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soil taxonomy
The Soil Survey Staff, in the context of this book, is the group of soil scientists making and interpreting soil maps in the United States Department of Agricul- ture, the land-grant universities, and many foreign countries.
This technical description of soil taxonomy defines the categories and classes, gives data and descriptions for selected soils, and explains the meanings of soil class names used in the publication "Soil Series of the United States, Puerto Rico, and the Virgin Islands: Their Taxonomic Classification."
The first six chapters present general principles and concepts and give cross references for definitions of selected criteria. Later chapters discuss the classifica- tion of specific soil orders.
The taxonomy differs in many ways from earlier systems and from others that are in current use. It has been in use in the United States for about 7 years at this writing, but this is its first complete publica- tion as it applies to the soils of the United States.
Soon after World War II, efforts were launched in many countries to improve agricultural production. Research was stimulated, and soil survey efforts were extended to many new areas.
With new research data and broader experience we came to realize that our soil classification was inade- quate in precision for the demands being made of it. In particular we recognized that we needed more pre- cise categories in order to make more quantitative and reliable interpretations for our soil surveys. Our foreign colleagues agreed with us, and so the decision was made to start work on a new classification system in 1951. We realized that to be sful this effort successful would require the knowledge and experience of soil scientists not only in the United States but also in all parts of the world.
About 5,500 soil series had been recognized in the United States when this new effort began in 1951. We were using a soil classification this publication as system, the 1938 system, that refe referred to in was very use- ful for grouping most of these series in higher catego- ries. As the geographic extent of soil surveys became greater and as the number of soil series increased, the
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