ABSTRACT
The North American Soil Organic Carbon Digital Database was created to determine carbon stocks for North America and to investigate the variations in existing estimates. Prior to this project, soil organic carbon was investigated by Agriculture and Agri-Food Canada (Tamocai, 1994) and the U.S. Department of Agriculture (USDA) (Bliss et al., 1995). The methods to create these two soil organic carbon digital databases were documented (Lacelle, 1998; Bliss et al., 1995). An evaluation of the techniques used to compile the source data for both countries revealed almost identical methodology, so it was expected that the process of combining and mapping these two data sets would be relatively easy. The purpose of this chapter is to discuss the differences in procedure that alter the results or skew perception of the data. After we mapped the United States and Canadian soil organic carbon contents together, a distinct break at the border was apparent. We describe the data characteristics that caused the break and the solutions that were devised to integrate the United States and Canadian soil carbon data. We also mention the general process for calculating soil organic carbon for North America, the data sources, the database model, methods for adding Mexico and Greenland to the database, and map generation.
