Scheffer/Schachtschabel Soil Science Hans-Peter Blume • Gerhard W

Home , Calcisol, Gleysol, Gypsisol, Kastanozem, Planosol, Regosol

Scheffer/Schachtschabel Soil Science Hans-Peter Blume • Gerhard W. Brümmer Heiner Fleige • Rainer Horn Ellen Kandeler • Ingrid Kögel-Knabner Ruben Kretzschmar • Karl Stahr Berndt-Michael Wilke

Scheffer/Schachtschabel Soil Science

123 Hans-Peter Blume Ingrid Kögel-Knabner Institute of Plant Nutrition and Soil Sciences Chair of Soil Science Christian-Albrechts-University zu Kiel Technische UniversitätMünchen Kiel Freising-Weihenstephan Germany Germany

Gerhard W. Brümmer Ruben Kretzschmar Institute of Crop Science and Resource Institute of Biogeochemistry Conservation and Pollutant Dynamics University of Bonn ETH Zurich Bonn Zurich Germany Switzerland

Heiner Fleige Karl Stahr Institute of Plant Nutrition and Soil Sciences Institute for Soil Science and Land Christian-Albrechts-University zu Kiel Evaluation Kiel Hohenheim University Germany Stuttgart Germany Rainer Horn Institute of Plant Nutrition and Soil Sciences Berndt-Michael Wilke Christian-Albrechts-University zu Kiel Institute of Ecology Kiel Technical University Berlin Germany Berlin Germany Ellen Kandeler Institute for Soil Science and Land Evaluation Hohenheim University Stuttgart Germany

G.W. Brümmer—Deceased

ISBN 978-3-642-30941-0 ISBN 978-3-642-30942-7 (eBook) DOI 10.1007/978-3-642-30942-7

Library of Congress Control Number: 2015937207

Springer Heidelberg New York Dordrecht London © Springer-Verlag Berlin Heidelberg 2016 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made.

Printed on acid-free paper

Springer-Verlag GmbH Berlin Heidelberg is part of Springer Science+Business Media (www.springer.com) Preface for the First English Edition

Soils provide us with food, feed, fiber, and fuel. Furthermore, they support many different forms of life on Earth. This book aims to promote the understanding of soils, their development, their functions and their distribution, and enable closer contact with this important natural resource. For most of the chapters, the first English edition of this soil science textbook represents a translation of the German 16th edition published in 2010, originating from the first edition in German in 1937. In keeping with the organization and contents that made the German editions bestsellers, the textbook covers all major aspects of soil science. However, the chapters on soil development and classification and soil geography were completely revised and adapted to international classification systems. A number of figures have also been redrawn and revised for the first English edition. This textbook aims to provide an up-to-date account of the current state of knowledge in soil science. This textbook is designed as a basic textbook for use in soil science courses and other courses that explore current develop- ments in this field and is an invaluable resource for students in agriculture, forestry, ecology, and environmental sciences. It will also be very useful as a basic work that provides scientists and professionals with a profound introduction to specific topics as well as the most relevant literature. It will guide students through soil physical, chemical, and biological processes and introduce them to soil geography, soil classification, and threats to soil functions. This book represents a joint effort by German authors who have diverse complementary backgrounds in soil science and who developed this book over the past decades. The group of authors has worked closely together, creating a textbook that has continuity in depth and style and that is state of the art at the time of publishing. The authors wish to thank the publisher for their excellent cooperation. We hope that the present and future generations will use the knowledge in this book for a better understanding of soils. We welcome any comments from all those who use this text. The authors acknowledge the eminent help by Jacinda Richman, Annett Büttner, and the publisher along the way to realizing this edition.

Spring 2015 The authors

v Preface and Brief Historical Outline for the 16th Edition

Scheffer/Schachtschabel is renowned as the standard textbook on soil science both for students in the fields of agriculture, forestry, and natural sciences in German-speaking countries, and for scientists and users concerned with soils. Written by the agricultural chemist Friedrich (Wilhelm) Scheffer, the first edition was published in 1937 under the title “Agrikulturchemie, Teil A: Boden” (Agricultural Chemistry, Part A: Soil). Its 112 pages contained an evaluation of soils according to their capacity for producing plants, whereby the focus was on the properties lending fertile soils their high productivity. This first edition therefore only dealt with a portion of what was con- sidered “soil science” at the time, since in “Teil B: Pflanzenernährung” (Part B: Plant Nutrition), Scheffer provided a detailed explanation of the air, heat, and nutrient balance of soils as the basis for plant production. The second edition of “Teil A: Boden” (Part A: Soil) (1944) included a more detailed description of humic substances as a product of microbial transformation of organic matter, clay minerals based on X-ray diffraction, and of the soil types including their genesis. The third edition, published in 1952 and expanded to 240 pages, was called “Lehrbuch der Agrikulturchemie und Bodenkunde, 1. Teil Bodenk- unde” (Agricultural Chemistry and Soil Science, Part 1 Soil Science). From now on, it was written by Fritz Scheffer in collaboration with Paul Schach- tschabel (Fig. 1) and was revised at regular intervals of 4–6 years. With the ninth edition (1976), the textbook was finally given its present name “Scheffer/Schachtschabel: Lehrbuch der Bodenkunde” (Scheffer/ Schachtschabel: Textbook of Soil Science), which remained as a “trademark” for all later editions. From this time on, new information was compiled by a team of authors, which was expanded or developed according to the specialized requirements. In the last three decades, this was mainly ensured by the authors Blume, Brümmer, Hartge, Schachtschabel, and Schwertmann. A more extensive description of the evolution of “Scheffer/Schachtschabel” can be found in Blume et al. (2007). With the continuously increasing number of pages in the last editions (the 15th edition comprised 593 pages), the contents of “Scheffer/

vii viii Preface and Brief Historical Outline for the 16th Edition

Fig. 1 Prof. Dr. Dr. h.c. F. Scheffer (left) and Prof. Dr. Dr. h.c. P. Schachtschabel (right) at the International Soil Science Conference in 1960 in Madison, USA

Schachtschabel” had also become differentiated to such an extent that a new concept became necessary for the 16th edition. This involved focusing on the condensation of the knowledge to the essentials, to do better justice to the textbook character, and still maintain the integrity of the respective subject matter. The contents of the 16th edition represent the basis for this English translation. In the 16th edition, Chap. 4 “Soil Organisms and Their Habitat” was completely revised by Prof. Dr. E. Kandeler, and Chap. 5 “Chemical Prop- erties and Processes” by Prof. Dr. R. Kretzschmar, while all of the other chapters were updated by including the current state of research. Chapter 6 presents more recent insights into soil structural development, soil mechan- ics, and the water balance, and the section on soil color was also revised. Parts of Chap. 7 were rewritten for the English edition. The names for the soil horizons (Sect. 7.3) and the soil classifications (Sect. 7.4) were mainly pre- sented according to the World Reference Base for Soil Resources (WRB) and the US Soil Taxonomy, and the chapter on German classification was reduced. Section 7.5 now discusses the properties, genesis, ecology, and use of all significant soils on Earth, primarily according to the WRB. Similar to the WRB and the US Soil Taxonomy, the Reductosols were also treated as oxygen-poor soils without water surplus and were supplemented with the Preface and Brief Historical Outline for the 16th Edition ix

Asphaltic Reductosols. New additions included soils characterized by a yermic horizon in continental hot and cold deserts. The same applies for Zoosols, i.e., soils with profound conditioning by animals (in addition to earthworms and steppe mammals in Chernozems, also termites in subtropical regions and penguins in Antarctica). Section 7.6 is now dedicated to Pa- leosols on Earth, Mars, and Titan. More than thirty representative soil profiles are shown on three color pages, as well as a deep colored soil section on the planet Mars compared to a soil from India. Chapter 8 Soil Geography was restructured accordingly, while Chap. 9 Soils–Plant Relations was completely restructured and expanded with the physical properties of soils (Sects. 9.1–9.4). The sections on nutrient supply (9.5) and on plant macronutrients (9.6) were also largely rewritten; Sects. 9.7 (micronutrients) and 9.8 (beneficial elements) were revised. Chapter 10 deals with the threat to soil functions by chemical and nonchemical degradation, possible remediation measures, and methods for the assessment of chemical soil contaminations. The significance of soil protection is discussed in detail in Chap. 11, including the fundamental laws and chemical issues involved in soil protection. Methodical details are not discussed in any of the chapters, since there are enough other textbooks and practical manuals for this purpose; furthermore, the literature was reduced, since modern specialized literature today is easily accessible to those interested in soil science. The chapters were divided among the authors as follows: 1. Brümmer † (Blume, Stahr) 2. Stahr 3. Kögel-Knabner 4. Kandeler 5. Kretzschmar 6. Horn 7. Blume, Fleige 8. Stahr 9. Brümmer † (Amelung, Horn) 10. Wilke (Horn, Thiele-Bruhn, Welp) 11. Stahr Numerous staff members and colleagues have contributed in many ways to the production of the 16th German edition; without their collaboration, the completion of the German textbook as a basis for the English translation in the present form would not have been possible. We would like to thank you all sincerely. In particular, we would like to mention Prof. Dr. J. Bachmann, Dr. R. Baritz, Dr. Iso Christl, Prof. Dr. W. Foissner, Prof. T. Friedel, Dr. T. Gaiser, Dr. J. Gauer, Dr. S. Haase, B. Heilbronner, Dr. A Kölbl, Prof. Dr. B. Ludwig, Dr. M. von Lützow, Dr. S. Marhan, Dr. W. Markgraf, Dr. S. Peth, Dr. L. Philippot, Dr. C. Poll, Prof. Dr. L. Ruess, Dr. D. Stasch, Prof. Dr. R. Tippkötter, Dr. A. Voegelin, Dr. J. Wiederhold, and Dr. M. Zarei. x Preface and Brief Historical Outline for the 16th Edition

We thank the lector Dr. J. Lorenzen-Peth for didactical correction and critical review, and the publisher, particularly Dr. C. Iven, for his trustworthy and patient collaboration. Not only are soil scientists interested in soils, but also farmers, foresters, gardeners, landscapers and landscape planners, ecologists, crop technicians, hydrologists, geographers, geologists, mineralogists, chemists, biologists, and archeologists. This is equally true for all those who deal with problems associated with nature conservation, environmental protection, and legisla- tion, as well as with soil remediation in the political, administrative, stan- dardization, and business sectors. In all of these sectors, Scheffer/ Schachtschabel has become an indispensable source of information on soils. This is particularly true for students and for the next generation of scientists. May the new edition ﬁnd like-minded readers and serve them as a useful companion. We also hope that the translation of the German version will spread the knowledge contained in Scheffer/Schachtschabel around the world, and contribute to a better and more comprehensive understanding of the processes taking place in soils as a vulnerable and especially nonre- newable resource. The book cover shows a Podzol, an Albeluvisol/Retisol, and a Fluvic Gleysol.

Spring 2015 The authors

Reference

Blume H-P, Hartge KH, Schwertmann U (2007) Die Bedeutung des Ferdinand Enke Verlages für die Verbreitung bodenkundlichen Wissens. In: Blume H-P, Stahr K (Hg) Zur Geschichte der Bodenkunde (Chapter 4). Hohenheimer Bodenkundliche Berichte Nr. 83 Contents

1 Introduction: Soils—The Earth’s Skin ...... 1 1.1 Soils as Natural Bodies in Ecosystems...... 1 1.2 Functions of the Soils in the Ecosphere ...... 3 1.3 Soils as an Open System Worth Protecting...... 5 References...... 6

2 Inorganic Soil Components—Minerals and Rocks ...... 7 2.1 The Rock Cycle ...... 7 2.2 Minerals ...... 7 2.2.1 General ...... 7 2.2.2 Silicate Structure...... 9 2.2.3 Primary (Lithogenic, Pyrogenic) Silicates. . . . . 10 2.2.4 Clay Minerals...... 15 2.2.5 Clay Mineral Formation and Transformation ...... 21 2.2.6 Oxides and Hydroxides ...... 22 2.2.7 Carbonates, Sulfates, Sulfides and Phosphates...... 30 2.3 Rocks ...... 30 2.3.1 Igneous Rocks ...... 31 2.3.2 Sediments and Sedimentary Rocks ...... 32 2.3.3 Metamorphic Rocks ...... 38 2.3.4 Anthropogenic Substrates...... 39 2.4 Weathering ...... 40 2.4.1 Physical Weathering ...... 40 2.4.2 Chemical Weathering ...... 41 2.4.3 Role of the Biota ...... 45 2.4.4 Weathering Stability ...... 46 2.5 Mineral Constituents of Soils ...... 49 References...... 52

3 Soil Organic Matter ...... 55 3.1 Origins, Distribution and Dynamics...... 55 3.2 Contents and Quantities of Organic Matter in Soils . . . . 56

xi xii Contents

3.3 Plant Residues and Their Transformation During Decomposition...... 60 3.3.1 Composition and Structure of Organic Residues ...... 60 3.3.2 Decomposition and Transformation Reactions in the Soil ...... 63 3.4 Formation of Stable Organic Matter ...... 66 3.4.1 Stabilization by Interactions with the Mineral Phase ...... 67 3.4.2 Stabilization by Spatial Separation ...... 70 3.4.3 Organic Matter in Functional Soil Fractions . . . 71 3.5 Composition and Properties of Soil Organic Matter. . . . 71 3.5.1 Binding Forms of C, N, P and S in Soil Organic Matter...... 71 3.5.2 Properties of Soil Organic Matter ...... 73 3.6 Soil Organic Matter Dynamics ...... 74 3.6.1 Turnover Rates and Turnover Time of Organic Matter in Soils ...... 74 3.6.2 Estimation of the Turnover Time ...... 75 3.6.3 C Turnover Modeling ...... 78 3.6.4 Soils as a Carbon Reservoir and Source...... 79 References...... 84

4 Soil Organisms and Their Habitat ...... 87 4.1 Soil Organisms...... 87 4.1.1 Microflora and Viruses in Soils ...... 87 4.1.2 Soil Fauna (Micro-, Meso-, Macro- and Megafauna) ...... 92 4.1.3 Numbers and Biomass of Soil Organisms . . . . 97 4.1.4 Soil Organisms as a Biocoenosis ...... 100 4.2 Environmental Conditions ...... 104 4.2.1 The Soil as a Source of Nutrients and Energy for Soil Organisms ...... 104 4.2.2 Water and Atmosphere ...... 105 4.2.3 pH Value and Redox Potential ...... 107 4.2.4 Temperature ...... 107 4.3 Functions of Soil Organisms ...... 108 4.3.1 Function of Soil Organisms in Matter Cycles ...... 108 4.3.2 Function of Soil Organisms in Redox Reactions ...... 112 4.3.3 Function of Soil Organisms in Soil Structure Stabilization ...... 114 4.4 Soil Organisms as Bioindicators ...... 115 4.4.1 Effect of Soil Management on Soil Organisms ...... 115 4.4.2 Environmental Pollution ...... 117 4.4.3 Climate Change ...... 118 Contents xiii

4.5 Methods in Soil Biology ...... 119 4.5.1 Microorganisms ...... 119 4.5.2 Soil Fauna ...... 121 References...... 121

5 Chemical Properties and Processes ...... 123 5.1 Soil Solution ...... 123 5.1.1 Composition of Rainwater ...... 123 5.1.2 Composition of the Soil Solution ...... 124 5.2 Gas Equilibria ...... 127 5.3 Speciation and Complex Formation...... 127 5.3.1 Ionic Strength, Concentration, and Activity . . . 128 5.3.2 Solution Speciation ...... 129 5.4 Solubility and Dissolution Kinetics ...... 131 5.4.1 Solubility Constant, Ion Activity Product, and Saturation Index ...... 132 5.4.2 Stability Diagrams ...... 132 5.4.3 Dissolution and Precipitation Kinetics ...... 135 5.5 Sorption...... 136 5.5.1 Reactive Surfaces and Surface Charge ...... 137 5.5.2 Ion Exchange ...... 142 5.5.3 Surface Complexation of Cations and Anions ...... 144 5.5.4 Sorption of Organic Substances on Mineral Surfaces ...... 147 5.5.5 Sorption Kinetics ...... 148 5.5.6 Sorption Modeling ...... 149 5.6 Soil Reaction and pH Buffering ...... 154 5.6.1 Soil Reaction ...... 154 5.6.2 Soil Acidity and Base Neutralization Capacity (BNC) ...... 156 5.6.3 H+ Sources ...... 157 5.6.4 pH Buffering, Soil Acidification and Acid Neutralization Capacity (ANC) . . . . . 160 5.6.5 Liming of Acidic Soils ...... 163 5.7 Redox Reactions and Redox Dynamics ...... 165 5.7.1 Redox Reactions and Redox Potential ...... 166 5.7.2 pe-pH Diagrams ...... 167 5.7.3 Redox Reaction Kinetics ...... 169 5.7.4 Redox Processes in Soils ...... 170 5.7.5 Soil Redox Potential ...... 171 References...... 172

6 Physical Properties and Processes ...... 175 6.1 Texture and Packing ...... 175 6.1.1 Particle Formation...... 176 6.1.2 Particle Size ...... 176 6.1.3 Particle Classification ...... 177 6.1.4 Particle Properties ...... 180 xiv Contents

6.1.5 Common Particle Distributions ...... 181 6.1.6 Packing of the Primary Particles ...... 182 6.1.7 Temporal Changes ...... 188 6.1.8 Correlation Between the Solid Phase and Other Soil Properties ...... 189 6.2 Interactions Between the Solid and Liquid Phases. . . . . 189 6.2.1 Flocculation and Peptization...... 190 6.2.2 Shrinkage and Swelling ...... 195 6.2.3 Wettability ...... 199 6.2.4 Cohesion, Consistency and Hydraulic Pressure Head ...... 200 6.3 Soil Structure ...... 202 6.3.1 Structural Morphology...... 202 6.3.2 Stresses and Deformations ...... 208 6.3.3 Soil Structural Stability ...... 215 6.3.4 Biological, Climatic and Anthropogenic Effects on Soil Structure...... 220 6.3.5 Assessment of the Soil Structure for Agricultural Purposes ...... 227 6.4 Soil Water ...... 228 6.4.1 Introduction—Binding Forms ...... 229 6.4.2 Water Binding Intensity...... 232 6.4.3 Water Movement in the Liquid Phase ...... 239 6.4.4 Water Movement in the Vapor Phase ...... 249 6.4.5 Soil Water Balance ...... 252 6.4.6 Water Balance of Landscapes...... 257 6.5 Soil Air ...... 261 6.5.1 Composition and Origin of the Constituents . . . 262 6.5.2 Transport Mechanisms...... 264 6.5.3 Gas Balance...... 266 6.6 Soil Temperature ...... 267 6.6.1 Significance of Thermal Phenomena ...... 267 6.6.2 Energy Gains and Losses...... 267 6.6.3 Thermal Properties ...... 268 6.6.4 Heat Movement ...... 269 6.6.5 Heat Balance ...... 271 6.7 Transport Processes and Translocations ...... 273 6.7.1 Transport in Soils in the Liquid Phase ...... 274 6.7.2 Transport in Soils in the Gaseous Phase . . . . . 276 6.8 Soil Color ...... 277 6.8.1 Color Classification...... 277 6.8.2 Coloring Components ...... 278 6.8.3 Correlations Between Color and Soil Properties and Processes ...... 279 References...... 279

7 Soil Development and Soil Classification ...... 285 7.1 Factors of Soil Formation ...... 286 7.1.1 Parent Rock ...... 286 7.1.2 Climate ...... 288 Contents xv

7.1.3 Gravity and Relief ...... 289 7.1.4 Water ...... 290 7.1.5 Fauna and Flora ...... 291 7.1.6 Human Activities ...... 292 7.1.7 Time ...... 293 7.2 Processes of Soil Development ...... 294 7.2.1 Transformations and Depletions of the Mineral Body...... 294 7.2.2 Humus Accumulation—Development of Humus Forms...... 297 7.2.3 Structure Formation...... 300 7.2.4 Translocations ...... 301 7.2.5 Redoximorphosis ...... 306 7.2.6 Turbations ...... 308 7.2.7 Soil Landscape Processes...... 311 7.2.8 Profile Differentiation ...... 313 7.3 Diagnostic Criteria of Soils ...... 316 7.3.1 Soil Horizon Designation...... 316 7.3.2 Diagnostic Horizons, Properties and Materials ...... 322 7.4 Soil Classification ...... 322 7.4.1 Soil Classification According to the WRB . . . . 323 7.4.2 Soil Classification According to the US Soil Taxonomy ...... 325 7.4.3 Soil Classification in Germany ...... 327 7.5 Representative Soil Units ...... 332 7.5.1 Leptosols (LP) ...... 333 7.5.2 Arenosols (AR) ...... 337 7.5.3 Regosols (RG) ...... 339 7.5.4 Cambisols (CM) and Umbrisols (UM) ...... 339 7.5.5 Chernozems (CH), Phaeozems (PH) and Kastanozems (KS) ...... 345 7.5.6 Soils with Clay Migration ...... 348 7.5.7 Podzols (PZ) ...... 351 7.5.8 Stagnosols (ST) and Planosols (PL)...... 353 7.5.9 “Reductosols” and Reductic Technosols (TC). . . . 356 7.5.10 Vertisols (VR) ...... 357 7.5.11 Andosols (AN) ...... 359 7.5.12 Ferralsols (FR) and Plinthosols (PT) ...... 359 7.5.13 Calcisols (CL) and Gypsisols (GY) ...... 361 7.5.14 Durisols (DU) ...... 362 7.5.15 Solonchaks (SC) ...... 362 7.5.16 Solonetz (SN)...... 364 7.5.17 Desert Soils–Soils with a Yermic Horizon and Aridic Properties...... 365 7.5.18 Gleysols (GL) ...... 367 7.5.19 Fluvisols (FL) ...... 370 7.5.20 Peat Soils—Histosols (HS)...... 376 7.5.21 Cryosols (CR) and Other Soils with Permafrost ...... 379 xvi Contents

7.5.22 Anthrosols (AT) ...... 380 7.5.23 “Zoosols” (ZO)...... 382 7.6 Paleosols on Earth, and Soils on Mars and Titan . . . . . 384 7.6.1 Paleosols on Earth ...... 384 7.6.2 Soils on Mars and Titan ...... 385 References...... 387

8 Soil Geography...... 391 8.1 The Pedosphere ...... 391 8.2 Paradigms of Soil Landscapes and Soil Genesis ...... 392 8.2.1 Basic Principles of Soil Associations...... 392 8.3 Soil Association Systematics and Soil Regions of Central Europe ...... 397 8.3.1 Soil Regions of Central Europe (Fig. 8.4) . . . . 397 8.3.2 Soil Regions in Urban Industrial Areas ...... 398 8.4 Soil Zones of the World ...... 399 8.4.1 Ferralsols-Gleysols-Fluvisols Soil Zones in the Inner (Humid) Tropics (Rain Forest) . . . 399 8.4.2 Acrisols-(Luvisols-Plinthosols)-Nitisols-Vertisols Soil Zones in the Outer (Seasonal) Tropics (Savannah) ...... 401 8.4.3 Regosols-Calcisol-Solonchak Soil Zones in Semi-deserts ...... 402 8.4.4 Arenosol-(Leptosol)-Gypsisol-Solonchak Soil Zones in (Extreme) Deserts (Fig. 8.1) . . . . 403 8.4.5 Planosol-Luvisol-(Acrisol)-Cambisol Zones in the Mediterranean Region ...... 403 8.4.6 Chernozem-Kastanozem-Solonetz Zones of the Grasslands (Steppe, Prairie, Pampa, Veld) (Fig. 8.2) ...... 404 8.4.7 Cambisol-Luvisol-Gleysol Zone of Temperate Zones (Mixed Forest and Forest Steppe) . . . . . 405 8.4.8 Podzol-Cambisol-Histosol Zone of Boreal Forests (Taiga) ...... 405 8.4.9 Leptosol-Regosol-Gleysol-Histosol Zone of the Tundra (Polar Steppe) ...... 406 8.4.10 Leptosol-Gelic-Regosol-Cryosol Zone of Cold Deserts ...... 406 References...... 407

9 Soil-Plant Relations...... 409 9.1 Rootability and Rooting Zone...... 409 9.1.1 Root System of Plants and Rootability...... 409 9.1.2 Potential Rooting Zone ...... 410 9.2 Water Supply to Plants ...... 410 9.2.1 Plant-Available Water ...... 411 9.2.2 Water Transport in the Soil–Plant–Atmosphere Continuum...... 414 9.2.3 Water Consumption and Plant Yields ...... 417 Contents xvii

9.3 Soil Air and Oxygen Supply to Plant Roots ...... 419 9.3.1 Soil Air Budget ...... 419 9.3.2 Oxygen Supply to Plant Roots ...... 420 9.4 Soil Thermal Budget, Soil Temperature and Plant Growth ...... 421 9.5 Plant Nutrient Supply ...... 422 9.5.1 Nutrient Contents, Binding Forms and Budgets ...... 423 9.5.2 Nutrient Availability and Nutrient Supply inSoils...... 426 9.5.3 Nutrient Fertilization ...... 431 9.6 Essential Nutrient Elements ...... 433 9.6.1 Nitrogen ...... 433 9.6.2 Phosphorus ...... 444 9.6.3 Sulfur ...... 454 9.6.4 Potassium ...... 457 9.6.5 Calcium...... 461 9.6.6 Magnesium ...... 462 9.6.7 Sodium ...... 464 9.7 Micronutrient Elements ...... 464 9.7.1 Manganese...... 465 9.7.2 Iron...... 468 9.7.3 Copper ...... 470 9.7.4 Zinc ...... 472 9.7.5 Boron ...... 474 9.7.6 Molybdenum ...... 476 9.7.7 Chlorine ...... 477 9.8 Beneficial Elements...... 478 9.8.1 Silicium...... 478 9.8.2 Cobalt ...... 479 9.8.3 Selenium ...... 480 References...... 481

10 Threats to the Soil Functions...... 485 10.1 Threats to the Soil Functions Through Chemical Contaminations...... 486 10.1.1 Entry Paths of Pollutants in Soils ...... 487 10.2 Inorganic Substances ...... 488 10.2.1 Sulfur Dioxide and Nitrogen Compounds—ForestDecline...... 488 10.2.2 Fluorine...... 493 10.2.3 Cyanides ...... 494 10.2.4 Heavy Metals ...... 496 10.2.5 Salts ...... 509 10.2.6 Radionuclides...... 510 10.3 Organic Pollutants...... 517 10.3.1 Classification, Use, Inputs and Contents inSoils...... 517 10.3.2 Processes at the Soil Surface ...... 523 xviii Contents

10.3.3 Fixation in the Soil ...... 524 10.3.4 Decomposition and Translocation ...... 528 10.3.5 Uptake by and Effects on Organisms...... 530 10.4 Farmyard and Secondary Raw Material Fertilizers, Dredged Material ...... 533 10.5 Toxicological/Ecotoxicological Evaluation of Chemical Soil Pollution ...... 536 10.5.1 Values for the Soil—Human Path ...... 538 10.5.2 Values for the Soil—Crop Plant Path ...... 540 10.5.3 Soil Values for the Soil—Groundwater Path. . . 541 10.5.4 Biological Evaluation of Soil and Soil Material ...... 542 10.6 Remediation of Chemical Contaminations ...... 543 10.7 Threats to Soil Functions Through Non-chemical Contaminations ...... 546 10.7.1 Soil Erosion ...... 546 10.7.2 Mechanical Soil Deformation ...... 553 References...... 558

11 Land Evaluation and Soil Protection ...... 561 11.1 Principles of Soil Evaluation/Assessment ...... 562 11.2 Evaluation for Taxing and Agricultural Use ...... 564 11.2.1 Soil Evaluation—German Soil Taxation Framework...... 565 11.2.2 Soil Evaluation—Grassland Taxation Framework...... 567 11.2.3 Assessment for Special Crops...... 567 11.3 Assessment for Forest Use ...... 568 11.4 Evaluation for Societal Requirements Without Use of the Primary Production ...... 573 11.5 Common International Soil Evaluation Methods ...... 575 11.5.1 Storie Index Rating (SIR) ...... 575 11.5.2 Fertility Capability Classification (FCC) . . . . . 575 11.5.3 Land Capability Classification (LCC) ...... 576 11.5.4 Land Suitability Classification (LSC)...... 577 11.5.5 Agro-Ecological Zones ...... 578 11.5.6 Soil Quality Assessment ...... 578 11.6 Soil Information Systems ...... 579 11.7 Soil Protection ...... 581 11.7.1 Reasons for Soil Protection ...... 581 11.7.2 Protection of the Natural Body ...... 581 11.7.3 Soil Functions and Potentials ...... 582 11.7.4 German Federal Soil Protection Act ...... 582 References...... 584

Appendix ...... 587

Index ...... 593