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Soil Genesis and Classification, Fifth Edition. STANLEY W. cusses the Interpretations of Soil Surveys and TechnicalBUOL, RANDAL J. SOUTHARD, ROBERT C. GRAHAM, Soil Classification.and PAUL A. McDANIEL. Iowa State Press, 2121 South State The first chapter outlines the main themes of soil genesisAvenue, Ames, Iowa 50014. 2003. Hardback, 494 p. $79.99. and classification as soil morphology, soil characterization,ISBN 0-8138-2873-2. soil classification, soil mapping, and soil interpretation. The

historical perspectives and relationships among soil formationThis book contains the most current information for theconcepts and soil classification are well presented. The authorsscientific field of pedology, the study of soil genesis, morphol-warn about “avoiding rigor mortis” in soil classification andogy, and classification. As stated in the preface, it “presentsadvise soil classifiers to maintain a “self-destruct mechanism,”the current understanding of soil as a thin layer of the earth’swhich allows continued reevaluation of the theories that makesurface that forms an interface between the inorganic mineralsup the genetic thread of soil taxonomy.of the earth’s crust and the organic components of biological

The vertical movement of the volume we classify as soil isentities living on the land and in the surrounding environ-stressed in Chapter 5, Space and Time in Soil Formation. Thement.” Soil genesis, or the understanding of soil formationauthors point out that the surface of the soil is not a fixedprocesses, is presented using the concept of soil as a “dynamicplain but is subject to lowering from both erosion and dissolu-natural entity that interfaces with ecosystems and human en-tion and raising by deposition from both sedimentation anddeavors.” Major international soil classification systems areaerosol deposition (i.e., surficial geologic processes are criticalbriefly discussed with a major emphasis on the most recentto understanding spatial patterns of soil).1999 edition of Soil Taxonomy.

All of the United States soil taxonomy information hasFour previous editions preceded this fifth edition of Soilbeen made current with the most recently published 1999Genesis and Classification. The first edition of this book wasedition of Soil Taxonomy (USDA Agric. Handb. 436). Newpublished in 1973. The second edition was published seventaxonomic formative elements, such as “oxyaquic,” have beenyears later in 1980, the third edition in 1989, and the fourthincluded and discussed in this edition. The chapter on Gelisolsedition in 1997.has been updated to reflect the latest information about theseThis fifth edition of the book is dedicated to Francis D.very cold soils. The several categories of U.S. soil taxonomyHole and Ralph J. McCracken, “stalwart authors” of the firstare discussed in one chapter rather than separating the Familyfour editions, and their former teacher, James A. Thorp. Theand Series categories from higher taxa as was done in ear-primary author for all five editions is Stanley W. Buol. Randalllier editions.J. Southard began as an author with the fourth edition and

The relationship between soil classification and soil map-now moves up to second author of this edition. Robert C.ping is discussed in Chapter 20. The important distinctionGraham and Paul A. McDaniel are added as new authorsbetween soil map units (the soilscapes) and soil taxonomicfor this fifth edition. Contributions of these new authors hasunits (taxonomic abstractions) is emphasized. Many excellentbrought new perspectives to several chapters and has helpedexamples of soilscapes are illustrated and discussed to demon-to advance the understanding of soil formation concepts.strate soil spatial variability. Human land use considerationsThere are 21 chapters in this edition. The first six chaptersrelated to each of the 12 U.S. soil orders are presentedappear are Introduction, Morphology and Classification, Bio-throughout the book, with a discussion of soil interpretationsgeochemical Processes in Soil Formation, Soil as a Componentand technical soil classification in the last chapter.of the Ecosystem, Space and Time in Soil Formation, and

Especially worthy of note is the 82-page bibliography thatModern Soil Classification Systems. Chapter 7 introduces U.S.is likely the most extensive listing of classical and modern soilSoil Taxonomy. Chapters 8 through 19 thoroughly (and alpha-genesis and classification publications. Throughout this fifthbetically) discuss the 12 U.S. soil orders as follows: Alfisols:edition, many new citations of literature published since theHigh Base Status Soils with Finer-Textured Subsoil Horizons,fourth edition have been added.Andisols: Soils with Andic Properties, Aridisols: Soils of Dry

In summary, I thoroughly enjoyed this book and especiallyRegions, Entisols: Recently Formed Soils, Gelisols: Very Coldappreciated the incorporation of the most recent U.S. soilSoils, Histosols: Organic Soils, Inceptisols: Embryonic Soilstaxonomy revisions. This new edition is a most valuable text-with Few Diagnostic Features, Mollisols: Grassland Soils ofbook resource for introductory and advanced universitySteppes and Prairies, Oxisols: Low-Activity Soils, Spodosols:classes in soil genesis, morphology, and classification. It willSoils with Subsoil Accumulations of Humus and Sesquioxides,also serve well as a recommended textbook for several otherUltisols: Low Base Status Soils with Finer-Textured Subsoilenvironmental soil science and geoarcheology courses.Horizons, and Vertisols: Shrinking and Swelling Dark Clay

Soils. Chapter 20 is entitled the Spatial Arrangement of Soils: Thomas J. RiceSoilscapes and Map Units. Chapter 21, the final chapter, dis- Earth and Soil Sciences Department

California Polytechnic State UniversityOne Grand AvenuePublished in Vadose Zone Journal 2:767 (2003).

San Luis Obispo, CA 93407 Soil Science Society of America677 S. Segoe Rd., Madison, WI 53711 USA (trice@calpoly.edu)

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