"Kellogg Soil Survey Laboratory Methods Manual, Soil Survey Investigations Report (SSIR) No. 42, Version 6.0," is now available. The files for both Part 1, Current Methods, and Part 2, Obsolete Methods, are available on the KSSL Guidance page. The methods described in the manual are those used by the USDA Kellogg Soil Survey Laboratory (KSSL) at the National Soil Survey Center.

• Part 1, Current Methods
• Part 2, Obsolete Methods

The purpose of the manual is to document methodology and to serve as a reference for the laboratory analyst. The development of laboratory methods for Soil Survey is the cumulative effort of decades of investigation. The manual has changed over time as new knowledge and technologies resulted in the development of new methods and the modification or retirement of old methods.

Laboratory data are critical to the understanding of the properties and genesis of a single pedon, as well as to the understanding of fundamental soil relationships based on many observations of a large number of soils. All of the methods in the manual are documented by codes that link them to analytical results stored in the National Cooperative Soil Survey (NCSS) Soil Characterization Database. This linkage between laboratory method codes and the respective analytical results are reported on the KSSL data sheets.

Some analytical results in the NCSS Soil Characterization Database were obtained using procedures that are no longer used at the KSSL. Descriptions for these procedures are in Part two, Obsolete Methods, and provide a historical perspective.

The methods currently in use at the laboratory are described in enough detail that they can be performed at many laboratories without reference to other sources. An introduction to each group of related methods describes common characteristics.