ABSTRACT
This chapter describes an approach to characterizing soil organic carbon (SOC) pools at a 4-km spatial resolution over the Pacific Northwest region of the United States. SOC was estimated at the great group level of Soil Taxonomy found that it was at this level and finer of soil classification that factors important to SOC accumulation become most apparent. The relationship of SOC pools to various climatic and soil-texture-related variables was examined using multiple linear regression with all variables averaged at the level of the soil map polygons. SOC at 0- to 50-cm and 50- to 100-cm depths were estimated using a soil characterization database aggregated by soil taxonomic unit. These estimates were spatially extrapolated using the spatial distribution of soil taxonomic units, rock fragment content, and soil depth from a soil geographic database. Additional information related to soil taxonomy includes the fractionation into slow and fast turnover pools.
