4 Deep sands or texture contrast soils with deep (sandy) surfaces on Palaeozoic granitic material

These soils have developed on granitic parent material (rock or colluvial material) in the Western Uplands.

The surface soil is often a dark weakly coherent to massive sandy loam over a massive or moderately coherent conspicuously bleached loamy sand to sandy loam subsurface horizon with variable amounts of coarse fragments (quartz). There may be a clear change at depth to a mottled yellow brown (occasionally light grey or dark grey) strongly medium to coarsely structured medium clay, often with a red mottle and some quartz or rock fragments, or grade directly into weather parent material (saprolite).

The depth is often more than 100 cm or more with variable depths of the surface horizon, generally 15 cm for the surface. Site BD8 in the Lal Lal area is an example of a texture contrast soil with deep surface horizons (77 cm). Notable features include: the difference in structure between the surface horizons and subsoil where they exist, the coarse fraction component of the soil and associated poor water holding and low nutrient capacities, and lateral movement of water. These features make these soils vulnerable to erosion, particularly on sloping terrain given lighter surface materials and variable drainage characteristics, leading to seepage areas.

Soil Sites

Site Code	Soil-landform unit	Component	ASC	FK	1:100 000 mapsheet
BD8	17	Crest	Melanic, Mottled-Mesonatric, Grey Sodosol	Dy3.71	T7722 - Bacchus Marsh
MM236	19	Upper slope	Melanic, Mottled-Subnatric, Grey Sodosol	Dy5.51	T7522 - Skipton

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