The soil series is characterised by having a sporadically bleached A2 ‘subsurface' horizon, followed by grey to yellowish grey subsoil. In the present survey, this series consists of the following soil type:
Wal Wal Clay (WWc)
Profile Morphology:
Surface Soil (A1 horizon)
- 5-10 cm thick.
- Dark reddish grey to brown or dark greyish brown.
- Medium to heavy clay.
- Very hard to extremely hard (dry), non-friable (moist), plastic and sticky (wet).
Sub-Surface Soil (A2 horizon)
- 3-10 cm thick.
- Reddish grey to yellowish brown with a sporadic bleach. Bleaching may occur (in nests only) at the interface between the A and B horizons.
- Soil texture and consistence are usually similar to those of the A1 horizon.
Subsoil
- Greyish brown to reddish brown, changing gradually to pale brown or light reddish brown with depth. Slight colour mottling may occur in the deep subsoils.
- Heavy clay.
- Slightly friable to non-friable.
- Trace to slight amounts of soft and/or hard CaCO3; may increase up to light amounts in the deep subsoils.
Analytical Data for Selected Depths Down the Profile:
Depth | pH | Total Soluble Salts | Sodium Chloride | Moisture Retention @ 15-Bar | Moisture Retention @ 1/3-Bar |
. | . | % | % | % | % |
A | 7.1 | 0.026 | * | 12.2 | 23.1 |
B | 8.4 | 0.065 | 0.027 | 19.4 | 36.6 |
C | 8.7 | 0.533 | 0.130 | 20.9 | 38.5 |
* Sodium Chloride contents were not measured and are expected to be very low (based on TSS <0.05%).
Occurrence:
Wal Wal clay occurs in the shallow depressions, low lying areas and slight gilgai depressions found on the gently undulating plains.