Victorian State Soil Contender - Red Sodosol

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Why should the Red Sodosol be Victoria’s State Soil?

• Victoria has a greater proportion of Sodosols than any other state. It is quite possible that Sodosols may not be selected as the State Soil for another state – and as Sodosols are a very widespread soil in Australia it would be fitting if one was nominated as a State Soil by Victoria.
• Red Sodosols are widespread throughout much of Victoria and are common in mid to low rainfall areas of the state - particularly in the Wimmera plains, parts of the Mallee, North Central, Goulburn Broken and western Port Phillip and Westernport regions.
• These soils are important cropping soils in Victoria. They support dryland cropping (mainly cereals) in the Wimmera region. In other parts of the state, they are important irrigation soils supporting high value irrigated pasture, orchards and vegetable cropping on the northern plains (especially Shepparton Irrigation region), as well as high value irrigated vegetable production (e.g. lettuce) in the Werribee region.

Any reasons why this soil should not be Victoria’s State Soil? Red Sodosols are not "nice" soils. They are difficult to manage as they have hard, dense subsoils, with a high clay content. The subsoil, and often the topsoil, is potentially dispersive. The range of soil water content which is conducive to root growth is severely limited due to poor aeration at the wet end and high soil strength at the dry end. However, in saying this, it is a credit to the farmers of Victoria that they can achieve high productivities from these inherently difficult soils. Key features of the Red Sodosol Sodosols are texture contrast soils that have lighter textured surface horizons (e.g. sandy loam or clay loam) overlying more clayey subsoil (B) horizons. The subsoil horizons are sodic and often dispersive. Red Sodosols have reddish coloured upper subsoils that are often quite dense and coarsely structured (blocky, prismatic or columnar peds are common). These soils have often previously been referred to as ‘red-brown earths’. They usually have an acidic surface soil and are often alkaline at depth and frequently include carbonate (i.e. lime). These soils can be difficult to manage and need careful management to maintain soil health.

Red Sodosols are major cropping soils in the Werribee region.

This example Red Sodosol occurs in the Werribee area. It has formed on alluvial deposits of older streams (prior streams) that traversed this region in wetter climate periods. Some windblown (aeolian) material has also been incorporated.			Red Sodosol near Werribee
Surface Soil
A1	0-12 cm	Brown; fine sandy loam; moderately acid pH.
A2	12-30 cm	Brown; fine sandy clay loam; neutral pH; abrupt change to:
Subsoil
B21	30-60 cm	Dark red; medium clay; coarse prismatic structure, parting to coarse blocky structure; slightly alkaline pH.
B22	60-75 cm	Strong brown; light clay (fine sandy).
B23	75-100 cm	Brown; light clay (fine sandy); contains small amounts of carbonate (lime); moderately alkaline pH.