Reducing agricultural nitrogen inputs in the German Baltic Sea catchment - Trends and policy options

Abstract

We depict recent agricultural nitrogen input and future loads to be expected in 2021 in the German Baltic Sea catchment to assess the feasibility of reaching water quality targets defined by the Marine Strategy Framework Directive (MSFD). We calculate recent and future nitrogen balances from agriculture by applying an interdisciplinary modelling system, also considering the effects of the Nitrate Directive. The nitrogen surpluses are transferred to a nutrient emission model to simulate nitrogen emissions, in-stream retention and resulting riverine loads to the sea until 2021. Finally, we analyse input reduction demands and agri-environmental measures necessary to attain water quality targets of the MSFD. The results are target-oriented mitigation options relevant for implementation, based on regional land use and nitrogen reduction demands. Furthermore, this paper discusses the effects of policies and measures implemented to reduce nitrogen loads.