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Persistence of soil organic matter in eroding versus depositional landform positions

June 2, 2012

Soil organic matter (SOM) processes in dynamic landscapes are strongly influenced by soil erosion and sedimentation. We determined the contribution of physical isolation of organic matter (OM) inside aggregates, chemical interaction of OM with soil minerals, and molecular structure of SOM in controlling storage and persistence of SOM in different types of eroding and depositional landform positions. By combining density fractionation with elemental and spectroscopic analyses, we showed that SOM in depositional settings is less transformed and better preserved than SOM in eroding landform positions. However, which environmental factors exert primary control on storage and persistence of SOM depended on the nature of the landform position considered. In an annual grassland watershed, protection of SOM by physical isolation inside aggregates and chemical association of organic matter (complexation) with soil minerals, as assessed by correlation with radiocarbon concentration, were more effective in the poorly drained, lowest-lying depositional landform positions, compared to well-drained landform positions in the upper parts of the watershed. Results of this study demonstrated that processes of soil erosion and deposition are important mechanisms of long-term OM stabilization.

Citation Information

Publication Year 2012
Title Persistence of soil organic matter in eroding versus depositional landform positions
DOI 10.1029/2011JG001790
Authors Asmeret Asefaw Berhe, Jennifer W. Harden, Margaret S. Torn, Markus Kleber, Sarah D. Burton, John Harte
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Geophysical Research: Biogeosciences
Series Number
Index ID 70118265
Record Source USGS Publications Warehouse
USGS Organization