Rapid immobilisation and leaching of wet-deposited nitrate in upland organic soils

Evans, Chris D. ORCID: https://orcid.org/0000-0002-7052-354X; Norris, Dave; Ostle, Nick; Grant, Helen; Rowe, Edwin C. ORCID: https://orcid.org/0000-0003-4784-7236; Curtis, Chris J.; Reynolds, Brian. 2008 Rapid immobilisation and leaching of wet-deposited nitrate in upland organic soils. Environmental Pollution, 156 (3). 636-643. 10.1016/j.envpol.2008.06.019

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Official URL: http://dx.doi.org/10.1016/j.envpol.2008.06.019

Abstract/Summary

Nitrate (NO3−) is often observed in surface waters draining terrestrial ecosystems that remain strongly nitrogen (N) limited. It has been suggested that this occurs due to hydrological bypassing of soil or vegetation N retention, particularly during high flows. To test this hypothesis, artificial rain events were applied to 12 replicate soil blocks on a Welsh podzolic acid grassland hillslope, labelled with 15N-enriched NO3− and a conservative bromide (Br−) tracer. On average, 31% of tracer-labelled water was recovered within 4 h, mostly as mineral horizon lateral flow, indicating rapid vertical water transfer through the organic horizon via preferential flowpaths. However, on average only 6% of 15N-labelled NO3− was recovered. Around 80% of added NO3− was thus rapidly immobilised, probably by microbial communities present on the surfaces of preferential flowpaths. Transitory exceedance of microbial N-uptake capacity during periods of high water and N flux may therefore provide a mechanism for NO3− leaching. Nitrate retention occurs rapidly in organic soils along preferential flowpaths.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.envpol.2008.06.019
Programmes:	CEH Programmes pre-2009 publications > Biogeochemistry
UKCEH and CEH Sections/Science Areas:	Emmett Shore
ISSN:	0269-7491
Additional Keywords:	Nitrate, Atmospheric deposition, Nitrogen saturation, 15N tracer, Immobilisation
NORA Subject Terms:	Agriculture and Soil Science Ecology and Environment
Date made live:	02 Dec 2008 10:36 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/4444

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.envpol.2008.06.019

Programmes:

CEH Programmes pre-2009 publications > Biogeochemistry

UKCEH and CEH Sections/Science Areas:

Emmett
Shore

ISSN:

0269-7491

Additional Keywords:

Nitrate, Atmospheric deposition, Nitrogen saturation, 15N tracer, Immobilisation