Detailed USDA SSURGO soil map data for Accomack and Northampton Counties, VA, 2008-2010.

This dataset contains detailed USDA SSURGO soil information and mapped soil extents for the soils of Accomack and Northampton Counties on Virginia's Eastern Shore, including those areas of focused study by the Virginia Coast Reserve LTER project. This USDA soil data is collected and combined here to make it more accessible to VCRLTER researchers and students, in a more GIS-friendly format, and to supersede previous digitized versions of more generalized soil maps created by the VCRLTER and included as part of the 1995 VCRLTER-Northampton County GIS data archive (dataset VCR14219). Data was downloaded in Jan. 2014 and tabular data for both counties was imported into a MS Access database using the provided standard SSURGO US 2003 template. Spatial data for the two counties was merged together into a single ArcGIS shapefile and selected fields from the MAPUNIT and MUAGGATT tables were joined to the final shapefile's attribute table. Each polygon represents all or part of a SSURGO "mapunit", which may contain multiple component soils; usually very similar soils that grade together or else so heterogeneously mixed together at fine spatial scales to make mapping the component soils individually impractical. Also, each soil typically has multiple vertical soil horizons, each with its own distinct composition (mineral, textural, etc.) and other characteristics. Detailed information about component soils (including typical soil moisture, dry albedo, erodibility indices, taxonomic nomenclature, flooding and ponding characteristics, engineering, crop, forest, and habitat suitability indices and yield tables, and geomorphic descriptions) and component horizons (including horizon depths, grain size distributions, sand/silt/clay fractions, mineral and organic content, and pore space characteristics) is included in the MS Access database but NOT in the combined ArcGIS shapefile. Users interested in exploring or displaying component or horizon information may use the report and query forms within the MS Access database, or they may join selected database tables to the shapefile using the appropriate mukey, cokey, and chkey indices in a one-to-many join within a chosen GIS software.