Previous Versions of Keys to Soil Taxonomy

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7th Approximation (PDF; 9.52 MB)

Supplement to the 7th Approximation (PDF; 5.37 MB)

Soil Taxonomy, 1975 (PDF; 60.5 MB)
   Amendments to Soil Taxonomy, 1975 (obsolete)

1st Edition of Keys to Soil Taxonomy, 1983 (PDF; 3.65 MB)

2nd Edition of Keys to Soil Taxonomy, 1985 (PDF; 3.12 MB)

3rd Edition of Keys to Soil Taxonomy, 1987 (PDF; 4.22 MB)

4th Edition of Keys to Soil Taxonomy, 1990 (PDF; 7.60 MB)

5th Edition of Keys to Soil Taxonomy, 1992 (PDF; 7.96 MB)

6th Edition of Keys to Soil Taxonomy, 1994 (PDF; 8.91 MB)

7th Edition of Keys to Soil Taxonomy, 1996 (PDF; 8.50 MB)

8th Edition of Keys to Soil Taxonomy, 1998 (PDF; 1.19 MB)
   Summary of Changes (DOC; 59 KB)

9th Edition of Keys to Soil Taxonomy, 2003 (PDF; 3.23 MB)