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Inceptic Soils

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Inceptic Soils

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Cumulic subgroup (neocutanic or neocarbonate B, alluvium, or regic sand)


Other soils are youthful even though they may have formed in relatively deep, unconsolidated sediments such as colluvium, alluvium, or aeolian sands. In some cases there is clear evidence of incipient soil development in the form of colour variegation caused by cutanic character (textural differentiation, clay skins or lamellae), carbonate accumulation and/or faunal incorporation of darker surface soil. In other cases this may be barely noticeable. Unifying features are the absence of a distinctive surface or subsurface horizon and a parent material that has originated through the accumulation of unconsolidated material (Soil forms: Tukulu, Oakleaf, Montagu, Augrabies, Dundee, Namib).


Lithic subgroup (lithocutanic B or hard rock)


Many soils are youthful either because of limited weathering or on account of rejuvenation through natural erosion on steeper, convex slopes, ensuring intimate contact between a surface horizon which is maintained by biological activity and the underlying rock or saprolite. Even where the rock is weathered the subsoil has a predominantly geogenic character although tonguing of soil and illuviated clay (cutans) into the saprolite is evident. The saprolitic material may have incipient features such as gleying, calcareousness or softening due to weathering but these are insufficiently expressed to qualify for one of the other distinctive subsurface horizons. Penetration of roots and water is typically non-uniform and restricted to spaces between fragments of rock or saprolite (Soil forms: Glenrosa, Mispah).


Anthropic subgroup (disturbed deposits).


Incipient soil formation can be detected in most disturbed materials associated with mining or waste disposal. This subgroup is also “cumulic” in that the parent material represents an unconsolidated accumulation, which ranges from municipal garbage to various mine spoils and metallurgical tailings on slimes dams and could include land that has been sufficiently disturbed by civil engineering projects to have lost any recognisable solum that might have been present. Deep cultivation in preparing land for some types of agriculture could also be included. (Soil form: Witbank)



Inceptic Soils