soil layer Distinctive successive layers of soil produced by internal redistribution processes. Conventionally the layers have been divided into A, B and C horizons. The A horizon is the upper layer, containing humus and is leached and/or eluviated of many minerals. The B horizon forms a zone of deposition and is enriched with clay minerals and iron/aluminium oxides from the A layer. The C layer is the parent material for the present soil and may be partially weathered rock, transported glacial or alluvial material or an earlier soil | |
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