Soil/Landform Unit 157

The undulating rises south-east of Cobden provide deep soils with high rainfall that support a variety of land uses

Area:

1192 ha

0.09% of CMA region

This grouping of very small dissected remnant cappings occurs within the Western Plains of the Corangamite region. Located south of Cobden and east of Jancourt, the gently undulating rises are derived from Neogene non-

calcareous

sediments (sands) over Neogene limestone and marl. The surrounding streams and tributraries of the Curdies River are relatively steep and prone to some mass movement. The unit is comprised of broad low crests, gently undulating slopes and plains, with only limited remnant native vegetation (less than 1% Plains Grassy Woodland). Soils of these landform elements include alkaline and neutral (

sodic

)

mottled

brown, grey and yellow texture contrast soils (

Kurosols

Chromosols

). Susceptibility to waterlogging occurs in the depressions but site drainage is moderately rapid elsewhere on the plains and crests. Given the higher rainfall of the area, the susceptibility to nutrient decline is moderate to high, particularly where surface soils are light. Slight susceptibility to sheet erosion occurs on the slopes. Land use is mainly intensive grazing (dairying) with some associated cropping.

Undulating rise cappings of sedimentary and volcanic geological source
	Residual cappings of the undulating rises near Cobden are mainly used for dairying

Component	1	2	3
Proportion of soil-landform unit	25%	60%	15%
CLIMATE Rainfall (mm)	Annual: 790
Temperature (^oC)	Minimum 9, Maximum 19
Precipitation less than potential evapotranspiration	October-March
GEOLOGY Age and lithology	Quaternary basalt and scoria, Neogene fluvial-marine clay, sand and gravel
Geomorphology	6.2.2 Dissected sedimentary plains, rises and low hills of the Western Plains
LANDUSE	Uncleared areas: Hardwood forestry for sawlogs, posts and poles; softwood plantations; water supply; nature conservation Cleared areas: Dairy farming; sheep and beef cattle grazing; softwood plantations; water supply
TOPOGRAPHY Landscape	Gently undulating plains
Elevation range (m)	67-165
Local relief (m)	15
Drainage pattern	Parallel
Drainage density (km/km²)	0.6
Landform	Rises		Undulating plains
Landform element	Broad low crest	Slopes	Plain
Slope and range (%)	2 (1-4)	4 (3-10)	1 (0-3)
Slope shape	Convex	Convex	Straight
NATIVE VEGETATION Ecological Vegetation Class	Plains Grassy Woodland (0.8%)
SOIL Parent material	Clay, silt, sand and marl	Clay, silt, sand and marl	Clay, silt and sand
Description (Corangamite Soil Group)	Alkaline, neutral and acidic, brown, grey or yellow mottled texture contrast soils (23)	Alkaline, neutral and acidic, brown, grey or yellow mottled texture contrast soils (23)	Alkaline, neutral and acidic, brown, grey or yellow mottled texture contrast soils (23)
Soil type sites	CLRA8, CLRA9, MM231	CLRA8, CLRA9, MM231	CLRA8, CLRA9, MM231
Surface texture	Clay loam, fine sandy loam	Clay loam	Fine sandy loam
Permeability	Moderate	Moderate to low	Low
Depth (m)	<2	<2	<2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Large or moderate texture contrast with low to moderate nutrient holding capacity and water holding capacity in subsurface and surface soil, higher in subsoil. Heavy, possibly expansive clay subsoil. Moderately rapid site drainage.	Moderate texture contrast with low to moderate nutrient holding capacity and water holding capacity in subsurface and surface soil, higher in subsoil. Heavy, possibly expansive clay subsoil. Moderately rapid site drainage.	Large texture contrast with low nutrient holding capacity and water holding capacity in subsurface and surface soil, higher in subsoil. Heavy, possibly expansive clay subsoil. Slow site drainage, higher susceptibility to waterlogging and compaction.

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