'D iaye M, Keita B. 1994. L 'alcalin isation /sod isation , un danger pour les perim etres irrigues saheliens. Secheresse 3: 161-171. Borlaug ME, Dowsweil CR. 1994. Feeding a human population that increasingly crow ds a fragile plant. 15th W orld C ongress of Soil Science, A capulco (M exico), July 1994.

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  Soil Remediation

  Applications and New Technologies

  • Jose T. V. S. de Albergaria, Hendrikus P. A. Nouws, Jose T. V. S. de Albergaria, Hendrikus P. A. Nouws(Authors)
  • 2016(Publication Date)
  • CRC Press

    (Publisher)

  3 CIIMAR, University of Porto, Rua dos Bragas 289, 4050-123 Porto, Portugal. * Corresponding author: [email protected] 150 Soil Remediation: Applications and New Technologies Extent and Worldwide Distribution of Soil Salinization Soil Salinization can be described as the excess of salts and/or of sodium ions, either in the soil solution or in its cation exchange sites (Qadir et al. 2000). The main causes for this accumulation of salts in the soil profile derives from natural events (geological deposition, saline groundwater) or is anthropogenically formed or is enhanced by degradation processes. These include loss of vegetative cover, poor irrigation schemes, saline wastewater, saline intrusion due to aquifer overexploitation, etc. A saline soil is characterized by an electrical conductivity of the saturated soil paste (ECe) above 4 dS m –1 and a sodium adsorption ratio (SAR) below 13. A sodic soil, on the other hand, is characterized by an ECe under 4 dS m –1 and a SAR above 13. A saline-sodic soil is a combination of the previous ones with an ECe above 4 dS m –1 as well as a SAR above 13 (US Soil Salinity Laboratory Staff 1954; Qadir et al. 2000). Soil Salinization affects several continents (Table 1) and over 100 different countries, having a conservatively estimated impact of 12 billion dollars per year worldwide (Pitman and Läuchli 2004). While it is estimated that food production needs to be increased by 50% by the year 2050 (Rengasamy 2006), at the same time the area available for agriculture expansion is limited due to salinization and other problems. Recovering areas not suited for agriculture such as salt affected soils, may be essential for sustainable development. Asia is the continent (particularly Central Asia) with the highest area occupied by saline and sodic soils (Table 1), a result of a combination of intense irrigation schemes and arid and semi-arid climate that is dominant in the region.

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  Soil Chemistry

  • Daniel G. Strawn, Hinrich L. Bohn, George A. O'Connor(Authors)
  • 2019(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  13 SALT‐AFFECTED SOILS

  13.1 Introduction

  Salt‐affected soils are common in arid and semiarid regions, where annual precipitation is insufficient to meet the evapotranspiration needs of plants and to prevent salt buildup (salinization). “Making the desert bloom” has been a dream for many generations. Salt problems, however, are not restricted to arid or semiarid regions; under some conditions, soil salinity can develop in subhumid and humid regions. Salt accumulation in soils is detrimental to plant growth, and thus management of salt affected soils is necessary.

  Sustainability in growing crops in arid regions requires that adequate drainage to remove accumulated salts is provided. Drainage is costly and requires water use in excess of what is required for the plant growth. Correctly managing soil salinity requires understanding soil chemical processes related to soil and irrigation water salinity so that the amount of water needed for drainage to prevent salinization can be minimized.

  13.2 Distribution and origin of salt‐affected soils

  As much as 20% of all irrigated lands in the world (or approximately 45 million ha) may have irrigation‐induced soil salinity problems. In addition, vast areas of land have native salinity and limited arability. Salt buildup in soils is a problem in much of Australia and Africa, western United States, Middle East, north and central Asia, and western South America. Wherever there is a low amount of rainfall and limited availability of water for leaching salts out of the soils, salinization is a risk. Salt problems associated with greenhouse crops, mine spoils, and waste disposal further increase the amount of land that has salt problems.

  The three main natural sources of soil salinity are mineral weathering, atmospheric precipitation, and fossil salts (those remaining from former marine or lacustrine environments). The human activities that add salts to soil include irrigation and land application of saline industrial wastes. Seawater encroachment can also harm soils.

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  Recent Advances in Crop Physiology Vol. 2

  • Singh, Amrit Lal(Authors)
  • 2018(Publication Date)
  • Daya Publishing House

    (Publisher)

  A distinction can be made between primary and secondary salinisation processes. Primary salinisation involves accumulation of salts through natural processes due to high salt contents in parent materials or groundwater. Secondary salinisation is caused by human interventions such as inappropriate irrigation practices, e.g. with salt-rich irrigation water or insufficient drainage. This ebook is exclusively for this university only. Cannot be resold/distributed. The state-wise distribution of salt affected soils in India is presented in Table 3.2. Mapping of salt affected soils of India by the NRSA and Associates, (1996) indicated occurrence of about 3.77 m ha of sodic soils in India, out of which about 1.77 m ha represents the sodic nature among the irrigated/unirrigated black soil region (Vertisols) occurring in Rajasthan, Gujarat, Madhya Pradesh, Maharashtra, Andhra Pradesh, Karnataka and Tamil Nadu states. 3.1 Saline Vertisols Saline soils contain excess neutral soluble salts like chlorides and sulphate of sodium, calcium and magnesium with ECe > 4 dS m –1 , pH <8.2 and ESP <15. Saline black soils due to their inherent physico-chemical properties, high clay content, low hydraulic conductivity and narrow workable moisture range are very difficult to manage. Osmotic effect of salt, toxic concentration of soluble ions like Na, Cl, B and reduced availability of essential nutrients due to competitive uptake affect plant growth in this type of soil. Excess salinity in these black soils results into delay germination, poor crop stand, stunted growth and reduced yield. Table 3.2: State-wise Extent of Salt Affected Soils in India (ha) This ebook is exclusively for this university only. Cannot be resold/distributed. 3.2 Sodic Vertisols The distinguishing characteristics of sodic soils are high ESP, electrical conductivity (ECe) less than 4 dS m –1 , pH more than 8.2 and presence of higher amount of carbonate and bicarbonates of sodium.

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  Soil Contamination

  Current Consequences and Further Solutions

  • Marcelo L. Larramendy, Sonia Soloneski, Marcelo L. Larramendy, Sonia Soloneski(Authors)
  • 2016(Publication Date)
  • IntechOpen

    (Publisher)

  Chapter 8 Soil Salinization and Mitigation Measures in Land Reclamation Regions Shiguo Xu, Yi Xu, Yanzhao Fu and Qi Wang Additional information is available at the end of the chapter http://dx.doi.org/10.5772/64720 Abstract Soil Salinization and underground structure erosion usually occur in land reclamation regions, especially under semi‐humid climate that annual evaporation is larger than annual rainfall in Northern China. Based on investigations into the status and trends of land reclamation soil along the Bohai Rim, China, this chapter summarizes the evolution of groundwater system and soil environment and analyzes the main reasons contribu‐ ting to these problems. Physical and mathematical models are established to simulate the mechanism of water‐salt migration in land reclamation regions. Results show that evapotranspiration and groundwater discharge during wet seasons are the main driving forces of status of Soil Salinization. It was pointed out that the key to soil salinity control in the reclamation region was by utilizing rainwater and flood resources to build a long‐ term leaching mechanism. Meanwhile, in order to rebuild and maintain a healthy and stable ecosystem in the reclaimed areas, it is necessary to design the structure of soil layers in advance, enhance the salt leaching process and plant vegetation according to the local conditions. Keywords: land reclamation, Soil Salinization, mechanism, environmental change, mitigation measures 1. Introduction Coastal regions are identified as productive and sensitive ecosystems with abundant biodi‐ versity. They are water bodies connected with both the land and the sea, and within which seawater mixes with inland freshwater discharge. Most of the megacities in the world are located in coastal regions, and more than 3 billion people which cover almost half of the world's population live along the coastline. The overloaded population increases the pressure on land © 2016 The Author(s).

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  Current Perspective on Irrigation and Drainage

  • Suren Kulshreshtha, Amin Elshorbagy, Suren Kulshreshtha, Amin Elshorbagy(Authors)
  • 2017(Publication Date)
  • IntechOpen

    (Publisher)

  Artificial drainage is always needed, except in cases with deep groundwater levels. In most river delta regions, drainage is a must to avoid water logging. This is not the only reason, because avoiding salinization is a recognized aim of drainage, as is illustrated in this chapter. Research on irrigation and drainage has been considerable and this is not surprising as irrigated agriculture has been practiced during the past 5000 years, e.g,. in Mesopotamia. Due to long-term changes, water availability for irrigation could decline or salinity problems could develop. The underlying cause for agricultural yield depressions upon salinization is that most terrestrial plants tolerate only a limited salinity of soil water. The term salinity is usually associated with concentrations of sodium chloride (NaCl), but may be interpreted more broadly as the presence of ions in water. Rainfall usually contains few ions, but agricultural fields are often irrigated with groundwater or surface water, where this is different. The salts that may give problems in agriculture may be derived from different sources: (i) water in contact with soil material induces physical and chemical weathering, which is associated with release of ions, of which the concentrations may be increased due to evapotranspiration; (ii) groundwater may be brackish or saline due to different geohydrological causes such as sea Figure 1. Distribution of dryland regions (from: Millenium Ecosystem Assessment, Chapter 22, 2005). Current Perspective on Irrigation and Drainage 2 water intrusion and the presence of old marine sediments; and (iii) use of river water with some level of salinity, originating from groundwater, sea, or industry. Salinity is often expressed as concentration (mass per volume of water), electrical conductivity (EC), or total dissolved solids (TDS).

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  Agricultural Drainage and Water Quality

  • Sharma, Premjit(Authors)
  • 2021(Publication Date)
  • Genetech

    (Publisher)

  Stability of soil aggregates prevents dispersion and formation of deposit crusts and infiltration can be maintained by application of small quantities of organic polyelectrolytes to the soil surface. They can be effective when introduced in the irrigation water or when sprayed over the soil surface. Mineral fertilisers : Salt accumulation affects nutrient content and availability for plants in one or more of the following ways: by changing the form in which the nutrients are present in the soil; by enhancing loss of nutrients from the soil through heavy leaching or, as in nitrogen, through denitrification, or by precipitation in soil; through the effects of non-nutrient (complementary) ions on nutrient uptake; and by adverse interactions between the salt present in saline water and fertilisers, decreasing fertiliser use efficiency. Crop response to fertiliser under saline or sodic conditions is complex since it is influenced by many soil, crop and environmental factors. The benefits expected from using soil management measures to facilitate the safe use of saline water for irrigation will not be realised unless adequate, but not excessive, plant nutrients are applied as fertilisers. The level of salinity may itself be altered by excess fertiliser application as mineral fertilisers are for the most part soluble salts. The type of fertiliser applied, when using saline water for irrigation, should preferably be acid and contain Ca rather than Na taking into consideration the complementary anions present. Timing and placement of mineral fertilisers are important and unless properly applied they may contribute to or cause a salinity problem. Organic and green manures and mulching : Incorporating organic matter into the soil has two principal beneficial effects of soils irrigated with saline water with high SAR and on saline sodic soils: improvement of soil permeability and release of carbon dioxide and certain organic acids during decomposition.

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