SW109

Location: Mt Gellibrand.

Australian Soil Classification: Vertic (& Hypercalcic), Mottled-Mesonatric, Black SODOSOL (very deep soil profile).

General Landscape Description: Lower slope of Mt Gellibrand, northerly aspect.
Site Description: Grazing paddock. A flat area just at the foot of a steeper slope, with a basalt dyke or flow just up slope. Subject to soil creep and wash from above.
Geology: Late Quaternary basalt (Bartley 1984).
Soil Type: “Low slopes (lighter type)” (Leeper et al., 1936)

SW109 Landscape

Soil Profile Morphology:

Surface Soil

A1	0-15 cm	Very dark greyish brown (10YR3/2); fine sandy loam; firm consistence dry; pH 6; clear change to:	SW109 Profile
A2	25-40 cm	Light grey (10YR7/1 dry) with yellowish brown (10YR5/4) rusty root channel mottling; conspicuously bleached; sandy loam; firm to very firm consistence dry; pH 6.2; sharp and wavy change to:
Subsoil
B21	25-40 cm	Very dark grey (10YR3/1) with many brown (7.5YR5/4) rusty mottles; medium clay; strong coarse blocky structure; in parts there is strong very coarse columnar structure, with bleached capping associated with domes; strong consistence dry; pH 6.4; clear change to:
B22	40-60 cm	Very dark grey (10YR3/1) with many brown (10YR5/4) mottles; medium heavy clay; strong coarse blocky, parting to moderate medium sub-angular blocky structure; strong consistence dry; slickensides present; pH 7.9; clear change to:
B23	60-80 cm	Very dark grey (10YR3/1); heavy clay; strong coarse polyhedral structure; very firm consistence dry; slickensides present; pH 8.6; clear change to:
B24	80-100 cm	Grey (2.5Y5/1); heavy clay; strong coarse prismatic, parting to strong coarse blocky structure; very firm consistence dry; few fine-earth carbonates and fine calcareous nodules (2-4 mm in size); slickensides present; pH 9.3; clear change to:
B25	100-130 cm	Grey (10YR5/1) with very few yellowish brown (10YR5/6) mottles; medium heavy clay; strong coarse prismatic, parting to strong coarse sub-angular blocky structure; very firm consistence moist; few fine-earth carbonates and very few very coarse (up to 30 mm in size) ferruginous nodules; few weathered ferruginous basalt fragments (20 mm in size); slightly effervescent; smooth faced peds; pH 9.3; clear change to:
B26k	130-160 cm	Greyish brown (2.5Y5/2); heavy clay; strong coarse polyhedral structure; firm consistence moist; many fine-earth carbonates and semi-hard carbonate nodules, few very coarse (10-30 mm in size) ferruginous nodules; very few isolated ferruginous basalt cobbles (100 mm in size); visible carbonates; pH 9.7; gradual change to:
B27k	130-160 cm	Greyish brown (2.5Y5/2); heavy clay; strong coarse polyhedral structure; very firm consistence moist; very few fine (1-2 mm in size) soft and hard manganese nodules and few coarse (5-15 mm in size) ferruginous nodules; very few very fine (<1 mm in size) quartz fragments; slightly audible effervescence.

Key Profile Features:

Strong texture contrast between surface (A) horizons and subsoil (B21) horizon.
Dense and coarsely structured upper subsoil (columnar in some areas).
Accumulations of calcium carbonate in deeper subsoil.
Vertic features (slickensides, lenticular structure) in subsoil.

Domes / columnar structure evident in the B21 horizon in some areas.

Soil Profile Characteristics:

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	Moderately Acid	Low	Non-Sodic	None¹
Subsoil (B21 horizon)	Slightly Acid	Low	Strongly Sodic	Strong²
Deeper subsoil (at 80-100 cm)	Very Strongly Alkaline	Moderate - High	Strongly Sodic	Strong²

¹Slight dispersion after remoulding. ²Complete dispersion after remoulding.

The surface soil is moderately acid. The upper subsoil is slightly acid becoming very strongly alkaline at depth.

The salinity rating is low in the surface and upper subsoil. It becomes moderate to high lower down the profile.

The upper surface is non-sodic. The lower surface is sodic at 15 cm depth. The subsoil is strongly sodic.

The clay content is moderate throughout the profile.

Horizon	Horizon Depth (cm)	pH (water)	pH CaCl2	EC dS/m	NaCl %	Total Nitrogen %	Organic Carbon %	Exchangeable Cations
								Ca	Mg	K	Na
								meq/100g
A1	0-15	6	5.2	0.1		0.21	2.9	2.9	2.3	0.24	0.59
A2	15-25	6.2	4.9	0.06				0.94	1.3	0.1	0.59
B21	25-40	6.4	5.3	0.19				3.5	10	0.44	5.7
B22	40-60	7.9	6.9	0.54	0.08			5.9	18	0.7	10
B23	60-80	8.6	7.7	0.65	0.1			6.4	19	0.8	11
B24	80-100	9.3	8.6	0.87	0.11			6.2	25	0.8	12
B25	100-130	9.3	8.6	0.7	0.09			5.2	21	0.7	11
B26k	130-160	9.7	9	0.8	0.09			4.9	17	0.5	10

Horizon	Horizon Depth (cm)	Extractable Iron %	Extractable Aluminium %	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			<10	7.3	-	9.1	35	37	10	13
A2	15-25			<10	4.2	27.8	4.2	33	42	10	10
B21	25-40	1.4	0.21	<10	12	-	19.9	22	26	8	41
B22	40-60	1.2	0.18			40.5	26.7	17	22	8	49
B23	60-80					47.2	28.1	18	23	10	46
B24	80-100					52.2	29	17	22	14	42
B25	100-130
B26k	130-160

Notes: Geology and landform described by Bernie Joyce.

Profile Described By: Mark Imhof, John Martin, Jack Holland and Bernie Joyce (October 2004).

Reference:

Leeper GW, Nicholls A and Wadham SM (1936). Soil and Pasture Studies in the Mount Gellibrand area, Western District of Victoria. Proceedings Royal Society Victoria, 49.

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