SW97

Location: Batesford

Australian Soil Classification: Vertic (& Sodic), Calcic, Black DERMOSOL (deep profile depth)

General Landscape Description: Undulating rises.
Site Description: Simple slope on side of open depression.
Geology: Quaternary Basalt - Newer Volcanics

SW97 Landscape

Soil Profile Morphology:

Surface Soil

Ap	0-15/20 cm	Very dark brown (10YR3/2); fine sandy clay loam; pH 6.0:	SW97 Profile - Note: Surface stripped from soil profile.
Subsoil
B21t	15/20-40/50 cm	Black (7.5YR2.5/1 moist) with dark red (10R3/6 moist) mottles; light clay; very coarse roughly prismatic, parting to very coarse angular blocky structure; slickensides present; pH 5.2:
B22gt	40/50-110 cm	Strong brown (7.5YR5/8 moist), dark greyish brown (10YR4/2 moist) and grey (7.5Y5/1 moist) vertically mottled; light clay; slickensides prominent; band of soft carbonate at 90cm depth in mottled clay matrix; pH 9.4:
B23k	110-130 cm	Band of soft carbonate in mottled clay matrix; pH 9.6; clear change to:
C	130+ cm	Grey (5Y5/1 moist); soft vesicular weathered basalt.

• Gradual increase in texture between surface (A) horizon and subsoil (B2) horizon.
• Calcium carbonate in deeper subsoil.
• Vertic features (i.e. slickensides in deeper subsoil)

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	Moderately Acid	Low	Non-Sodic	None1
Subsoil (B21 horizon)	Moderately Alkaline	Low	Strongly Sodic	Strong
Deeper subsoil (at 70+ cm)	Extremely Alkaline	Medium	Strongly Sodic	None2
1 Moderate - strong dispersion after remoulding. 2 No aggregate dispersion probably due to high level of soluble salts, strong dispersion after remolding.

The surface is moderately acid. The subsoil is moderately alkaline becoming extremely alkaline at depth.

Salinity rating is low in the surface and upper subsoil and medium in the subsoil.

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

The clay content is moderate throughout the profile.

Horizon	Sample Depth (cm)	pH (water)	pH (CaCl2)	EC 1:5	NaCl %	Exchangeable Cations
						Ca	Mg	K	Na
						meq/100g
Ap	0-10	6	5.2	0.16		6.5	5.8	0.91	1
B21t	20-40	8.2	7	0.24		6.6	9.8	0.74	4.1
B22gk	60-80	9.4	8.4	0.58	0.03	7.7	11	0.8	7.5
B23k	90-110	9.6	8.7	0.65	0.04	8.9	13	0.5	9.3

Horizon	Sample Depth (cm)	Exchangeable Aluminium mg/kg	Exchangeable Acidity meq/100g	Organic Carbon %	Nitrogen %	Field Capacity pF2.5	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)
Ap	0-10	<10	10	2.7	0.25	24.9	13	18.6	36.9	9.5	29
B21t	20-40					40.3	19.3	17.3	31.2	8.5	38
B22gk	60-80					44.6	21.3	14.9	26.2	20	34.5
B23k	90-110					45.7	21.2	16.2	27.4	13.5	38.5

Management Considerations:

Subsoil (B) Horizons

• The subsoil displays vertic features (i.e. slickensides) which indicates that significant shrinking and GPelling 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 disperses strongly in water. This will result in restricted root and water movement into the subsoil.