Tenosols

Tenosols have only weak soil profile development and are often shallow. In the Australian Soil Classification they are defined as having limited subsoil (B horizon) development (less than 15% clay content). However, Tenosols have more development than the most rudimentary soils i.e. Rudosols as they include bleached layers and colour changes. Using the Australian Soil Classification, Tenosols can be subdivided according to surface organic matter depth and percentage, bleached layers, development of a subsoil and contact with material immediately below.

North East Tenosols.

This broad-scale overview map of Tenosols in the North East region has been developed chiefly by Ken Rowe and is based on the Land Systems of Victoria (1:250 000). Other contributors have also assisted in updating the map in areas where they have specialist knowledge. The map shows areas where Tenosols are most likely to occur within the region and should only be used as a general indication of their distribution.

Note that other soil types may also occur within these mapped areas either dominantly or sub-dominantly, depending on factors such as climate, landform, geology, vegetation and degree of weathering. This map will continue to be updated as new information becomes available.

Access the

Soil and Land Survey Directory

from this website to find out about more detailed information from various soil and land surveys that cover parts of this region.

These soils tend to develop on rocky areas in the uplands or on alluvial or aeolian (wind blown) deposits where soil development is weak.

The main Tenosol groups recognised in the North East region are:

Chernic Tenosols
Orthic Tenosols
Leptic Tenosols

Chernic Tenosols
Chernic Tenosols have a well-developed organic A horizon (peaty, humose, melacic or melanic) which 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.

Chernic Tenosols are the most common soils of the sub-alpine and alpine high plains and broad mountain ridges. In North East Victoria they have usually been known as alpine humus or organic loam soils. They are typically strongly acid with pH's as low as 3.8 and are characterised by low plant-nutrient status, except for the upper few centimetres. There is much evidence that many of the Chernic Tenosols on the high plains have formed on remnants of earlier soils (pedoderms) (Brewer et al. 1970). These can have weakly developed B horizons that are separated from the A horizon by a stone line. This indicates an old erosion surface.

Orthic Tenosols
These soils occur on the younger parts of the landscape in lower rainfall areas. They are formed on the steep hills in the north and in the rain shadow area around Omeo. They are more prevalent on the drier north and northwest aspects. These soils often merge with Kandosols as the clay content can be slightly higher than specified as the upper limit for Tenosols (i.e. 15%).

Leptic Tenosols
Previously, these soils have been referred to as meadow soils and prairie soils (Rowe 1967) as well as brown and grey loam soils (Rowe 1984). Leptic Tenosols occur on fine textured alluvium along the major streams. They have well structured, organic matter darkened surface (A) horizons but no significant pedologic development at depth. They are moderately to strongly acid and are commonly underlain by a gravel bed at about one metre depth.

Chernic Tenosols

Previously referred to as:

Alpine humus soils, organic loam soils.

Occurrence:

Common in sub-alpine and alpine high plains and broad, high mountain ridges.

Generalised Description:

Surface (A) horizons
Thick organic rich A horizon, loam texture, strong fine granular structure, high porosity, extremely acid, gradual boundary change.

C horizon
Weathering rock e.g. granite.

Chernic Tenosol - alpine humus soil.

Orthic Tenosols

Previously referred to as:

Various names including leptopodzols.

Occurrence:

Younger parts of the landscape in the lower rainfall areas.
Formed on steep hills in the north.

Photo: Orthic Tenosol developed on granite in Tallangatta valley.

Orthic Tenosol developed on granite in the Tallangatta Valley.

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

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

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