Soils as a Key Component of the Critical Zone 1

This introductory book to the six volume series includes an introduction defining the critical zone for mankind that extends from tree canopy and the lower atmosphere to water table and unweathered rock. Soils play a crucial role through the functions and the services that they provide to mankind. The spatial and temporal variability of soils is represented by information systems whose importance, recent evolutions and increasingly performing applications in France and in the world must be underlined. The soil functions, discussed in this book, focus on the regulation of the water cycle, biophysicochemical cycles and the habitat role of biodiversity. The main services presented are those related to the provision of agricultural, fodder and forest products, energy, as well as materials and the role of soil as infrastructure support. They also include the different cultural dimensions of soils, their representations being often linked to myths and rites, as well as their values of environmental and archaeological records. Finally, the issue is raised of an off-ground world.

Auteur

Jacques Berthelin, French National Center for Scientific Research, Paris, France

Jean-Charles Munch, TUM School of Life Sciences Weihenstephan, Munich, Allemagne

Christian Valentin, Institute for Research for Development, Paris, France

Contenu

Foreword xiii

Chapter 1. Soils as a Key Component of the Critical Zone 1
*Jacques BERTHELIN, Guilhem BOURRIÉ, Michel-Claude GIRARD, Guillaume DHÉRISSARD and Christian VALENTIN*

1.1. What are soils? 1

1.2. The Earth, land, soils, soil cover and the Critical Zone 2

1.3. The term soil has various meanings according to use and function processes 5

1.4. The concept of soil varies according to the user 6

1.4.1. Agricultural sector 7

1.4.2. Scientific communities 7

1.4.3. Urban communities 8

1.4.4. Current pressures and questions 8

1.5. The approaches and procedures of soil scientists and pedologists 9

1.6. Two principles to take into account: geographical continuity and multi-temporality 10

1.6.1. Principle of continuity 10

1.6.2. Principle of multi-temporality 13

1.7. Nature, organization and major modes of soil processes 15

1.7.1. Soils before the arrival of humans 15

1.7.2. Specifics and origins of the Earth's soils 17

1.7.3. The parameters controlling differentiation and diversity of soils 18

1.8. The functions and services of soils 23

1.8.1. Major functions 23

1.8.2. Services provided by soils 24

1.8.3. The role of soils within our culture and our history 25

1.9. The need and significance of soil information systems 29

1.10. Conclusion and recommendation 29

1.11. Bibliography 30

Chapter 2. Understanding Soils for Their More Efficient Management: A National Soil Information System 35
*Marion BARDY, Dominique ARROUAYS, Claudy JOLIVET, Bertrand LAROCHE, Christine LE BAS, Manuel MARTIN, Céline RATIÉ, Anne C. RICHER-DE-FORGES, Nicolas SABY, Véronique ANTONI, Antonio BISPO, Michel BROSSARD, Jean-Luc FORT, Joëlle SAUTER and Chantal GASCUEL*

2.1. Introduction 35

2.2. The inventory and monitoring of soils in Europe and in the world 36

2.3. National mechanisms for the acquisition of soil data 37

2.3.1. Issues and demands 37

2.3.2. Structuring of national data collection mechanisms 38

2.4. Data exploitation for the production of maps and indicators 44

2.5. Dissemination and availability of data 49

2.5.1. A national soil information system focused on data dissemination 49

2.5.2. A progressive enrichment of data and metadata supply 50

2.5.3. Assisting the use, improvement and control of data 52

2.6. Conclusion 52

2.7. Bibliography 53

Chapter 3. Soils and Regulation of the Hydrological Cycle 9
*Marc VOLTZ, Cécile DAGÈS, Laurent PRÉVOT and Ary BRUAND*

3.1. The soil facilitator within the hydrological cycle 59

3.2. Soil control mechanisms 61

3.2.1. Infiltrationrunoff partition 61

3.2.2. Aquifer recharge 65

3.2.3. Evaporation and transpiration flows 67

3.2.4. Capillary rise 70

3.2.5. Soil water budget 71

3.2.6. Hydrological flows along hillslopes 72

3.3. Impacts on the hydrological cycle at soil cover scale 74

3.3.1. Influence of soil and land use variations 75

3.3.2. Influence of land use changes 77

3.3.3. Influence of landscape infrastructures 78

3.4. Conclusions 79

Chapter 4. Soils as Bio-physicochemical Reactors 81
*Fabienne TROLARD and Guilhem BOURRIÉ*

4.1. What is a reactor? 81

4.2. Soil components 85

4.3. Reactivity drivers 86

4.4. Main reactions within soils 90

4.4.1. Master variables: pH and pe 90

4.4.2. Acidbase reactions 91

4.4.3. Reactions of oxido-reduction 94

4.4.4. Degradation of organic matter 95

4.5. Biogeochemical evolution of the Earth's surface and the consequences for soils 96

4.5.1. Availability of chemical elements changed with the Earth's evolution 96

4.5.2. The evolution of the Earth's reactor imposed the evolution of living organisms 99 4.5.3. Emergence of the soil function within the Critical Zone 10...