The lowest horizon of a soil profile. It is below the B-horizon and is made up of weathered bedrock.

Related terms:

• Ao horizon
• Aoo horizon
• D horizon
• natric horizon
• B horizon
• spodic horizon
• B-horizon
• placic horizon
• fog horizon
• albic horizon

The portion of the parent material in soils which has been penetrated with roots.

Related terms:

• Ao horizon
• Aoo horizon
• A Horizon