SW54

Location: Cooriemungle.

Australian Soil Classification: Acidic, Eutrophic, Grey DERMOSOL.

General Landscape Description: Gleyed soil on an alluvial fan at the toe slope of a landslide.
Geology: Quaternary alluvium derived from Gellibrand Marl.
Land Use: Dairy cattle grazing.

SW54 Landscape.

Soil Profile Morphology:

Surface Soil

A1	0-15 cm	Very dark greyish brown (10YR3/2); fine sandy loam; weak medium polyhedral structure; pH 5.7: abrupt and smooth change to:	SW54 profile. Note: Surface (A) horizon has been stripped from the soil profile.
A2	15-35 cm	Grey (2.5Y6/1) conspicuously bleached (2.5Y7/2 dry); clay loam; apedal; strong consistence dry; pH 5.4; abrupt and smooth change to:
Subsoil
B21g	35-80 cm	Grey (2.5Y5/1) with yellowish brown (10YR5/6) mottles common; light clay; fine polyhedral structure; very firm consistence dry; pH 5.2; diffuse and smooth change to:
B22g	80-130 cm	Grey (2.5Y5/1) with many yellowish brown (10YR5/6) mottles; medium clay; coarse polyhedral or angular blocky, parting to coarse polyhedral structure; pH 5.2; diffuse and smooth change to:
B23gss	130 cm+	Dark grey (2.5Y4/1) with a few yellowish brown (10YR5/6) mottles; medium heavy clay; coarse polyhedral or angular blocky, parting to coarse polyhedral structure; slickensides (up to 100 mm); pH 5.4.

Key Profile Features:

Gradual increase in clay content down the soil profile.

Soil Profile Characteristics:

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	Moderately Acid	Medium	Non-Sodic	None
Subsoil (B21 horizon)	Strongly Acid	Low-Medium	Sodic	None
Deeper Subsoil (at 80+ cm)	Strongly Acid	Low	Sodic	None

The surface is moderately acid. The subsoil is strongly acid.

Salinity rating is medium in the surface. The upper subsoil is low to medium becoming low at depth.

The surface is non-sodic the subsoil is sodic.

Clay content increases markedly at the surface / subsoil boundary.

Exchangeable Aluminium increases to very high levels in the subsoil.

Horizon	Horizon Depth (cm)	pH (water)	pH (CaCl₂)	EC (dS/m)	NaCl %	Exchangeable Cations
						Ca	Mg	K	Na
						meq/100g
A1	0-15	5.7	5.1	0.44	0.09	8.3	3.7	0.6	0.8
A2	15-35	5.4	4.5	0.19		2.7	3.2	0.44	1.2
B21	35-80	5.2	4.4	0.25		3.2	4.9	0.41	1.6
B22	80-130	5.2	4.4	0.26	0.06	3.7	6.5	0.2	1.5
B23	130+	5.4	4.5	0.23

Horizon	Horizon Depth (cm)	Oxidisable Organic Carbon %	Total Nitrogen %	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	4.3	0.37	<10	14	42	16	7	31	27	22
A2	15-35			170	10	29	12	2	44	25	26
B21	35-80			270	11	32	32	2	40	21	36
B22	80-130			180	9.2	15	17	1	35	19	42
B23	130+

Management Considerations:

Whole Profile

The high exchangeable aluminium levels measured in the strongly acid soil profile (below surface horizon) are likely to restrict the growth of aluminium sensitive species.

Subsoil (B) Horizons

The subsoil is slightly sodic but does not disperse. The high levels of exchangeable aluminium are likely to prevent dispersion occurring.

Profile Described By: Mark Imhof and Richard MacEwan (March 1999).

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