Keys to Soil Taxonomy
United States Department of Agriculture
United States Department of Agriculture: Natural Resources Conservation Service
The publication of this edition of Keys to Soil Taxonomy (the 10th edition) coincides with the 18th World Congress of Soil Science, to be held at Philadelphia, Pennsylvania, in July 2006. The last time the World Congress was hosted in the United States was in 1960 at Madison, Wisconsin. At that time, Soil Classification: A Comprehensive System, 7th Approximation was released for review and testing. The classification system was officially adopted for use in the United States soil survey program in 1965. The first edition of Soil Taxonomy: A Basic System of Soil Classification for Making and Interpreting Soil Surveys was published in 1975. Over the years Soil Taxonomy has been modified and expanded to reflect our increased knowledge of the world’s soils. After the first eight editions of the Keys to Soil Taxonomy were released, the second edition of Soil Taxonomy was published in 1998. Since then, the 9th edition of the keys was published in 2003, and now this 10th edition in 2006. The publication Keys to Soil Taxonomy serves two purposes. It 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 the taxonomic system with recent changes in the system. This edition of the Keys to Soil Taxonomy incorporates all changes approved since publication of the ninth edition in 2003. We plan to continue issuing updated editions of the Keys to Soil Taxonomy as changes warrant new editions. The authors of the Keys to Soil Taxonomy are identified as the “Soil Survey Staff.” This term is meant to include all of the soil classifiers in the National Cooperative Soil Survey program and in the international community who have made significant contributions to the improvement of the taxonomic system.
soil taxonomy, mineral soils, organic soils