36. Sodic, brown, yellow and grey texture contrast soils/Ridges with sand and flats: Prominent ridge tops and oriented swales

These soils have developed on Quaternary unconsolidated material, generally of aeolian origin in the North West Dunefields and Plains, north of the Little Desert. The soil has a slightly acidic surface, slightly alkaline upper subsoil and strongly alkaline below the upper subsoil.

The surface soil is usually a dark brown, sandy clay loam, which is apedal (sandy) to weakly structured. It occasionally overlies a bleached apedal subsurface horizon. There is a sharp to abrupt change to a yellowish brown, medium heavy clay subsoil horizon. This is moderately structured (coarse to medium sized peds), often with a red mottle and a few ferruginous concretions. This soil grades into a light brownish grey or yellowish brown, medium heavy clay with some to many calcium carbonate segregations. This then grades into a yellower heavy clay with slickensides and may lighten in texture with depth and be mottled where grading into weathered sandstone. The profile depth is about 100 cm or more with variable depths of the surface horizons, generally 5-15 cm for the surface and 10 cm for the subsurface.

Notable features include:

• Texture contrast soil.
• Little surface friability (generally hardsetting).
• Strong consistence (strength) when dry.
• Occasional sporadic bleached subsurface soil.
• Strong consistence contrast (strength) between shallow surface soil and subsoil.
• Free (visible) calcium carbonate is common to dominant in subsoil.
• Mottling generally absent except where grading into parent material.