A typical soil profile

A soil profile is a cross section through the soil that reveals its horizons (layers). Soil generally consists of visually and texturally distinct layers, which can be summarised as follows (from top to bottom):

A) Humus: organic matter in relatively undecomposed form. This layer tends to be dark and rich in smell and texture.
B) Topsoil: well decomposed organic matter, mixed with a smaller amount of minerals.
C) Layer of mixed decomposed organic matter and mineral content.
D) Subsoil or mineral layers, the content of which varies according to the nature of the soil and its parent material.
E) Bedrock or parent material, which breaks down at the upper surface due to the effects of mad.

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