From the Foreward: "The 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 soil taxonomy with recent changes in the classification system. The twelfth edition of the Keys to Soil Taxonomy incorporates all changes approved since the publication in 1999 of the second edition of Soil Taxonomy: A Basic System of Soil Classification for Making and Interpreting Soil Surveys."
"Web Soil Survey (WSS) provides soil data and information produced by the National Cooperative Soil Survey. It is operated by the USDA Natural Resources Conservation Service (NRCS). ... NRCS has soil maps and data available online for more than 95 percent of the nation’s counties."
Maintained by the Food and Agriculture Organization of the United Nations. "This portal is designed as a source of soil information... for policy makers, development planners, soil scientists, agricultural extension officers, students and other practitioners."
"The Soil and Water Resources Conservation Act (RCA) provides broad natural resource strategic assessment and planning authority for the U.S. Department of Agriculture (USDA). The purpose of the RCA is to ensure that USDA programs for the conservation of soil, water, and related resources are responsive to the long-term needs of the Nation."