Elements of the Nature and Properties of Soils, Brady, Nyle et al, 2000, Prentice Hall; This is the simple version of the text I had in my soil class. It is really dense and a good reference when you settle in to teach soils, but unless you have a lot of organic chemistry under your belt, it will probably serve you as a door stop more than a book.
Out Of The Earth: Civilization and the Life of the Soil, Hillel, Daniel. 1991 Free Press; The paperback is published by University of California Press. Not strictly a soils text, I recommend this book very highly. It is a grand overview of how soils shape civilization and how failure to understand and conserve them has resulted in the fall of civilizations – much more than even losing battles! Worth every second you invest in it!
Soil Science Simplified, 4th Edition, Dohnke, Helmut et al, 1995, Waveland Press; Just like the title says it is very much a simplification of the concepts and scientific principles of soil. A lot of big scientific words, and not light reading, but still highly recommended.
Teaming with Microbes: The Organic Gardener's Guide to the Soil Food Web, Revised Edition Lowenfels, Jeff et al, 2006 Timber Press; Look up all the titles in the Timber Press catalog – one of the more important horticultural publishing houses in business today! I wish I had this book when I started gardening – this book presents the latest research on the ecology of the soil. A must read!
The Gardeners’ Guide to Better Soil, Logsdon, Gene, 1975, Rodale Press; The first book to turn me on to soils and a real page turner, although it’s out of print and a real bear to find. Gene Logsdon is brash, outspoken, political and opinionated. He goes on tangential tirades about the price of gas (in 1975!), but, in part because he is brash, outspoken and opinionated, still he pulls off a book that is informative and easily read and digested.
The Soul of Soil; A Guide to Ecological Soil Management, Gershuny, Grace et al, 1986 Gaia Services; This is a small book, only 109 pages including back notes, but is chock full of information about how to care for your soil. The ‘ecological’ in the title cues you to know that it’s a total organic approach. A great text and easy to read.