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Competency Area 5: Soil conservation AEM

PO 40. Understand the main agronomic and environmental consequences of soil erosion and sedimentation.


  • Organic-matter rich surface soil is removed.
  • Nitrogen, phosphorus, potassium, and other nutrients in mineral and organic form are lost from the field.
  • Herbicides and other pesticides attached to soil particles will be removed from the field.
  • Since silt particles are preferentially removed in erosion, the soil tends to either become more clayey or more sandy.
  • Soil depth is reduced, leading to reduced root volume and increased moisture stress.
  • Rill and gully formation will compromise field work.
  • Deposition can cause newly planted crops to be lost.

erosion to stream.jpg

Runoff from farm fields reaches a sediment-laden stream

Photo courtesy of NRCS


  • Increased need for channel dredging.
  • Adverse impacts on the recovery of underwater grass beds because the sediment reduces the amount of light reaching plants.
  • Benthic (bottom-dwelling) organisms suffer increased mortality and reduced reproduction.
  • Fish may be affected as increased sediment affects their feeding, clogs gill tissues, and smothers eggs.
  • Siltation can alter the habitat of aquatic organisms.
  • Increased turbidity may change the abundance of plankton, a prey which is important for larval and juvenile fish.
  • Phosphorus is carried with the sediment, contributing to eutrophication.