%0 Journal Article %A Wendland, F. %A Behrendt, H. %A Gömann, H. %A Hirt, U. %A Kreins, P. %A Kuhn, U. %A Kunkel, R. %A Tetzlaff, B. %T Determination of nitrogen reduction levels necessary to reach groundwater quality targets in large river basins: The Weser basin case study, Germany Nutrient Cycling in Agroecosystems %J Nutrient cycling in agroecosystems %V 85 %@ 1385-1314 %C Dordrecht [u.a.] %I Springer Science + Business Media B.V %M PreJuSER-5097 %P 63 - 78 %D 2009 %Z This project was commissioned by Germany's Federal Ministry of Food, Agriculture and Consumer protection (BMELV), the River Basin Commission Weser (RBC Weser) and the Federal States Bremen, Hessen, Niedersachsen, Nordrhein-Westfalen, Sachsen-Anhalt and Thuringen. %X We used the interdisciplinary model network REGFLUD to predict the actual mean nitrate concentration in percolation water at the scale of the Weser river basin (Germany) using an area-differentiated (100 m x 100 m) approach. REGFLUD combines the agro-economic model RAUMIS for estimating nitrogen surpluses and the hydrological models GROWA/DENUZ for assessing the nitrate leaching from the soil. The areas showing predicted nitrate concentrations in percolation water above the EU groundwater quality standard of 50 mg NO3/l, have been identified as priority areas for implementing nitrogen reduction measures. For these "hot spot'' areas a backward modelling approach was used to quantify the maximal permissible nitrogen surplus levels in agriculture to guarantee a mean long-term nitrate concentration in percolation water below 50 mg NO3/l. Research work will directly support the implementation of the EU-Water Framework Directive in the Weser basin, e.g. by using the maximal permissible nitrogen surplus levels as a framework for the derivation of regionally adapted and hence effective nitrogen reduction measures. %K J (WoSType) %F PUB:(DE-HGF)16 %9 Journal Article %U <Go to ISI:>//WOS:000269686900005 %R 10.1007/s10705-009-9248-9 %U https://juser.fz-juelich.de/record/5097