This is generally the most productive layer of the soil. This is the layer that soil conservation efforts are focused. As water moves down through the topsoil, many soluble minerals and nutrients dissolve. The dissolved materials leach downward into lower horizons. The next layer is the B horizon or subsoil .
Subsoils are usually lighter in color, dense and low in organic matter.
Most of the materials leached from the A horizon stops in this zone. Still deeper is the C horizon . It is a transition area between soil and parent material. Partially disintegrated parent material and mineral particles may be found in this horizon. At some point the C horizon will give up to the final horizon, bedrock .