Development of peat land and types of peat - Geotechnics of Organic Soils and Peat - page 18

Figure 2.4 LPC classification of organic soils ( after Magnan, 1994).
According to the American Society for Testing and Materials (ASTM) standard
(ASTM, 1990), peat classification has been narrowed to only three classes, based on
fibre content, ash content and the acidity of the soil. In the fibre content classification,
peat is divided into three groups: (i) fibric (fibrous; least decomposed, with more than
67% fibre content), (ii) hemic (semi-fibrous; intermediate decomposition) and (iii)
sapric (amorphous; most decomposed, with less than 33% fibre content).
Fibrous peat has a high organic and fibre content, with a low degree of humifica-
tion. It consists of undecomposed fibrous organic materials, is easily identifiable and
extremely acidic. Sapric peat contains highly decomposed materials. The original plant
fibres have mostly disappeared and the water-holding capacity is generally less than
that of either fibrous or hemic peat. It is generally very dark grey to black in colour and
is quite stable in its physical properties. Compared with fibrous peat deposits, sapric
peat deposits are likely to exist at lower void ratios and display lower permeability,