Vertosols (Australian Soil Classification) are clay soils that display significant shrinking and swelling during wetting and drying cycles i.e. display vertic characteristics. They exhibit strong cracking when dry and at depth have slickensides and/or lenticular peds. Due to the strongly vertic nature of these soils, gilgai i.e. 'crabholey' microrelief is common.
Vertosols are most extensive in the region on basalt plains and rises as well as on some alluvial plains, swamps and lunettes. Black and grey Vertosols can occur throughout the basalt plains and often have self-mulching surfaces, although more coarsely structured surface soils also occur. Subsoils are often sodic and can be calcareous at depth, often with visible free lime, both soft and as calcareous nodules.
Vertosols in the Corangamite Region
This broad scale map presents an overview and should only be used as a general indication of the distribution of Vertosols in the Corangamite Region. It shows areas where Vertosols are most likely to occur within the region. Note that other soil types may also occur within these mapped areas.
This map has been developed from work undertaken by Robinson et al. (2003) as part of the Corangamite Land Resource Assessment project. This work utilised existing surveys, remote sensing information and additional field-work to develop an updated 1:100 000 scale soil/landform coverage across the region.
Soils are difficult to map at this broad scale because of their diversity. Even in relatively small areas, a number of soils may occur which relate to differences in topography and landscape position. Variation in some of the major soil profile properties can also occur within these mapped areas. Any agricultural enterprise should be based on a proper on-site assessment of the soil and landscape.
A number of soil surveys have been completed in this region at varying scales and intensity. However, in some areas very little soil survey has taken place. See the Soil and Land Survey Directory for details.
Black Vertosol on a sedimentary plain
Black Vertosol with calcium carbonate in the
deeper subsoil, on the slopes of Mount Pollock.
Example of subsoil variability on Black Vertosols near Lara, reflecting gilgai microrelief.
Vertosol on a lunette associated with Lake Corangamite.
Black Vertosol on the Bellarine Peninsula.