Using δ15N and δ18O to evaluate the sources and pathways of NO 3− in rainfall event discharge from drained agricultural grassland lysimeters at high temporal resolutions

• Published in: Rapid communications in mass spectrometry 2008-06, Vol.22 (11), p.1681-1689
• Main Authors: Granger, Steven J., Heaton, Tim H.E., Bol, Roland, Bilotta, Gary S., Butler, Patricia, Haygarth, Philip M., Owens, Philip N.
• Format: Article
• Language: English
• ISSN: 0951-4198; 1097-0231
• DOI: 10.1002/rcm.3505

The origin of NO 3− yielded in drainage from agricultural grasslands is of environmental significance and has three potential sources; (i) soil organic mater (SOM), (ii) recent agricultural amendments, and (iii) atmospheric inputs. The variation in δ15N‐NO 3− and δ18O‐NO 3− was measured from the ‘inter‐flow’ and ‘drain‐flow’ of two 1 ha drained lysimeter plots, one of which had received an application of 21 m3 of NH 4+‐N‐rich agricultural slurry, during two rainfall events. Drainage started to occur 1 month after the application of slurry. The concentrations of NO 3−‐N from the two lysimeters were comparable; an initial flush of NO 3−‐N occurred at the onset of drainage from both lysimeters before levels quickly dropped to