This data set consists of georeferenced digital map data and computerized attribute data. The source map data are in a 7.5 minute quadrangle format and include a detailed, field-verified inventory of soils and nonsoil areas that normally occur in a repeatable pattern on the landscape and that can be cartographically shown at the scale mapped. A special soil features layer (point and line features) is optional. This layer displays the location of features too small to delineate at the mapping scale, but they are large enough and contrasting enough to significantly influence use and management. The soil map units are linked to attributes in the Map Unit Interpretations Record relational database (oasoil.mdb), which gives the proportionate extent of the component soils and their properties.
Soil scientists identify small areas of soils or miscellaneous (nonsoil) areas that have properties and behavior significantly different than the named soils in the surrounding map unit. These minor components may be indicated as special features. If they have a minimal effect on use and management, or could not be precisely located, they may not be indicated on the map.
Specific National Cooperative Soil Survey standards and procedures were used in the classification of soils, design and name of map units, and location of special soil features. These standards are outlined in Agricultural Handbook 18, Soil Survey Manual, 1993, USDA, SCS; Agricultural Handbook 436, Soil Taxonomy, Soil Survey Staff, 1975, USDA, SCS; and all Amendments; Keys to Soil Taxonomy, Soil Survey Staff, (current issue); National Soil Survey Handbook, title 430-VI, (current issue).
The actual composition and interpretive purity of the map unit delineations were based on data collected by scientists during the course of preparing the soil maps. Adherence to National Cooperative Soil Survey standards and procedures is based on peer review, quality control, and quality assurance. Quality control is outlined in the memorandum of understanding for the soil survey area and in documents that reside with the Natural Resources Conservation Service state soil scientist. Four kinds of map units are used in soil surveys: consociations, complexes, associations, and undifferentiated groups.
Consociations - Consociations are named for the dominant soil. In a consociation, delineated areas are dominated by a single soil taxon and similar soils. At least one half of the pedons in each delineation are of the same soil component so similar to the named soil that major interpretations are not affected significantly. The total amount of dissimilar inclusions of other components in a map unit generally does not exceed about 15 percent if limiting and 25 percent if nonlimiting. A single component of a dissimilar limiting inclusion generally does not exceed 10 percent if very contrasting.
Complexes and associations - Complexes and associations are named for two or more dissimilar components with the dominant component listed first. They occur in a regularly repeating pattern. The major components of a complex cannot be mapped separately at a scale of about 1:24,000. The major components of an association can be separated at a scale of about 1:24,000. In each delineation of either a complex or an association, each major component is normally present, though their proportions may vary appreciably from one delineation to another. The total amount of inclusions in a map unit that are dissimilar to any of the major components does not exceed 15 percent if limiting and 25 percent if nonlimiting. A single kind of dissimilar limiting inclusion usually does not exceed 10 percent.
Undifferentiated groups - Undifferentiated groups consist of two or more components that do not always occur together in the same delineation, but are included in the same named map unit because use and management are the same or similar for common uses. Every delineation has at least one of the major components and some may have all of them. The same principles regarding proportion of inclusions apply to undifferentiated groups as to consociations.
Minimum documentation consists of three complete soil profile descriptions that are collected for each soil added to the legend, one additional per 3,000 acres mapped; three 10 observation transects for each map unit, one additional 10 point transect per 3,000 acres.
A defined standard or level of confidence in the interpretive purity of the map unit delineations is attained by adjusting the kind and intensity of field investigations. Field investigations and data collection are carried out in sufficient detail to name map units and to identify accurately and consistently areas of about 10 acres in areas of low-intensity mapping (Order 3), about 1 acre in areas high intensity mapping (Order 2), and about 20 acres in areas of reconnaissance mapping (Order 4).
codes (database codes) - stores information on all codes used in the database comp (map unit component) - stores information for soil map unit components compyld (component crop yield) - stores crop yield information for soil map unit components forest (forest understory) - stores information for plant cover as forest understory for soil map unit components. Table not populated. helclass (highly erodible lands class) - stores the highly erodible land classification for wind and water assigned to the soil map units hydcomp (hydric component information) - stores data related to the hydric classification, criteria, landform, etc. inclusn (map unit inclusion) - stores the names of soils included in the soil map units interp (interpretation) - stores soil interpretation ratings (both limitation ratings and suitability ratings) for soil map unit components layer (soil layer) - stores characteristics of soil layers for soil map unit components mapunit (map unit) - stores information that applies to all components of a soil map unit mucoacre (map unit county acres) - stores the number of acres for the map unit within a county muident (map unit indentification) - stores the NASIS data base record number of each map unit. This is internal to NRCS and contains no relevant data for external users. muyld (map unit yield) - stores crop yield information for the soil map unit plantcom (plant composition) - stores plant symbols and percent of plant composition associated with components of a soil map unit. Table not populated. plantnm (plant name) - stores the common and scientific names for plants used in the database rangenm (range name) - stores the range site names. Table not populated. rsprod (range site production) - stores range site production information for soil map unit components. Table not populated. ssacoac (soil survey area county acreage) - stores the acreage for the county within the boundary of the soil survey area. ssarea (soil survey area) - stores information that will apply to an entire soil survey area taxclass (taxonomic classification) - stores the taxonomic classification for soils in the database windbrk (windbreak) - stores information on recommended windbreak plants for soil map unit components wlhabit (wildlife habitat) - stores wildlife habitat information for soil map unit components woodland (woodland) - stores information on common indicator trees for soil map unit components woodmgt (woodland management) - stores woodland management information for soil map unit components yldunits (yield units) - stores crop names and the units used to measure yield
Special features are described in the feature table. It includes a feature label, feature name, and feature definition for each special and ad hoc feature in the survey area.
The U.S. Department of Agriculture, nor any of its agencies are liable for misuse of the data, for damage, for transmission of viruses, or for computer contamination through the distribution of these data sets. The U.S. Department of Agriculture prohibits discrimination in its programs on the basis of race, color, national origin, sex, religion, age, disability, political beliefs, and marital or familial status. (Not all prohibited bases apply to all programs.)