NOTICE (September 2017): Data previously stored at the CDIAC archive are being transitioned to the new, ESS-DIVE archive. This website provides access to the CDIAC data during the transition. If you have any questions regarding the new archive or the data transition, please contact

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Estimated Annual Net Change in Soil Carbon per US County

These data represent the estimated net change (Megagram per year) in soil carbon due to changes in the crop type and tillage intensity. Estimated accumulation of soil carbon under Conservation Reserve Program (CRP)lands is included in these estimates. Negative values represent a net flux from the atmosphere to the soil; positive values represent a net flux from the soil to the atmosphere. As such, soil carbon sequestration is represented here as a negative value.

The method of analysis is based on empirical relationshipsbetween land management and soil carbon. The method for modeling land management and estimating soil carbonchange, used to generate these data, is described in the following publication:

West, T.O., C.C. Brandt, B.S. Wilson, C.M. Hellwinckel, D.D.Tyler, G. Marland, D.G. De La Torre Ugarte, J.A. Larson, and R.G. Nelson. 2008. Estimating Regional Changes in Soil Carbon withHigh Spatial Resolution. Soil Science Society of America Journal 72: 285-294.

Tabular data are provided by county and by year in Excel and CSV formats.

Spatial data are provided below in Excel, CSV, and zipped ArcGIS Shapefile formats (v.9.2) Shapefile.

Years 1990-2004 Years 1990-2008 (Version 2)
Excel file Excel (948Kb) Excel 2007 file Excel (1.11Mb)
CSV file CSV (461Kb) CSV file CSV (737Kb)
Zipped ArcGIS Shapefile ArcGIS (0.99Mb)