MM496

Site: MM496	Land Unit: Mortlake Sedimentary
*Aust. Soil Class.:* Episodic, Epipedal, Black VERTOSOL (confidence level 2)

General Land Unit Description:
This land unit consists of Episodic Black Vertosols or Black Sodosols on near level sedimentary and alluvial plains. The largest occurrence of this unit occurs south-east of Mortlake.

Site Description:

Geology: Tertiary sedimentary	Landform pattern: Level to gently undulating plains
Position in landscape: Lower slope	Internal drainage: Imperfectly drained

Soil Profile Morphology

A1	0-20 cm	Black (10YR2/1) medium clay, strong blocky structure (5-10 mm), pH 5.6. Clear transition to;
	Subsoil
B21	20-40 cm	Black heavy clay, strong blocky structure (10-20 mm), pH 6.6. Gradual transition to:
B22	40-70 cm	Very dark grey (10YR3/1) heavy clay, strong blocky structure (10-20 mm), ferruginised nodules are common. Gradual transition to:
B23	70+ cm	Dark grey (10YR4/1) heavy clay, strong blocky structure (10-50 mm), pH 8.2.

Key profile features:

Strongly acidic topsoil
Strong textural contrast between topsoil and subsoil\
Mottled subsoil
Topsoil dispersive when worked when wet
Subsoil dispersive when worked when wet

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