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.

 SERIES NAME  SOIL TYPE   DRAINAGE  PARENT MATERIAL
 Bilbster  Humus iron podzol and podzol  Free and imperfect  Drift
 Camster  Peaty podzol  Free and imperfect
 below iron pan
 Drift
 Hunster  Noncalcareous gley (SW)  Poor and very poor  Drift
 Knitchen  Alpine podzol  Free  Drift
 Mousland  Saline gley  Poor  Drift and thin drift
 Ness  Noncalcareous gley  Poor  Thin drift
 Olrig  Peaty gley (SW)  Poor and very poor  Drift
 Sibster  Noncalcareous gley  Poor  Drift with partially
 sorted upper layers
 Thurso  Noncalcareous gley (SW)  Poor  Drift
 Thurskel  Skeletal soil  Variable  Very shallow drift
 and residual