Organosols

Organic rich soils in the North East region are mainly Organosols and Chernic Tenosols.

Organosols are soils which are dominated by organic materials. They either have more than 40 cm of these organic materials within the upper 80 cm of the soil profile or they have organic materials extending from the surface to a minimum of 10 cm depth that directly overlies weathered hard rock or fragmented material.

Organosols can be subdivided into three main suborders based on the amount of decomposition of the organic materials:

Fibric - organic material undecomposed or weakly decomposed
Hemic - moderately well decomposed
Sapric - strongly to completely decomposed.

Organosols are associated with the sub-alpine to alpine sphagnum moss-beds. Those that have little or no recognisable plant remains appear to be remains of sphagnum moss bogs that have become humified as the bogs have dried out. They have been referred to as humified peat soils and occur in only small isolated areas.

Chernic Tenosols have well-developed organic A horizons that are peaty, melacic or melanic and contain humose but they have insufficient amounts of organic matter to be classified as an Organosol. The A horizon is more than 20 cm thick overlying a weakly developed subsoil horizon or a transitional subsoil/weathered rock horizon occurring in fissures, in the parent rock or saprolite i.e. weathered bedrock. These are discussed further in the Tenosols section.

References

Rowe, R.K (1967). A Study of the Land in the Victorian Catchment of Lake Hume. Soil Conservation Authority. Victoria. Technical Communication 5.

Rowe, R.K (1972). A Study of the Land in the Catchment of the Kiewa River. Soil Conservation Authority. Victoria. Technical Communication 8.

Rowe, R.K (1984). A Study of the Land in the Catchments of the Upper Ovens and King Rivers. Soil Conservation Authority. Victoria. Technical Communication 16.

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