LWA8

Location: Shelford

Australian Soil Classification: Vertic, Mottled-Subnatric, Grey SODOSOL

General Landscape Description: Gently undulating plain.
Site Description: Stubble paddock – controlled traffick trial.
Geology: Quaternary basalt.

LWA8 Landscape

Soil Profile Morphology:

Surface Soil

A1	0-12 cm	Dark greyish brown (10YR4/2) with rusty root channel mottling; fine sandy clay loam; hardsetting surface with some surface cracking; weak to moderate coarse blocky structure; upper part of horizon is better structured – moderate medium polyhedral structure; strong consistence dry; pH 5.1; sharp change to:	LWA8 Profile
A2		NOTE: In some areas an A2 (12-25 cm) is present that can be as deep as 30 cm. Light brownish grey (10YR6/2) with dark greyish brown (10YR4/2) mottles; fine sandy clay loam; contains a few (2-5%) ferro-manganiferous nodules in patches (2-5 mm).
Subsoil
B21	12-40 cm	Dark grey (10YR4/1) with many (40%) dark yellowish brown (10YR4/6) diffuse mottles; medium clay; moderate very coarse prismatic, parting to moderate coarse blocky structure; strong consistence dry; pH 6.1; gradual change to:
B22	40-80 cm	Dark grey (10YR4/1) with common (20%) yellowish brown (10YR5/6) mottles in patches; medium heavy clay; moderate coarse blocky structure; strong consistence dry; very few (<2%) fine (1-2 mm in size) ferro-manganiferous nodules; large slickensides present; some deep cracks in profile to around 80 cm deep; pH 8.0; gradual change to:
B23	80-100 cm	Greyish brown (2.5Y5/2); medium heavy clay; moderate coarse prismatic, parting to strong coarse to medium subangular blocky structure; firm consistence moist; very few (<2%) fine (1-2 mm in size) ferro-manganiferous nodules; slickensides present; pH 8.4; gradual change to:
B24	100-130+ cm	Greyish brown (2.5Y5/2) with many (40%) brownish yellow (10YR6/8) mottles; light medium clay; moderate coarse prismatic, parting to strong coarse medium lenticular structure; patches of fine sand with some layering; pH 8.5.

Key Profile Features:

Strong texture contrast between surface (A) horizons and subsoil (B21) horizon.

Soil Profile Characteristics:

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	Strongly Acidic	Low	Non Sodic	None
Subsoil (B21 horizon)	Slightly Acidic	Low	Sodic	Strong
Deeper Subsoil (at 70-100 cm)	Moderately Alkaline	Medium	Strongly Sodic	Strong

The pH in the surface is strongly acid. The pH in the subsoil is slightly acid, becoming moderately alkaline with depth.

The salinity rating is low in both the surface and upper subsoil. The salinity rating increases to medium in the deeper subsoil.

The surface soil is non sodic. The subsoil is sodic becoming strongly sodic with depth.

The clay content in the surface is low and sharply increases at the surface / subsoil interface.

Horizon	Horizon Depth (cm)	pH (water)	pH (CaCl₂)	EC (dS/m)	NaCl %	Exchangeable Cations
						Ca	Mg	K	Na
						meq/100g
A1	0-12	5.1	4.5	0.17		4.2	3.3	0.25	1.0
A2	12-25	5.4	4.4	0.11		3.1	2.9	0.11	1.1
B21	12-40	6.1	5.2	0.19		7.3	9.7	0.34	3.2
B22	40-70	8	7.2	0.51	0.07	8.4	13	0.3	5.9
B23	70-100	8.4	7.7	0.56	0.08	7.2	15	0.3	7.4
B24	100-130+	8.5	7.8	0.62	0.09	7.5	16	0.3	7.9

Horizon	Horizon Depth (cm)	Total Nitrogen %	Oxidisable Organic Carbon %	Exchangeable Acidity meq/100g	Exchangeable Aluminium mg/kg	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	0-12	0.19	2.4	9.6	28	31.0	9.3	6	43	26	19
A2	12-25	0.1	1.3	5.5	27	27.6	8.0	4	46	28	19
B21	12-40			8.9	<10	43.3	20.7	3	31	21	42
B22	40-70			4.0	<10	47.7	22.2	2	25	23	49
B23	70-100					38.8	18.7	1	31	28	39
B24	100-130+					43.4	21.1

Profile Described By: Mark Imhof (January 2007).

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