Site WW12

Location: Lillimur

Australian Soil Classification: Vertic (and Calcic), Subnatric, Grey SODOSOL
Northcote Factual Key: Dy3.43
Great Soil Group: solodised solonetz

Site WW12 Landscape

General Landscape Description: This soil type occurs on the lower slope in association with the crests (WW11) when the slope flattens out to form clay plains or drainage depressions. It is similar to WW13 and WW15. This soil type is regarded as the most appropriate to represent these land units as it is located on a long gentle slope which is a common land element in the Shire. The land tends to have gilgai micro-relief. Soil profile variability (ie. when darker pockets of soil are close to the surface) is also an indication of the gilgaied nature of the soil. The common soil type on the crests and slopes are Sodosols with a hardsetting bleached sandy surface horizon over large hardsetting clay columns or prisms (solodised solonetz). There are scattered occurrences of Ferric Sodosols (soils with an ‘ironstone’ horizon below the bleached horizon and above the clay. The small rises are commonly divided by low lying flat clay plains which support Buloke. The vegetation is a reasonable indication of the soil type. Yellow Gums tend to occur with solodised solonetz forms; Red Gums with Ferric Sodosols and Bulokes on the heavier clay soils. When this soil type occurs further south, the hardsetting columns in the top of the subsoils are more acidic.

Soil Profile Morphology:

Surface Soil

A1	0-15 cm	Very dark greyish brown (10YR3/2) sandy loam; structureless; weak consistence when dry; structure increases to weak blocky structure (peds 20-50 mm) when roots penetrate; pH 6.3; sharp and wavy transition to:	Site WW12 profile
A2	15-20 cm	Pale brown (10YR6/3) loamy sand; conspicuously bleached; strong consistence when dry; occurs as capping on top of columnar structure; pH 6.7; sharp and wavy transition to:
Subsoil
B21	20-40 cm	Brown (7.5YR5/2) medium heavy clay; many very coarse distinct red mottles; strong columnar structure (peds >200 mm) parting to weak blocky structure (peds 50-100 mm); dispersive when worked; pH 7.5; gradual transition to:
B22	40-60 cm	Yellowish red (5YR5/8) medium heavy clay; moderate blocky structure (peds 20-50 mm); completely dispersive; pH 8.8:
B23	60-90 cm	Light yellowish brown (10YR6/4) medium clay; soft calcium carbonate segregations common; pH 9.4:
B24k	90-130 cm	Very pale brown (10YR7/3) light clay (sandy); moderate polyhedral structure (peds 10-20 mm parting to 5-10 mm); many soft calcium carbonate segregations and a few hard carbonate/silica nodules (5-15 mm in size); pH 9.5:
B25	130-170+ cm	Light grey (2.5Y7/2) medium clay; moderate to strong lenticular structure with some slickensides; smooth fabric, with sand along ped faces; pH 9.5.

Soil Profile Characteristics:

Horizon	pH	Salinity	Sodicity	Dispersion	Internal Drainage	Hydro-phobicity
Surface (A1 horizon)	slightly acid	low	non-sodic	-	-	moderate
Subsoil (B21 horizon)	slightly alkaline	low	sodic	slight¹	Imperfectly drained³	-
Deeper subsoil (at 1 metre)	very strongly alkaline	high	-	nil²	-	-

¹ Complete dispersion after remoulding.
² Possible due to high soluble salts (moderate dispersion after remoulding).
³ Most impeding horizon of the profile that will affect plant growth.

Key Profile Features:

Sandy surface soil.
Hydrophobic surface soil.
Shallow depth of surface soil.
Strong texture contrast between the surface soil and subsoil.
Thin hardsetting bleached capping (A2) forming domes on top of large columns.
Columnar subsoil structure.
Top of the subsoil is dispersive following cultivation when wet.
Sodic subsoil.
Subsoil mottling.
Alkaline subsoil.
Soil salinity at depth.
Vertic properties (ie. lenticular structure) in the deeper subsoil.

Soil Restrictions and Management Prescriptions:

Feature	Result	Management Prescription
Sandy surface soil.	Poor plant available water holding capacity. Poor nutrient holding capacity. Increased risk of wind erosion. Potential for hydrophobicity.	Dryland cropping. Minimum tillage and stubble retention, improve organic matter through maintenance of vegetative cover and growing green manure crops. Establish wind protection barriers.
Hydrophobic surface soil.	Poor infiltration of water into the soil. Increased risk of water erosion. Poor seed germination.	Maintenance of surface vegetative cover. Claying (application of subsoil clay from other areas directly to the soil surface).
Shallow surface soil depth.	Reduced water and nutrient holding capacity. Reduced root growth. Potential for waterlogging.	Improve organic matter through maintenance of vegetative cover and growing green manure crops. Reduce tillage to protect against water and wind erosion. Optimise plant growth through a regular and balanced fertiliser programme. Consider sub-surface drainage (if appropriate).
Bleached A2 horizon.	Indication of waterlogged condition (impeded internal drainage) within the surface soil. Poor soil structure (often massive). Low organic matter, water holding capacity and nutrition within the horizon.	Dryland cropping. Include deep rooted crops in the rotation, minimum tillage and stubble retention. Apply gypsum if the surface soil is responisive to gypsum. Optimise plant growth through a regular and balanced fertiliser program. Install subsoil drainage (if appropriate).
Strong textural contrast between surface soil and subsoil (duplex).	Strong texture and structure difference between the surface soil and the subsoil. Can result in impeded internal drainage and restricted root growth	Improve organic matter through maintenance of vegetative cover and growing green manure crops. Reduce tillage. Optimise plant growth through regular balanced fertiliser programme. Consider sub-surface drainage (if appropriate).
Sodic clay subsoil.	Poor water and air movement into the subsoil resulting in waterlogging (impeded internal drainage). Poor root growth into the subsoil reducing the volume of the soil able to be exploited. Very difficult to cultivate particularly if surface soil is shallow.	Gypsum applications if the subsoil is close to the surface and surface soil textures are light. Dryland cropping. Include deep rooted crops in the rotation, minimum tillage and stubble retention.
Columnar or prismatic subsoil structure.	Often indicates sodic clay subsoil.	These soil are difficult to manage, not suitable for high levels of production unless substantial modification can be achieved.
Mottled subsoil.	Indication of periodic waterlogging, particularly if grey and yellow mottles predominate.	Consider sub-surface drainage (if appropriate). Apply gypsum if subsoil is sodic and close to the surface.
Dispersion when reworked.	Indication of soil sodicity. Soil structure collapses following tillage and wetting, resulting in poor soil structure that reduces water movement and plant root growth. Increases water erosion hazard.	Don’t cultivate wet soil (cultivate when moist.) Apply gypsum if growing high value crops.
Alkaline subsoil.	Potential nutrient imbalance. Unsuitable for alkaline intolerant plants. May indicate subsoil sodicity.	Grow alkaline tolerant plants.
Soil salinity at depth.	Poor or no plant growth for deeper rooted species. Indication of waterlogging (impeded internal drainage) or high water table.	Increase plant water use throughout the catchment. Install subsoil drainage (if appropriate). Minimise irrigation water loss below the root zone (improve irrigation efficiency).

Land Suitability Rating Table:

LAND USE	SUITABILITY CLASS	MAJOR LIMITING COMPONENT
Wheat	2	Climate, soil
Canola	2	Climate, soil
Chickpeas	3	Soil
Lentils	3	Soil
White clover seed	2	Soil
Lucerne forseed production	3	Soil
Viticulture	3	Soil
Apples	3	Soil
Potatoes	3	Soil
Carrots	3	Soil
Onions	3	Soil
Sweet corn	3	Soil
Radiata Pine	3	Climate
Blue Gum	3	Climate

Land Suitability Assessment and Primary Limitations:

Wheat	Climate	2	Moderate frost risk, slightly high rainfall.
	Landscape	1	No major limitation.
	Soil	2	Slightly impeded internal drainage, hydrophobicity.
Canola	Climate	2	Moderate frost risk.
	Landscape	1	No major limitation.
	Soil	2	Soil salinity, hydrophobicity, slightly impeded internal drainage.
Chickpeas	Climate	2*	Moderate frost risk, moderate to high rainfall.
	Landscape	2	Wind erosion hazard.
	Soil	3	Impeded internal drainage.
Lentils	Climate	2	Moderate frost risk, slightly high rainfall.
	Landscape	2	Wind erosion hazard.
	Soil	3	Impeded internal drainage.
White clover seed	Climate	1	No major limitation.
	Landscape	1	No major limitation.
	Soil	2	Soil salinity, slightly impeded internal drainage, hydrophobicity.
Lucerne for seed production	Climate	1	No major limitation.
	Landscape	1	No major limitation.
	Soil	3	Soil salinity, impeded internal drainage.
Viticulture	Climate	2	Moderate frost risk.
	Landscape	1	No major limitation.
	Soil	3	Soil salinity, impeded internal drainage.
Apples	Climate	2	Moderate frost risk, slightly high mean maximum January temperature.
	Landscape	1	No major limitation.
	Soil	3	Soil salinity.
Potatoes	Climate	2	Slightly high mean maximum January temperature.
	Landscape	2	Wind erosion hazard.
	Soil	3	Shallow surface soil, impeded internal drainage.
Carrots	Climate	1	No major limitation.
	Landscape	2	Wind erosion hazard.
	Soil	3	Shallow surface soil, impeded internal drainage.
Onions	Climate	2	Moderate frost risk.
	Landscape	2	Wind erosion hazard
	Soil	3	Impeded internal drainage.
Sweet corn	Climate	2	Slightly low mean monthly temperature (October - March).
	Landscape	1	No major limitation.
	Soil	3	Impeded internal drainage.
Radiata Pine	Climate	3	Low rainfall.
	Landscape	1	No major limitations.
	Soil	2	Soil salinity, slightly impeded internal drainage.
Blue Gum	Climate	3	Low rainfall.
	Landscape	1	No major limitations.
	Soil	2	Soil salinity, slightly impeded internal drainage.

* Some areas may have high rainfall.

Profile Described By: Mark Imhof, Nathalie Baxter (08/01/97).

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