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ORGANIC SOILS
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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.
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here to see map of distribution
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- 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.
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Eroded peat, with deep
hagging, in the Monadhliath Mountains,Central Scotland |
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Hand-cut peat |
Recent forest planting on peat deposit
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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.
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.
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Immature
soils |
Podzols | Brown
earths | Gleys | Organic
soils | Alpine soils
Introduction Page | Soils Introduction |
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