Long-term nitrogen deposition increases heathland carbon sequestration

Field, Chris D.; Evans, Chris D. ORCID: https://orcid.org/0000-0002-7052-354X; Dise, Nancy B. ORCID: https://orcid.org/0000-0003-0463-6885; Hall, Jane R.; Caporn, Simon J.M.. 2017 Long-term nitrogen deposition increases heathland carbon sequestration. Science of the Total Environment, 592. 426-435. 10.1016/j.scitotenv.2017.03.059

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Official URL: http://dx.doi.org/10.1016/j.scitotenv.2017.03.059

Abstract/Summary

The large increases in reactive nitrogen (N) deposition in developed countries since the Industrial Revolution have had a marked impact on ecosystem functioning, including declining species richness, shifts in species composition, and increased N leaching. A potential mitigation of these harmful effects is the action of N as a fertiliser, which, through increasing primary productivity (and subsequently, organic matter production), has the potential to increase ecosystem carbon (C) storage. Here we report the response of an upland heath to 10 years of experimental N addition. We find large increases in plant and soil C and N pools, with N-driven C sequestration rates in the range of 13–138 kg C kg −1. These rates are higher than those previously found in forest and lowland heath, mainly due to higher C sequestration in the litter layer. C sequestration is highest at lower N treatments (10, 20, and 40 kg N ha− 1 yr− 1 above ambient), with evidence of saturation at the highest N treatment, reflecting a physiologically aged Calluna vulgaris (Calluna) canopy. To maintain these rates of sequestration, the Calluna canopy should be managed to maximise it's time in the building phase. Scaling our results across UK heathlands, this equates to an additional 0.77 Mt CO2e per annum extra C sequestered into plant litter and the top 15 cm of heathland soil as a result of N deposition. The bulk of this is found in the litter and organic soil horizons that hold an average of 23% and 54% of soil C, respectively. This additional C represents around 0.44% of UK annual anthropogenic GHG emissions. When considered in the context of falling biodiversity and altered species composition in heathland, policy focus should remain on reducing N emissions.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.scitotenv.2017.03.059
UKCEH and CEH Sections/Science Areas:	Dise Emmett
ISSN:	0048-9697
Additional Keywords:	nitrogen deposition, heathlands, carbon sequestration, storage, pools
NORA Subject Terms:	Ecology and Environment Agriculture and Soil Science
Date made live:	24 Apr 2017 11:10 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/516916

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.scitotenv.2017.03.059

UKCEH and CEH Sections/Science Areas:

Dise
Emmett

ISSN:

0048-9697

Additional Keywords:

nitrogen deposition, heathlands, carbon sequestration, storage, pools

NORA Subject Terms:

Ecology and Environment
Agriculture and Soil Science