Final answer:
The B horizon is heavily influenced by leaching from the topsoil, affecting its mineral content and fertility.
Explanation:
The B horizon is most heavily influenced by leaching from the topsoil. Leaching is the process where water removes minerals and nutrients from the top layers of soil and transports them to lower layers, affecting the B horizon the most. This horizon may contain deposited minerals from upper layers, influencing fertility but not as rich as the topsoil (A horizon).
Learn more about Soil Horizons here:
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