OTR490

Location: Torquay

Australian Soil Classification: Calcic, Mesonatric, Brown SODOSOL

Humose-Mottled, Melacic, Red KANDOSOL
Northcote Factual Key: GN2.41

General Landscape Description: Hills
Site Description: Hilslope - Lower Slope Slope: 5% Aspect: South-East
Native Vegetation: Woodland; E. viminalis (Manna Gum)
Geology: Qra: Quaternary Alluvium/Colluvium; gravel, sand, silt.

This was located in the housing estate

Soil Profile Morphology:

Surface Soil

A10	0-15 cm	Very dark greyish brown (10YR3/2); fine sandy loam; weak subangular blocky structure;abrupt boundary to:
Subsoil
B21	15-35 cm	Brown (10YR4/3); heavy clay; strong coarse subangular blocky structure; some ironstone gravel; hard when dry; diffuse boundary to:
B22	35-70 cm	Yellowish brown (10YR5/4); heavy clay; strong coarse subangular blocky structure; hard when dry; diffuse boundary to:
C	70+ cm	Mottled light yellowish brown (10YR6/4), and yellowish red (5YR5/6); sandy clay; moderate very coarse subangular blocky structure; hard when dry.

Soil Profile Characteristics:

	pH	Salinity Rating	Sodicity
Surface (A1 horizon)	Very Strongly Acid	Low	Non-Sodic
Subsoil (B21 horizon)	Slightly Acid	Medium	Strongly Sodic
Deeper Subsoil (at 120 cm)	Moderately Alkaline	Low	Strongly Sodic

The surface is very strongly acid. The upper subsoil is slightly acid. The deeper subsoil is moderately alkaline.

The salinity rating in the surface and deeper subsoil is low. The upper subsoil has a salinity rating of medium.

The surface is non sodic. The subsoil is strongly sodic.

The clay content is very low at the surface, and sharply increases at the A/B interface.

Horizon	Horizon Depth (cm)	pH (water)	EC dS/m	Cl %	Organic Carbon %	Total N %	P ppm	K ppm	Free Fe %	Exchangeable Cations				Total Bases cmolc/kg	Ex Ac cmolc/kg	CEC cmolc/kg
										Ca	Mg	K	Na
										cmolc/kg
A1	0-10	5.3	0.076	0.011	2.0	0.16	9	90	1.8	3.3	1.4	0.1	0.3	5.1	2.6	10.3
A1	10-15	5.5	0.083	0.011	1.4	0.10	5	70	2.1	2.6	1.3	0.1	0.4	4.4	3.3	7.6
B21	20-30	6.6	0.280	0.028	1.0	0.099	3	200	5.7	5.0	7.5	0.4	3.4	16.3		16.0
B22	50-60	8.2	0.510	0.048	0.3	0.043	3	220	6.2	3.6	9.1	0.3	4.1	17.1		17.5
C	100-110	8.1	0.110	0.045			3	140	5.8	2.5	6.8	0.4	4.1	13.8		9.4

Horizon	Horizon Depth (cm)	Gravel %	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	0-10	3	30	51	6	9
A1	10-15	3	31	50	6	10
B21	20-30	1	15	22	2	59
B22	50-60	6	13	13	<1	67
C	100-110	1	23	23	1	50

Management Considerations:
The strong texture contrast between the surface soil and the subsoil can have a major effect by reducing and/or redirecting the internal drainage and restricting root growth beyond the upper horizons.

Soil salinity at depth may affect deeper rooting plants and may indicate water movement restrictions. The sandy topsoil is likely to have poor plant water holding capacity and poor nutrient holding.

These soils may be hydrophobic (in conjunction with organic coatings) when dry, taking time to reabsorb moisture. Acidic surface soil (topsoil) are often associated with sandy surfaces due the lack of base minerals and may or may not have organic matter (humose or peaty surfaces).

The subsoils usually have poor structure (generally as coarse domed columns) resulting in dispersion (and subsequent clogging of pores), restricting water and gas movement through the subsoil.
The soils are hardsetting and have limited opportunity for cultivation without further damage to soil structure.

Profile Described By: A. Thornley, 12th August 1969.

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