The NitroEurope IP – or NEU for short – addresses the major question: What is the effect of reactive nitrogen (Nr) supply on net greenhouse gas budgets for Europe? The objectives are to:

• establish robust datasets of N fluxes and net greenhouse-gas exchange (NGE) in relation to C-N cycling of representative European ecosystems, as a basis to investigate interactions and assess long-term change,
• quantify the effects of past and present global changes (climate, atmospheric composition, land-use/land-management) on CN cycling and NGE,
• simulate the observed fluxes of N and NGE, their interactions and responses to global change/land-management decisions, through refinement of plot-scale models,
• quantify multiple N and C fluxes for contrasting European landscapes, including interactions between farm-scale management, atmospheric and water dispersion, and consideration of the implications for net fluxes and strategies,
• scale up Nr and NGE fluxes for terrestrial ecosystems to regional and European levels, considering spatial variability and allowing assessment of past, present and future changes,
• assess uncertainties in the European model results and use these together with independent measurement/inverse modelling approaches for verification of European N2O and CH4 inventories and refinement of IPCC approaches.

These objectives are met by a programme that integrates:

1. an observing system for N fluxes and pools [Component 1]
2. a network of manipulation experiments [Component 2]
3. plot-scale C-N modelling [Component 3]
4. landscape analysis [Component 4]
5. European up-scaling [Component 5] and
6. uncertainty and verification of European estimates [Component 6].

In addition to that, the project organisation comprises cross-cutting activities addressing management, databases, training and dissemination.

NEU will advance the fundamental understanding of C-N interactions at different scales and deliver: process-based models, landscape-level assessments, European maps of C-N pools, Nr fluxes and NGE, and independent verification of GHG inventories, as required under the Kyoto Protocol.