The Nature and Properties of Soils, Global Edition

Book Preface

By opening this 15th edition of The Nature and Properties of Soils, you are tapping into a narrative that has been at the forefront of soil science for more than a century. The first version, published in 1909, was largely a guide to good soil management for farmers in the glaciated regions of New York State in the northeastern United States. Since then, it has evolved to provide a globally relevant framework for an integrated understanding of the diversity of soils, the soil system, and its role in the ecology of planet Earth.

This latest edition is the first to feature full color illustrations throughout. If you are a student reading this, you have chosen a truly auspicious time to take up the study of soil science. This new edition was completed as the United Nations and countries around the world celebrated the International Year of Soils (2015). Soils are now widely recognized as the underpinning of terrestrial ecosystems and the source of a wide range of essential ecosystem services. An understanding of the soil system is therefore critical for the success and environmental harmony of almost any human endeavor on the land. This importance of soils and soil science is increasingly recognized by business and political leaders, by the scientific community, and by those who work with the land. Scientists and managers well versed in soil science are in short supply and becoming increasingly sought after. Much of what you learn from these pages will be of enormous practical value in equipping you to meet the many natural-resource challenges of the 21st century. You will soon find that the soil system provides many opportunities to see practical applications for principles from such sciences as biology, chemistry, physics, and geology.

This newest edition of The Nature and Properties of Soils strives to explain the fundamental principles of Soil Science in a manner that you will find relevant to your interests. Throughout, the text emphasizes the soil as a natural resource and soils as ecosystems. It highlights the many interactions between soils and other components of forest, range, agricultural, wetland, and constructed ecosystems. This book will serve you well, whether you expect this to be your only formal exposure to soil science or you are embarking on a comprehensive soil science education. It will provide both an exciting, accessible introduction to the world of soils and a reliable, comprehensive reference that you will want to keep for your expanding professional bookshelf.

If you are an instructor or a soil scientist, you will benefit from changes in this latest edition. Most noticeable is the use of full-color throughout which improves the new and refined figures and illustrations to help make the study of soils more efficient, engaging, and intellectually satisfying. Every chapter has been thoroughly updated with the latest advances, concepts, and applications. Hundreds of new key references have been added.

This edition includes in-depth discussions on such topics of cutting edge soil science as the pedosphere concept, new insights into humus and soil carbon accumulation, subaqueous soils, soil effects on human health, principles and practice of organic farming, urban and human engineered soils, cycling and plant use of silicon, inner- and outer-sphere complexes, radioactive soil contamination, new understandings of the nitrogen cycle, cation saturation and ratios, acid sulfate soils, water-saving irrigation techniques, hydraulic redistribution, cover crop effects on soil health, soil food-web ecology, disease suppressive soils, soil microbial genomics, indicators of soil quality, soil ecosystem services, biochar, soil interactions with global climate change, digital soil maps, and many others. In response to their popularity in recent editions, I have also added many new boxes that present either fascinating examples and applications or technical details and calculations. These boxes both highlight material of special interest and allow the logical thread of the regular text to flow smoothly without digression or interruption.

Examples of applications boxes or case study vignettes include:

• “Dirt for Dinner”
• “Subaqueous Soils—Underwater Pedogenesis”
• “Practical Applications of Unsaturated Water Flow in Contrasting Layers”
• “Char: Is Black the New Gold?”
• “Where have All the Humics Gone?”
• “Tragedy in the Big Easy—A Levee Doomed to Fail”
• “Costly And Embarrassing Soil pH Mystery”
• “Gardeners’ Friend not Always so Friendly
• “Soil Microbiology in the Molecular Age”
• “The Law of Return Made Easy: Using Human Urine”
Boxes also are provided to explain detailed calculations and practical numerical problems. Examples include:
• “Estimating CEC and Clay Mineralogy”
• “Calculating Lime Needs Based on pH Buffering”
• “Leaching Requirement for Saline Soils”
• “Calculation of Percent Pore Space in Soils”
• “Calculating Soil CEC From Lab Data”
• “Toward a Global Soil Information System”
• “Calculation of Nitrogen Mineralization”
• “Calculating a Soil-Quality Index for Plant Productivity”

As the global economy expands exponentially societies face new challenges with managing their natural resources. Soil as a fundamental natural resource is critical to sustained economic growth and the prosperity of people in all parts of the world. To achieve balanced growth with a sustainable economy while improving environmental quality, it will be necessary to have a deep understanding of soils, including their properties, functions, ecological roles, and management. I have written this textbook in a way designed to engage inquisitive minds and challenge them to understand soils and actively do their part as environmental and agricultural scientists, in the interest of ensuring a prosperous and healthy future for humanity on planet Earth.

This understanding must include the role of healthy soils in agricultural applications and the pressing need for increasing food production. However, it must also include knowledge of the many other ecosystem services provided by soils. In this textbook I have tried to take a broad view of soils in the environment and in relation to human society. In so doing, the book focuses on six major ecological roles of soil. Soils provide for the growth of plants, which, in turn, provide wildlife habitat, food for people and animals, bio-energy, clothing, pharmaceuticals, and building materials. In addition to plant production, soils also dramatically influence the Earth’s atmosphere and therefore the direction of future climate change. Soils serve a recycling function that, if taken advantage of, can help societies to conserve and reuse valuable and finite resources. Soils harbor a large proportion of the Earth’s biodiversity—a resource which modern technology has allowed us to harness for any number of purposes. Water, like soil, will be a critical resource for the future generations. Soils functions largely determine both the amount of water that is supplied for various uses and also the quality and purification of that water. Finally, knowledge of soil physical properties and behavior, as well as an understanding of how different soils relate to each other in the landscape, will be critical for successful and sustainable engineering projects aimed at effective and safe land development.

For all these reasons it will be essential for the next generation of scientists, business people, teachers, and other professionals to learn enough about soils to appreciate their importance and to take them into full consideration for development projects and all activities on the land. It is my sincere hope that this book, early editions of which have served so many generations of soil students and scientists, will allow new generations of future soil scientists to benefit from the global ecological view of soils that this textbook expounds.

Dr. Nyle Brady, although long in retirement and recently deceased, remains as co-author in recognition of the fact that his vision, wisdom, and inspiration continue to permeate the entire book. Although the responsibility for writing the 15th edition was solely mine, I certainly could not have made all of the many improvements without innumerable suggestions, ideas, and corrections contributed by soil scientists, instructors, and students from around the world. The 15th edition, like preceding editions, has greatly benefited from the high level of professional devotion and camaraderie that characterizes the global soil science community.

Special thanks go to Dr. Rachel Gilker for her invaluable editorial and research assistance. I also thank the following colleagues (listed alphabetically by institution) for their especially valuable suggestions, contributions, reviews, and inspiration: Pichu Rengasamy (The University of Adelaide); Michéli Erika (Univ. Agricultural Science, Hungary); Duane Wolf (University of Arkansas); Tom Pigford (University of California, Berkeley); Thomas Ruehr (Cal Poly State University); J. Kenneth Torrence (Carleton University); Pedro Sanchez and Cheryl Palm (Columbia University); Harold van Es and Johannes Lehmann (Cornell University); Eric Brevik (Dickinson State University); Dan Richter (Duke University); Owen Plank (University of Georgia); Robert Darmody, Laura Flint Gentry, Colin Thorn, and Michelle Wander (University of Illinois); Roland Buresh (International Rice Research Institute); Lee Burras (Iowa State University); Aurore Kaisermann (Laboratoire Bioemco); Daniel Hillel (University of Massachusetts, Emeritus); Lyle Nelson (Mississippi State University, Emeritus); Jimmie Richardson (North Dakota State University); Rafiq Islam and Rattan Lal (The Ohio State University); David Munn (Ohio State ATI); Darrell Schultze (Purdue University); Joel Gruver (Western Illinois University); Ivan Fernandez (University of Maine); David Lobb (University of Manitoba); Mark Carroll, Glade Dlott, Delvin Fanning, Nicole Fiorellino, Robert Hill, Bruce James, Natalie Lounsbury, Brian Needelman, Martin Rabenhorst, Patricia Steinhilber, and Stephane Yarwood (University of Maryland); Martha Mamo (University of Nebraska); Jose Amador (University of Rhode Island); Russell Briggs (State University of New York); Allen Franzluebbers, Jeff Herrick, Scott Lesch, and Jim Rhoades (USDA/Agricultural Research Service); Bob Ahrens, Bob Engel, Maxine Levine, Paul Reich, Randy Riddle, Kenneth Scheffe,
and Sharon Waltman (USDA/Natural Resources Conservation Service); Markus Kleber (Oregon State University); Henry Lin (The Pennsylvania State University); Joseph Heckman (Rutgers, The State University of New Jersey); Fred Magdoff and Wendy Sue Harper (University of Vermont); W. Lee Daniels, John Galbraith (Virginia Tech); Peter Abrahams (University of Wales); Luther Carter (Washington, DC); Clay Robinson (West Texas A & M University); Tor-G. Vagen (World Agroforestry Center); Larry Munn (University of Wyoming); and Tom Siccama (Yale University).

Last, but not least, I deeply appreciate the good humor, forbearance, and patience of my wife, Trish, and those students and colleagues who may have felt some degree of neglect as I focused so much of my energy, time, and attention on this labor of love.
RRW
College Park, Maryland, USA
February 2016