The University of Southampton
University of Southampton Institutional Repository

Climate- and crop-responsive emission factors significantly alter estimates of current and future nitrous oxide emissions from fertiliser use

Climate- and crop-responsive emission factors significantly alter estimates of current and future nitrous oxide emissions from fertiliser use
Climate- and crop-responsive emission factors significantly alter estimates of current and future nitrous oxide emissions from fertiliser use
The current Intergovernmental Panel on Climate Change (IPCC) default methodology (tier 1) for calculating nitrous oxide (N2O) emissions from nitrogen applied to agricultural soils takes no account of either crop type or climatic conditions. As a result, the methodology omits factors that are crucial in determining current emissions, and has no mechanism to assess the potential impact of future climate and land-use change. Scotland is used as a case study to illustrate the development of a new methodology, which retains the simple structure of the IPCC tier 1 methodology, but incorporates crop- and climate-dependent emission factors (EFs). It also includes a factor to account for the effect of soil compaction because of trampling by grazing animals. These factors are based on recent field studies in Scotland and elsewhere in the UK. Under current conditions, the new methodology produces significantly higher estimates of annual N2O emissions than the IPCC default methodology, almost entirely because of the increased contribution of grazed pasture. Total emissions from applied fertilizer and N deposited by grazing animals are estimated at 10 662 t N2O-N yr1 using the newly derived EFs, as opposed to 6 796 t N2O-N yr1 using the IPCC default EFs. On a spatial basis, emission levels are closer to those calculated using field observations and detailed soil modelling than to estimates made using the IPCC default methodology. This can be illustrated by parts of the western Ayrshire basin, which have previously been calculated to emit 89 kg N2O-N ha1 yr1 and are estimated here as 6.258.75 kg N2O-N ha1 yr1, while the IPCC default methodology gives a maximum emission level of only 3.75 kg N2O-N ha1 yr1 for the whole area. The new methodology is also applied in conjunction with scenarios for future climate- and land-use patterns, to assess how these emissions may change in the future. The results suggest that by 2080, Scottish N2O emissions may increase by up to 14%, depending on the climate scenario, if fertilizer and land management practices remain unchanged. Reductions in agricultural land use, however, have the potential to mitigate these increases and, depending on the replacement land use, may even reduce emissions to below current levels.
agricultural soils, climate change, emission factors, fertilizer, grazing, IPCC, land-use change, nitrous oxide, modelling, scotland
1354-1013
1522-1536
Flynn, H.C.
54ec4fd0-6e83-4a8b-b336-e124c20e3c55
Smith, J.
306ead64-2109-42a9-8d5d-56539de3a863
Smith, K.A.
f3a924e6-ae3e-4a8c-b7c5-d394a1228b04
Wright, J.
94990ecf-f8dd-4649-84f2-b28bf272e464
Smith, P.
11f678ab-4aee-426a-aedd-19719d80bbbc
Massheder, J.
21ab7f6f-2501-4216-8253-b1b44db2d66b
Flynn, H.C.
54ec4fd0-6e83-4a8b-b336-e124c20e3c55
Smith, J.
306ead64-2109-42a9-8d5d-56539de3a863
Smith, K.A.
f3a924e6-ae3e-4a8c-b7c5-d394a1228b04
Wright, J.
94990ecf-f8dd-4649-84f2-b28bf272e464
Smith, P.
11f678ab-4aee-426a-aedd-19719d80bbbc
Massheder, J.
21ab7f6f-2501-4216-8253-b1b44db2d66b

Flynn, H.C., Smith, J., Smith, K.A., Wright, J., Smith, P. and Massheder, J. (2005) Climate- and crop-responsive emission factors significantly alter estimates of current and future nitrous oxide emissions from fertiliser use. Global Change Biology, 11 (9), 1522-1536. (doi:10.1111/j.1365-2486.2005.00998.x).

Record type: Article

Abstract

The current Intergovernmental Panel on Climate Change (IPCC) default methodology (tier 1) for calculating nitrous oxide (N2O) emissions from nitrogen applied to agricultural soils takes no account of either crop type or climatic conditions. As a result, the methodology omits factors that are crucial in determining current emissions, and has no mechanism to assess the potential impact of future climate and land-use change. Scotland is used as a case study to illustrate the development of a new methodology, which retains the simple structure of the IPCC tier 1 methodology, but incorporates crop- and climate-dependent emission factors (EFs). It also includes a factor to account for the effect of soil compaction because of trampling by grazing animals. These factors are based on recent field studies in Scotland and elsewhere in the UK. Under current conditions, the new methodology produces significantly higher estimates of annual N2O emissions than the IPCC default methodology, almost entirely because of the increased contribution of grazed pasture. Total emissions from applied fertilizer and N deposited by grazing animals are estimated at 10 662 t N2O-N yr1 using the newly derived EFs, as opposed to 6 796 t N2O-N yr1 using the IPCC default EFs. On a spatial basis, emission levels are closer to those calculated using field observations and detailed soil modelling than to estimates made using the IPCC default methodology. This can be illustrated by parts of the western Ayrshire basin, which have previously been calculated to emit 89 kg N2O-N ha1 yr1 and are estimated here as 6.258.75 kg N2O-N ha1 yr1, while the IPCC default methodology gives a maximum emission level of only 3.75 kg N2O-N ha1 yr1 for the whole area. The new methodology is also applied in conjunction with scenarios for future climate- and land-use patterns, to assess how these emissions may change in the future. The results suggest that by 2080, Scottish N2O emissions may increase by up to 14%, depending on the climate scenario, if fertilizer and land management practices remain unchanged. Reductions in agricultural land use, however, have the potential to mitigate these increases and, depending on the replacement land use, may even reduce emissions to below current levels.

Other
Flynn_et_al2005_aspublished.PDF - Version of Record
Restricted to Registered users only
Download (590kB)
Request a copy

More information

Published date: 2005
Keywords: agricultural soils, climate change, emission factors, fertilizer, grazing, IPCC, land-use change, nitrous oxide, modelling, scotland

Identifiers

Local EPrints ID: 17399
URI: http://eprints.soton.ac.uk/id/eprint/17399
ISSN: 1354-1013
PURE UUID: 7531af38-2b90-499f-b41a-c4d5688e78da
ORCID for J. Wright: ORCID iD orcid.org/0000-0002-8842-2181

Catalogue record

Date deposited: 06 Sep 2005
Last modified: 16 Mar 2024 03:40

Export record

Altmetrics

Contributors

Author: H.C. Flynn
Author: J. Smith
Author: K.A. Smith
Author: J. Wright ORCID iD
Author: P. Smith
Author: J. Massheder

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×