The standards and procedures of the National Cooperative Soil Survey program evolve to keep current with scientific knowledge about soils, advances in technical tools being used to conduct soil survey, and the emerging needs of data and information. The primary documents conveying the policy, standards, and procedures include the Soil Survey Manual (Ag. Handbook #18, 1993), the National Soil Survey Handbook (thru Amendment#29, 2014), Soil Taxonomy (2nd
Edition, 1999), and the Keys to Soil Taxonomy (12th
edition, 2014). Several other procedural manuals, field books, National Instructions and technical notes round out the principle guidance documents. These include the Laboratory Methods Manual (SSIR#42, ver5.0, 2014), Field Book for Describing and Sampling Soils (Version 3.0, 2013), Field Soil Survey Laboratory Manual (SSIR#51, 2014), Major Land Resource Regions and Major Land Resource Areas (Ag Handbook #296, 2006), National Instruction 305, 3rd
edition (Soil Data Join and Recorrelation Initiative), and the NASIS User Guides (NASIS ver. 6.4, 2015).
The instructions, guidance, and policy conveyed in these documents are updated regularly to reflect current program requirements. Several of the older documents are under revision at this time. These documents are maintained on the soil survey web pages (soils.usda.gov) and changes and updates are posted for comment and review by users and members of the National Cooperative Soil Survey before integrated into standards. Members are encouraged to conduct research, propose changes, and provide critical review of standard documents, policies, and operating procedures.