Purpose: This soil survey depicts information about soil features on or near the surface of the Earth. These data were collected as part of the National Cooperative Soil Survey
Soil scientists identify small areas of soils or nonsoil areas (special soil features) that have properties and behavior significantly different than the named soils in the surrounding map unit. Other inclusions that have a minimal effect on use and management, or those that could not be precisely located, were not mapped.
Specific limits were established on the classification of soils, design and name of map units, location of special soil features, and the percentages of allowable inclusions. These limits are outlined in the U.S. Department of Agriculture. 1975. Soil Taxonomy: A basic system of soil classification for making and interpreting soil surveys. Soil Conserv. Serv., U.S. Dep. Agric. Handb. 436.; U.S. Department of Agriculture. 1992. Keys to Soil Taxonomy. SMSS Technical monograph No. 19. Soil Surv. Staff, Soil Conserv. Serv.; U.S. Department of Agriculture. 1993. National Soil Survey Handbook, title 430-VI. Soil Surv. Staff, Soil Conserv. Serv.; and U.S. Department of Agriculture. 1993. Soil Survey Manual. Soil Surv. Staff, U.S. Dep. Agric. Handbook 18.
The actual composition and interpretive purity of the map unit delineations were based on statistical analysis of field ovservations and transect data. 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 kins of map units are used in soils 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 componenets so similar the 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 componenet 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 dissimlar 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 esceed 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 inerpretive purity of the map unit delineations is attained by adjusting the kind and intensity of field investigations. field investigations and data collection are carred out in sufficient detail to name map units and to identify accurately and consistently areas of about 6 acres.
For example, on long gently sloping landscapes the transition occurs gradually over many feet. Where landscapes change abruptly from steep to level, the transition will be very anorrow. Soil delineation boundaries and special soil features generally were digitized within 0.01 inch of their locations on the digitizing source. The digital map elements are edge matched between data sets. The data along each quadrangle edge are matched aginast the data for the adjacent quadrangle. Edge locations generally do not deviate from centerline to centerline by more than 0.01 inch.
The map unit symbol uniquely identifies each closed delineation map unit. Each symbol is linked to a map unit name. The map unit symbol is also the key for linking information in the Map Unit Interpretations Record tables. The map unit symbols are not carried within the modified Digital Line Graph file; however, they are made available in a companion attribute file. the attribute file links the minor codes in the Digital line Graph files to the map unit symbols.
Map Unit Delineations are described by the Map Unit Interpretations Record data base. this attribute data base gives the proportionate extent of the componenet soils and the properties for each soil. The data base contains both estimated and measured data on the physical and chemical soil properties and soil interpretations for engineering, water management, recreation, agronomic, woodland, range, and wildlife uses of the soil The soil Map Unit Interpretations Record data base consists of the folllowing relational tables: codes (data base codes) - stores information on all codes used in the data base comp (map unit component) - stores information for soil map 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 heldclass (highly erodible lands class - stores the highly erodible land classification for wind and water assigned to the soil map units. Table not populated. 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) - sotres 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 muyld (map unit yield) - stores crop yield information for the soil map unit plantcom (plant composition) - stores plant symbols and percent of plant composition assocaited with components of a soil map unit. Table not populated. plantnm (plant name) - stores the common and scientific names for plants used in the data base 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 data base 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 tis programs on the basis of race, coor, national origini, sex, religion, age, disability, political beliefs, and marital or familial status. (Not all prohibited bases apply to all programs.)