MySoil: Alkaline shallow duplexes (Stirlings to Ravensthorpe)

Grey, brown or red sands or loams over alkaline clay at <30 centimetres (cm) depth.

Broad scale map (1:250 000) of the Stirling to Ravensthorpe Agzone showing the distribution of alkaline shallow duplexes. Distribution is scattered with 50–100% and 25–50% from Bremer Bay to northern region of Jerdacuttup.
A stylised diagram of the soil profile showing the topsoil and subsoil layers for alkaline grey shallow sandy duplex for soil group 402. The profile consists of shallow sand in the top 30cm, with clay in the middle and unknown substrates from 50cm depth.
Soil pit showing the profile of alkaline grey shallow sandy duplexes (soil group 402) in the Stirling to Ravensthorpe region. The soil profile shows shallow sand on the top, with clay below.

Summary

Table 1 Alkaline shallow duplexes summary

Occurrence

Stirlings to Ravensthorpe (18%)

Soil Groups of Western Australia (WA)

402 Alkaline grey shallow sandy duplex (Scaddan sand)

502 Alkaline grey shallow loamy duplex (Grey Clay, Moort soil)

503 Alkaline red shallow loamy duplex (Salmon Gum soil, York Gum soil)
Also known as

Scaddan sand, grey clay, Moort soil, Salmon gum soil, York gum soil

Australian soil classifications

402 Calcic Grey Yellow or Brown Sodosol, Calcic Grey Yellow or Brown Sodosol

502 Calcic Grey Sodosol, Calcic Grey Sodosol

503 Calcic Red Sodosol, Calcic Red Sodosol

Distinguishing features

Generally associated with transition from sandplain to Mallee.

Topsoil

  • Sand (402) or loamy textures (502,503) soils to a maximum depth of 30cm.
  • Loams prone to hard setting.
  •  Gravel (<20 %) can be present usually at the base of the topsoil (sand) layer.

Subsoil

  • Abrupt boundary between sand and loam  to clay layers within 30cm of the surface.
  • Subsoil clays alkaline and mainly sodic.
  • Clays may contain boron and calcareous nodules.

Constraints

The following data has been derived from actual site samples taken. These results are recorded in this Excel spreadsheet.

Table 2 Common management constraints key
Rating Implications

Not applicable (n/a)

No constraints identified
Minor

Minor constraint - reduces crop yields in some years
Major

Major constraint - reduces crop yields in most years
Severe

Severe constraint - will always reduce crop yields
Table 3 Management constraints for Alkaline shallow duplexes

Soil Groups of WA

402 Alkaline grey shallow sandy duplex*

402 Alkaline grey shallow sandy duplex*

502 Alkaline grey shallow loamy duplex*

502 Alkaline grey shallow loamy duplex*

503 Alkaline red shallow loamy duplex*

503 Alkaline red shallow loamy duplex*
Constraints Topsoil Subsoil Topsoil Subsoil Topsoil Subsoil

Acidity and Aluminium toxicity

 Minor n/a

n/a

n/a

n/a

n/a

Salinity

Minor

 Major

Minor

 Major

Minor

 Major

Sodicity and alkalinity

n/a

 Major

n/a

 Major

n/a

 Major

Boron toxicity

n/a

 Minor

n/a

 Minor

n/a

 Minor

Poor nutrient retention

n/a

n/a

n/a

n/a

n/a

n/a

Aggregate stability

n/a

 Major Major Major

n/a

 Minor

Compaction and hard layers

n/a

n/a

n/a

n/a

n/a

n/a

Hard setting and crusting

n/a

n/a

 Minor

n/a

 Minor

n/a

Water repellence

 Minor

n/a

n/a

n/a

n/a

n/a

Low plant available water

 Major Major

n/a

 Major

n/a

 Major

Water-logging (seasonal)

n/a

n/a

n/a

n/a

n/a

n/a

Wind erosion (seasonal)

n/a

n/a

n/a

n/a

n/a

n/a

Water erosion (seasonal)

n/a

n/a

n/a

n/a

n/a

n/a

*Note - Data derived from site identifications (ID's).

  • Soil Group of WA - 402 Alkaline grey shallow sandy duplex site ID includes: RAV 0235, JSI 0133.
  • Soil Group of WA - 502 Alkaline grey shallow loamy duplex site ID includes: JSI 0511, RAV 0245.
  • Soil Group of WA - 503 Alkaline red shallow loamy duplex site ID includes: JSI 1143.

Further information

Department of Agriculture and Food (2013) Report card on sustainable natural resource use in agriculture, Department of Agriculture and Food, Western Australia.

McArthur, WM (2004) Reference Soils of South-western Australia (Reprint). Department of Agriculture, Western Australia.

Moore, G (2004) Soil Guide: A Handbook for Understanding and Managing Agricultural Soils. Bulletin 4343. Department of Agriculture, Western Australia.

Overheu, TD (1995) Soil Information Sheets for Ravensthorpe and Part of the Jerramungup Agricultural Areas. Department of Agriculture Western Australia and Landcare Western Australia.

Stoneman, TC (1990) An Introduction to the Soils of the Jerramungup Advisory District. Western Australian Department of Agriculture. Bulletin 4201.

Schoknecht, N and Pathan, S (2013) Soil Groups of Western Australia. Resource Management Technical Report 380. Department of Agriculture and Food, Western Australia.

See also

MySoil

Further information

Soils

Topics

Page last updated: Wednesday, 18 November 2015 - 9:20am