3 Mottled brown and grey texture contrast soils 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 to sandy clay loam over a massive or moderately coherent conspicuously bleached loamy sand to sandy clay loam subsurface horizon with variable amounts of coarse fragments (quartz). There is a clear change 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, grading into lighter weathered material. The subsoil may be sodic at depth. The depth is about 100 cm or more with variable depths of the surface horizons, generally 15 cm for the surface and 25 cm for the subsurface, often deeper (as in the Lal Lal area).

Notable features include: texture contrast and associated structure differences between the surface horizons and subsoil, the strongly sodic subsoil, coarse fraction component of the soil with low nutrient capacity and low water holding capacity. These features make these soils vulnerable to erosion, particularly on sloping terrain given poor drainage characteristics, subsoil dispersion and lighter surface materials.

Soil Sites

Site Code	Soil-landform unit	Component	ASC	FK	1:100 000 mapsheet
MM5150	20	Undulating plains and drainage lines	Mottled, Mesotrphic Brown Chromosol	Dy3.41	T7722 - Bacchus Marsh

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