Technical Reviews

Building Soils for Better Crops (Second Edition)

Fred Magdoff and Harold Van Es

Sustainable Agriculture Network, Washington D.C. 2000

This book is a practical guide to understanding and managing soil. It was written primarily for farmers, extension advisors, students, and gardeners, and focuses on the importance of soil health in sustaining agricultural production and rural communities. The first edition of this book focused exclusively on soil organic matter as a key component of productive soils. In the second edition, organic matter is still the main emphasis, but it is now more comprehensive with additional information on managing soil physical properties, and farmer profiles that provide insight into the practical issues and challenges of managing soils. The text is clearly written in a farmer-friendly format, and provides clear descriptions of how soil systems function and how farming practices impact those systems.

The book consists of three main sections: 1) The Basics of Soil Organic Matter, Physical Properties, and Nutrients; 2) Ecological Soil and Crop Management; and 3) Putting It All Together.

Section 1 covers some of the basic aspects of soil health. Magdoff and Van Es (faculty members at University of Vermont and Cornell University, respectively) define soil health as “how good the soil is in its role of supporting the growth of high yielding healthy crops.” They briefly address the various factors that determine soil health (e.g., nutrients, tilth and depth, drainage, level of disease and weed organisms, level of toxic chemical residues, and how well the soil can resist degradation) and then turn their attention to the very deliberate process of building healthy soil. Organic matter is the critical factor in this process, and is the major focus for this first section: What it is, why it is so important to farmers, and how to increase the level in soils. Continuing the theme of “soil building,” this section also covers the importance soil physical properties, and provides excellent discussions of water and aeration, tillage effects, erosion, and compaction, to complement the discussion of organic matter.

The second section looks at specific practices that can be used to increase soil quality and productivity. Specific chapters address: animal manures, cover crops, crop rotations, making and using composts, reducing soil erosion, preventing/lessening compaction, and reducing tillage. Ecological approaches may not result in as precise a nutrient supply as with conventional fertilizers, so two chapters are devoted to managing nutrients in sustainable systems. Nitrogen and phosphorus receive special consideration because of their potential to pollute water supplies. The authors provide an informative and realistic discussion of the benefits and challenges of managing these two nutrients in more biologically based systems. Having accurate information about soil nutrient levels is key in this task; one entire chapter focuses on soil testing. Because soil tests have limitations and cannot be solely relied upon for making management decisions, the authors provide recommendations on how to conduct soil tests wisely, and examples of interpreting the results for different geographic and soil conditions.

Through the first two sections, Building Soils for Better Crops looks at a wide range of practices that can increase the quality and health of soil. The final section, Putting It All Together, gives guidance about how to assess the effectiveness of these practices, and how to modify and combine them in ways that make the most sense for your farm. As previously noted, soil tests provide a limited snapshot of one aspect of soil health: nutrient levels. The concept of soil quality goes much further than just nutrients, however. Assessing soil health, according to the authors, requires a combination of intuition, qualitative measures, and some quantitative analyses. Table 1 provides an overview of recommended measures as determined by research conducted in Maryland, Oregon and Wisconsin.

Decisions about which practices to use on your farm need to be based on the economic bottom line. But that assessment, say Magdoff and Van Es, should be made for the long-term, i.e., looking at potential economic returns over a generation, not just the immediate crop season. This long-term perspective needs to be supported by careful observations and record keeping, clear goal setting and planning, and a thorough knowledge of the limitations and opportunities of your particular farming system.

Building Soils for Better Crops is 230 pages in length and includes a glossary, resource list, index, and many useful tables and figures.

For more information: Sustainable Agriculture Network, (301) 504-6425. Web site: www.sare.org

DEC. 605

Contributed by David Chaney