Determining Rates of Carbon Sequestration in Soil: Carbon stabilization after 2.5 years of incubation. (6205)
Authors:
C.E. Stewart* - NREL, Colorado State Univ.
A.F. Plante - NREL, Colorado State Univ.
R.T. Conant - NREL, Colorado State Univ.
J. Six - University of CA, Davis
K. Paustian - NREL, Colorado State Univ.
Abstract:
Increasing soil C through changes in land use and management is a low cost and environmentally beneficial method of sequestering atmospheric CO2. However, it has been hypothesized that soils have an inherent upper limit above which no additional C can be stored regardless of increasing C inputs.
The magnitude of this upper or ‘saturation’ limit will govern the ultimate significance of the soil sink and the time period over which it can be exploited for CO2 sequestration. We investigated the role of physiochemical soil characteristics in determining soil C saturation levels and impacts on C
sequestration rates. Specifically, we examined the C saturation concept by incubating soils from six agricultural sites that are close to (i.e. A-horizon) or far from (i.e. C-horizon) saturation with low and high addition rates of 13C-labeled wheat straw. We report whole soil C-stabilization results after 0.5, 1.5 and 2.5 years of incubation. Over time, there was little effect of addition rate, while the C- horizon retained a greater fraction of added residue than the A-horizon of most sites. Higher C stabilization in the C-horizon soils occurs because those soils are further from their ‘saturation’ limits.
Speaker Information: Catherine Stewart, NREL, Colorado State Univ., Natural Resource Ecology Lab, Fort Collins, CO 80523-1499; Phone: 970-491-1604; E-mail: [email protected]
Session Information: Tuesday, November 2, 2004, 7:55 AM-12:05 PM Presentation Start: 8:45 AM
Keywords: carbon pools; carbon sequestration; aggregation; incubation
