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Organic Soils

Eroded peat, with deep hagging, in the Monadhliath Mountains,Central Scotland
Eroded peat, with deep hagging, in the Monadhliath Mountains,Central Scotland
Often referred to as peat deposits, organic soils represent accumulations of partly or completely decomposed plant residues formed under anaerobic conditions. Deposits at low elevations generally occur in distinct depressions (BASIN PEAT) and contrast with peat formed under cool, wet climatic conditions, which, in combination with high acidity and nutrient deficiency, depress microbiological activity. The latter deposits are known as climatic or blanket peat and are widespread in upland areas of Scotland.

Hand-cut peat
Hand-cut peat
Characteristics of Organic Soils

  • Soils have greater than 60% organic matter
  • Organic surface layers are greater than
    50cm deep
  • Shallow peat has a prescribed depth of organic matter of 50 - 100cm
  • Deep peat has a prescribed depth of organic matter of >1 metre
  • Peat can be described as fibrous, semi-fibrous or amorphous according to its degree of decomposition
  • Peat is usually acidic (pH <5) unless associated with calcareous or base rich water
  • Peats possess a low bulk density, high water holding capacity and low load-bearing strength
  • Peats are often characterised by mire and blanket bog plant communities.

Recent forest planting on peat deposit
Recent forest planting on peat deposit

Current land management practice does not consider extending areas of for cropping. However, in the past the suitability of these soils for arable cropping, when adequately drained, hinges on their sense of working and capacity to supply nitrogen whilst retaining water and nutrients. Continual cropping does result in significant shrinkage and the soil being subject to various physical and chemical limitations.

Distribution of Organic Soils In the semi-natural state, peat provides grazing of low quality but has no other agricultural value. Use for fuel or on land below about 400 metres for afforestation, is well documented. On upland sites, peat is of limited use outwith low quality grazing for sheep or deer.

Learning & Resources

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The James Hutton Research Institute is the result of the merger in April 2011 of MLURI and SCRI. This merger formed a new powerhouse for research into food, land use, and climate change.