Catalogus

Results show that the presence of U. dioica resulted in large differences in root length density (RLD) among dike vegetation communities. Observed RLD values in the topsoil ranged from 129 to 235?km?m-3 for dike vegetation communities without U. dioica, while smaller values ranging from 22 to 58?km?m-3 were found for vegetation communities with U. dioica. The erosion-reducing effect of the dike vegetation communities was estimated based on a global Hill curve model, linking the root length density to the soil detachment ratio (SDR; i.e. the ratio of the soil detachment rate for root-permeated topsoils to the soil detachment rate for root-free topsoils). Concentrated flow erosion rates are likely to be reduced to 13 – 16% of the erosion rates for root-free topsoils if U. dioica is present compared to 22 – 30% for vegetation communities without U. dioica. Hence, to maintain a high resistance of the soil against concentrated flow erosion it is important to avoid the overgrowth of grassland by U. dioica through an effective vegetation management.