The use of terrain analysis and cesium isotope data in the hydropedologic modeling of soil organic carbon.
(S05-venteris862488-poster)
Authors:
E.R. Venteris* - USDA-ARS-EQL G.W. McCarty - USDA-ARS-EQL J.C. Ritchie - USDA-ARS-HRSL
Abstract:
Soil organic carbon (SOC) distribution at the field scale is controlled by vegetative production, microbial oxidation, and transport by tillage and water. Such processes are partially related to topography-driven hydrology. Digital elevation models (DEMs) are potentially useful for spatial modeling. Field scale soil sampling was conducted in Ames, Iowa (till with prairie potholes, mollisols), Coshocton, Ohio (residual/colluvial ultisols and alfisols), and Beltsville, Maryland (coastal plain ultisols).
SOC and radioactive fallout 137Cs were measured. Regressions were calculated between carbon,
137Cs, and terrain attributes from high-resolution (2-5m) DEMs. Attributes include indexes commonly used for soil wetness and erosion modeling (stream power, 2-D slope-length factor). In the Iowa, SOC was highly correlated (r2=0.8) to 137Cs and the wetness index (r2=0.7). In Ohio, results contrasted with management and topography. Steep and extensively tilled watersheds showed the highest correlation between 137Cs and SOC. Carbon was weakly predictable (r2=0.2-0.6) and erosion was not predictable from terrain parameters. In Maryland SOC was not strongly correlated to 137Cs or topographic parameters (r2= ~0.30). Terrain models work well on the glacial soils of central Iowa, consistent with past work. Topography alone is insufficient for carbon and erosion prediction for the Ohio and Maryland sites.
Speaker Information: Erik Venteris, USDA-ARS-EQL, Environmental Quality Laboratory Animal and Natur, Beltsville, MD 20705; Phone: 301 504 5086; E-mail: [email protected]
Session Information: Wednesday, November 5, 2003, 4:00 PM-6:00 PM Presentation Start: 4:00 PM (Poster Board Number: 1308)
Keywords: hillslope processes; soil organic carbon; terrain analysis; cesium
