Soil/Landform Unit 70

Barrabool Hills in the distance are pronounced as a dominant relief pattern over the neighbouring sedimentary and volcanic plains west of Geelong

Area:

9154 ha

0.69% of CMA region

Rolling hills with fertile soils to the west of Geelong lie mainly to the north of the present study area, but a small section forms the northern part of the catchment of Thompson Creek. These hills are on Lower

Cretaceous

sandstones and mudstones similar to those outcropping extensively in the Otway Range, but the landscape is more subdued and the rainfall is significantly lower. The original structure and species composition of the native vegetation are difficult to determine. The area has been extensively cleared for cropping and grazing and subdivided into somewhat smaller paddocks than the less fertile areas to the south. From the presence of isolated trees,

Eucalyptus globulus

and

E. cypellocarpa

formed part of the original vegetative community, and it is probable that

E. radiata

was also common.

Hillslopes and valley floors are used mainly for cropping
	Extensively cleared rolling hills with windbreaks of radiata pine and cypress pine

Component	1	2	3	4	5
Proportion of soil-landform unit	5%	35%	30%	15%	15%
CLIMATE Rainfall (mm)	Annual: 630
Temperature (^oC)	Minimum 9, Maximum 19
Precipitation less than potential evapotranspiration	October-April
GEOLOGY Age and lithology	Cretaceous fluvio-volcanic deposits, Paleogene and Neogene marine clay and silt, minor Quaternary basalt and alluvium
Geomorphology	3.2.2 Dissected upland ranges of the Southern Uplands
LANDUSE	Uncleared: Nature conservation (including grassy woodland, floodplain riparian woodland and streambank shrubland) Cleared: Broadacre cropping (including cereals and pulses); sheep and cattle grazing
TOPOGRAPHY Landscape	Rolling hills
Elevation range (m)	9-212
Local relief (m)	150
Drainage pattern	Dendritic
Drainage density (km/km²)	2.0
Landform	Hills				Drainage line and valley floor
Landform element	Gentle crests	Undulating rises	Rolling hills	Dissected mid slopes	Drainage line/stream channel
Slope and range (%)	4 (1-7)	8 (3-15)	12 (5-25)	10 (5-20)	4 (2-9)
Slope shape	Convex	Straight	Convex	Concave	Concave
NATIVE VEGETATION Structure	Woodland	Open forest	Open forest	Open forest	Open forest
Dominant species	E. ovata, E. viminalis	E. globulus, E. cypellocarpa	E. globulus, E. cypellocarpa	E. globulus, E. cypellocarpa	E. globulus, E. cypellocarpa
SOIL Parent material	Sandstone and mudstone	Sandstone and mudstone and colluvium	Sandstone and mudstone and colluvium	Sandstone and mudstone and colluvium	Sandstone and mudstone derived colluvium and alluvium
Description (Corangamite Soil Group)	Alkaline and neutral mottled brown mottled grey or yellow (5/6) and black texture contrast soils (5)	Alkaline mottled brown and black texture contrast soils (5)	Alkaline mottled brown and black texture contrast soils (5)	Alkaline mottled brown and black texture contrast soils (5)	Alkaline mottled brown and black texture contrast soils (5/6)
Soil type sites	MM5050, SW71, OTR424	MM5050, MM5078	MM5050, MM5078, CLRA40	MM5050, MM5078	MM5078, OTR735, SW71
Surface texture	Fine sandy loam, clay loam	Fine sandy loam, clay loam	Fine sandy loam, clay loam	Fine sandy loam, clay loam	Fine sandy loam, clay loam
Permeability	Moderate	Moderate	Moderate to low	Low	Low
Depth (m)	<1.5	<2	<2	<2	>2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Texture contrast, low water holding capacity and nutrient holding capacity in surface soil, possible sheet and rill erosion. Often sodic clay subsoil, hardsetting when dry. Moderately rapdi site drainage and better soil drainage.	Texture contrast, low water holding capacity and nutrient holding capacity in surface soil, possible sheet and rill erosion. Sodic clay subsoil, hardsetting when dry. Moderately rapid site drainage.	Texture contrast, low water holding capacity and nutrient holding capacity in surface soil, possible sheet and rill erosion. Sodic clay subsoil, hardsetting when dry. Rapid site drainage	Texture contrast, low water holding capacity and nutrient holding capacity in surface soil, possible sheet and rill erosion with slope. Sodic clay subsoil, hardsetting when dry.	Texture contrast, low to moderate water holding capacity and nutrient holding capacity in surface soil. Sodic clay subsoil, hardsetting when dry. Moderate to poor site drainage.

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