{Agri-Environmental Nitrogen Indicators for EU27}

Publication Type:

Book Chapter


Bio-Economic Models applied to Agricultural Systems, Springer Netherlands, Dordrecht, p.109–123 (2011)








Nitrogen is a key element to ensure modern agriculture's output, sustaining global food, feed, fibre and now bio-energy production. But it also accounts also for, or at least contributes to, key environmental problems that challenge the well functioning of today's societies (Sutton et al. 2011). One molecule of nitrogen can contribute to one or many environmental problems, including eutrophication, groundwater pollution via leaching and run-off of nitrates and organic nitrogen, climate change via N2O emissions, acidification via ammonia emissions and may affect human health via ozone formation or biodiversity via nitrogen deposition on natural areas. This multiple impact of nitrogen is often referred to as the “nitrogen cascade” (Galloway et al. 2003). Accordingly, agri-environmental indicator frameworks typically feature several indicators related to nitrogen such as ammonia emissions, use of nitrogen fertilisers, gross N surplus, nitrates in water or GHG emissions (EEA 2005). Often, however, these indicators are calculated independently from each other based on sometimes contradicting data sources, methodologies or assumptions (see e.g. Grizzetti et al. 2007). This includes also the first overview of the “European Nitrogen Case” that was presented by van Egmond et al. (2002) at the second International Nitrogen Conference held in Potomac (USA). Thus, a system that calculates the detailed nitrogen balance and the related indicators for agriculture in Europe on the basis of consistent data sets and advanced methodologies is highly desirable. A closed balance of nitrogen is calculated in the CAPRI (Common Agricultural Policy Regionalized Impact) model, i.e., next to monetary values and product balances, also the nutrient fluxes are in accordance with the law of mass-conservation (Britz et al., 2007). This has been exploited by Leip et al. (2011b) to develop nitrogen budgets for the system boundaries of the soil, land, and the farm. The authors provide for the first time mutually consistent calculations of farm, land and soil N-budgets for all member states of the European Union and quantify the two major indicators, namely the nitrogen use efficiency and the nitrogen surplus for each of the N-budgets. The data showed that the nitrogen surplus increases for the soil {\textless} land {\textless} farm budget, while the nitrogen use efficiency decreases analogically for soil {\textgreater} land {\textgreater} farm budgets. The farm N-budget appeared to be the most relevant one giving a picture of the overall N management of agriculture and is accordingly recommended for integrative studies assessing the “nitrogen footprint” of society. Based on the work of Leip et al. (2011b), we propose in this chapter three additional nitrogen indicators focusing even more on the use society in European countries makes of their productive land.