Reintroduction of flooding and change in denitrification rates on a leveed Midwestern floodplain
Abstract
We examined the response of soil denitrification to a floodplain restoration project that reintroduced controlled flooding to a previously isolated 900 hectare site adjacent to the Baraboo River, Wisconsin. Monthly June-August for one year prior and two years post restoration we measured denitrification in static cores (SC μgN2O-N/kgsoil-hr) and potential denitrification in carbon and nitrate amended soil slurry samples (DEA μgN2O-N/kgsoil-hr). Rates showed high temporal and spatial variability. Individual sample SC rates ranged widely (0.00 to 16.7) with a mean value of 1.10 (SD = 3.02). DEA rates were in the same general range (0.00 to 15.0) but with a slightly higher mean (mean 1.41, comparison p<0.05). Denitrification was not highly correlated with soil nutrient content. However, the difference in rates between SC and DEA samples pre-restoration was higher than post-restoration, suggesting that denitrification was less limited after the reintroduction of flooding. Vegetation type and history of flooding were better predictors of denitrification than current soil water content. Despite large variability in measured rates, these results demonstrate that there is potential for denitrification to remove significant amounts nitrate from river systems. Management of water levels to provide adequate exchange between river and floodplain is important to this process.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2005
- Bibcode:
- 2005AGUSMNB24D..01O
- Keywords:
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- 1615 Biogeochemical processes (4805);
- 1821 Floods;
- 1845 Limnology;
- 4845 Nutrients and nutrient cycling