AbstractThe United States National Cooperative Soil Survey Program has prepared soil maps for much of the country. Both field and laboratory data are used to design map units and provide supporting information for scientific documentation and predictions of soil behavior. Coordination of mapping, sampling site selection, and sample collection in this program contributes to the quality assurance process for laboratory characterization. Requisites to successful laboratory analysis of soils occur long before the sample is analyzed. In the field, these requisites include site selection, descriptions of site and soil pedon, and careful sample collection. A complete description of the sampling site not only provides a context for the various soil properties determined, but it is also a useful tool in the evaluation and interpretation of the soil analytical results. Landscape, landform, and pedon documentation of the sampling site serves as a link in a continuum of analytical data, sampled horizon, pedon, landscape, and overall soil survey area.