Groundwater Nitrate Concentration Reductions in a Riparian Buffer Enrolled in the NC Conservation Reserve Enhancement Program |
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Authors: | Jacob D. Wiseman Michael R. Burchell Garry L. Grabow Deanna L. Osmond T.L. Messer |
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Affiliation: | 1. Department of Soil Science, North Carolina State University, , Raleigh, North Carolina, 27695;2. Department of Biological and Agricultural Engineering, North Carolina State University, , Raleigh, North Carolina, 27695 |
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Abstract: | Riparian buffers have been used for many years as a best management practice to decrease the effects of nonpoint pollution from watersheds. The NC Conservation Reserve Enhancement Program (NC CREP) has established buffers to treat groundwater nitrate‐nitrogen (NO3?‐N) from agricultural sources in multiple river basins. A maturing 46 m wide riparian buffer enrolled in NC CREP was studied to determine its effectiveness in reducing groundwater NO3?‐N concentrations from a cattle pasture fertilized with poultry litter. Three monitoring blocks that included groundwater quality wells, water table wells, and soil redox probes, were established in the buffer. NO3?‐N concentrations decreased significantly across the buffer in all of the monitoring blocks with mean reductions of 76‐92%. Many biological processes, including denitrification and plant uptake, may have been responsible for the observed NO3?‐N reductions but could not be differentiated in this study. However, mean reductions in Cl? concentrations ranged from 48‐65% through the blocks, which indicated that dilution was an important factor in observed NO3?‐N reductions. These findings should be carefully considered for future buffer enrollments when assigning nitrogen removal credits. |
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Keywords: | riparian buffer
CREP
nitrate denitrification dilution nitrogen |
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