Recommended by users for its clear explanations and readability. Troeh and Thompson's Soil; and Soil Fertility provides and excellent overview of soils for students in agriculture and the environmental sciences. Now in its sixth edition, this book has been updated throughout and incorporates discussions of GIS (geographic information system) and GPS (global positioning system), humus and its function in soil structure and fertility, soil reclamation for sites contaminated by pesticides or petroleum spills, and advances in the understanding of water flow. In addition a new chapter on soil mechanics has been added, explaining the use of soils as foundation and construction material.

Although fully updated, the text retains essential information on basic topics such as soil formation, soil chemistry, physical properties of soil, organic matter, mineralogy, and soil water movement and storage. It includes a detailed discussion of plant nutrients, their deficiency symptoms, and the fertilizers and soil amendments used to correct those deficiencies.

Troeh and Thompson make a special effort to provide a uniquely broad perspective, complementing the varied backgrounds and interests of today's students. Instructors and students will appreciate this broad-based approach and through coverage.

Frederick R. Troeh is Professor Emeritus, Agronomy, Iowa State University, Ames, who taught for 32 years. Dr. Troeh also worked for seven years as a soil scientist for the Soil Conservation Society in Idaho and California and served four years as a soil technologist for Cornell University in New York.

Louis M. Thompson is Emeritus Associate Dean of Agriculture and Emeritus Professor of Agronomy, also at Iowa State University. Dr. Thompson based the early editions of Solis and Soil Fertility on thirty years of teaching at Texas A&M and iowa State University. He continued teaching seminars and returned to teach introductory soil science while in the position of Associate Dean of Agriculture. Since retirement, he has published several articles related to the effects of climatic cycles on crop yields.