RILL EROSION AS A FUNCTION OF THE CHARACTERISTICS OF CULTIVATED CATCHMENTS IN THE NORTH OF FRANCE

This study analyses variations in rill erosion as a function of the morphological, pedological and land use characteristics of cultivated catchments. 20 elementary catchments in Northern France, from 3.7 to 100 ha, were studied during the winter of 1988/89. The between-catchment differences in total and talweg rill volumes (m3) and rates (m3/ha) were very large, and could not be explained by the variations in rainfall. The size of runoff contributing area, defined by combining soil susceptibility to crusting and certain land use characteristics, was found to be the main factor accounting for variations in erosion. Other factors, such as the soil sand content, talweg incisable length, catchment compacity index and proportion of upslope contributing areas were also correlated with total and talweg rill volumes, but slope characteristics were not. Cropping systems greatly affected the catchment susceptibility to rill erosion through their influence on runoff generation, runoff concentration and soil susceptibility to scouring.