Soil/Landform Unit 162

The cleared land denotes the undulating crests and slopes of this unit while the vegetation marks the steeply dissected rivers and streams around Timboon

Area:

13 450 ha

1.01% of CMA region

The undulating low hills in the Timboon West area are characterised by broad crests and slopes that abruptly change to scarps and steep slopes lining the streams and rivers of the lower Heytesbury area. The sedimentary dissected plains are a prominent and unique landform of the Western Plains. The area is generally formed on Neogene marl and limestone where dissection of later deposited Neogene sandy sediments has exposed the underlying sedimentary strata of marl and limestone. Soils of the low hills are typically acidic friable brown gradational soils (Dermosols). These soils are free draining but have low nutrient levels in the topsoil from leaching due to the higher rainfall of this area. Sandy cappings are also common with uniform sands (Podosols). Remnant vegetation includes stringybarks, peppermints and heathy vegetation as part of the vegetation classes Lowland Forest, Damp Heath Scrub and Herb-rich Foothill Forest. This unit is quite fragmented and dissected by streams and rivers. Land use is mainly grazing, generally for dairying, with some minor associated cropping. Some mass movement may occur at geological boundaries (capping material over marl or limestone), with sandy material moved downslope.

Many of the undulating plains and cappings have thin veneers of sands of the Hanson Plain Sand
	Remnant vegetation stand near Timboon

Component	1	2	3	4
Proportion of soil-landform unit	20%	35%	40%	5%
CLIMATE Rainfall (mm)	Annual: 900
Temperature (^oC)	Minimum 10, Maximum 18
Precipitation less than potential evapotranspiration	November-March
GEOLOGY Age and lithology	Neogene fluvial-marine marl, silt, gravel and limestone
Geomorphology	6.2.2 Dissected plains, rises and low hills of the Sedimentary 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	Undulating low hills
Elevation range (m)	5-156
Local relief (m)	40
Drainage pattern	Dendritic
Drainage density (km/km²)	0.8
Landform	Hills			Drainage lines
Landform element	Broad crests	Upper slope	Lower slope
Slope and range (%)	4 (1-7)	12 (5-25)	5 (2-10)	0 (0-1)
Slope shape	Convex	Convex	Concave	Linear
NATIVE VEGETATION Ecological Vegetation Class	Lowand Forest (4.2%), Damp Heath Scrub (2.7%), Herb-rich Foothill Forest (1.5%)
SOIL Parent material	Unconsolidated sand, limestone	Unconsolidated sand, limestone	Unconsolidated sand, limestone	Unconsolidated sand, limestone
Description (Corangamite Soil Group)	Acidic, friable brown gradational soils (22)	Acidic, friable brown gradational soils (22)	Acidic, friable brown gradational soils (22)	Acidic, friable black and brown gradational soils (34)
Soil type sites	CLRA10, SW52, OTR413	CLRA10, SW52, OTR413	CLRA10, SW52, OTR413	SW39, CLRA15, CLRA1
Surface texture	Clay loam, sandy clay loam	Clay loam	Clay loam	Clay loam
Permeability	Moderate to high	Moderate to high	Moderate	Moderate
Depth (m)	<2	<2	>2	>2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Friable, generally modeately deep to deep soils. Often strongly acidic, moderate nutrient holding capacity. Moderately weel to poorly drained drainage. Varialbe surface soil sand content, but high organic matter.	Friable, generally moderately deep to deep soils. Often strongly acidic, moderate nutrient holding capacity. Moderately well to poorly drained drainage. Variable surface soil sand content, but high organic matter.	Friable, generally deep to very deep soils. Often strongly acidic, moderate nutrient holding capacity. Moderately well to poorly drained drainage. Variable surface soil and content, but high organic matter.	Friable, generaly deep to very deep soils. Often strongly acidic, moderate nutrient holding capacity. Poor site drainage. Variable surface soil sand content, but high organic matter.

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