Ammonia emissions from UK agriculture – the NARSES model TFEIP Workshop, Thessaloniki, Greece, October 2006 Tom Misselbrook IGER, North Wyke, UK Imperial College

Introduction Inventory model for a major emission source - NARSES as an example Detailed partial emission factors (incl. process-based) Detailed activity data Spatial and temporal disaggregation Introduction of abatement measures Cost curve development Mapped output

NARSES National Ammonia Reduction Strategy Evaluation System Ammonia emissions from UK agriculture >80% total UK emission Replaces ‘old-style’ UK ammonia emissions inventory Nitrogen flow model, mass-conservative EF now expressed as % of available N rather than ‘fixed’ units

Ammonia sources 1. Nitrogen fertiliser applications NH 3 Emission = fn (fertiliser type, land use, temperature, rainfall, soil pH) Monthly time-step Fertiliser types associated with different potential emissions Activity data from British Survey of Fertiliser Practice EF

Ammonia sources 2. Nitrogen excretion by livestock NH 3 Total N (RAN) NH 3 grazing yards housing storage spreading measures

Emission factors Livestock group grazingyardshousing - slurry housing – straw-bed Slurry store lagoonFYM heap … Dairy cow6%75%30%25%5%50%35% Dairy heifer Beef cow Beef heifer Bull Cattle 1-2 yrs Calves Sows …. All expressed as % RAN in the emission pool

Activity data Data sources: June agricultural census (livestock numbers) Farm practice surveys Ad-hoc surveys Expert opinion

Technical measures For each potential abatement technique: Emission reduction efficiency Applicability Current implementation Cost e.g. shallow injection 70% 80%? 1% £2.40 per m3 slurry

NARSES Model : 8 Sectors, 269 Nodes, 349 Links, 162 Measures

Operates at 10 x 10 km grid Cost-curve optimisation

Model developments Increasingly link EF to environmental and management variables Include links with N 2 O emission and NO 3 leaching models Include ‘front-end’ linking diet with N excretion

Projections NARSES a robust model for making projections: Defines key parameters which need to be surveyed/estimated Accounts for bulk changes in livestock numbers Also accounts for management changes – policy, environment or market forces

Projections – Dairy cows UK milk production to stay the same Cow numbers declining, increasing milk yield per cow Increasing N excretion per cow

Projections – Pigs and poultry Implementation of IPPC [No change in livestock numbers]

Summary To make robust projections: Sufficient level of detail within model EF linked to environmental and management variables Ability to gather activity data at sufficient level Ability to predict changes in key management and environmental variables

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