Nitrate leaching

Abstract

Nitrate leaching has a signifi cant infl uence on plant nitrogen supply and groundwater quality. Spatially detailed information on nitrate leaching is required to assess land-use management options and to develop effective groundwater resource protection measures. Comprehensive information for decision support can be derived based on spatiotemporally dynamic modelling. Coupled simulations with the DANUBIA simulation system (plant growth, balances of carbon, nitrogen, water, energy) were performed for several test sites and for the Upper Danube catchment. Model validation results for soil mineral nitrogen show good correspondence between the model results and fi eld measurements without a site-specifi c calibration. For the spatially explicit analysis on the catchment scale, land-use and cultivation practice (timing, fertilisation) were set according to best-practice recommendations. Modelled nitrate concentrations in the leachate from the vadose zone were analysed for the period 1995-2000. A comparison of simulated and measured data proved the consistency of the model results. In general, nitrate concentrations above 50 mg l -1 were calculated mainly for regions characterised by intensive agriculture or peatland soils. The lowest nitrate concentrations occur in forested areas and regions with little arable land. Overall, the results reveal the potential for dynamic and comprehensive modelling of nitrogen leaching with DANUBIA