Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 4, 2004
Publication Date: November 4, 2004
Citation: Kaspar, T.C., Parkin, T.B. 2004. Soil CO2 Flux on a Hillslope Transect in Relation to Terrain Variables, Soil Texture, Soil OM, and Residue Inputs [CD-ROM]. ASA-CSSA-SSSA Annual Meeting Abstracts. Madison, Wisconsin.
Increasing soil organic matter in agricultural systems has been promoted as one approach for reducing the rate of carbon dioxide accumulation in the atmosphere. Increasing soil carbon requires that either inputs of carbon increase or that losses of carbon decrease. Carbon dioxide flux from the soil surface is the primary pathway for carbon loss from soil. Therefore, it is important to understand how carbon dioxide flux varies across hillslopes in relation to terrain variables, soil texture, soil organic matter, and crop residue inputs. Measurements of soil carbon dioxide flux were made using a 15-cm diameter circular chamber and a portable infra-red gas analyzer. Two measurements were made at weekly intervals from June to August in 2002 and 2003 at each of 12 georeferenced locations along a hillslope in a normal corn-soybean production field. Crop plants were removed in a 2-m radius around the chambers. Carbon dioxide flux averaged over sampling dates for each location were not strongly correlated with slope, elevation, soil texture, or soil carbon in the initial analysis. Carbon dioxide flux did vary among the sampling locations and the ratio of carbon inputs to carbon flux at the summit location was much lower than at the other locations.