Effect of Soil Organic Carbon Level On the Erodibility of a U.S. Piedmont Soil.

Intensive soil cultivation and high soil erosion has impoverished levels of soil organic carbon (SOC) in the southeastern U.S. Piedmont region. Sound soil management practices that build SOC levels are needed to reduce soil erodibility and restore soil quality. We studied the relationship of SOC content and soil erodibility using a Piedmont soil that has been managed for 7-years using key practices that increase SOC levels, including winter cover cropping, compost applications and no tillage. The soil used, an Enon sandy loam (fine, mixed, thermic, Ultic Hapludalf), was collected in June 2010 from the following treatments in a field study that began in 2003: (i) no tillage summer vegetable planting, (ii) fall applied poultry hatchery compost + winter rye-clover cover crop + no tillage summer vegetable planting, (iii) summer vegetable planting after disk tillage and, (iv) fall applied poultry hatchery compost + winter rye-clover cover crop + summer vegetable planting after disk tillage. A rainfall simulator was used to apply 75 mm hr^-1 intensity rain for 1.5 h on a 1 m² soil pan adjusted to a 9% gradient. Soil erodibility was found to decrease by 14% with each 1% increase in SOC.