What is the difference between SSURGO and STATSGO soils data?

The two most used soils databases are the State Soil Geographic (STATSGO) and Soil Survey Geographic (SSURGO).

"The STATSGO data base was designed primarily for regional, multistate, river basin, state and multicounty resource planning, management, and monitoring. STATSGO data are not detailed enough to make interpretations at a county level." (SSURGO Data Use Information, USDA, p. 2) The STATSGO database is produced by generalizing more detailed databases.

SSURGO data are much more detailed than STATSGO data. "The SSURGO data base provides the most detailed level of information and was designed primarily for farm and ranch, landowner/user, township, county, or parish natural resource planning and management. Using the soil attributes, this data base serves as an excellent source for determining erodible areas and developing erosion control practices; reviewing site development proposals and land use potential; making land use assessments and chemical fate assessments; and identifying potential wetlands and sand and gravel aquifer areas." (SSURGO Data Use Information, USDA, p. 1)

For our purposes, the main difference between STATSGO and SSURGO data is the number of components that a map unit can contain. The detailed SSURGO map units can contain a maximum of three components and many contain only one or two components. The STATSGO map units, on the other hand, can have up to twenty-one different component soils.