THE CONTRIBUTION OF AGRICULTURALLY USED RAISED BOGS TO THE TOTAL P-INPUT FROM DIFFUSE SOURCES TO SURFACE WATERS - THE RIVER EMS CASE STUDY (NW-GERMANY)

摘要

A model for calculating the total phosphorus output from diffuse sources through drainage, overland flow, groundwater, soil erosion and from urban areas is presented. It is developed by the example of the river Ems, a catchment in the lowlands of North-West Germany, 12,900 km~2 in size, which is characterized by high portions of bog and sandy soils with intensive agricultural usage. Large-scale livestock farming takes place in parts of this catchment. The model works on an emissions approach, which uses area units with homogeneous P output potential for which export coefficients are assigned and calibrated. The article focuses on the relevance of various types of cultivated raised bogs under agricultural use for the total P output from diffuse sources in the River Ems catchment.