2013 journal article

Riparian buffer located in an upland landscape position does not enhance nitrate-nitrogen removal

ECOLOGICAL ENGINEERING, 52, 252–261.

By: S. Johnson n, M. Burchell n, R. Evans n, D. Osmond n  & J. Gilliam n

co-author countries: United States of America πŸ‡ΊπŸ‡Έ
author keywords: Riparian buffer; Conservation programs; Groundwater; Hydrology; Nitrate; NO3--N
Source: Web Of Science
Added: August 6, 2018

Relatively narrow (<50 m) riparian buffers strategically reestablished in correct landscape positions have been shown to significantly reduce agricultural non-point source pollution to streams. Because of this, conservation programs have been established to encourage landowners to enroll lands near surface waters to improve water quality. Former cropland enrolled in a conservation program was evaluated to determine its effectiveness in reducing nitrate-nitrogen (NO3βˆ’-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 NO3βˆ’-N, groundwater hydrology, total organic carbon, and soil redox potential were measured throughout both the CB and the EHB for 18 months. Groundwater NO3βˆ’-N concentrations, often 5–15 mg Lβˆ’1 within the CB, were not significantly reduced from concentrations that entered from the agricultural field edge. However, a decrease in NO3βˆ’-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 NO3βˆ’-N reduction compared with the EHB. While the CB enrollment likely provided additional habitat benefits it did not appear to provide treatment of groundwater NO3βˆ’-N. It is our conclusion that landscape position is a more important defining variable for buffer site selection than buffer width if NO3βˆ’-N reduction is a primary goal.