Soils as a Key Component of the Critical Zone 5

Christian Valentin is an agronomic engineer and soils specialist at l’Institut de Recherche pour le Développement, France. With 40 years of soil erosion and conservation research experience behind him, he teaches at Sorbonne University, France, and Hanoi, Vietnam, and is Deputy Director of l'Institut d'Ecologie et des Sciences de l'Environnement de Paris. He is the coordinator of the Soils Group of the French Academy of Agriculture.

• Foreword xiChapter 1. The State and Future of Soils 1Christian VALENTIN1.1. Soils as a key component of the critical zone 11.1.1. Definitions 11.1.2. Soil functions and services 11.1.3. Soil and land degradation, desertification 31.2. The difficult assessment of the state and kinetics of soil degradation or enhancement 31.2.1. Global assessment 41.2.2. Forms of degradation 51.2.3. Main factors of soil degradation 81.2.4. What’s the trend: degradation spiral or U-curve? 91.2.5. The necessity for monitoring mechanisms 121.3. Conservation, restoration, rehabilitation and compensation 121.3.1. Definitions 121.3.2. Implementation 131.3.3. Concept of neutrality in terms of land degradation 141.4. Conclusions 151.5. References 16Chapter 2. Soil Surface Crusting of Soil and Water Harvesting 21Christian VALENTIN2.1. Surface conditions and surface crusts 212.2. Crust types and formation processes 232.2.1. Structural crusts 232.2.2. Gravel crusts 242.2.3. Erosion crusts 242.2.4. Depositional crusts 252.2.5. Saline crusts and efflorescence 252.2.6. Biological soil crusts (or Biocrusts) 262.3. Crusting factors and principles for improving aggregate stability 262.3.1. Soils 262.3.2. Rain 262.3.3. Slope 272.3.4. Cover 272.3.5. Agricultural practices 282.4. Consequences of surface crusting 292.4.1. Hydrological: Hortonian flow 292.4.2. Ecological: example of the tiger bush 302.4.3. Agronomic: water harvesting 322.5. Conclusions 332.6. References 34Chapter 3. Erosion and Principles of Soil Conservation 39Christian VALENTIN and Jean Louis RAJOT3.1. Definitions 393.2. The importance of erosion 403.2.1. On a global scale 403.2.2. Effects of erosion 413.3. Processes and factors 453.3.1. Splash detachment 453.3.2. Sheet erosion (also called inter-rill erosion) 473.3.3. Linear erosion 523.3.4. Mass movements 543.3.5. Tillage erosion 553.3.6. Wind erosion 563.4. Erosion: a question of scale 603.4.1. Space scales 603.4.2. Time scales 613.4.3. Space scales 623.4.4. Particulate and soluble transport 633.4.5. Aeolian dust 633.5. Modeling 643.5.1. Statistical approaches 653.5.2. Physically based models 653.5.3. Hybrid models 663.6. Principles of soil conservation 663.6.1. Field level: limiting detachment 663.6.2. Catchment scale: slowing runoff and promoting deposition 693.7. Population density, economic contexts and public policies 703.8. Conclusions 723.9. References 73Chapter 4. Soil Acidity and Acidification 83Étienne DAMBRINE4.1. Acidity 834.2. Definitions of acidification and its evolution 854.3. Illustration: long-term theoretical evolution of the acidity of a limestone loess 874.4. Acidifying processes 884.5. Involvement of large biogeochemical cycles in soil acidification 894.5.1. Nitrogen cycle 894.5.2. Carbon cycle 894.5.3. Absorption of cations/anions by plants 894.5.4. Acid or alkaline deposits 904.5.5. Other cycles: P, S, Fe, Mn 904.6. Neutralization of acidification 904.7. Biogeography of acidity 914.8. Physical and biological consequences of soil acidity 924.9. References 93Chapter 5. Soil Salinization and Management of Salty Soils 97Jean-Pierre MONTOROI5.1. Introduction 975.2. Natural salty environments 975.2.1. Salts, dissolved particulate entities 975.2.2. Typical landscapes 985.2.3. Continuous movement of salts 995.2.4. Ecosystemic services 1005.3. Characterization and functioning of salty soils 1025.3.1. Diagnosis of the degree of salinization 1025.3.2. Intrinsic physical–chemical processes 1025.3.3. Chemical concentration and evolution pathways of soil water 1055.3.4. Mineralogy of saline efflorescences 1075.4. Typology of salty soils 1085.4.1. Soil characteristics 1085.4.2. Vertical distribution of salinity 1095.4.3. Spatial distribution of salinity 1105.4.4. Classification of salty soils 1105.4.5. Worldwide distribution of salty soils 1125.5. Secondary soil salinization 1125.5.1. Anthropogenic input of salts in soils 1125.5.2. Salinization of irrigated systems 1135.5.3. Control of salts in irrigation 1145.5.4. Use of non-conventional waters 1155.6. Agricultural development of sodic soils 1165.6.1. Historical context 1165.6.2. Effects of soil salt water on plants 1165.6.3. Agronomic solutions 1175.6.4. Macroeconomic solutions 1195.6.5. Social and political solutions 1205.7. Conclusions 1205.8. References 122Chapter 6. Metal Pollution 127Denis BAIZE6.1. General information 1276.1.1. Definitions: trace elements 1276.1.2. Risks and hazards: exposure and transfer routes 1296.1.3. Different forms and locations of trace elements in soils 1326.1.4. Measurement and estimation methods available 1336.1.5. How should the pollution level of soil be assessed? 1356.2. Famous polluted sites (France) 1416.2.1. Metaleurop at Noyelles-Godault 1426.2.2. Mortagne-du-Nord 1446.2.3. Pierrelaye plain (polymetallic pollution) 1456.3. Locally polluted sites and diffuse contamination 1476.3.1. Pole treatment site polluted by copper in podzol context 1476.3.2. Soil contamination by sewage sludge 1476.3.3. Copper contamination in vineyard soils 1536.3.4. Copper and zinc soil contamination from repeated spreading of pig manure 1556.3.5. Atmospheric deposition of lead since antiquity 1566.3.6. Metal nanoparticules 1576.4. Impacts of metal pollution 1586.4.1. Bio- and phytoavailability – absorption routes 1586.4.2. Mobility 1586.4.3. Mobility and bioavailability estimation 1596.4.4. The importance of soil properties for speciation, bioavailability and mobility 1596.5. What should be done about metal polluted soils? 1606.5.1. Strategies without treatment 1616.5.2. Stripping polluted horizons 1616.5.3. In situ immobilization and phytoremediation 1616.5.4. An example: the Maatheide-Lommel site (Belgium) 1636.6. References 166Chapter 7. Organic Pollution and Soil Rehabilitation 169Corinne LEYVAL, Aurélie CÉBRON and Pierre FAURE7.1. Organic pollution: its origins and diversity 1697.2. Origin and distribution of PAHs in soils 1707.3. Characteristics, properties and toxicity of PAHs 1717.4. Fate and impact of organic pollution in soils: tools and approaches 1737.4.1. Sorption of PAHs in soils 1737.4.2. Bioavailable form and ageing of PAH contamination in soils 1757.4.3. Biodegradation and the microorganisms involved 1767.5. Fate of PAHs in the plant rhizosphere 1777.6. Remediation techniques: limitations and constraints 1797.7. From remediation to restoration 1817.8. Conclusions 1827.9. References 183Chapter 8. Urban Soils: Artificialization and Management 189Laure VIDAL-BEAUDET and Jean-Pierre ROSSIGNOL8.1. Introduction 1898.2. Soil urbanization 1908.2.1. History and origin of urban soils 1908.2.2. Artificialization and sealing 1928.3. Soil characteristics in urban areas 1938.3.1. Typology of urban soils 1948.3.2. The properties of artificialized urban soils 1968.4. Urban soil classification and mapping 1978.4.1. Classification 1978.4.2. Mapping 1998.5. Fertile soils for vegetated areas 2028.5.1. Reconstituted soils 2038.5.2. The particular case of aggregate structural soil 2048.5.3. Soils built from the “waste” from cities 2058.6. Conclusions 2068.6.1. The “brown belt” 2068.6.2. Urban soil value and protection 2078.7. References 208Chapter 9. Recycling Organic Waste Products in a Tropical Context 211Frédéric FEDER9.1. Definition, typology and main characteristics of organic waste products 2119.1.1. Definition of organic waste products and associated issues 2119.1.2. Typology of organic waste products 2129.2. Analytical characterizations of organic waste products 2159.2.1. Chemical elements of agronomic interest (C, N, P, K) 2169.2.2. Specific analyses of organic properties 2169.2.3. Organic and metallic trace contaminants 2179.3. Agricultural interests and environmental risks 2189.3.1. Fertilizing aspects of organic waste products 2189.3.2. Amending aspects of organic waste products 2209.3.3. Metallic, organic and biological contaminants 2239.3.4. Other environmental impacts 2249.4. Examples of recycling organic waste products in tropical contexts 2269.4.1. In weakly intensified systems 2269.4.2. In intensive systems 2279.5. References 231List of Authors 235Index 237