Abstract Relatively narrow ( 3 − -N) in shallow groundwater. This conservation buffer (CB) was up to 80 m wide and was planted with loblolly pine ( Pinus taeda ). It was situated upslope of an existing 30–60 m wide riparian hardwood forest buffer (EHB) located within the floodplain of an intermittent stream. Shallow groundwater NO 3 − -N, groundwater hydrology, total organic carbon, and soil redox potential were measured throughout both the CB and the EHB for 18 months. Groundwater NO 3 − -N concentrations, often 5–15 mg L −1 within the CB, were not significantly reduced from concentrations that entered from the agricultural field edge. However, a decrease in NO 3 − -N concentration was observed within the EHB (17–83%). The hydrology of the CB coupled with relatively low organic carbon contributed to a low denitrification potential and lack of NO 3 − -N reduction compared with the EHB. While the CB enrollment likely provided additional habitat benefits it did not appear to provide treatment of groundwater NO 3 − -N. It is our conclusion that landscape position is a more important defining variable for buffer site selection than buffer width if NO 3 − -N reduction is a primary goal.