Modelling uncertainty for decision making on ammonia mitigation with trees in the landscape (MUDMAT)

David Cameron, Bill Bealey, Cristina Martin Hernandez (UKCEH), Benjamin Loubet (INRAE), William Lassman (Colorado State University)

The harmful effects of ammonia pollution and how tree ‘shelter-belts’ can help

– Over 60% of the UK’s semi-natural habitats exceed threshold limits where damage (species composition changes and reduced biodiversity) is caused by nitrogen.

– Agricultural practices account for over 80% of nitrogen emissions, in the form of ammonia (NH3), within the UK.

– Government guidance (Code of Good Agricultural Practice for Reducing Ammonia Emissions COGAP, Defra 2018) supports farmers to reduce their ammonia emissions including mitigation options like planting tree shelter-belts around livestock housing to ‘scavenge’ ammonia.

– Farmers need tools to help them quantify how options for planting tree shelter-belts will influence their NH3 pollution.

Our aim in MUDMAT

– We aim to improve decision making tools by bringing state-of-the-art statistical methods to quantify the uncertainty of predictions through modelling of tree shelter belts.


 – There is an existing web-based decision tool but it needs improving.

– The very simple empirical model used in the web-tool demonstrated proof of concept but is unlikely to give accurate predictions.

– Indeed the accuracy of the predictions from the web-tool are not currently quantified.


– Decisions makers (e.g farmers) cannot use the current tool to make important and potentially costly decisions


– MUDMAT will create an explicit link from the web-tool to a model (MODDAS) which has demonstrated skill in predicting the effect of tree-belts in capturing ammonia (Bealey et al 2014).

– A statistical emulator of OpenFOAM-MODDAS will be created allowing model parameter uncertainty to be quantified, reduced and presented in the web-tool.

Improving the model used in the web-tool and presenting uncertainty in the predictions will aid UK land managers in their decision making in mitigating harmful ammonia emissions from agricultural sources. 

Principle Investigator David Cameron introduces the project in this short video
Link to the project page on the UKRI Gateway to Research