The next soil horizon is thesubsoil,which is called the B horizon. This is the region where
soluble minerals and clays accumulate. This layer will be lighter brown in color and more
water holding than the top soil, due to the presence of iron and clay minerals. There will be
less organic material in this layer. The next layer down, called the C horizon will be a layer
of partially altered bedrock. There will be some evidence of weathering in this layer, but
pieces of the original rock can still be seen and it would be possible to identify the original
type of rock from which this soil formed (Figure9.9).
Figure 9.9: A soil profile is the complete set of soil layers. Each layer is called a horizon.
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Not all climate regions develop soils, and not all regions develop the same horizons. Some
areas develop as many as five or six distinct layers, while others develop only very thin soils
or perhaps soil doesn’t form well at all.