Soil/Landform Unit 20

Gentle undulating sedimentary plains with many forested remants soulth of Lal Lal

Area:

7855 ha

0.59% of CMA region

The gently undulating plains occur near Napoleons, Lal Lal and Durdidwarrah are composed of Neogene fluvio-marine sand overlying

Ordovician

marine sandstone and shale. These sedimentary plains of the Western Uplands support a wide range of vegetation classes including forests and woodlands. Some of the major classes are plains Grassy Woodland, Heathy Dry Forest, Valley Grassy Forest, Damp Sands Herb-rich Woodland and Grassy Dry Forest. Dominant species are

Callitris columellaris, Eucalyptus viminalis, E. obliqua, E. radiata, E. rubidia, E. ovata

and

E. pauciflora.

The low fertility and low water holding capacity of the soils have discouraged further clearing. Soils include an association of bleached sandy

mottled

texture contrast soils or unbleached equivalents in better drained areas. Heavier surface textured soils may occur in drainage lines. These soils can be prone to gully erosion which is minor to moderate in severity in some cleared areas.

Grazing is the major land use for these plains

Component	1	2	3	4	5	6	7	8
Proportion of soil-landform unit	50%	7%	6%	2%	20%	5%	5%	5%
CLIMATE Rainfall (mm)	Annual: 730
Temperature (^oC)	Minimum 7, Maximum 18
Precipitation less than potential evapotranspiration	October-March
GEOLOGY Age and lithology	Neogene fluvial sand, Quaternary sand, gravel and minor basalt, Orodivician marine sandstone and gravel
Geomorphology	2.1.3 Dissected Western Uplands associated with Cainozoic gravel and sediments
LANDUSE	Uncleared: Nature conservation; hardwood; gravel extraction Cleared: Sheep and beef cattle grazing; cropping (cereal); gravel extraction
TOPOGRAPHY Landscape	Gently undulating sedimentary plains
Elevation range (m)	334-502
Local relief (m)	3
Drainage pattern	Dendritic
Drainage density (km/km²)	2.6
Landform	Undulating plains	Flat plains	Drainage lines	Lakeside sandridges associated with Lal Lal swamp	Undulting plains		Minor hill
Landform element	Well drained non-sandy areas	Poorly drained non-sandy areas	Low-lying areas		Long gentle slope	Crest	Dry exposed slope	Crest
Slope and range (%)	2 (1-3)	0 (0-2)	1 (1-3)	3 (2-3)	3 (3-9)	2 (1-3)	15 )10-35)	3 (1-6)
Slope shape	Convex	Flat	Concave	Convex	Straight	Convex	Straight	Convex
NATIVE VEGETATION Structure	Low open forest-woodland	Low open forest-woodland	Low open forest-woodland	Open forest	Open forest	Open forest	Open forest	Open forest
Dominant species	Callitris columellaris, E. viminalis, E. obliqua, E. radiata, E. rubida, E. ovata, E. pauciflora	E. ovata	E. ovata	E. viminalis, E. radiata	E. viminalis, E. obliqua	E. obliqua, E. radiata	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 and clay	Unconsolidated gravel, sand and clay	Unconsolidated sand	In situ weathered sandstone and shale	In situ weathered sandstone and shale	In situ weathered sandstone and shale	In situ weathered sandstone and shale
Description (Corangamite Soil Group)	Red mottled, bornw, grey or yellow texture contrast soil, fine structure (13)	Brown, grey or yellow sodic texture contrast soil, coarse structure (14)	Mottled brown, grey or yellow texture contrast soil (13)	Yellow sand soils, uniform texture (8)	Mottled red, brown, grey or yellow texture contrast soils (26)	Mottled brown, grey or brown, grey or yellow texture contrast soils (25)	Red mottled brown or yellow gradational or texture contrast soils, fine structure (25/26)	Shallow stony red and brown, grey or yellow gradational soil (25)
Soil type sites	CLRA3, OTR601, SW67	SW99, OTR734, MM204	CLRA3, OTR601, SW67	CLRA5, OTR608, OTR740	BD13, BD11, MM204	CLRA53, CLRA54, BD10	CLRA54, BD10, CLRA58	CLRA53, CLRA58
Surface texture	Sandy clay loam to loamy sand	Clay loam	Clay loam, sandy clay loam	Sand	Clay loam	Loam to clay loam	Fine sandy loam	Gravelly loam
Permeability	Moderate	Low	Moderate	High	Moderate to low	High	High	High
Depth (m)	2	2	2	>2	0.8-1.8	0.5-1.0	2	0.5
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Hardsetting surfaces, dispersible subsoils and overland flow result in leaching of salts, sheet and rill erosion and gully erosion.	Hardsetting surfaces, dispersible subsoils and overland flow result in leaching of salts, sheet and rill erosion and gully erosion.	Hardsetting surfaces, dispersible subsoils and overland flow result in leaching of salts, sheet and rill erosion and gully erosion.	Low water and nutrient hilding capacity lead to leaching and fertility decline.	Harsetting surfaces, dispersible subsoils and overland flow result in leaching of salts, surface compaction, sheet and rill/gully erosion.	Hardsetting surfaces, dispersible subsoils and overland flow result in leaching of salts, surface compaction, sheet and rill/gully erosion.	Steep slopes, hardsetting surfaces and overland flow result in sheet and rill erosion and surface compaction.	Moderate hardsetting surfaces and overland flow result in sheet and rill erosion and surface compaction.

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