Soil/Landform Unit 37

Gently undulating plains graduating east into the gently undulating rises and long slopes

Area:

2205 ha

0.17% of CMA region

The basaltic plains and rises that occur in the Midlands of the Western Uplands are located south of Ballan and south-east of Skipton. These separate fragments are characterised by long gently undulating rises with Plains Grassy Woodlands and Plains Grassland as the major vegetation classes. The gently undulating rises coincide with the gently undulating plains of Unit

. The dissection has produced gentle rises that have been derived from weathering of

Pleistocene

basalt. Soils of the rises consists of texture contrast soils with areas of

gilgai microrelief

that are usually found to commonly be

mottled

black texture contrast soils with minor occurrences of other mottled texture contrast soils. The soils on the mounds and in the depressions are similar apart from those on the mounds having shallower surfaces. A few scattered surface stones may occur on the upper slopes and crests. Land use includes beef cattle and sheep grazing, water supply, softwood plantations and residential development around the smaller communities. Erosion hazards are minor including sheet and rill erosion on steeper slopes and gully erosion in depressions where

sodic

subsoils prevail. Areas with shallow stony gradational soils are susceptible to leaching of nutrients, and

compaction

is a problem on the flatter gilgaied areas.

Long gentle slopes of the basalt rises near Ballan
	Grazing by beef cattle is one of many land uses

Component	1	2	3	4	5
Proportion of soil-landform unit	90%	2%	2%	3%	3%
CLIMATE Rainfall (mm)	Annual: 690
Temperature (^oC)	Minimum 7, Maximum 18
Precipitation less than potential evapotranspiration	October-March
GEOLOGY Age and lithology	Pleistocene basalt
Geomorphology	2.1.4 Dissected Western Uplands associated with bolvanic landforms
LANDUSE	Uncleared: Nature conservation Cleared: Beef cattle and sheep grazing; water supply; cropping (cereal); softwood plantations; residential development
TOPOGRAPHY Landscape	Gently undulating plains with a scarp beside main creek including channel
Elevation range (m)	313-533
Local relief (m)	2 (on plains), 45 (at the scarp)
Drainage pattern	Dendritic
Drainage density (km/km²)	1.3
Landform	Depression			Scarp with local rock outcrop	Creek bed
Landform element	Long gentle upper slopes	Depression	Stony rise	Slope	Floodplain
Slope and range (%)	1 (1-3)	1 (1-2)	3 (2-5)	13 (7-25)	2 (0-3)
Slope shape	Straight	Straight	Convex	Convex	Straight
NATIVE VEGETATION Ecological Vegetation Class	Plains Grassy Woodland (0.5%), Plains Grassland (0.2%)
Dominant species	E. ovata, E. viminalis, E. rubida, E. obliqua			E. viminalis, E. ovata	E. viminalis, E. ovata
SOIL Parent material	In situ weathered basalt	Alluvium	In situ weathered basalt	In situ weathered basalt	Unconsolidated sedimentary and in situ weathered basalt
Description (Corangamite Soil Group)	Mottled brown, grey or yellow, grey sodic texture contrast soil, coarse structure (35)	Black cracking clay soil, coarse structure (31)	Red shallow, stony gradational soil (40)	Shallow brown texture contrast (37) or gradational soils (41)	Black clay soil, coarse strucutre (39)
Soil type sites	SW86, CLRA49, SW90	CLRA15, SW37, CLRA48	BD4, BD5, SW96	SFS5b, SW48, BD2	SW101, SW89, SFS2
Surface texture	Clay loam	Clay	Clay loam	Clay loam	Clay
Permeability	Moderate to low	Moderate	High	High	Low
Depth (m)	1.5	1.5	0.5	1	1.5
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Hardsetting surfaces and slowly permeable subsoils result in significant overland flow. Sheet and rill erosion also occur from this overland flow. Soil compaction is also a limitation for soils with shallow topsoils. Periodic waterlogging also occurs.	Clay soils beside creeks are prone to periodic waterlogging. Streambank undercutting and stream bank erosion common. Slowly permable subsoils are also quite sodic and prone to gully erosion.	Overland flow, nutrient leaching and decline all reflect highly permeable soils. Sheet erosion is common with excessive rainfall events.	Steep slopes and hardsetting surfaces result in significant overland flow. Sheet and rill erosion also occur from this overland flow.	Poorly drained site with a low permeability (waterlogging). Streambank erosion is possible with large rainfall events.

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