Setting out the aims of ammonia emissions research

TODAY Dr John McIlroy, of AFBI, begins a series of articles on the issue of ammonia. Ammonia emissions from livestock present a major challenge to the Northern Ireland agricultural in-dustry. Funded by the Department of Agriculture, Environment and Rural Affairs (DAERA), the Agri-Food and Biosciences Institute (AFBI) is currently conducting a major programme of research to address this issue.

Driven by a team of environmental and animal scientists along with agricultural economists, the pro-gramme is providing the scientific evidence for policymakers and stakeholders to better understand the sources and environmental impacts of ammonia emissions from agricultural practices, and the most cost effective ways to lower these emissions in Northern Ireland.

What is ammonia?

Ammonia (NH3) is a gaseous form of Nitrogen which is released from animal manures and nitrogen containing fertilisers. Ammonia is considered an air pollutant and when it is deposited to land from the atmosphere it can have significant negative effect on natural habitats. Most ammonia will be deposited close to where it is emitted (within a few km). A smaller proportion will be transported for significant distances (up to a few hundred km).

In many designated sites and priority habitats, such as Special Areas of Conservation (SAC) and Areas of Special Scientific Interest (ASSI), naturally occurring forms of nitrogen are scarce and local species of plants, bryophytes and fungi have a low nitrogen tolerance. Extra nitrogen entering these environments encourages the grow-

th of nitrogen loving species, such as grasses and nettles, which are fast-growing and out compete sensitive, slow-growing species such as lichens and mosses. The deposition of ammonia onto these habitats significantly disrupts them and reduces important aspects of biodiversity in these areas.

The need for research:

Northern Ireland has almost 250 sites designated for protection which are sensitive to the impacts of ammonia and nitrogen. DAERA has legal obligations to protect these sites and to enhance and promote biodiversity. The vast majority of designated sites are currently experiencing ammonia concentrations and nitrogen de-position above the critical levels and loads at which damage to plants may occur. For example, 98 per cent of Special Areas of Conservation (SACs) and 83.3 per cent of Special Protection Areas (SPA) in NI have nitrogen deposition rates which indicate an ecosystem is at risk from potential harmful effects.

A significant proportion of this deposited nitrogen is understood to be derived from local agricultural ammonia sources, in large part from livestock manure management. The cattle sector in NI produces 64 per cent of agricultural ammonia emissions, followed by the poultry sector (18 per cent) and the pig sector (eight per cent). Nitrogen fertilisers account for eight per cent of these emissions (Fig. 1).

The UK has committed to reduce ammonia and other emissions under the international Gothenburg Protocol and the National Emissions Ceiling Regulations (2018). The agreed reductions in ammonia emissions are eight per cent by 2020 and by 16 per cent by 2030, based on 2005 levels. Northern Ireland is expected to contribute to these targets. In the DEFRA Clean Air Strategy of 2019, the UK reiterated its commitment to the reduction of ammonia emissions by 16 per cent by 2030.

Although the level of ammonia produced aligns with the scale of agricultural outputs, Northern Ireland is a disproportionate contributor to UK ammonia emiss-ions, accounting for 12 per cent of the total, despite having only six per cent of the land area.

This is mainly due to the large export market in NI which supports the UK food system.

Some of the early outputs from the AFBI Ammonia Research Programme have been communicated through a DAERA Ammonia Stakeholder series of webinars which can

be viewed at www.youtube.com/watch?v=9uPzHkARqa8

These early outputs have informed the CAFRE Code of Good Agricultural Practice for the Reduction of Ammonia Emissions and the forthcoming DAERA Ammonia Strategy.

n Over the coming weeks, this series of articles focusing on the AFBI research programme to address ammonia emissions in NI will outline the work being undertaken in more detail and the key findings to date. Next week, the levels of reduction realised as a result of adopting mitigations across NI will be reported from one of the detailed modelling exercises.