Sediment budget for five millennia of tillage in the Rockenberg catchment (Wetterau loess basin, Germany)

The long-cultivated loess landscapes of central Europe provide the opportunity to explore the long-term perspective on the evolution human-natural sediment systems that are driven by human-caused soil erosion processes. A balance of spatially non-uniform sediment production, sedimentation and delivery was developed to highlight the quantitative dimensions and functioning of anthropogenic sediment redistribution in an undulating loess catchment of temperate Europe. The presented long-term perspective relies on analysing pedostratigraphic and lithostratigraphic field data from 728 corings across ∼10-km2, GIS-based data processing, and the analysis of data uncertainty. For a period of 5000 years of tillage, anthropogenic sediment production equals ∼9425 t ha−1, of which 62% still reside as colluvial sediment on the catchment's hillsides. The valley floors fulfil a sediment-conveyor function through transporting 77% of the sediment received from the hillsides. Whole-catchment yield to the contiguous higher-order valley is 29% of the amount of anthropogenic sediment production. The average catchment-scale depth of soil truncation is 0.64 m while the remaining anthropogenic sediment cover has an average thickness of 0.46 m (effective surface denudation: ∼0.18 m). The long-term integral net erosion rate is ∼0.5 t ha−1 a−1 because of extensive sediment retention on hillsides. The inherited human imprint on the soilscape, eventually, can be judged as beneficial rather than detrimental: the ubiquitous cover of humic colluvia generally is more suitable for intense cultivation than pristine pedostratigraphies. The sediment budget, although build from a historic perspective, also provides a plausible reference for realistic objectives of managing the soil erosion problem in human-natural sediment systems.

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► A sediment budget reveals the operation of a human-natural sediment system for 5000 years.
► Sediment yield from hillsides is limited equalling 38% of the sediment detached from soil surfaces.
► Within the sediment system, hillslopes act as main storages; valley floors as sediment conveyors.
► Long-term catchment-scale net erosion rate is 0.55 t ha−1 a−1; catchment trap efficiency is 71%.
► The budget provides a reference for realistic management objectives of the soil erosion problem.