Soil erosion processes and sediment fluxes in a Mediterranean marl landscape, Campina de Cadiz, SW Spain

Marl landscapes, especially in the Mediterranean, show evident traces of high present-day and past soil erosion rates. The tendency to develop hillslope channels leads even at moderate rainstorm magnitudes to a significant increase of slope-to-slope connectivity, resulting in high amounts of mass transfer from upper parts of the hillslopes towards foot-slopes and valleyfloors. To analyse the intensity of this transfer a study was conducted focussing on late Holocene sediments correlative to modern-time soil erosion in the marl landscape of SW Spain. Based on field observations and sediment analysis several landscape positions within a medium-scale catchment were explored. Depending on landscape constellation, the sediment characteristics reflect the influence of past processes at this position, referring to either hilislope processes or alluvial processes or an interchange of them. For a temporal context a method to trace young sediments by analysing nutrients originating from modern-time application of mineral fertiliser was applied. Results show high rates of sedimentation (>1cm/year) for this period in several profiles. By identifying the predominant geomorphic components and processes in the study area a conceptual model of the studied system was developed.