Soil/Landform Unit - Lillimur South clay plains

Landform Unit Description

Lillimur South clay plains

Area: 12 656 ha

0.54% of CMA region

Clay plains south and east of Servicetown are recognised for the grey and brown cracking clay soils (

Vertosols

) that are often

self-mulching

. Gentle subdued rises with sodic red texture contrast soils (

Sodosols

) also occur as part of former stranded beach ridges that have minor occurrences of superimposed dunes. As part of the ridges with sand, and flats geomorphology sequence (5.5.1), this soil-landform unit occurs on the northern boundary of the Little Desert. Cereal cropping is the major land use with vegetation communities including Ridged Plains Mallee, Plains Grassland and Plains Savannah found mostly on clay soils and plains. Shallow Sand Woodland is found on lunettes or sandy soils and Red Gum Wetland, Lignum Swampy Woodland and Seasonally Inundated Shrubby Woodland found in wetter areas of the landscape. Low Rises Woodland has also been recorded.

Valley flat selectively cleared and used for cropping
	Remnant vegetation and cereal crop

Component	1	2	3	4	5
Proportion of soil-landform unit	5%	10%	20%	10%	55%
CLIMATE Rainfall (mm)	Annual: 485
CLIMATE Rainfall (mm)	Annual: 485
Temperature (^oC)	Minimum 8, Maximum 22
Precipitation less than potential evapotranspiration	September–April
GEOLOGY Age and lithology	Quaternary paludal silt and clay
GEOLOGY Age and lithology	Quaternary paludal silt and clay
Geomorphology	5.5.1 Prominent ridges and oriented swales of the North West Dunefields and Plains
LANDUSE	Uncleared areas: Nature conservation Cleared areas: Dryland cropping; sheep grazing
LANDUSE
TOPOGRAPHY Landscape	Clay plains
TOPOGRAPHY Landscape	Clay plains
Elevation range (m)	110–138
Local relief (m)	2
Drainage pattern	Dendritic
Drainage density (km/km²)	0.1
Landform	Rises		Plains
Landform element	Rise crest	Rise slope	Drainage line	Swale	Plain
Slope and range (%)	3 (1-8)	4 (1-8)	2 (1-4)	1 (0-4)	1 (0-3)
Slope shape	Convex	Convex	Concave	Concave	Straight
NATIVE VEGETATION Ecological Vegetation Class	Low Rises Woodland (30.6%), Ridged Plains Mallee (22.9%), Plains Savannah (18.6%), Shallow Sands Woodland (12.4%), Other (14.0%)
NATIVE VEGETATION Ecological Vegetation Class
SOIL Parent material	Marine sand and silt, aeolian sand	Marine sand and silt, aeolian sand	Paludal silt and clay	Paludal silt and clay, marine sand and silt	Paludal silt and clay
SOIL Parent material	Marine sand and silt, aeolian sand	Marine sand and silt, aeolian sand	Paludal silt and clay	Paludal silt and clay, marine sand and silt	Paludal silt and clay
Description (Corangamite Soil Group)	Sodic red texture contrast soils (35)	Sodic red texture contrast soils (35)	Grey and brown cracking clay soils (37)	Grey and brown cracking clay soils (37)	Grey and brown cracking clay soils (37)
Soil type sites	LS15, LS8, LS23	LS15, LS8, LS23	LS3, LSWW9, LSWW5	LS3, LSWW9, LSWW5	LS3, LSWW9, LSWW5
Surface texture	Sandy clay loam	Sandy clay loam	Medium clay	Medium clay	Medium clay
Permeability	Moderate	Moderate	Slow to very slow	Slow	Slow
Depth (m)	1.6	2	> 2	> 2	> 2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS Critical land features, processes, forms	Hardsetting soil surface susceptible to sheet and rill erosion, and wind erosion where exposed. Dispersive and deep subsoils susceptible to gully erosion on steeper slopes. Compaction of soil dependent upon depth of force and moisture content. Topsoil may be susceptible to acidification.	Hardsetting soil surface susceptible to sheet and rill erosion, and wind erosion where exposed. Dispersive and deep subsoils susceptible to gully erosion on steeper slopes. Compaction of soil dependent upon depth of force and moisture content.	Susceptible to seasonal inundation and waterlogging. Surface soils friable and only slightly susceptible to wind erosion. Soils susceptible to compaction at critical moisture contents.	Susceptible to periodic inundation and waterlogging in lower areas, but can be variable due to micro relief (gilgai). Gully erosion can occur where dispersive subsoils are exposed. Surface soils friable and only slightly susceptible to wind erosion. Soils susceptible to compaction at critical moisture contents.	Susceptible to inundation and waterlogging in lower areas, but can be variable due to micro relief (gilgai). Slightly susceptible to surface sheet erosion where soils are exposed. Soils susceptible to compaction at critical moisture contents.

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