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Soil images from the cover of the Keys to Soil Taxonomy.

Keys to Soil Taxonomy

Taxonomic keys for field classification.

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Keys to Soil Taxonomy
Illustrated Guide to Soil Taxonomy
Keys to Soil Taxonomy, Spanish version
Ordering Keys to Soil Taxonomy


Keys to Soil Taxonomy

The Keys to Soil Taxonomy provides the taxonomic keys necessary for the classification of soils in a form that can be used easily in the field. It also acquaints users of soil taxonomy with recent changes in the classification system.

Link to previous versions of Keys to Soil Taxonomy.

Recommended Citation

Soil Survey Staff. 2022. Keys to Soil Taxonomy, 13th ed. USDA-Natural Resources Conservation Service.

Illustrated Guide to Soil Taxonomy

The Illustrated Guide to Soil Taxonomy was produced for use by multiple audiences and is not intended to replace the full version of the Keys to Soil Taxonomy for the professional soil classifier. Some of the more technical and complicated criteria have been omitted or referenced in notes to make the user aware that there are exceptions. More complete criteria and definitions are available in the full version of the Keys to Soil Taxonomy.

This edition of the illustrated guide (version 2.0) is based upon the twelfth edition of the Keys to Soil Taxonomy.

When using the illustrated guide, open the bookmarks tab on the left side of the screen in Adobe Acrobat to navigate the document. 

Recommended Citation

Soil Survey Staff. 2015. Illustrated guide to soil taxonomy. U.S. Department of Agriculture, Natural Resources Conservation Service, National Soil Survey Center, Lincoln, Nebraska.

Keys to Soil Taxonomy, Spanish Version

For decades, NRCS has worked with soil scientists from around the world to increase awareness and expand knowledge of the importance of soil and its impact on all aspects of life. The translation expands the horizons of the Keys to Soil Taxonomy by allowing professionals around the world to apply and interpret the system in a more uniform and consistent way. While soils differ globally, the ability to apply a system that is universally understood and accepted is a goal shared by many soil scientists.

As the world struggles with global warming and other environmental challenges, having a universally accepted method that can be applied when soil problems are addressed will contribute to successful outcomes. Soil scientists and other professionals from Latin America, the United States, and other countries will benefit from this translation effort for years to come.

The translation of the “Keys” into Spanish was performed by Carlos Alberto Ortiz-Solorio, Ma del Carmen Gutiérrez-Castorena, and Edgar V. Gutiérrez-Castorena of Área de Génesis, Morfología y Clasificación de Suelos, Programa de Edafología, Campus Montecillo, Colegio de Postgraduados en Ciencias Agrícolas.

Recommended Citation

Soil Survey Staff. 2014. Claves para la Taxonomía de Suelos, 12th ed. USDA-Natural Resources Conservation Service, Washington, DC.

Ordering Keys to Soil Taxonomy

One copy may be ordered through the NRCS Distribution Center. For larger quantities, please contact your State Soil Scientist.

  1. Order on-line: Go to the NRCS Distribution Center
  2. Order by phone: 888-526-3227
  3. Order by e-mail:

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