Soil/Landform Unit 174

The gently undulating plains are mainly used for cropping and grazing (note the discoloured dam waters indicating dispersible soils)

Area:

3779 ha

0.28% of CMA Region

This unit is characterised by gently undulating plains that have primarily developed on Neogene and

Quaternary

sediments. With the few occurrences of this unit centred on Inverleigh in the Western Plains, south flowing streams such as the Leigh River have dissected this unit. This is a complex unit with many components grouped into undulating plains, upper and lower terraces and a variable terrain component. This is a drier part of the Corangamite catchment that supports the vegetation class Plains Grassy Woodland. The soils are dominantly (light) brown

mottled

texture contrast soils that are often

sodic

, with a large clay difference between the light surface soil and the heavy subsoil. Limited

organic

matter and structure in the surface will increase sheet erosion susceptibility, which will also be dependent on slope. Land use is generally grazing with some cropping.

Stubble from cropping of the gentle plains
	Remnant Eucalyptus camaldulensis and other eucalypt species on the cleared cropping country near Inverleigh

Component	1	2	3	4	5	6	7	8
Proportion of soil-landform unit	13%	2%	37%	6%	18%	5%	3%	16%
CLIMATE Rainfall (mm)	Annual: 550
Temperature (^oC)	Minimum 9, Maximum 19
Precipitation less than potential evapotranspiration	October–April
GEOLOGY Age and lithology	Quaternary basalt	Neogene and older Quaternary unconsolidated clay and sand				Quaternary alluvium
Geomorphology	6.2.4 Plains, rises and low hills of the Sedimentary Western Plains
LANDUSE	Uncleared: Nature conservation Cleared: Beef cattle and sheep grazing; occasional cropping (cereal)
TOPOGRAPHY Landscape	Complex pattern of gently undulating plains
Elevation range (m)	50–120
Local relief (m)	3
Drainage pattern	Dendritic
Drainage density (km/km²)	1.2
Landform	Upper undulating plains					Upper terraces	Lower terrace and associated billabongs/swamps	Sandy ridges, scarps and hummocks
Landform element	Long gentle upper slopes	Crests	Upper plain	Lower plain	Mid and lower slopes	Higher terraces	Lower terraces	Upper slope
Slope and range (%)	2 (1–3)	1 (0–3)	3 (2–5)	2 (1–5)	2 (1–5)	2 (0–3)	1 (0–2)	5 (2–15)
Slope shape	Straight	Convex	Straight	Straight	Straight	Straight	Straight	Convex
NATIVE VEGETATION Ecological Vegetation Class	Plains Grassy Woodland (7.2%)
Dominant species	E. ovata, E viminalis, E. rubida, E. obliqua	E. leucoxylon	E. leucoxylon, Acacia pycnantha, E. melliodora, Casurina stricta, E. viminalis	E. leucoxylon, Acacia spp.	E. leucoxylon	E. leucoxylon, E. camaldulensis	E. camaldulensis	E. camaldulensis
SOIL Parent material	In situ weathered basalt	Ferricrete and ferruginous sandy gravels	Unconsolidated clay, silt, sand and gravel	Unconsolidated clay, silt, sand and gravel	Unconsolidated older alluvium - clay, sand and gravel	Unconsolidated gravel, sand, silt and clay	Unconsolidated gravel, sand, silt and clay	Unconsolidated sediments
Description (Corangamite Soil Group)	Mottled brown, yellow or grey sodic texture contrast soil, coarse structure (14)	Gravelly red mottled brown, grey or yellow texture contrast soils, fine structure (15)	Mottled yellow and red texture contrast soils, both fine structured (13)	Mottled brown, grey or yellow sodic soils, coarse structure (14)	Mottled brown, grey or yellow texture contrast soils with red medium to coarse structured texture contrast soils (14)	Red duplex soils, some dark texture contrast soils (13)	Dark uniform loams (34)	Brown sand soils (34)
Soil type sites	SW99, SW93, MM204	MM5109, SW63, MM5308	SW67, SW42, CLRA3	SW99, SW93, MM204	SW99, SW93, MM204	SW67, SW42, CLRA3	CLRA1, SW39, SW56	SW39, SW56
Surface texture	Clay loam	Fine sandy loam	Fine sandy loam	Sandy loam	Fine sandy loam	Loamy sand and sandy loam	Loam to clay loam	Loamy sand
Permeability	Moderate to low	Moderate	Moderate	Low	Moderate	Moderate	High	High
Depth (m)	1.5	0.3–0.9	1.0–2.0	2	0.8–1.5	0.5–1.0	0.2–0.8	0.7–1.5
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Hardsetting surfaces, slowly permeable subsoils and overland flow lead to periodic waterlogging and soil compaction.	Limited permeability, overland flow, minor sheet erosion on exposed soil.	Hardsetting surfaces, overland flow, minor sheet erosion.	Dispersible, overland flow, sub-surface flow, moderate gully erosion.	Limited permeability, overland flow, minor sheet erosion on exposed soil.	Limited permeability, overland flow, minor sheet erosion on exposed soil.	Low situation affected by flooding from river, overland flow, periodic waterlogging and siltation.	Nutrient holding capacity and leaching lead to nutrient decline.

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