structure of a soil profile

• Ao Horizon

  • Closest to the surface
  • contains organic matter fron dead plants and organisms (humus)
  • Depth varies depending on the type of soil
• A horizon

  • Top layer of surface
  • sometimes known as topsoil
  • a mixture of humus and other mineral particles
  • usually nutriant rich and fine textures
• B horizon

  • Subsoil layer
  • consists of courser material and less organic matter
  • Soluble soil material may be leached out of horizon A and into B
• C horizon

  • also known as regolith
  • made up of weathered bedrock from the parent material