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Groundwater Nitrate Concentration Reductions in a Riparian Buffer Enrolled in the NC Conservation Reserve Enhancement Program
Author(s) -
Wiseman Jacob D.,
Burchell Michael R.,
Grabow Garry L.,
Osmond Deanna L.,
Messer T.L.
Publication year - 2014
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/jawr.12209
Subject(s) - riparian buffer , riparian zone , nitrate , environmental science , groundwater , water quality , denitrification , buffer zone , hydrology (agriculture) , nonpoint source pollution , buffer strip , environmental chemistry , nitrogen , ecology , chemistry , biology , habitat , geotechnical engineering , organic chemistry , engineering
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 ( NO 3 − ‐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 NO 3 − ‐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. NO 3 − ‐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 NO 3 − ‐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 NO 3 − ‐N reductions. These findings should be carefully considered for future buffer enrollments when assigning nitrogen removal credits.