Soil erosion contributes to the loss of soil quality and pollution of surface waters. Soil erosion above a certain level will reduce soil productivity over the long haul. Soil erosion exposes subsoil, which has often poor qualities for crop establishment and growth. It can also lead to stand loss by sediment deposition. Three types of soil erosion are classified as water erosion, wind erosion, and tillage erosion. Water and tillage erosion are the more important types of erosion in Pennsylvania and will be discussed here. A survey by USDA-NRCS revealed that 60 percent of the cropland in Pennsylvania is “highly erodible land” (HEL). In 2003, 40 percent of the HEL cropland eroded at greater than tolerable levels. Eleven percent of non-HEL cropland eroded above the tolerable level. In summary, more than one-quarter of cropland in Pennsylvania is losing soil at a rate that affects soil productivity in the long run.
Reference: The Agronomy Guide - Section 1: Soil Management