Biophysical Controls That Make Erosion-Transported Soil Carbon a Source of Greenhouse Gases

Soil erosion is a selective process which removes the light fraction comprised of soil organic carbon (SOC) and colloidal particles clay fine silt. Thus, large amount (C) transported by erosional processes, its fate (i.e., emission, redistribution, burial, translocation into aquatic ecosystems) has strong impact on global cycle. The processes affecting dynamics C emission as greenhouse gases CO2, CH4, N2O), or deposition vary among different stages erosion: detachment, transport, ecosystems. Specific biogeochemical biogeophysical transformative make erosion-transported source are determined type (rill vs. inter-rill in hydric saltation air-borne dust aeolian erosion), temperature moisture regimes, initial SOC content, texture, raindrop-stable aggregates water repellency, crusting, slope gradient, physiography slope-based flow patterns, landscape position, attendant aerobic anaerobic conditions within where sediment-laden being carried alluvial processes. As much 20–40% eroded may be oxidized after erosion, erosion-induced redistribution C. In addition, human activities (e.g., land use management) have altered—and altering—the pattern sediments transported. addition to O2 availability, other factors emissions from ecosystems include sub-surface currents high winds, also affect CH4 efflux. transport affected wind speed, texture structure, vegetation cover, etc. Lighter fractions (SOC, clay, silt) selectively removed wind-blown dust. SOC-ER originating sand-rich range 2 41. A majority (and nutrients) lost saltation. Even over short period three seasons, can remove up 25% total (TOC) N (TN) top 5 cm soil. proportion emitted atmosphere CO2 along with N2O. While some buried at depositional site deep encapsulated reformed protected against microbial even vulnerable future loss use, management, alkalinity pH, time lag between burial subsequent loss, mineralogical properties, warming.