Soil/Landform Unit 123

The gently undulating plains with soils derived from ash deposits are used extensively for cropping

Area:

2817 ha

0.21% of CMA region

Gently undulating plains in the Alvie area are derived layers of volcanic ash deposited during volcanic eruptions of the

Quaternary

period. These ash derived volcanic landforms of the Western Plains are characterised by undulating plains and rises with occasional depressions. The ash deposits support the remnant vegetation class Stony Rises Herb-rich Woodland which is unique to this area of Victoria. The relatively young landscape has shallow to moderately deep neutral black gradational soils with minor alkaline

friable

loams and red gradational soils. As the major parent material of these soils, the ash deposits are generally friable and highly productive (due to high fertility). Rainfall decreases from south to north, influencing grazing intensity for dairying or beef/sheep production and cropping. The land acts as a footslope to the volcanic low hill complex of Unit

101

. Erosion hazards are minor, with waterlogging and sheet and rill erosion the major concerns. Soils are susceptible to

leaching

of nutrients, and

compaction

is a problem on the lower slopes and depressions.

Gentle plains near Coragulac
	Irrigated plains between Alvie and Lake Corangamite

Component	1	2	3
Proportion of soil-landform unit	70%	25%	5%
CLIMATE Rainfall (mm)	Annual: 670
Temperature (^oC)	Minimum 8, Maximum 19
Precipitation less than potential evapotranspiration	October-March
GEOLOGY Age and lithology	Quaternary scoria and basalt
Geomorphology	6.1.3 Volcanic Western Plains with poorly developed drainage
LANDUSE	Uncleared areas: Nature conservation Cleared aras: Sheep and beef cattle grazing; cropping (cereal)
TOPOGRAPHY Landscape	Gently undulating plains
Elevation range (m)	117-185
Local relief (m)	60
Drainage pattern	Radial
Drainage density (km/km²)	<0.1
Landform	Plains with minor rises
Landform element	Undulating plains	Low rises	Depressions
Slope and range (%)	2 (0-5)	4 (2-8)	1 (0-2)
Slope shape	Straight	Convex	Concave
NATIVE VEGETATION Ecological Vegetation Class	Stony Rises Herb-rich Woodland (1.2%)
SOIL Parent material	Basaltic ash	Basaltic ash	Basaltic ash, colluvium and alluvium
Description (Corangamite Soil Group)	Neutral black gradational soils, alkaline friable loams and neutral red gradational soils (40) and black texture contrast soils (37)	Neutral black gradational soils, alkaline friable loams and neutral red gradational soils (40) and black texture contrast soils (37)	Neutral black gradational soils, alkaline friable loams and neutral red gradational soils (4) and black texture contrast soils (37)
Soil type sites	SW8, SW26, SW25	SW8, SW26, SW25	SW8, SW26, SW25
Surface texture	Clay loam	Clay loam	Clay loam to light clay
Permeability	Moderate	High	Low to moderate
Depth (m)	<1.5	<1	<2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Friable structured soil. Soil depth may be moderately deep with limited water holding capacity. Generally well drained and high nutrient holding capacity. Upper soil may be acidic.	Friable structured soil. Soil depth may be moderately deep with limited water holding capacity. Generally well drained and high nutrient holding capacity. Upper soil may be acidic.	Friable structured soil. Soil depth may be moderately deep with limited water holding capacity. Moderately well to imperfectly drained and high nutrient holding capacity. Upper soil may be acidic. May be subject to waterlogging and compaction.

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