SW80

Location: Yeo

Australian Soil Classification: Vertic, Mottled--Mesonatric, Grey SODOSOL
Great Soil Group: solodized solonetz

General Landscape Description: Undulating rises
Site Description: Open depression
Geology: Mapped as Tertiary-Gellibrand Marl but has alluvial material overlying it

SW80 Landscape

Soil Profile Morphology:

Surface Soil

A1	0-15 cm	Very dark greyish brown (10YR3/2 moist), greyish brown (10YR5/2 dry) loam, fine sandy; weakly pedal; weak consistence dry.	SW80 Profile. Note: Surface (A1) horizon has been stripped from the soil profile.
A2e	15-40 cm	Brown (10YR5/3 moist), conspicuously bleached (10YR7/2 dry); loamy sand; pH 5.4; sharp domed change to:
Subsoil
B21t	40-90 cm	Very dark grey (10YR3/1 moist) with fine yellowish brown (10YR5/8) mottles ; heavy clay; coarse (up to 400 mm) columnar structure, parting with difficulty to coarse blocky structure; slickensides across ped; pH 7.5 gradual change to:
B22gss	90-140 cm	Very dark grey (10YR3/1 moist) with ~ 50% coarse olive brown (2.5Y4/4 moist) mottles; heavy clay; coarse columnar peds continuous from B21; slickensides more prominent than in B21 above; pH 7.5; clear change to:
B23g	140+ cm	Conspicuously mottled, gleyed clay; massive; pH 7.5.

• Strong texture contrast between surface (A) horizons and subsoil (B) horizons.
• Coarse columnar structure in upper subsoil.

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A2 horizon)	Strongly Acid	Very Low	Non-Sodic	None
Subsoil (B21 horizon)	Slightly Alkaline	Low	Strongly Sodic	Strong
Deeper Subsoil (at 100-120 cm)	Slightly Alkaline	Low - Medium	Strongly Sodic	Strong - Complete

The surface soil is strongly acid. The subsoil is slightly alkaline.

Salinity rating is very low in the surface becoming low in the subsoil, increasing to moderate levels in the deeper subsoil.

The soil is non sodic in the surface and strongly sodic in the subsoil.

The clay content increases markedly at the A/B boundary.

Horizon	Sample Depth (cm)	pH (water)	pH (CaCl2)	EC 1:5	NaCl %	Exchangeable Cations
						Ca	Mg	K	Na
						meq/100g
A1	0-15	-	-	-	-	-	-	-	-
A2	20-40	5.4	4.5	<0.05		1.2	0.29	0.19	0.07
B21t	50-70	7.5	6.4	0.16		4.5	10	0.23	2.7
B22gss	100-120	7.5	6.6	0.41	0.06	3.7	8.4	0.2	4.1
B23g	140+	7.5	6.6	0.46	0.09

Horizon	Sample Depth (cm)	Exchangeable Aluminium mg/kg	Exchangeable Acidity meq/100g	Coarse Sand (0.2- 2.0 mm)	Fine Sand (0.02- 0.2 mm)	Silt (0.002- 0.02 mm)	Clay (<0.002 mm)
A1	0-15	-	-	-	-	-	-
A2	20-40	17	5.6	4	62	23	8
B21t	50-70			2	36	14	46
B22gss	100-120
B23g	140+

Management Considerations:

Subsoil (B) Horizons

• The subsoil displays vertic features (i.e. slickensides) which indicates that significant shrinking and swelling occurs during wetting and drying cycles. This may have engineering implications and is likely to explain the variability in surface horizon depth across the trench.
• The dense and coarsely structured subsoil is strongly sodic and disperse strongly in water. This will result in restricted root and water movement down the soil profile.