The soils of Orkney are developed on a range of parent materials. Where the till is thin or absent, soils are developed directly from weathered or shattered sandstone. The till is generally sandy and therefore free-draining but clay-rich variants give waterlogged soils on low ground. Dune sands offer exceptional drainage and high Ca contents.
Of great interest is the long term human influence on Orkney soils. With over 5000 years of human occupation, Orkney offers exceptional opportunities to study soil transformation. The archaeological record provides evidence of woodland clearance, soil erosion, turf cutting and the addition of manure, seaweed and shell, all practices which had profound influence on local soils.