SW5

Location: Ayrford

Australian Soil Classification: Mottled-Sodic, Eutrophic, Brown DERMOSOL/ ferric kaolinitic clay

Northcote Factual Key: Gn 3.71
Great Soil Group: brown podzolic

General Landscape Description: Level gently undulating plain.
Geology: Tertiary deposits: Hanson Plain Sand (Tpb). Lateritization evident.
Native Vegetation: Swamp Gum ( Eucalyptus regnans).

SW5 Landscape

Soil Profile Morphology:

Surface Soil

A1	0-15 cm	Brown (10YR4/3); very fine sandy clay loam; weak to moderate medium blocky structure; weak consistence moist; contains few (2- 5%) ferromanganiferous nodules (2-4 mm size); pH 5.9; abrupt change to:	SW5 Profile
Subsoil
B21	15-25 cm	Yellowish red (5YR5/6); light clay (subplastic); moderate medium blocky structure; weak consistence moist; contains few (2-5%) ferro-manganiferous nodules (2 -10 mm size); pH 6.0; clear change to:
B22	25-50 cm	Yellowish brown (10YR5/6) with strong brown (7.5YR5/6) mottles; light clay (subplastic); moderate medium blocky structure; weak consistence moderately moist; contains a few (5%) ferro-manganiferous concretions (2-10 mm size); pH 6.0; clear change to:
B23	50-75 cm	Yellowish brown (10YR5/6) with strong brown (7.5YR5/6) mottles; light medium clay (subplastic); strong coarse polyhedral, parting to fine polyhedral structure; shiny faced peds; contains few (5%) iron stone concretions (10-25 mm in size); pH 6.8:
B24	75-95cm	Yellowish brown (10YR5/6); light clay (subplastic); strong medium-coarse polyhedral, breaking to strong fine polyhedral structure; very firm consistence moderately moist; contains a common (20%) amount of ferruginous concretions (2 - 8 cm size) ; pH 5.9:
B3	95+ cm	Light grey (2.5Y7/0) with brownish yellow (10YR6/6) mottles; light clay (silty); strong consistence dry; contains many (50%) ferruginous concretions (2-10 cm in size) with a surrounding mottle; pH 5.6.

• Lack of strong texture contrast between surface (A) horizon and subsoil (B21) horizon.
• Deeply weathered late Tertiary clay horizon in deep subsoil.

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	Moderately Acid	Low	-	None
Subsoil (B21 horizon)	Moderately Acid	Low	-	None
Deeper Subsoil (at 95+ cm)	Moderately Acid	Low	-	None

The surface and upper subsoil is moderately acid. The subsoil becomes slightly acid at bout 50 cm depth and them becomes moderately acid again with depth.

The salinity rating is low throughout most of the profile.

There is only a slight texture contrast at the A/B horizon boundary. The deeper subsoil has a very high clay content..

Horizon	Horizon Depth (cm)	pH (water)	pH (CaCl2)	EC (dS/m)	NaCl %	Exchangeable Cations
						Ca	Mg	K	Na
						meq/100g
A11	0-15	5.9	5.4	0.19		9.4	1.7	0.64	0.70
B21	15-25	6.0	5.7	0.22		5.4	1.3	0.33	0.47
B22	25-30	6	5.8	0.17		4.1	3.4	0.21	0.65
B23	50-75	6.8	6.3	0.16		3.1	6.0	0.20	0.87
B24	75-95	5.9	5.4	0.61	<0.05	3.5	5.2	0.15	0.84
B3	95+	5.6	4.9	0.32	<0.05	4.3	4.1	0.14	0.94

Horizon	Horizon Depth (cm)	Exchangeable Aluminium mg/kg	Oxidisable Organic Carbon %	Total Nitrogen %	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)
A11	0-15		4.6	0.51	19.0	9	37	12	29
B21	15-25		1.1		17.0	8	36	13	41
B22	25-30				19.4	8	31	9	52
B23	50-75				27.5	5	17	6	74
B24	75-95				26.0	9	17	5	72
B3	95+	<10			23.0	17	19	4	62

Management Considerations:

Whole Profile

• Plant available water capacity (PAWC) is considered to be moderate (estimated at 120 mm) for the top metre of the soil profile. This is based on available laboratory data.

• The surface soil has a high organic matter content. Organic matter is important in terms of promoting aggregation of soils such as these with high fine sand and silt contents.

• The subplastic properties of the subsoil may lead to problems with sealing of earth dams. Sealing can be improved by compaction at the optimum water content and treatment with sodium tri-polyphosphate or addition of bentonite (Rolfe 1989).