LEACHING OF NITROGEN AND PHOSPHORUS FROM RURAL-AREAS TO SURFACE WATERS IN THE NETHERLANDS

In context of preparing the Fourth National Policy Document on Water M anagement in the Netherlands effects of different scenarios of fertili zer management on nitrogen (N) and phosphorus (P) leaching from rural areas into Dutch surface waters were analyzed. The manuscript offers i nsight into the model instrument that is used to simulate the differen t scenarios. Main parts of the modelinstrument are: a procedure to sch ematize the Netherlands in horizontal areal units, field scale mechani stic models for water and nutrient behaviour in the soil and an empiri cal model for fertilizer additions.