Croajingalong (Symbol: Cj)

EG245

Geology
Recent aeolian sediments.

Landform
Dunefield comprising of low dunes, swales (shallow broad depressions) and plains. This map unit is associated with coastal areas behind the foredunes and south of the lowlands of the Waygara map unit. . The map unit may be subdivided into low dunes, plains and broad depressions.


Low dunes east of Marlo typical of component 2

Original vegetation
Banksia woodland with areas of wet heathland. This includes areas of Coastal Sclerophyll Forest, Coastal Heath and Banksia species.

Soils
The soils are typically deep acidic sands generally with a layer of variably cemented sands (or ‘coffee rock’) at depth.

Component 1: Soils on the plains.
On the plains the surface soils are very dark grey to black acidic sands with high amounts of organic matter. Below are paler acidic sands which in turn overlay dark coloured cemented sands or coffee rock. Coffee rock is an accumulation of organic-aluminium and/or organic-sesquioxide complexes (iron and aluminium oxides) cemented sands and generally occurs before 1 m.

Component 2: Soils on the dunes.
The dune soils are similar but the surface soils are generally not as black and the coffee rock tends to be softer.

Component 3: Soil on the depressions.
Although not examined, the soils in the depressions are also likely to be black acidic sands with high amounts of organic matter in the surface and coffee rock in the subsoil.

Land use
Some of the area has been cleared for grazing and urban development, but most of the public land is part of the Croajingalong National Park.

Site EG245

Location: Marlo	Geo. Ref. 0638500E 5815600N
Australian Soil Classification: Melacic Humic/Humosequic, Semiaquic PODOSOL	Deep acidic black sand
General landscape description: Undulating rises
Geology: Recent aeolian sediments
Site description: Level
Land use: Residential subdivision (undeveloped)
Native vegetation: Banksia Woodland and Wet Heathland
Mapping unit: Croajingalong (Component 1)

Surface soil
A1	0 – 50 cm	Black (10YR2/1); loamy sand; clear change to:
A2	50 – 60 cm	Greyish brown (10YR5/2); loamy sand; abrupt change to:
Subsoil
Bhs	60 -65 cm	Dark brown (10YR3/3); cemented sand; clear change to
B2	65 – 80 cm	Yellowish brown mottled with light yellowish brown; clayey sand.

Horizon	Depth	EC	pH water	pH CaCl2	Exchangeable cations meq/100 g							Ca:Mg	ESP
	cm	dS/m			Ca	Mg	K	Na	Total	H	CEC
A1	0-20	<0.05	4.9	3.6	0.33	0.28	0.03	0.28	0.92	1.3	2.0	1.2	14
B2	65-80	0.08	5.8	4.7	0.48	0.58	0.05	0.58	1.69	0.99	3.3	0.8	18

• The surface soil is strongly acid and a response to lime would be expected.
• The surface soil has a very low inherent fertility (based on the sum of the exchangeable basic cations). Such strongly leached soils are also likely to be naturally deficient in nitrogen, phosphorus, sulphur and potassium.