FATES OF ERODED SOIL ORGANIC CARBON: MISSISSIPPI BASIN CASE STUDY.

The article presents a case study on the eroded soil organic carbon (SOC) in the Mississippi Basin (MS). The soil erosion, translocation, redeposition, oxidation, and carbon dioxide sequestration across the five major river subsystems in the MS was quantitatively analyzed to study the role of soil and soil erosion in the carbon cycle. A significant. portion of eroded SOC is exposed to greater oxidation rates during and after erosion creased oxidation due to the breakdown of aggregates, exposing more SOC to the atmosphere and thus reducing organic carbon of eroded soil. The SOC was analyzed using the State Soil Geographic Database. The major medium for eroded material transport is water, so the river gaging station near the downstream boundary of each subsystem is the monitoring point for transport. The problem in the analysis of MS Basin sediment and organic carbon (OC) budget is that erosion estimates are model-based estimates with inherent biases and do not include erosional processes such as gullying and river-bank erosion. Though the water bodies and alluvial soils are carbon dioxide sources, but they must be compared to the locations from which the decomposing OC came. The soil erosion in the MS Basin results in soil degradation due to the removal of organic matter (OM) from upland soils and relocation to depositional sites rather than by net loss of OM to oxidation.