MySoil: Alkaline shallow duplexes (Southern Wheatbelt)

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

Broad scale map (1:250 000) of the Southern Wheatbelt Agzone showing the distribution of alkaline shallow duplexes. Distribution is scattered with small propotion of 50–100% near Lake Grace.
A stylised diagram of the soil profile showing the topsoil and subsoil layers for alkaline grey shallow sandy duplex for soil group 402. The soil profile consists of sand in the top 30cm, with clay in the middle and sometimes unknown substrates from 50cm
Soil pit showing the profile of alkaline grey shallow sandy duplexes (soil group 402) in the Southern Wheatbelt region. The soil profile shows shallow sand on the top, with clay below at <30cm.

Summary

Table 1 Alkaline shallow duplexes summary
Occurrence

Southern Wheatbelt (13%)

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 soil, 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 30 cm 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

n/a

 Minor

n/a

 Major

n/a

 Minor
Sodicity and alkalinity

n/a

 Minor

n/a

 Major

n/a

 Major
Boron toxicity

n/a

n/a

n/a

n/a

n/a

n/a
Poor nutrient retention

n/a

n/a

n/a

n/a

n/a

n/a
Aggregate stability

n/a

 Minor Minor Minor

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 Minor Minor

n/a

 Minor

n/a

n/a
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: TBO 0470, TBO 0471, TBO 1387, JSI 0142, JSI 0139, JSI 0140, NYA 0494, COR 1782, FFS 0146, NYA 0488, NYA 0729, JSI 0150, JSI 0143, SC2 NSS1, SC2 NSU4, SC2 NSL4.
  • Soil Group of WA - 502 Alkaline grey shallow loamy duplex site ID includes:  KLC 0067, KLC 1586.
  • Soil Group of WA - 503 Alkaline red shallow loamy duplex site ID includes:  KLC 0070, KLC 2338, NYA 0495.

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.

Percy, H (2003) Nyabing-Kukerin Area Land Resource Survey. Land Resources Series No. 18. Department of Agriculture, Western Australia.

Sawkins, D (2010) Landscapes and Soils of the Katanning District. Bulletin 4817. Department of Agriculture and Food, Western Australia.

Sawkins, D (2011) Landscapes and Soils of the Lake Grace. Bulletin 4825. Department of Agriculture and Food, Western Australia.

Stoneman, TC (1990) An Introduction to the Soils of the Lake Grace Advisory District. Bulletin 4178. Western Australian Department of Agriculture.

Stoneman, TC (1991) An Introduction to the Soils of the Narrogin Advisory District. Bulletin 4221. Western Australian Department of Agriculture.

Stoneman, TC (1991) An Introduction to the Soils of the Katanning Advisory District. Bulletin 4202.  Western Australian Department of Agriculture.

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

Stuart-Street, A (2005) Tonebridge-Frankland Area Land Resource Survey. Land Resources Series No. 19. Department of Agriculture, Western Australia.

Verboom, B and Galloway, P (2004) Corrigin Area Land Resource Survey. Land Resources Series No. 20. Department of Agriculture, Western Australia.

See also

MySoil

Further information

Soils

Topics

Page last updated: Wednesday, 18 November 2015 - 9:29am