This study examines how coupled geomorphic and biologic processes influence the potential for hillslope soils to store organic carbon. A mass-balance model of soil organic carbon on hillslopes is developed by combining soil transport with biologic carbon production and respiration. The model is compared with soil carbon measurements on three hillslopes that represent various stages of hillslope evolution at Land-Between-the-Lakes National Recreation Area, northwest Tennessee. Both model results and field measurements suggest that locations of soil thickening are able to store more organic carbon than locations of soil thinning. In model simulations of a hillslope relaxing onto a fluvial terrace, locations of soil thickening, which propagate upslope, represent the greatest potential to increase soil organic carbon through time. The downslope increase in soil organic carbon seen in modeling and field measurements arises from the systematic variation in soil thickness associated with soil transport and hillslope evolution. Varying soil transport parameters (e.g. diffusivity, initial soil production) in model simulations reveals that physical soil transport processes exert greater control than biological carbon production and respiration on the change in soil organic carbon storage of a hillslope through time. At locations where thinned soils are converted to locations of soil thickening, the organic carbon storage of the soil increased in model simulations by 5-25%. This study suggests that physical soil processes are more important than biological carbon production and respiration processes in sequestering organic carbon in forested hillslope soils.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-04032009-155414 |
| Date | 22 April 2009 |
| Creators | Roseberry, John Coley |
| Contributors | Guilherme Gualda, David Jon Furbish |
| Publisher | VANDERBILT |
| Source Sets | Vanderbilt University Theses |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.vanderbilt.edu/available/etd-04032009-155414/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Vanderbilt University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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