Soil/Landform Unit 133

The undulating rises are mainly used for sheep and cattle grazing, with some cropping on the more gentle slopes

Area:

15 275 ha

1.14% of CMA region

This unit of gently undulating basalt plains is a member of the volcanic plains with well developed drainage and

. As part of the Western Plains, this single unit lies on an east/west axis from Winchelsea to Barwon Heads and is bound by units of the Southern Uplands and eruption points, with the Barrabool Hills and Mount Duneed to the north. Unit components include undulating rises, plains and depressions. The soils are strongly

sodic

black, grey and brown texture contrast soils (

Sodosols

) and some cracking clays (

Vertosols

) in the depressions. Site drainage is dependent on landform and adjacent landform, with greater susceptibility to waterlogging occurring on the flatter lower terrain. Soil sodicity and structure decline are also concerns. Rainfall is moderate, with land use being dominated by grazing (mainly cattle, some sheep) and cropping where drier.

Looking over the gently undulating plains and rises from Mount Duneed
	Basalt stone extracted from a dam site is relatively shallow beneath soils of variable structure

Component	1	2	3	4	5
Proportion of soil-landform unit	30%	10%	40%	15%	5%
CLIMATE Rainfall (mm)	Annual: 620
Temperature (^oC)	Minimum 10, Maximum 19
Precipitation less than potential evapotranspiration	October-March
GEOLOGY Age and lithology	Quaternary basalt, Neogene fluvial-marine sediments and alluvium
Geomorphology	6.1.4 Volcanic Western Plains with well developed drainage
LANDUSE	Uncleared: Nature conservation; passive and active recreation; water supply Cleared: Sheep and beef cattle grazing; cropping (cereal); residential development
TOPOGRAPHY Landscape	Gently undulating basalt rises
Elevation range (m)	7-171
Local relief (m)	20
Drainage pattern	Dendritic
Drainage density (km/km²)	1.1
Landform	Plains	Undulating rises		Valley flats and swamps	Lunettes
Landform element	Level plains	Upper slopes and crest	Middle and lower slopes
Slope and range (%)	1 (0-2)	3 (1-7)	3 (0-6)	1 (0-1)	3 (0-5)
Slope shape	Linear	Convex	Linear	Linear	Convex
NATIVE VEGETATION Ecological Vegetation Class	Plains Grassland (0.4%), Plains Grassy Woodland (0.4%)
SOIL Parent material	In situ basalt and colluvium	In situ basalt	In situ basalt and colluvium	Basaltic colluvium and alluvium; sand, silt and clay	Aeolian clay, silt and sand
Description (Corangamite Soil Group)	Neutral and alkaline mottled brown, grey or yellow texture contrast soils (36/35)	Neutral and alkaline mottled brown, grey or yellow and alkaline brown texture conrast soils (37/36)	Neutral and alkaline mottled grown, grey or yellow texture contrast soils (36/35)	Neutral and alkaline mottled brown, grey or yellow texture contrat soils (36) and black cracking clays (39)	Neutral and alkaline mottled brown, grey or yellow texture contrast soils (10)
Soil type sites	SFS6, MM5015, SW86	MM5102	SFS6, MM5015, SW86	SFS6, MM5015, SW86	SFS3, CLRA5
Surface texture	Sandy clay loam	Fine sandy loam	Sandy clay loam	Fine sandy clay loam	Fine sandy clay loam
Permeability	Low	Moderate	Low to moderate	Very low	Moderate to high
Depth (m)	<2	<1.5	<2	>2	>2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Strong texture contrast with vriability in permeability, water holding capacity and nutrient holding capacity. Subsoil strongly sodic, surface possibly sodic and hardsetting. Expansive clay subsoil. Poor site drainage.	Strong texture contrast soils with variablility in permeability, water holding capacity and nutrient holding capacity. Subsoil sodic, surface possible sodic and hardsetting. Expansive clay subsoil. Moderate site drainage and permeability.	Strong texture contrast soils with variablility in permeability, water holding capacity and nutrient holding capacity. Subsoil strongly sodic, surface possibly sodic and hardsetting. Expansive clay subsoil. Moderate to low site drainage.	Strong texture contrast woils with variability in permeability, water holding capacity and nutrient holding capacity. Subsoil strongly sodic, surface possible sodic and hardsetting. Expansive clay soil or subsoil. Very poor site drainage.	Strong texture contrast soils with variability in permeability, water holding capcity and nutrient holding capacity. Subsoil strongly sodic, surface possibly sodic and hardsetting or friable. Expansive clay subsoil. Moderate to high site drainage.

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