Victorian Resources Online (archived)

LP72

Group: Oakvale Farm Advance Group	Australian Soil Classification: Epihypersodic, Pedal, Hypercalcic CALCAROSOL
Northcote Factual Key: Dy 2.23	Great Soil Group: no suitable group
General Landscape Description: Long flat slope of a plain associated with a subdude Cannie Ridge. Native Vegetation: Included Red Mallee (E. socialis) and Square Fruited Mallee (E. Calycogona).

LP72 Landscape

Soil Profile Morphology

Surface Soil

A1	0-10 cm	Dark reddish brown (5YR3/2); sandy clay loam; weakly structured; weak consistence moist; pH 8.0; abrupt change to:	LP72 Profile
Subsoil
B1	10-20 cm	Dark reddish brown (5YR4/4); sandy clay; weak coarse blocky structure; firm consistence moist; pH 8.9; sharp change to:
B21	20-35 cm	Yellowish red (5YR5/6); medium clay; moderate sub-angular blocky structure; strong consistence dry; pH 9.5; clear and wavy change to:
B22k	35-100 cm	Yellowish red (5YR5/6); medium clay (sandy); moderate sub-angular blocky structure; strong consistence dry; contains a few (2%) carbonate nodules (up to 10 mm in diameter) and many (45%) soft carbonates in tongues, as well as a few (2%) sandstone gravels (up to 15 mm diameter); pH 9.6; gradual and wavy change to:
BC	100 + cm	Yellowish red (7.5YR5/6); medium clay (sandy); moderate sub-angular blocky structure; strong consistence dry; pH 8.5; mixed with weathered sandstone.

Key Profile Features

Moderate texture contrast between surface (A1) horizon and subsoil (B) horizons.
Sodic

Key Profile Characteristics

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	moderately alkaline	very low	non-sodic	none¹
Subsoil (25-45 horizon)	very strongly alkaline	low	sodic	slight
Deeper subsoil (1 m)	moderately alkaline	extremely high	strongly sodic	none²
¹ Slight dispersion with remoulding. ² Due to high soluble salt levels.

Horizon	Horizon Depth	pH (water)	pH CaCl₂	EC 1:5	NaCl	Exchangeable Cations
						Ca	Mg	K	Na
						meq/100g
A1	0-10	8	7.1	0.09		9	4	1.1	0.3
B1	10-20	8.9	8.2	0.19		11	9.6	0.8	1.1
B21	2-35	9.5	8.6	0.39	<0.05	5.9	12	1	3
B22K	35-50	9.6	8.9	0.99	0.11	5	10	1.2	8.3
B22K	80-100	8.7	8	0.95	0.12	1	5.8	0.6	4.2
BC	100+	8.5	8.3	3.4	0.49	6.3	10	1.1	11

Horizon	Horizon Depth	Ex Al mg/kg	Ex Ac meq/100g	Field pF2.5	Wilting Point pF4.2	Coarse Sand (0.2-2.0mm)	Fine Sand (0.02-0.2mm)	Silt (0.002-0.02mm)	Clay (<0.002mm)


A1	0-10			17.4	10.4	36	34	4	23
B1	10-20			37.3	23.4	30	23	4	35
B21	2-35			30.2	19	11	24	7	51
B22K	35-50			35.7	21.4	25	18	4	35
B22K	80-100					25	14	4	36
BC	100+

Management Considerations:

Surface (A) Horizons

The surface soil is non-sodic but disperses moderately after remoulding. Overstocking or excessive cultivation of the soil when wet may result in surface sealing and exacerbate the hardsetting condition
The overall nutrient status is high (based on the sum of the exchangeable basic cations). Total nitrogen and organic carbon levels are relatively low.

Subsoil (B) Horizons

The subsoil is sodic (becoming strongly sodic with depth). This is likely to result in restricted root and water movement throughout the profile. The B1 horizon (10-20 cm) disperses strongly after remoulding, so tillage in a moist to wet condition is likely to result in structural degradation (eg. plough pan development).
The very strongly alkaline subsoil (becoming extremely alkaline at 35 cm depth) indicates that some nutrients (e.g. copper, iron, manganese and zinc) may be poorly available to plants.
The salinity rating becomes medium-high at 35 cm depth. This is likely to restrict the growth of salt sensitive species such as linseed, maize, chickpeas, faba beans and some other legumes.
The B/C horizon (from 100 cm depth) has a very high salinity rating for plant growth.

Notes

Repeats of analyses are being undertaken for some of the horizons at this site, due to some irregular results.
Profile described by Mark Imhof, Paul Rampant and Sonia Thompson (25/5/95)

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