Soil/Landform Unit 13

Gently undulating plains north of Gordon have hardsetting surfaces and low permeabilities that lead to overland flow and waterlogging. Recent softwood planting have occurred on these texture contrast soils

Area:

2109 ha

0.16% of CMA region

The gently undulating plains north of Gordon are derived from sedimentary sources including

Quaternary

fluvial

and volcaniclastic sediments, Neogene marine sands and

Ordovician

marine shale and sandstone. Crop yields and pasture production have been limited due to the

hardsetting

nature of the soils and poor permeability aiding waterlogging. Recent softwood plantations beside the Western Highway have been able to benefit from these deep soils. Vegetation comprises Plains Grassy Woodland, Creekline Herb-rich Woodland and Herb-rich Foothill Forest. These stands of vegetation are significant reserves across the Western Uplands. The gentle plains consist of neutral mottled texture contrast soils with minor occurrences of acidic equivalents. Red

mottled

texture contrast soils are located in areas of better drainage (slightly elevated). Waterlogging, soil

compaction

and erosion are limiting factors of these soils that require careful monitoring in land management.

Near level plains looking towards the Western Highway north of Gordon. Waterlogging of these soils is common in wet.
	Land management of these soils is often reflected in ground cover. Ground coverage is vital to avoid degradation of these soils

Component	1	2	3	4	5	6
Proportion of soil-landform unit	36%	23%	17%	16%	4%	4%
CLIMATE Rainfall (mm)	Annual: 790
Temperature (^oC)	Minimum 7, Maximum 17
Precipitation less than potential evapotranspiration	November-March
GEOLOGY Age and lithology	Quaternary fluvial sediments and basalt, Neogene marine sand			Ordovician marine shale and sandstone
Geomorphology	2.1.1 Dissected Western Uplands associated with Palaeozoic sedimentary and metamorphic rocks
LANDUSE	Uncleared: Nature conservation; water supply Cleared: Sheep and beef cattle grazing; cropping (cereal); softwood plantations
TOPOGRAPHY Landscape	Gently undulating plains
Elevation range (m)	499-583
Local relief (m)	3
Drainage pattern	Dendritic
Drainage density (km/km²)	2.9
Landform	Undulating plain	Drainage depression and terraces	Slightly dissected plains	Rolling plain	Hill
Landform element	Well-drained non-sandy areas		Long gentle upper slopes	Long gentle slope	Dry exposed slopes	Crest
Slope and range (%)	2 (1-3)	1 (1-2)	1 (1-3)	5 (3-9)	15 (10-30)	3 (1-6)
Slope shape	Convex	Straight	Straight	Straight	Straight	Convex
NATIVE VEGETATION Ecological Vegetation Class	Plains Grassy Woodland (3.1%); Creekline Herb-rich Woodland (2.2%)			Herb-rich Foothill Forest (2.3%)
Dominant species		E. viminalis, E. radiata	E. ovata, E. viminalis, E. rubida, E. obliqua	E. obliqua, E. viminalis	E. obliqua, E. dives, E. radiata, E. viminalis	E. obliqua, E. dives, E. radiata, E. viminalis
SOIL Parent material	Unconsolidated gravel, sand and clay	Unconsolidated gravel, sand, silt and clay	In situ weathered rock	In situ weathered rock	In situ weathered rock	In situ weathered rock
Description (Corangamite Soil Group)	Red mottled, brown, grey or yellow texture contrast soil, fine structure (13)	Dark brown soil - variable (17)	Mottled brown, grey or yellow sodic texture contrast soil, coarse structure (14)	Red mottled brown, grey or yellow texture contrast soil (13)	Red mottled brown, grey or yellow gradational or texture contrast soils, fine structure (26)	Shallow stony red and brown grey or yellow gradational soil (25)
Soil type sites	CLRA3, MM358, MM363	OTR741, SW5, SW37	MM5006, SW99, OTR734	SW67, CLRA3, OTR601	BD13, BD11, MM204	CLRA53, CLRA57, BD10
Surface texture	Sandy clay loam to loamy sand	Fine sandy clay loam	Clay loam	Loamy clay	Fine sandy loam	Gravelly loam
Permeability	Moderate	Moderate to low	Moderate to low	Moderate to low	High	High
Depth (m)	2	3	1.5	1	2	0.5
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Hardsetting surfaces, dispersible subsoils and permeability results in leaching of salts and salt expression at the surface. Overland flow and sheet and rill erosion reflect these hardsetting surfaces.	Low-lying areas are prone to seasonal waterlogging and discharge as salinity. Overland flow and sheet and rill erosion reflect these hardsetting surfaces.	Hardsetting surfaces, dispersible subsoils, and permeability results in leaching of salts and salt expression at the surface. Overland flow and sheet and rill erosion reflect these hardsetting surfaces.	Hardsetting surfaces, dispersible suboils, and permeability results in leaching of salts and salt expression at the surface. Overland flow and sheet and rill erosion reflect these hardsetting surfaces.	Steep slopes are often responsible for overland flow and sheet and rill erosion. These also reflect the hardsetting surfaces. Soil compaction can benefit from addition of organic matter.	Steep slopes are often responsible for overland flow and sheet and rill erison. These also reflect the hardsetting surfaces. Soil compaction can benefit from addition of organic matter.

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