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Difficulty: MediumSoil Formation, Profiles, and Major Vegetation Types

In a mature soil profile, water carrying fine clay particles and dissolved mineral nutrients percolates downward from the upper layers and deposits these materials in a subsoil accumulation zone. Which process and soil horizon correctly identify this downward movement and accumulation layer?

  1. Illuviation depositing materials into Horizon BAnswer
  2. B
    Weathering disintegrating parent material in Horizon C
  3. C
    Mass wasting carrying organic debris into Horizon A
  4. D
    Metamorphism altering parent rock within Horizon R

Answer

Illuviation depositing materials into Horizon B
Illuviation is the process where minerals, clays, and oxides leached from the upper soil horizons (eluviation zone) accumulate in Horizon B, forming the subsoil accumulation zone.

Step-by-Step Solution

1
Identify the specific pedogenic translocation process responsible for depositing leached minerals.
Eluviation washes materials out of topsoil layers, while illuviation deposits and accumulates these materials lower down.
Illuviation specifically describes the accumulation phase of pedogenic leaching.
2
Determine the designated soil profile horizon where these illuviated materials accumulate.
Horizon B (the subsoil) functions as the primary illuviation zone.
Horizon A/E is the zone of eluviation, Horizon B is the zone of illuviation (accumulation), Horizon C contains weathered parent material, and Horizon R is solid bedrock.

Key Concept

Soil Profile Horizonation and Illuviation
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Topics

Soil Formation, Profiles, and Major Vegetation Types

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