40. Sodic red and brown texture contrast soils/Ridges with sand and flats: Prominent ridges with eroded ferruginised spurs

These soils have developed on Quaternary unconsolidated material, generally of riverine, aeolian and lacustrine origin in the North West Dunefields and Plains, south of the Little Desert. This soil has a slightly acidic surface with a neutral to alkaline subsoil.

The surface soil is usually a dark brown loamy sand, which is apedal (sandy) to weakly structured and loose consistence. It generally abruptly overlies a brownish yellow loamy sand subsurface horizon. This is bleached and has some ferromanganiferous concretions or indurated rock fragments. There is a sharp/abrupt change to a red, medium clay upper subsoil horizon. This is sodic, often with a brown mottle, strongly structured (with coarse to medium sized peds) and some ferro-manganiferous concretions or indurated rock fragments. This grades into more mottled and less structured subsoil which in turn grades into weathered material, often ferruginised (indurated) sandstone. The profile depth is about 80 cm or more with variable depths of the surface horizons, generally 10 cm for the surface and 5 cm for the subsurface, occasional deeper or absent on some crests.

Notable features include:

• Texture contrast soil.
• Variable surface friability (generally soft) with sandy surfaces.
• Strong consistence (strength) contrast between weak surface and strong subsoil when dry.
• Generally has a bleached subsurface soil.
• Ferro-manganiferous concretions or ferruginised sandstone occur on soil surface and in the surface and subsurface soil in particular.
• The sodic subsoil may be strongly sodic and highly dispersible.