Defra - Department for Environment, Food and Rural Affairs.

Science Search

Science and Research Projects

Return to Science Search homepage   Return to Project List

Emission factor for N2O from soils - CC0248

Signatory states to the United Nations Framework Convention on Climate Change (UNFCCC) are obliged to establish a national emissions inventory. The inventory aims to accurately assess all anthropogenic sources of greenhouse gases, including nitrous oxide (N2O), using comparable methodologies. Currently, the UK emission inventory of N2O loss from agriculture is derived using emission factors based on the Intergovernmental Panel on Climate Change (IPCC) methodology, which does not discriminate between soil types. It is recognised however, that this methodology needs to be improved in order to estimate N2O emissions with a greater degree of certainty.

Improved emission accuracy may be achieved via a number of approaches if the IPCC Good Practice Guidance is followed; e.g. through the development of mechanistic models such as, UK-DNDC or by evolving the IPCC method to include a subdivision of key source category factors. Studies have demonstrated that soil type influences N2O emission and this is corroborated through current scientific understanding of the processes involved. The application of spatially averaged parameters to regional scale models should not introduce bias to “modelled” emissions whatever type of model (mechanistic, semi-empirical) is employed. As N2O emissions are known to be extremely variable in space and time and likely, therefore, to be very sensitive to parameterisation, it is particularly important that sources of non-lineraity are fully explored.

The main objective of this project, therefore, is to evaluate current information in order to ascertain whether soil type can or should be included as a factor in IPCC calculations of N2O emission in a manner that satisfies IPCC ‘good practice’. Realising this objective will allow current estimates to be made more robust and will indicate the extent to which soil type should be considered in developing abatement options.
1. To review scientific understanding of the process of denitrification and N2O emission from soils, focussing in particular on the significance of soil attributes in affecting the development of anaerobic conditions. In addition, to review the scientific literature on the impact of the explicit representation of spatial variability of soil attributes on the output of mechanistic models.

2. To determine the effect of using mean rather a statistically-distributed soil parameters on the prediction of N2O by the DNDC model (i.e. introduces bias).

3. To determine whether ratios of DNDC-calculated N2O emissions between different soil types is geographically consistent.
Project Documents
• Final Report : Emission factor for N2O from soils   (6119k)
Time-Scale and Cost
From: 2002

To: 2003

Cost: £34,227
Contractor / Funded Organisations
Climate and Weather              
Climate Change              
Environmental Protection              
Greenhouse Effect              
Peer Review              
Sustainable Production              
Fields of Study
Agriculture and Climate Change