Soil erosion and driving factors of soil carbon distribution: a worldwide threat

Abstract

In many parts of the world, agriculture is threatened by climate change and land degradation in the form of soil erosion. Soil erosion involves the loss of fertile topsoil and reduction of soil productivity, as well as increased mobilization of sediment and delivery to rivers. Sedimentation of water bodies is especially problematic in arid regions where water scarcity is frequent. Furthermore, the dynamics of soil erosion and deposition processes substantially affects the redistribution of soil carbon in the landscapes. Despite being a significant risk to soil and water resources, soil erosion is an overlooked threat, especially in terms of climate change due to increased soil carbon emissions. Considerable discussion still exists about whether erosion results in enhanced emissions of carbon to the atmosphere (C source) or enhanced sequestration of carbon in the soil (C sink). More scientific information is essential to assess the role and impact of soil erosion on the terrestrial carbon budget, highlighting the effect of topography, soil type, land use/land cover and soil management. Another question of importance is the “intra-storage” of mobilized soil and carbon along the hillslopes and in different compartments within catchments. Driving factors of soil carbon distribution and the role of sediment connectivity across the landscape induced by erosion remain largely unknown. This session combines contributions on soil erosion and soil carbon at hillslope, small or large catchment scale in different agroecosystems, including both agricultural and forestry landscapes, using a diverse set of tools and data analyses such as field measurements, monitoring techniques, remotely sensed and GIS analyses, modelling, isotopic and non-isotopic erosion tracers, fingerprinting techniques, among others. Let’s come together and share findings, views and concepts to better understand soil erosion processes and its effect on the landscape-scale distribution of soil carbon.