text: Definition and Extent of Blackland – Blackland Centre
  Definition and Extent of Blackland
  The term blackland has been developed to refer to a range of highly organic, wet, acidic soils which appear to be common in many parts of the Hebridean islands and western Scottish mainland, and are often inaccurately referred to as peat. (Implications)
  Blackland is anthropic, meaning modified or 'built' by human intervention over time. Writings on the history of agriculture in the Hebrides, as well as current practice, reveal routine addition of materials such as dung, shell sand and seaweed, as well as the significant changes which occur simply through working and use. Blackland is distinct from plaggen, a term used to mean mineral soil modified by adding organic matter.
  The extent of blackland is unknown as is the distribution of anthropogenic soils in Scotland. "The former Soil Survey of Scotland when mapping soils from the 1950s to 1980s considered soils as 'natural entities' so there was little consideration given to anthropogenic influences" (Scottish Government 2006) .
  Frank Fraser Darling in the West Highland Survey (1955) stated that 'over one-sixth (of townships) are on predominately peaty soil', but that many were by intention on a mixture of land and that a detailed soil survey was necessary. The Survey identified 217,767 acres (88,130 ha) as the total in-bye in the crofting counties in the 1940s; to this, the 21st century estimate of 650,000 ha of common grazing must be added. (G. Jones, 2011).
  Therefore, through the roughest of estimates combining historical and current sources, we may estimate the extent of blackland in Scotland to be something over 100,000 ha.