A soil test shows that the B horizon contains a large amount of clay but relatively low organic content. What does this suggest about the B horizon's role in nutrient availability?

The B horizon, or subsoil, often accumulates clay and minerals washed down from upper layers, but it generally has less organic matter than the topsoil. Since organic matter supports nutrient cycling and many active roots are concentrated nearer the surface, the B horizon is less directly involved in feeding plant roots. Its clay can hold some nutrients, but that does not make it the main nutrient source for plants.

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