SOIL ASSOCIATIONS -
 THURSO

DERIVATION:

Sandstones and flagstones of Middle Old Red Sandstone age (Caithness Flagstones in Caithness, Rousay Flags and Stromness Flags in Orkney).

TYPES OF PARENT MATERIALS MAPPED:

Glacial drift
Moraine
Partially water-sorted material overlying till

COLOUR:

Greyish brown in subsoil, locally brown - ochreous mottling pronounced.

TEXTURE:

Topsoil usually a loam texture with sandy clay loam subsoil but subsoil textures can range from sandy loam to loam. Slightly to moderately stony in subsoil.

DOMINANT LAND USE:

Permanent pasture, arable.
 

LANDFORMS:

Gently undulating till plain with level and gentle slopes.

SOIL CHEMISTRY:

Percentage base saturation is high in the subsoil with pH values in the range 5.5 to 7.0.
Low to moderate total phosphorus and often high molybdenum.

SOIL PHYSICAL PROPERTIES:

Potential rooting depth is around 25-30cm due to compact, moderately-fine textured subsoil
which also restricts water movement through the profile. Bedrock is generally present at depths of about 1m. Massive soil structure at depth.