Although often difficult to recognise, sheet erosion is responsible for extensive soil loss in both cultivated and non-cultivated environments. Sheet erosion occurs as a shallow 'sheet' of water flowing over the ground surface, resulting in the removal of a uniform layer of soil from the soil surface.
Sheet erosion occurs when rainfall intensity is greater than infiltration (sometimes due to crusting).
- Rarely seen but accounts for large volumes of soil loss.
- Sheet erosion rarely flows for more than a few meters before concentrating into rills.
- Soil particles are only transported not detached.
- Typically results in the loss of the finest soil particles which contain the bulk of the available nutrients and organic matter.
- Difficult to observe in the field, sheet erosion is often only recognised when eroded soil is deposited along a fenceline.
Prevention and Control
Sheet erosion can be prevented by maintaining plant cover (preventing splash erosion) and maximising infiltration of ponded water through the maintenance of soil structure and organic matter. Organic matter acts as a glue, stabilising pore spaces which transmit surface water deeper into the soil and thus reduce the volume of ponded water available for erosion.
- Prevent splash erosion.
- Maintain ground cover.
- Maintain organic matter.
- Prevent surface soil compaction.
- Protect surface soils with geotextiles or mulch.