Comparison of models used for national agricultural ammonia emission inventories in Europe: Litter-based manure systems

• Published in: Atmospheric environment (1994) 2009-03, Vol.43 (9), p.1632-1640
• Main Authors: Reidy, B., Webb, J., Misselbrook, T.H., Menzi, H., Luesink, H.H., Hutchings, N.J., Eurich-Menden, B., Döhler, H., Dämmgen, U.
• Format: Article
• Language: English
• Subjects: abatement; Agriculture; Ammonia; Analysis methods; Applied sciences; Atmospheric pollution; cattle; dietary-protein content; Dispersed sources and other; Emission; Emission factor; Exact sciences and technology; Inventory; livestock; management; N-flow model; nitrous-oxide; Pollution; Pollution sources. Measurement results; Solid manure; storage; Total ammoniacal-N (TAN); volatilization
• ISSN: 1352-2310; 1873-2844
• DOI: 10.1016/j.atmosenv.2008.12.015

Six N-flow models, used to calculate national ammonia (NH 3) emissions from agriculture in different European countries, were compared using standard data sets. Scenarios for litter-based systems were run separately for beef cattle and for broilers, with three different levels of model standardisation: (a) standardized inputs to all models (FF scenario); (b) standard N excretion, but national values for emission factors (EFs) (FN scenario); (c) national values for N excretion and EFs (NN scenario). Results of the FF scenario for beef cattle produced very similar estimates of total losses of total ammoniacal-N (TAN) (±6% of the mean total), but large differences in NH 3 emissions (±24% of the mean). These differences arose from the different approaches to TAN immobilization in litter, other N losses and mineralization in the models. As a result of those differences estimates of TAN available at spreading differed by a factor of almost 3. Results of the FF scenario for broilers produced a range of estimates of total changes in TAN (±9% of the mean total), and larger differences in the estimate of NH 3 emissions (±17% of the mean). The different approaches among the models to TAN immobilization, other N losses and mineralization, produced estimates of TAN available at spreading which differed by a factor of almost 1.7. The differences in estimates of NH 3 emissions decreased as estimates of immobilization and other N losses increased. Since immobilization and denitrification depend also on the C:N ratio in manure, there would be advantages to include C flows in mass-flow models. This would also provide an integrated model for the estimation of emissions of methane, non-methane VOCs and carbon dioxide. Estimation of these would also enable an estimate of mass loss, calculation of the N and TAN concentrations in litter-based manures and further validation of model outputs.