MySoil: Alkaline shallow duplexes (Salmon Gums)

Shallow fine sand or fine sandy loam to 10-20 centimetres (cm) over domed, cemented sodic clay with lime and lime nodules throughout. Usually saline and boron toxic subsoil.

Broadscale map (1:250 000) of the Salmon Gums Agzone showing the distribution of alkaline shallow duplexes. The majority of the region shows shallow duplexes occupying 25–50% from Cascade to Salmon Gums with some areas of 10–25% and 50-100%.
A stylised diagram of the soil profile for alkaline shallow sandy duplexes (soil group 402). The soil profile consists of shallow brown sand in the top 30cm, with clay in the middle and sometimes unknown substrates from 50cm.
A stylised diagram of the soil profile for alkaline shallow loamy duplexes (soil group 502). The soil profile consists of shallow grey loam in the top 30cm, with clay in the middle and sometimes unknown substrates from 50cm.
A stylised diagram of the soil profile for alkaline shallow loamy duplexes (soil group 503). The soil profile consists of shallow red loam in the top 30cm, with clay in the middle and sometimes unknown substrates from 50cm.
Soil pit showing the profile of alkaline grey shallow loamy duplexes (soil group 502) in the Salmon Gums region. The soil profile shows shallow loam on the top, with clay below.

Summary

Table 1 Alkaline shallow duplex summary
Occurrence Salmon Gums Mallee (39%)

Soil Groups of Western Australia (WA)

402 Alkaline grey shallow sandy duplex

502 Alkaline grey shallow loamy duplex

503 Alkaline red shallow loamy duplex
Also known as Mallee soil, Scaddan soil, Circle Valley shallow soil, Parmango soil, Karlsberg soil
Australian soil classifications

402 Calcic Grey Yellow or Brown Sodosol,

502 Calcic Grey Sodosol, Pedal supracalcic Calcarosol (Karlsberg series)

503 Calcic Red Sodosol

Distinguishing features

Topsoil

  • Shallow grey sand <30cm deep which can be water repellent (402).
  • Loams are hardsetting (Karlsberg) (502, 503).
  • Mildly acid (402) to neutral pH (502, 503).

Subsoil

  • Alkaline clays with lime and calcrete present.
  • Domed sodic clays. Tops of domes often hard and cemented (402).
  • Often saline at depth with moderate to high levels of boron. (502, 503).

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 Limitation
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*

 503 Alkaline red shallow loamy duplex*

503 Alkaline red shallow loamy duplex*
Constraints Topsoil Subsoil Topsoil Subsoil
Acidity and aluminium toxicity n/a n/a

n/a

n/a
Salinity

n/a

 Major

n/a

 Severe
Sodicity and alkalinity

n/a

 Minor

n/a

 Major
Boron toxicity

n/a

 Minor

n/a

 Minor
Poor nutrient retention

n/a

n/a

 n/a n/a
Aggregate stability

n/a

 Minor

n/a

 Minor
Compaction and hard layers

n/a

n/a

n/a

n/a
Hard setting and crusting Minor

n/a

 Minor

n/a
Water repellence Minor

n/a

 Minor

n/a
Low plant available water

n/a

 Minor

n/a

 Severe
Water-logging (seasonal)

n/a

n/a

n/a

n/a
Wind erosion (seasonal)

n/a

n/a

n/a

n/a
Water erosion (seasonal)

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: SGS 0001, SC2 WHL4, SC2 WHS4.

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, T Muller, PG, Gee, ST and Moore, GA (1993) Esperance Land Resource Survey. Land Resources Series No. 8. Department of Agriculture, Western Australia.

Overheu, T Nicholas, B and Needham, P (1996). Soil Information Sheet for the Mallee Area, Mount Beaumont: Karlsberg Soil Series. Agriculture Western Australia.

Scholz, GGH and Smolinski, HJ (1996) Soils of the Mount Beaumont area. Land Resources Series No. 7. Agriculture Western Australia

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

Soil pH
MySoil

Further information

Soils

Topics

Page last updated: Wednesday, 7 December 2016 - 1:52pm