17. Brown and yellow texture contrast soils (sandy surfaces)/Strike ridges and valleys: Terraces and floodplains

These soils have developed on mainly associated alluvial and colluvial material of Palaeozoic sandstone in the Western Uplands, primarily in the Victoria Valley. This soil is generally slightly acidic throughout.

The surface soil is usually a dark greyish brown loamy sand, which is massive and has weak consistence (strength) or sometimes a hardsetting surface. It clearly overlies a conspicuously bleached yellow loamy sand subsurface horizon, which is massive and has weak consistence (strength). There is a clear change to a (red and yellow-brown) mottled yellow medium clay. This is strongly structured (coarse parting to medium sized peds) with few ferruginous nodules and some quartz or rock fragments, grading into lighter textured mottled clay with weathered sandstone fragments. The profile depth is about 100 cm or more with variable depths of the surface horizons, generally 15 cm for the surface and 20-30 cm for the subsurface, often deeper.

Notable features include:

• Texture contrast soil, hardsetting or non-hardsetting surface.
• Bleached subsurface soil often with some ferruginised nodules (buckshot).
• Mottled pale subsoil has restricted soil drainage, often sodic at depth.
• The upper soil has low nutrient capacity and limited water holding capacity.
• These features make these soils vulnerable to sheet and wind erosion, particularly on sloping terrain given low consistence/coherence and lighter surface materials.