Measures taken to decreasing N losses often focus at one specific nitrogen species (e.g., nitrate to water, ammonia to air, nitrous oxide to air). Such single-species policy measures may have both antagonistic and synergistic effects on other nitrogen (N) losses. A model (MITERRA-EUROPE) was developed to assess the effects and interactions of various policy measures in agriculture on N losses at a regional level in the 27 member states of the European Union. Results from the study were published in the March-April issue of the Journal of Environmental Quality.
Denitrification is the largest N loss pathway in European agriculture (on average 44 kg N ha-1 agricultural land in 2000), followed by ammonia volatilization (17 kg N ha-1), leaching (16 kg N ha-1) and emission of nitrous oxide (2 kg N ha-1). Losses between regions in the European union varied strongly. Some of the measures implemented to abate ammonia emission from livestock housing, manure storage, and manure application increase leaching and nitrous oxide emission. Balanced N fertilization has the potential of creating synergistic effects by simultaneously decreasing leaching and gaseous emissions. The most promising package of measures to decrease N losses from agriculture include balanced N fertilization, low protein animal feeding, and ammonia emissions abatement measures.
Following the recognition of the detrimental effects of nitrogen losses from agriculture on the quality of air, water, and natural vegetations, series of environmental policies have been launched in the European Union from the early 1990s onwards to decrease nitrogen losses. The N loss pathways are complex, and there are various N species and processes involved.
This project was carried out in 2006 and 2007 by a group of scientists of different European Countries and was funded by the Directorate-General Environment of the European Commission.
The research was also presented at different scientific meetings, including the Fourth Nitrogen Conference in Brasil in 2007 and the First Ammonia Conference in the Netherlands in 2007. The results were discussed with the European Commission and the United Nations Economic Commission for Europe (UNECE).They have fueled policy makers in a new way of thinking about controlling N emissions from agriculture. Moreover, the results were discussed with European farmers organizations (Copa Cogeca), European organizations on production of fertilizer (EFMA), and animal feed (FEFAC), the statistical office of the European Union (Eurostat), and the European Environmental Agency (EEA).
Research to improve the model is ongoing at Alterra of the Wageningen University and Research Centre. A module for calculation of carbon sequestration in soils is included, so that the effects of measures on the total greenhouse gas budget of agricultural systems can be quantified. Leaching of phosphorus from agricultural soils enhances the risk of eutrophication of surface water. Work is carried out to include a methodology to quantify phosphorus leaching on a catchment scale in the European Union. The methodology will also be applied for China. A model to calculate nitrogen and phosphorus flows in the Chinese agriculture and food chain is developed together with the Chinese Agricultural University in Beijing.
Related Alterra reports
- Velthof, G.L. D.A. Oudendag & O. Oenema (2007) Development and application of the integrated nitrogen model MITERRA-EUROPE. Task 1 Service contract “Integrated measures in agriculture to reduce ammonia emissions”. Alterra report 1663.1, Alterra, Wageningen.
- Oenema, O.& G.L. Velthof (2007) Analysis of international and European policy instruments: pollution swapping. Task 2 Service contract “Integrated measures in agriculture to reduce ammonia emissions”. Alterra report 1663.2, Alterra, Wageningen.
- Oenema, O., D.A. Oudendag, H.P. Witzke, G.J. Monteny, G.L.Velthof, S. Pietrzak, M. Pinto, W. Britz, E. Schwaiger, J.W. Erisman, W. de Vries, J.J.M. van Grinsven & M. Sutton (2007) Integrated measures in agriculture to reduce ammonia emissions. Final summary report. Service contract “Integrated measures in agriculture to reduce ammonia emissions”. Alterra report 1663.4 , Alterra, Wageningen