# Fate of Soil Carbon Transported by Erosional Processes
## 7 Summary  
Accelerated erosion, both hydric and aeolian, involves selective removal of soil C (both SOC and SIC) along with clay and fine silt fractions. On-site, the eroded soil becomes progressively depleted of the light and colloidal fractions, leaving coarse material (gravels, sand, course silt) behind. Because CER of the eroded material is high, erosion has severe adverse effects on the functionality of eroding landscapes. Globally, soil erosion by water and wind transports a large amount of C, but the fate of C being transported is governed by complex pedotransformative processes, and its stability against decomposition is governed by site-specific biophysical conditions and hydrothermal regimes. Therefore, soil erosion not only affects soil properties and processes on-site, but also along the landscape over which the water or windborne sediments are being redistributed and the depressional sites or barriers where the sediments are being deposited. Whereas a proportion of soil C being buried at depositional sites or into the water bodies may be protected against mineralization and may even be encapsulated within reformed aggregates, most of the C redistributed over the landscape and part of those carried into depositional sites is subject to decomposition by both biotic and abiotic processes. Off-site, a large proportion of transported C is released into the atmosphere as CO2, CH4, and N2O, depending on the biophysical and hydrothermal regimes. In total, the accelerated soil erosion has a drastic impact on the GCB. How much of soil C (SOC and SIC) is being removed by erosional processes and how it is being mineralized en route to depositional sites has significant environmental consequences, especially as a source or sink of GHGs, depending on the site-specific conditions. Nonetheless, the C displaced by erosional processes is not accounted for in the current processes of compiling the GCB. Not only should the impact of erosional process on the global C cycle be accounted for, but its impact as a source of GHGs should be considered in evaluating the economic and environmental impacts of erosion. The net effects of the erosional processes as a source or sink depend on a multitude of site-specific and highly interactive factors. Despite the on-site and off-site effects on productivity and off-site effects on the global C cycle and emission of GHGs, a prudent strategy is to minimize the risks of accelerated soil erosion by adoption of the conservation-effective measures.  
The global menace of soil erosion by water and wind may be aggravated by global warming, especially in the tropics and subtropics, and with agricultural intensification of agroecosystems. Thus, there is a strong need to:  
1. quantify the global magnitude of soil C (SOC, SIC) being transported by the erosional processes in relation to land use, farming/cropping systems, landscape characteristics, soil physical/chemical properties, and the dynamics of hydrothermal regimes along the landscape and at the depositional sites;
2. account for the global amount of C transported by hydric and aeolian processes in the GCB;
3. evaluate the site-specific conditions which make the eroded soil C a source (emission of CO2, CH4, and N2O) of GHGs or a sink if some C is buried, reaggregated, and taken out of circulation;
4. identify and implement site-specific conservation-effective management practices, which minimize the risks of soil erosion by water, wind, and other anthropogenic activities.  
This research received no external funding.  
**Institutional Review Board Statement:** Not Applicable.  
**Informed Consent Statement:** Not Applicable.  
Data Availability Statement: The data quoted in the manuscript are available in the specific reference number listed at the end of each statement or the paragraph.