The integrated DNDC-Europe model was developed to assess the affect of agri-environmental policy on greenhouse gas (GHG) emissions. The large scale economic model for agriculture, CAPRI (Common Agricultural Policy Regional Impact Assessment) detailed in Britz (2005), was integrated with the biogeochemical model DNDC (used DNDC v.8.9) to produce European simulations of GHG emissions, carbon stock exchanges and nitrogen budgets of soils. The modelling framework allows environmental impacts such as GHG emissions to be analysed in the context of economic and social indicators provided by the CAPRI model.
The CAPRI framework was developed to capture the complex interaction between the agricultural market, environmental policy, trade systems and the economic behaviours of farmers, consumers and processors at a regional scale and then provide a policy impact assessment on a global scale. The original DNDC model was developed to simulate nitrous oxide (N2O) emissions from annual cropping systems in the United States (Li et al., 1992). Linking the two models together required two key steps as outlined by Leip et al. (2008). Firstly spatially explicit information from EU agricultural statistics covering, landuse, crop levels and animal densities and climate were generated for a defined Homogenous Spatial Mapping Unit (HSMU). The HSMU were defined based on information on soil, slope, landcover and administrative boundaries and encapsulated conditions that lead to similar GHG emissions in terms of agronomic practices and the environment. Secondly a database was prepared to drive DNDC with data for each HSMU to include, agricultural management parameters such as fertilisation rates, irrigation, sowing dates etc. in order to calculate soil nitrogen and carbon turnover.