Keywords: Ammonia volatilisation, fertilisation, process-based model, reference measurements, national inventories.
France is the number one contributor to ammonia emissions in the European Union. Owing to the increasing constraints linked to the implementation of European legislation aimed at abating ammonia emissions, there is a need to update emission factors for France as well as to propose and evaluate better farming practices adapted to its agro-pedo-climatic context. Land application of organic products and nitrogen fertilisation represent more than half of the contribution of the agricultural sector to national emissions. It can thus be considered as the main lever of action on ammonia emissions.
But the variability of conditions encountered in agricultural practice makes the quantification of emissions difficult and the acquisition of typical French references necessary.
The current growing and concerted mobilisation within research institutes, technical institutes, mineral and organic fertiliser producers as well as stakeholders and policy makers is the key to achieving this objective. It requires the combination of several parallel actions, which are currently being carried out. This paper aims to present the general context and the particular applications of these actions.
First, the acquisition of new experimental references in real field conditions is necessary in order to account better for the French specificities concerning climate, soil and agricultural practices by deploying a low cost method on small multiple experimental plots. As a supplement to those field measurements, a specifically dedicated in-lab measurement set-up has been developed to screen a larger range of soils/organic products/mineral fertilisers for volatilisation potential. Using these sets of data, the French process-based model Volt’Air was validated and improved in a large range of conditions encompassing the French ones. It can thus be coupled to other models to (i) enable accounting for ammonia volatilisation in a realistic way in other models dealing with nitrogen behaviour and to (ii) help improve the quality of the national ammonia volatilisation inventory, accounting for spatial and temporal variations in ammonia emissions. Finally, the process-based model is being used to develop simpler and more robust ammonia volatilisation functions and emission factors based on the most determining variables and adapted to conditions encountered in France using a meta-modelling approach; it is thus expected to provide sub-models for other models dealing with nitrogen behaviour over the crop cycle, improving environmental evaluation of practices, and pollution swapping; it will also help to improve national inventories, promote the use of abatement techniques and properly account for their effect on ammonia emission calculations.
Sophie Génermont, INRA, AgroParistech, UMR1091 EGC route de la Ferme, Environment and Arable Crops Research Unit, F-78 850 Thiverval-Grignon, France.
44 pages, 14 figures, 3 tables, 83 references