Erosion and deposition redistribute large quantities of sediment and soil organic carbon (SOC) in agricultural landscapes.
In the perspective of global carbon cycling, the coupling between erosion processes and the fate of SOC is of particular interest.
However, different concepts have been proposed to assess the impact by erosion-induced lateral and vertical carbon fluxes.
On landscape scale, this resulted in contrasting conclusions if agricultural soils represent either a carbon sink or source.
The large global area of arable soil and generally high erosion rates, make these insights important. In this review, we aim
to give an overview of the different conceptual relations described governing C dynamics at sites of erosion, along the transport
pathway and at depositional sites and the current state of knowledge on the fate of SOC upon erosion, transport and deposition
in agricultural landscapes.
The impact of erosion on SOC dynamics differs for sites of erosion, deposition and during
transport, with further influences by agricultural practices (e.g. tillage and fertilisation). Controlling processes are the
detachment of sediment and SOC, net primary production resulting in dynamic replacement and changes in mineralisation upon
transport and deposition due to aggregate breakdown and deep burial, respectively. However, the exact magnitude and dominance
of these processes are debated, resulting in a controversy whether arable land functions as a sink or source for atmospheric
CO2. Global estimations range between a net sink strength of 0.06-1 versus a source of 0.27-1.14 Gt C yr−1 for agricultural
An eco-geomorphologic approach, which encompasses physical- and biological-driven factors (e.g. spatio-temporal
variation in biological, geomorphological and biological processes, environmental conditions, mineralisation, and net primary
production) is of importance to balance the carbon budget and ascertain sink or source formation at landscape scale. High
spatio-temporal variability on process-scale imposes constrains, to measure and model the fate of SOC upon erosion, with limited
quantitative data available. Prospective research across the landscape (eroding sites, transport pathway, and depositional
sites) should include all relevant processes at broad temporal and spatial scales. Definitive resolution of the sink/source
controversy lies in further eco-geomorphologic research on the fate of SOC, focussing on long-term and spatial extensive monitoring
studies, combined with advanced measuring, modelling and extrapolation techniques to cover broad spatio-temporal SOC dynamics.
Ascertainment of carbon dynamics in agricultural landscapes provides important insights to balance the carbon budget and finally
holds the answer on sink/source formation.