Soil/Landform Unit 25

Landform Unit Description

Gentle plains neighbouring the steeply dissected Moorabool River east branch north of Morrisons

Area:

265 ha

0.02% of CMA region

The gently undulating plains in the Myrniong and Morrisons area are derived from

Quaternary

volcanics. Vegetation classes include Plains Grassy Woodland and Plains Grassland.

Eucalyptus ovata

is prevalent over much of the low relief landscape elements where soils are poorly drained. The weathered basalt has reasonable inherent fertility levels and a moderate water holding capacity. Soils include acidic and neutral

mottled

black texture contrast soils. There are minor occurrences of

acidic

mottled brown, grey or yellow and mottled brown texture contrast soils, and neutral shallow grey clays with a few surface stones. There are areas of extensive

gilgai microrelief

where the soils are acidic mottled black or neutral mottled brown, grey or yellow texture contrast soils. Sheet and rill erosion is associated with major rainfall events while gully erosion and leaching of salts also occur lower in the topography.

The main land use of these plains is grazing for fat lamb production

Component	1	2	3	4
Proportion of soil-landform unit	70%	2%	15%	13%
CLIMATE Rainfall (mm)	Annual: 670
Temperature (^oC)	Minimum 7, Maximum 18
Precipitation less than potential evapotranspiration	October-March
GEOLOGY Age and lithology	Ordovician marine shale and sandstone, Neogene fluvio-marine sand, minor clay, sand and gravel
Geomorphology	2.1.3 Dissected Western Uplands associated with Cainozoic gravel and sediments
LANDUSE	Uncleared: Nature conservation, water supply Cleared: Sheep and beef cattle grazing; cropping (cereal)
TOPOGRAPHY Landscape	Gently undulating plains
Elevation range (m)	323-375
Local relief (m)	3
Drainage pattern	Dendritic
Drainage density (km/km²)	1.4
Landform	Undulating plain		Flat plain	Drainage lines
Landform element	Well drained non-sandy areas	Patches of deep sandy soil	Poorly drained non-sandy areas	Low lying areas
Slope and range (%)	2 (1-3)	2 (1-3)	0 (-02)	1 (1-3)
Slope shape	Convex	Convex	Flat	Concave
NATIVE VEGETATION Ecological Vegetation Class	Plains Grassy Woodland (2.6%), Plains Grassland (0.8%)
Dominant species	Callitris columellaris, E. viminalis, E. obliqua, E. radiata, E. rubida, E. pauciflora	Pteridium esculentum, E. viminalis	E. ovata	E. ovata
SOIL Parent material	Unconsolidated gravel, sand and clay	Unconoslidated sand	Unconsolidated gravel, sand and clay	Unconsolidated gravel, sand and clay
Description (Corangamite Soil Group)	Red mottled brown, grey or yellow texture contrast soil, fine structure (15)	Brown, grey or yellow sand soil, uniform texture (6)	Brown, grey or yellow sodic texture contrast soil, coarse structure (14)	Mottled brown, grey or yellow texture contrast soil (33/32)
Soil type sites	MM5109, OTR499, SW63	SW61, SW71, OTR742	SW99, MM204, SW93	SW2, SW88, SFS20
Surface texture	Sandy clay loam to loamy sand	Sand	Clay loam	Clay loam, sandy clay loam
Permeability	Moderate	High	Low	Moderate
Depth (m)	2	2	2	2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Harsetting surface and low permeability leads to overland flow. This flow often creates sheet and rill erosion with major rainfall events. Gully erosion and leaching of salts also occur.	Soils have low water holding capacity and low nutrient holding capacity. Soils experience leaching and soil fertility decline.	Hardsetting surfaces and low permeability leads to overland flow. This flow often creates sheet and rill erosion with major rainfall events. Gully erosion and leaching of salts also occur. Surface compaction can benefit from controlled traffic.	Hardsetting surfaces and low permeability leads to overland flow. This flow often creates sheet and rill erosion with major rainfall events. Gully erosion and leaching of salts occur.

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