The ORNL method uses land cover data derived from NASA satellites to refine geospatial cropland carbon fluxes nationwide. Meanwhile, the Department of Agriculture's cropland data layer enables field-scale delineation of specific crops and allows for refined estimates of carbon fluxes.
Ultimately, this effort provides estimates of net ecosystem exchange of carbon for any given agricultural point in the U.S. This information about carbon flux based on crop, soil and management practices gives a measure of the total vertical carbon flux, including fossil fuel emissions occurring on site.
The research effort also provides estimates of net ecosystem carbon balance, which includes all carbon sources and sinks associated with crop production in a defined area.
"This means that upstream emissions from fertilizer production, for example, are accounted for in the same place where the crop is produced," West said. "This method allows for an estimate of the total impact of changing cropland management on net CO2 emissions."
Cropland management has proved to be an important consideration. For example, researchers reported that reduced tillage practices from 1990 to 2004 resulted in a net emissions reduction of 8.8 million metric tons of CO2 from burning fossil fuels in the U.S.
West notes that this version of the carbon accounting framework can be improved by anticipated improvements in annual crop species-specific biomass and crop residue production.
|Contact: Ron Walli|
DOE/Oak Ridge National Laboratory