IS4

Location: Coromby

Soil Type: Minor Type A

Australian Soil Classification: Haplic, Self-Mulching, Grey VERTOSOL

Northcote Factual Key: Ug 5.2
Great Soil Group: grey clay

General Description: Plain within a gently undulating plain.
Geology: Quaternary Woorinen Formation: aeolian dune sand, calcareous clay

Soil Profile Morphology:

Surface Soil

A1	0-10 cm	Very dark greyish brown (10YR3/2); sandy clay; plastic; cracking and self-mulching surface condition; weak subangular blocky structure; strong consistence dry, sticky consistence wet; pH 7.6; sharp change to:
Subsoil
B21	10-30 cm	Dark grey (7.5YR4/0); heavy clay; plastic; moderate subangular blocky structure; strong consistence dry, sticky consistence wet; pH 7.6:
B22	30-60 cm	Dark grey (7.5YR4/0); heavy clay; plastic; moderate subangular blocky structure; strong consistence dry, sticky consistence wet; pH 8.1; gradual change to:
B31	60-90 cm	Greyish brown (2.5Y5/2); heavy clay; plastic; moderate subangular blocky structure; strong consistence dry, sticky consistence wet; pH 8.5:
B32	90-120 cm	Greyish brown (2.5Y5/2); heavy clay; plastic; moderate subangular blocky structure; strong consistence dry, sticky consistence wet; pH 8.7.

Chemical and Physical Analysis:

Horizon	Sample Depth cm	pH H₂O	EC dS/m	Sodium Chloride %	Exchangeable Calcium cmol-/kg	Exchangeable Magnesium cmol-/kg	Exchangeable Potassium cmol-/kg	Exchangeable Sodium cmol-/kg	Total Nitrogen %	Exchangeable Acidity cmol-/kg	Organic Carbon %	Permanent Wilting Point -1500^okPa	Coarse Sand %	Fine Sand %	Silt %	Clay %
Horizon	Sample Depth cm	pH H₂O	EC dS/m	Sodium Chloride %	Exchangeable Calcium cmol-/kg	Exchangeable Magnesium cmol-/kg	Exchangeable Potassium cmol-/kg	Exchangeable Sodium cmol-/kg	Total Nitrogen %	Exchangeable Acidity cmol-/kg	Organic Carbon %	Permanent Wilting Point -1500^okPa	Coarse Sand %	Fine Sand %	Silt %	Clay %
A1	0–10	7.6	0.11	0.01	13	5.8	1.4	0.1	0.14	6.2	1.71	14.7	29	22	8	39
B21	10–30	7.6	0.28	0.04	21.7	8.8	1.9	0.5	0.1	6.1	1.03	25.3	14	13	9	62
B22	30–60	8.1	0.41	0.08	22.3	9.3	1.7	1.5	0.06	2.2	0.59	25.6	15	12	9	63
B31	60–90	8.5	0.64	0.12	19.8	10.1	1.6	3.3	0.05	NA	0.46	30.8	16	12	9	60
B32	90–120	8.7	0.76	0.13	18.3	10.5	1.5	4.1	0.03	NA	0.35	26.0	15	12	8	60

Management Considerations:

Cracking clay profile, lighter surface soil.
Neutral thin surface soil and upper subsoil, increasingly alkaline below upper subsoil.
Massive surface, with sand. Some structure and possible self-mulching in places.
High calcium percentage in subsoil; decreasing with depth.
Subsoil is sodic and salinity increases at depth, particularly below 60 cm.
Cracking may allow air and seasonal moisture to penetrate.
Very strong consistence when dry, implications for compaction and implement use.
Landform element, flat: poor site drainage.

Profile Described By: John Martin, Nabil Badawy, Ron Cawood, Geoff Pope, John Galea, John Turner (1970).

Reference: "Major Agricultural Soils of the Wimmera Irrigation Area". John Martin, Mark Imhof, Lourey Ruth, Rob Nink, Karen DePlater, Paul Rampant, Sonia Thompson, S. Alexander. Department of Natural Resources and Environment, Victoria. 1996.

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