SW74

Location: Tulloh

Australian Soil Classification: Bleached-Vertic, Eutrophic, Brown CHROMOSOL

General Landscape Description: Undulating low hills.
Site Description: Waxing upper slope, western aspect.
Geology: Thin Tertiary (Dilwyn or Eastern View Formation) over Cretaceous (Otway Group) unconformity.

SW74 Landscape

Soil Profile Morphology:

Surface Soil

A1	0-15 cm	Very dark grayish brown (10YR3/2 moist), dark gray (10YR4/1 dry); loamy sand; apedal; hardsetting; pH 5.4; clear change to:	SW74 Profile. Note: Surface (A1) horizon has been stripped from the soil profile.
A2	15-40 cm	Olive brown (2.5Y4/3 moist) with faint mottling, conspicuously bleached (2.5Y6/3 dry); sandy loam; apedal, massive; contains few medium ferruginous nodules; pH 5.6; sharp and wavy change to:
Subsoil
B21t	40-70/80 cm	Sandy yellowish brown (10YR5/6) coarse angular blocky peds with dark grayish brown (10YR4/2) thick heavy clay coatings; some peds dominantly clay; vertic features; pH 6.0; gradual and wavy change to:
B22tg	70/80-140+ cm	White (gray N8/0) clay with gray (10YR5/1) coatings; red mottles in white clay; strongly vertic; pH 5.5. This horizon is probably a palaeosol developed on Otway Group sediments.

• Conspicuously bleached subsurface (A2) horizon
• Strong texture contrast between surface (A) horizons and subsoil (B21) horizon.

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	Strongly Acid	Low	Non-Sodic	None
Subsoil (B21 horizon)	Moderately Acid	Very Low	Non-Sodic	None
Deeper Subsoil (at 100+ cm)	Strongly Acid	Very Low	Non-Sodic	None

The surface soil is strongly acid. The subsoil is moderately acid becoming strongly acidic with depth.

Salinity rating is low in the surface becoming very low in the subsoil.

The soil is non sodic throughout.

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

Horizon	Sample Depth (cm)	pH (water)	pH (CaCl2)	EC 1:5	Organic Carbon %	Nitrogen %	Exchangeable Cations
							Ca	Mg	K	Na
							meq/100g
A1	0-15	5.4	4.7	0.14	7.6	0.65	2.6	0.97	0.37	0.27
A2	25-35	5.6	4.8	0.05			0.74	0.91	0.05	0.14
B21t	45-65	6	5.3	0.08			1.9	5.2	0.08	0.49
B22tg	100-120	5.5	4.4	0.08			1.4	8.2	0.11	0.8

Horizon	Sample Depth (cm)	Exchangeable Aluminium mg/kg	Exchangeable Acidity meq/100g	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)
A1	0-15	21	13	22.2	9.5	39	35	11	9
A2	25-35	15	5.3	13.7	4.2	46	28	13	10
B21t	45-65	<10	7.3	28.4	18.6	37	8	4	48
B22tg	100-120		13

Management Considerations:

Notes

• Possible unconformity of Palaeocene over Cretaceous.
• Strongly vertic with trench collapse.
• This site stood out from adjacent sections of the trench, because of white subsoil material in trench spoil.