SW12

Location: Lake Corangamite

Australian Soil Classification: Epicalcareous-Endohypersodic, Self-Mulching, Black VERTOSOL

General Landscape Description: Lunette.
Site Description: Virtual upper crest.
Land Use: Pasture grazing – sheep and beef.
Geology: Quaternary aeolian deposits derived from lake bed sediments.

Image: SW12 Landscape
SW12 Landscape - general view of Lake Corangamite showing lower slope and terrace of the lunette.

Soil Profile Morphology:

Surface Soil

A11	0-2 cm	Black (N2.5/0); loose, self-mulching surface condition; silty clay; fine polyhedral structure; moderately calcareous; pH 7.3; changing to:	SW12 Profile
A12	2-20 cm	Black (N2.5/0); light clay; coarse sub-angular blocky, parting to very fine polyhedral structure; rough faced peds; firm consistence dry; slight carbonate present; moderately calcareous; pH 7.6; changing to:
Subsoil
B21kt	18-30 cm	Black (N2.5/0) with many (30%) olive brown (2.5Y4/3) mottles; light medium clay; fine prismatic structure parting to fine polyhedral structure; rough faces on prismatic structure, and some shiny surfaces on polyhedral structure; fine pores (1.5 per cm²) present; very firm consistence dry; contains coarse roots that stop at boundary; carbonate present; very highly calcareous; pH 8.4; changing to:
B22k	30-52 cm	Light yellowish brown (2.5Y6/3) with olive brown (N4/0) infill; light clay; coarse prismatic, parting to medium platy and polyhedral structure; contains an abundant amount of visible carbonate; firm consistence dry; very fine (>5 per cm²) pores; very highly calcareous; pH 9.1; changing to:
B23k	52-75 cm	Light olive brown (2.5Y5/3) with dark grey (N4/0) infill; light clay; coarse prismatic, parting to medium platy and polyhedral structure; firm consistence dry; fine (1-5 per cm²) pores; very highly calcareous; pH 9.5; changing to:
B3	75-120 cm	Olive grey (5Y4/2); light clay; coarse prismatic parting to fine polyhedral structure; friable consistence moist, very firm consistence dry; contains small sized shell fragements and a medium amount of quartz fragments; small slickensides evident; very highly calcareous; pH 9.6.

Soil Profile Characteristics:

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A11 horizon)	Slightly Alkaline	Low	Non Sodic	None¹
Subsoil (B21 horizon)	Moderately Alkaline	Low	Non Sodic	None
Deeper Subsoil (at 75-120 cm)	Extremely Alkaline	Medium	Strongly Sodic	None²

¹Slight dispersion after remoulding. ²Strong dispersion after remoulding.

Graph: SW12

The surface horizon is slightly alkaline. The subsoil is moderately alkaline, becoming extremely alkaline with depth.

The salinity rating in the surface and upper subsoil is low becoming medium in the deeper subsoil.

The surface and the upper subsoil is non-sodic. The deeper subsoil is strongly sodic.

The clay content is high throughout the profile.

Horizon	Horizon Depth (cm)	pH (water)	pH (CaCl₂)	EC ds/m	NaCl %	Exchangeable Cations
						Ca	Mg	K	Na
						meq/100g
A11	0-2	7.3	6.8	0.21		16	25	3.5	0.81
A12	2-20	7.6	7.1	0.23		15	26	2.7	1.4
B21	20-30	8.4	8	0.33	0.05	12	23	1.4	1.2
B22	30-50	9.1	8.4	0.27	<0.05	15	30	1.4	1.8
B23	50-75	9.5	8.7	0.48	<0.05	1.2	21	1.7	4.6
B3	75-120	9.6	8.7	0.58	<0.05	1.2	19	2.1	6.4

Horizon	Horizon Depth (cm)	Total Nitrogen g/100g	Organic Carbon %	Wilting Point pF4.2	Coarse Sand (0.2- 2.0 mm)	Fine Sand (0.02- 0.2 mm)	Silt (0.002- 0.02 mm)	Clay (<0.002 mm)


A11	0-2	0.32	3.4	30	12	9	12	53
A12	2-20			32	12	9	10	58
B21	20-30			29	14	10	11	49
B22	30-50			23	15	11	5	47
B23	50-75			26	11	9	4	49
B3	75-120			27	8	8	16	42

Profile Described By: Richard MacEwan, John Martin, Mark Imhof (March 1997).

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