MM667

Site: MM667	Land Unit: Basalt Alluvial
*Aust. Soil Class.:* ?, Mottled-Subnatric, Brown SODOSOL (confidence level 3)

General Land Unit Description:
This land unit consists of the smaller swamps and depressions which occur on the basalt plains. Grey Vertosols tend to dominate the smaller swamps and depressions on the plains. Black Vertosols are commonly found in the swamps and depressions associated with the stony rise landscapes and the larger alluvial plains. Both soil types are typically sodic at depth and imperfectly drained. There are minor occurrences of Sodosols, similar to this site. In some areas of the basalt plain, this land unit would have been incorporated into the basalt land units.

Site Description:

Geology: Quaternary alluvium	Landform pattern: Gently undulating plain
Position in landscape: Drainage depression	Internal drainage: Imperfectly drained

Soil Profile Morphology

A11	0-15 cm	Very dark greyish brown (10YR3/2) clay loam, hard-setting surface, pH 4.6, clear transition to:
A12	15-40 cm	Greyish brown (10YR5/2) silty clay loam, conspicuously bleached (10YR7/1) when dry, pH 5.2, sharp transition to:
	Subsoil
B21	40-70 cm	Yellowish brown (10YR5/4) medium clay, brownish yellow mottles, pH 5.9, clear transition to:
B22	70+ cm	Brown (10YR5/3) heavy clay, brownish yellow mottles, pH 7.3.

Key profile features:

Strongly acidic topsoil
Strong texture contrasts between topsoil and subsoil
Bleached A2 horizon
Mottled subsoil
Sodic topsoil
Topsoil dispersive when dry
Sodic subsoil
Subsoil dispersive when dry

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