14. Sandy gradational soils/Strike ridges and valleys: Cuesta landscapes

These soils have developed on mainly Palaeozoic sandstone and colluvial material in the Western Uplands, primarily the Grampian Ranges. These soils are a heavier than Type 13, but have a comparative coarse sand component and are of minor occurrence.

The surface soil is usually a grey or brown loamy sand to sandy loam, which is weakly structured. It overlies a conspicuously bleached loamy sand to sandy clay loam subsurface horizon. This is massive to weakly structured with many coarse grained quartz sand. There may be a gradual to clear change to a yellow brown silty or clay loam subsoil horizon, with moderate medium structure (with medium sized peds) or sandy clay loam subsoil, which is weakly structured. This often has few to common quartz or rock fragments or grades directly into weathered sandstone parent material. The profile depth is about 70 cm or more with variable depths of the surface horizons, generally 5 -15 cm for the surface and 10-20 cm for the subsurface, often deeper.

Notable features include:

• Gradational or uniform change in clay percentage with depth.
• Occasional indurated or accumulation zones with in the predominantly coarse soil (Podosols).
• These soils have with low nutrient holding capacity and low water holding capacity.
• These features make these soils vulnerable to erosion, particularly on sloping terrain given low consistence/coherence and lighter surface materials.