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General Description for Soil Characterization DataData Product KeywordsSoils, soil survey investigations, soil characterization data, soil laboratory data, soil research data, physical soil data, chemical soil data, mineralogical soil data, pedon descriptions. SummaryThe database of the Soil Survey Laboratory (SSL), National Soil Survey Center, currently contains analytical data for more than 20,000 pedons of U. S. soils and about 1,100 pedons from other countries. Standard morphological pedon descriptions are available for about 15,000 of these pedons. Partial data for pedons currently being analyzed may be unavailable. Soil fertility measurements, such as those made by Agricultural Experiment Stations, were not made. Most of the data were obtained over the last 40 years. About 3/4 of the data is less than 20 years old. Analytical data for most of the pedons is fairly complete, according to the prevailing view of the research and characterization needs when the pedon was sampled. Generally, the kinds of analyses have increased over time. Extent of ProgramInternational. Available Product CoverageCoverage is for all 50 states, Puerto Rico, Virgin Islands, Trust Territories, and some foreign nations. Information ContentSample site selection, morphological pedon descriptions, and sample collection were by experienced soil scientists. Sample preparation and analytical procedures are described in Soil Survey Investigations Report, No. 42, Natural Resources Conservation Service, 1992. Analytical determinations were either made by soil scientists or by analysts supervised by soil scientists. Computer data handling techniques and calculations of primary and derived data were developed by experienced SSL soil scientists, competent in laboratory operations and computer programming. The National Soil Characterization Database is composed of the SSL working computer files. It includes data that may or may not represent the central concept of a soil series or map unit and pedons sampled to bracket a range of soil properties within a series or a landscape. For research purposes, all such data are retained in the database. Users unfamiliar with a given soil may want to consult a knowledgeable soil scientist to determine how well the data represents a soil series. Furthermore, the database has not been edited to remove all of the erroneous or sometimes misleading data. Users are responsible for the assessment of the accuracy and applicability of the data. Product Delivery FormatThe characterization data are stored in a fixed length, column positional, tab-delimited file structure, with a two-record freeform header, in master and state data sets, ASCII format. The data are available on one standard CD-ROM disk. The data are also available on-line through the Internet WWW at http://ssldata.nrcs.usda.gov/. Technical and Ordering InformationTo obtain technical information about these data, please contact Steven L. Baird at:
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