In planning soil surveys, this point needs to be emphasized. Such maps quickly become obsolete. They cannot be revised without fieldwork because vital data are missing, facts are mixed with interpretations, or boundaries between significantly different soil units have been omitted. The basic objective of soil surveys is the same for all kinds of land, although the number of mapping units, their composition, and the detail of mapping vary with the complexity of the soil patterns and the specific needs of the users. Thus a soil survey is matched to the soils and the soil-related problems of the area.
Soil surveys increase our general knowledge about soils and serve practical purposes.
They satisfy a need for soils information about specific geographic areas for State, county, and community land-use plans. These plans include resource conservation plans for farms and ranches, development of reclamation projects, forest management, engineering projects, as well as other purposes. ADP helps develop important interpretations and policy decisions for both the present and the future.