Soil/Landform Unit 167

Plains north of Peterborough in the extreme south-west of the Corangamite catchment

Area:

1482 ha

0.11% of CMA region

East of Warrnambool near Mepunga are extensive sand sheets with underlying Neogene sediments including Port Campbell Limestone and Gellibrand Marl. This area is characterised by an undulating terrain that has numerous blow-outs and depressions that have developed in the limestone. As part of the Western Plains, this unit is situated on the south-western margin of the Curdies River and continues well into the Glenelg-Hopkins catchment. Soils typically comprise sandy yellow and brown texture contrast soils (Podosols and Kurosols) associated with the sands, and black texture contrast soils (Kurosols) of the limestone. Native vegetation on these plains is mainly composed of Coastal Headland Scrub, Herb-rich Foothill Forest and Damp Heathland/Damp Heathy Woodland Mosaic. Land use is mainly grazing for beef and dairy cattle with some cropping. Residential development along the south-west coast is also prominent. The main hazards to land use are loss of soil structure by compaction and leaching of nutrients.

Undulating plains and rises with sand overlying limeston

Component	1	2
Proportion of soil-landform unit	97%	3%
CLIMATE Rainfall (mm)	Annual: 850
Temperature (^oC)	Minimum 10, Maximum 19
Precipitation less than potential evapotranspiration	October-March
GEOLOGY Age and lithology	Neogene marine and calcarenite
Geomorphology	6.2.3 Karst plains, rises and low hills with depressions of the Sedimentary Western Plains
LANDUSE	Uncleared areas: Hardwood forestry for sawlogs, posts and poles; water supply; nature conservation Cleared areas: Dairy farming; sheep and beef cattle grazing; residential development
TOPOGRAPHY Landscape	Undulating plain
Elevation range (m)	2-53
Local relief (m)	3-5
Drainage pattern	Dendritic
Drainage density (km/km²)	0.9
Landform	Undulating sand sheets	Depressions
Landform element	Plains	Blow out
Slope and range (%)	3 (1-7)	3 (1-8)
Slope shape	Straight	Concave
NATIVE VEGETATION Ecological Vegetation Class	Coastal Headland Scrub (606%); Herb-rich Foothill Forest (4.9%); Damp Healthland / Damp Heathy Woodland Mosaic (2.1%)
SOIL Parent material	Aeolian sediments over limestone	Limestone
Description (Corangamite Soil Group)	Sandy mottled brown, grey or yellow texture contrast soils (8)	Black texture contrast soils (23)
Soil type sites	CLRA5, OTR608, OTR740	CLRA9, CLRA8, MM331
Surface texture	Loamy sand	Fine sandy loam
Permeability	High to very high	High to moderate
Depth (m)	>2	<2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Uniform sands or deep sand over clay, very low water holding capacity and nutrient holding capacity in sandy soil, high in clays. Poor structured ins andy soil component, susceptible to nutrient decline. Moderate site drainage. Some susceptibility to wind and sheet erosion.	Texture contrst, moderate water holding capacity and high nutrient holding capacity in upper soil, higher in subsoils. Strong structure. Moderate to low site drainage. Some susceptibility to wind and sheet erosion.

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