What is the term for the material that has leached from horizon A and lies between horizons A and B?

• A. Eluviation
• B. Illuviation
• C. Pedogenesis
• D. Leaching

Answer: (A)

Eluviation is the process by which water moving downward through the soil removes fine, soluble materials from the upper horizon and transports them downward. In a soil profile, this leached material often ends up between the A and B horizons, leaving the A horizon depleted and the materials moving downward. Among the given terms, eluviation best fits because it names this downward movement of material. Illuviation refers to the deposition of materials in a lower horizon (often forming a richer B horizon), pedogenesis is the formation of soil, and leaching is the general removal of dissolved substances by water without specifying downward transport within horizons.