MySoil: Ironstone gravels (Swan Coastal Plain)

Gravelly sands and loams overlying sandy loams, clays or cemented gravels (ferricrete). Gravel content greater than 20% and is a dominant feature of the profile.

Broad scale map (1:250 000) of the Swan coastal plain Agzone showing the distribution of ironstone gravel soils. Distribution is scattered along the Darling scarp from Perth down to Margaret river with 50–100% ironstone gravelly soils.
A stylised diagram of the soil profile showing the topsoil and subsoil layers for deep sandy gravel. Ironstone gravel soil, with a predomintly sandy matrix, usually over clay, cemented gravels (ferricrete) or reticulite at >80cm.
Soil pit showing the profile of deep sandy gravel in the Swan coastal plain region.

Summary

Table 1 Ironstone gravels summary
Occurrence Swan Coastal Plain (13%)

Soil Groups of Western Australia (WA)

301 Deep sandy gravel

302 Duplex sandy gravel

303 Loamy gravel
Also known as Buckshot gravel, Coarse gravel, Sandy gravel, Loamy gravel

Australian soil classifications

301 - Ferric or Ferric-Petroferric Tenosol, Ferric Kandosol, Ferric Chromosol

302 - Ferric Chromosol, Ferric Sodosol, Ferric Kandosol

303 - Ferric Kandosol, Ferric Chromosol,  Ferric Dermosol

Distinguishing features

Topsoil

  • Yellow, brown or grey sandy (301, 302) or loamy soils (303).
  • Acidic to neutral pH throughout profile.
  • Increasing gravel with depth.

Subsoil

  • Gravels dominant feature (>20% by weight) and can be unconsolidated (pea, buckshot) or cemented.(conglomerate).
  • Gravels overly semi permeable clays or clay loams or reticulite at depth depths >80cm (301) or 30–80cm (302).

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 Implication

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 ironstone gravels

Soil Group of WA

302 Duplex sandy gravel*

302 Duplex sandy gravel*

303 Loamy gravel*

303 Loamy gravel*
Constraints Topsoil Subsoil Topsoil Subsoil

Acidity and aluminium toxicity

 Minor Minor n/a n/a
Salinity n/a

n/a

n/a

n/a
Sodicity and alkalinity

n/a

n/a

n/a

n/a
Boron toxicity

n/a

n/a

n/a

n/a
Poor nutrient retention Severe Severe

n/a

n/a
Aggregate stability

n/a

n/a

n/a

 Minor
Compaction and hard layers

n/a

n/a

n/a

 Major
Hard setting and crusting

n/a

n/a

 Minor

n/a
Water repellence Major

n/a

 Minor

n/a
Low plant available water Severe Severe Minor Minor
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 - 302 Duplex sandy gravel site ID includes: GWRDC MR_01_IS.
  • Soil Group of WA - 303 Loamy gravel site ID includes: GWRDC MR_A_KA , GWRDC MR_02_KA , GWRDC MR_07_RU.

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.

McArthur, WM and Bettenay, E (1960) The Development and Distribution of the Soils of the Swan Coastal Plain, Western Australia. Publication No.16. CSIRO, Melbourne, Vic.

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

Smolinski, HJ and Scholz, G (1997) Soils of the West Gingin Area. Land Resources Series No. 15. Agriculture Western Australia.

Tille, PJ and Lantzke, NC (1990) Busselton Margaret River Augusta Land Capability Study. Land Resources Series No. 5. Department of Agriculture, Western Australia.

Wells, MR (1989) Land Capability Study of the Shires of Mandurah and Murray. Land Resources Series No. 2. Western Australian Department of Agriculture.

See also

MySoil

Further information

Soils

Topics

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