Level Up

Arenosols [RE]

[Pronounced Ah-ren-oh-sols]


The core concept of this Order is "deep sandy soils".

Arenosols accommodate soils with predominantly sandy field textures (≤10% clay content), and with no horizons containing more than 15% clay within the upper 1.0 m of the profile. The presence of argic horizons are the only exception. Arenosols generally have no observable peds apart from some structural development in the A1 horizon. The upper 1.0 m of the soil profile can only contain relatively small amounts of coarse fragments or coarse, hard segregations and does not contain any hard layers such as pans or rock. Arenosols occur extensively in inland arid areas, in and adjacent to waterways, near to the coast (especially in the west), but are also present in many other parts of Australia. This Order incorporates the most widespread and abundant soils in Australia.

Distribution of Arenosols in Australia.
Soil Profile (View type example photo of Yellow Arenosol).


Soils that have, within the upper 1.0 m of the soil profile:

  1. A sandy field texture (i.e. a field texture of sand, loamy sand or clayey sand) in one or more layers or horizons with a combined thickness of at least 0.8 m; and
  2. No layer or horizon with a clay content that exceeds 15% (i.e. heavy sandy loam [SL+] or heavier) excluding argic horizon/s; and
  3. ≤10% (by visual abundance and weighted average) of coarse fragments and/or hard segregations >2 mm in size; and
  4. No hard layers (cemented pans, other cemented materials, rock, saprock or saprolite that do not soften when moist1)

1this qualification has been added since publication and is not reflected in CSIRO March 2021 published edition. The purpose is to not exclude from Arenosols soils with layers in the top 1.0 m that are hard when dry but soften when moist.


As B horizons are difficult to identify consistently in some Arenosols, specific mention of a B2 horizon is omitted from some Suborders. Arenosols will obviously grade to Kandosols and some difficulty may be experienced in separating them. Here Kandosols must have a clearly distinguishable, well-developed B2 horizon with more than 15% clay whereas Arenosols have less than 15% clay.

Reclassification may also be required for other sandy soils where deep examination below 1.0 m reveals deep more clayey B horizons. See How to Classify for assistance with determining whether the layer is a B or D horizon. If the layer is a D horizon, the soil remains classified as an Arenosol.

Bleached or Grey Arenosols are distinguished from Podosols by the absence of Podosol diagnostic horizons. These horizons can occur below 1.0 m deep and commonly at considerable depth. If no deep examination has been done in similar soils in similar environments, then the soil should classify as a Bleached or Grey Arenosol with a confidence level of 4. If evidence at a later date reveals the presence of Podosols diagnostic horizons at depth, the soil will need to be reclassified.

Some Arenosols may include one or more thin argic horizons (also termed lamellae) which are usually 5-10 mm thick.

Arenosols will also grade to Tenosols. This third edition of the Australian Soil Classification reflects a major change to the Tenosol Order. Many sandy soils previously classified as the colour-linked Orthic Suborders of Tenosols will now classify as Arenosols.

As the Arenosols Order includes soils with negligible development many deep sandy soils previously described as Rudosols will now classify as Arenosols.

This third edition of the Australian Soil Classification also reflects a significant change to the Calcarosol Order. Many deep sandy soils with pedogenic carbonates previously classified as Shelly, Calcic or Hypocalcic Calcarosols will now classify as Carbonatic or Calsilic Arenosols.


Soils in which the dominant colour class in the major part of the upper 1.0 m of the soil profile is:


The Hypergypsic soils normally occur as gypsum lunettes and the Hypersalic soils are most common in many of the saline playas of the arid interior of the continent. The Chernic soils typically occur in low lying, wetter, cooler areas of southern Australia where organic matter accumulates in surface horizons. The Carbonatic and Calsilic soils occur on coastal dunes as well as inland spreads of calcareous sands in southern Australia. The Bleached, Red, Brown, Yellow, Grey and Black soils mainly cater for the widespread siliceous dunes and sandsheets, as well as some coastal dunes, with the soils largely concentrated in southern Australia. The Stratic soils occur where sands have been deposited through water action.

The Carbonatic soils are typically highly calcareous and dominated by sand-sized fine-earth carbonates throughout the profile. The Carbonatic Suborder in Arenosols partially replaces the former Shelly Suborder in Calcarosols. Other shelly soils are is now restricted to soils dominated by shell fragments in Rudosols.

The Calsilic Suborder includes sands that are calcareous throughout (with the possible exception of the surface) but are generally lower in carbonates and more siliceous than the Carbonatic Suborder.

The most commonly recorded Suborders are Carbonatic, Calsilic, Bleached, Red, Brown, Yellow, and Grey.

Great Groups

No Great Groups are presently proposed for the Hypergypsic and Stratic Suborders as data are limited, plus the limited pedological development of these soils means that subsoils are generally only weakly developed.

If a diagnostic feature in the key begins more than 1.5 m from the soil surface it may not have a significant impact on the performance of the soil. Refer to diagnostic features in the glossary for guidance on the use of such features in the classification.

Hypersalic Arenosols

Chernic Arenosols

Suitable Great Groups may be found as listed for Bleached and coloured Arenosols

Carbonatic and Calsilic Arenosols

The Great Groups that include hard layers (cemented pans, other cemented materials, rock, saprock or saprolite) can only apply to layers that occur below 1.0 m.


Epibasic and Hypervescent Great Groups are only applicable to Calsilic Suborder.

Chernic, Bleached, Red, Brown, Yellow, Grey and Black Arenosols

The Great Groups that include hard layers (cemented pans, other cemented materials, rock, saprock or saprolite) can only apply to layers that occur below 1.0 m. In Great Groups that include a ferric horizon overlying a hard layer (i.e. Ferric-Duric, Ferric-Petroferric and Ferric-Reticulate) the ferric horizon may begin within the top 1.0 m.


The calcareous classes above approximately correspond to those of Wetherby and Oades (1975) as follows: Hypocalcic - Class IV, Lithocalcic - Class III B and IIIC, Supracalcic - Class III B, Hypercalcic - Class III A, Calcic - Class 1 and IIIA. In the Lithocalcic and Supracalcic classes the coarse fragments may be >0.2 m in size and soft carbonate may or may not be present.


No Subgroups are proposed for the Hypergypsic, Hypersalic, Carbonatic, Calsilic and Stratic Suborders. The Humose-Calcareous, Melanic-Calcareous and Calcareous Subgroups are not required for the Hypocalcic, Lithocalcic, Supracalcic, Hypercalcic, Calcic and Pertrocalcic Great Groups

Subgroups of Chernic, Bleached, Red, Brown, Yellow, Grey and Black Arenosols

Family Criteria

Use of the term A horizon may be inappropriate for some of these soils because of either minimal development due to an arid environment, or common surface deflation or accumulation caused by wind. Hence it is thought better to use the term surface soil for texture and to delete the thickness criteria. In general, surface soil in this context will probably be in the range of 0.1-0.2 m in thickness.

Gravel of surface and/or A1 horizon

Non-gravelly [E] : <2%
Slightly gravelly [F] : 2 - <10%
Gravelly [G] : 10 - <20%
Moderately gravelly [H] : 20 - 50%
Very gravelly [I] : >50%

Soil surface texture

Peaty [J] : Dominated by organic materials
Sandy [K] : S-LS-CS (≤10% clay)
Loamy [L] : SL-L (10-20% clay)

Maximum texture below the surface or A1 (within the upper 1.0 m of the soil soil profile)

Sandy [K] : S-LS-CS (≤10% clay)
Loamy [L] : SL-L (10-20% clay)

Soil depth

Deep [W] : 1.0 - <1.5 m
Very deep [X] : 1.5 - 5 m
Giant [Y] : >5 m

Water repellence of surface soil

Non water repellent [NR] : Water absorbed in 10 seconds or less
Water repellent [WR] : Water takes more than 10 seconds and 2 Molar ethanol takes 10 seconds or less to be absorbed into soil
Strongly water repellent [SR] : 2 Molar ethanol takes more than 10 seconds to be absorbed into soil

1Based on numerous fine-earth analyses by Primary Industries, South Australia.

2Note that the Humose-Calcareous Subgroup is not required for the six calcic Great Groups.

3Note that the Melanic-Calcareous Subgroup is not required for the six calcic Great Groups.

4Note that the Calcareous Subgroup is not required for the six calcic Great Groups.

[ AN ] [ OR ] [ PO ] [ VE ] [ HY ] [ KU ] [ SO ] [ CH ] [ CA ] [ FE ] [ DE ] [ KA ] [ RE ] [ RU ] [ TE ]