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Title: CARBON CYCLING IN UPLANDS PERSPECTIVES LESSONS AND QUESTIONS RAISED FOR WETLANDS

Author
item HUNTINGTON, T - USGS
item MARKEWICH, H - USGS
item Kramer, Larry
item DABNEY, S - USGS
item MARION, D - USFS
item DILLON, L - USGS
item BRITSCH, L - USGS
item FRIES, T - USGS

Submitted to: Meeting Abstract
Publication Type: Other
Publication Acceptance Date: 4/27/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Uplands and wetlands also are linked through the processes of erosion, transport, and deposition that route water, nutrients, and sediment from uplands to wetlands. The fate of soil organic carbon (SOC) in eroded sediments depends on stability of the SOC in the buried sediments. Our data suggest that on an annual basis, decomposition fluxes predominate, but that over the long term, particularly after the most labile SOC pools are decomposed, erosion fluxes become more important. Currently there is considerable optimism about the potential of improved crop management and reforestation to reverse historical trends in SOC losses. However, there are several concerns that may limit this potential: (1) SOC sequestration, particularly into long-lived, more recalcitrant forms, is a relatively slow process compared with heterotrophic decomposition and erosion; (2) even short-term changes in cropping systems that increase cultivation, length of fallow period, or reduce residue inputs may result in a rapid loss of gains during previous years; (3) increasing soil temperature or decreasing plant-available soil moisture has the potential to minimize gains over the long term; (4) optimistic assessments of potential SOC gains are based on extrapolation of data from long-term plots at agricultural experiment stations that have not eroded; erosion might reduce potential gains significantly; (5) intensive management in some systems has not reversed the trend for declines in SOC.