Soil/Landform Unit 84

Landform Unit Description

Northern edge of the plateau scarp west of Drysdale

Area:

709 ha

0.05% of CMA region

This single narrow scarp and capping unit is exposed within the Neogene plateau (Unit

) due to dissection, and forms the south-western boundary of the plateau onto the

alluvial

plains and flats (Unit

200

) associated with the Barwon River lake system. There is arguably also a scarp face along all of the western edge and much of the eastern edge of the plateaux (Unit

). There are two components based on lithology. The soils are red and brown (often ferruginous) texture contrast soils (

Chromosols

) associated with ferruginised sand, and shallow dark calcareous medium texture soils on limestone on the mid and/or lower slopes. The texture contrast soils are susceptible to sheet and rill erosion and surface nutrient decline, while the calcareous soils are mainly susceptible to sheet erosion (

friable

) on the steeper slopes. Land use tends to be grazing and conservation.

Drainge depression associated with plains near Marcus Hill

Component	1	2
Proportion of soil-landform unit	40%	60%
CLIMATE Rainfall (mm)	Annual: 590
Temperature (^oC)	Minimum 10, Maximum 19
Precipitation less than potential evapotranspiration	October-April
GEOLOGY Age and lithology	Neogene marine marl and calcarenite, fluvio-marine sand, Recent clay, sand and gravel and Paleogene tholeiites and pryoclastics
Geomorphology	3.3.2 Dissected rolling low hills of the Southern Uplands
LANDUSE	Uncleared: Nature conservation; passive and active recreation Cleared areas: Seep and beef cattle grazging; regional development
TOPOGRAPHY Landscape	Low hills
Elevation range (m)	6-85
Local relief (m)	40
Drainage pattern	Dendritic
Drainage density (km/km²)	1.7
Landform	Low scarp
Landform element	Upper and mid slope	Mid and lower slope
Slope and range (%)	10 (3-30)	10 (3-30)
Slope shape	Concave	Straight, concave
NATIVE VEGETATION Ecological Vegetation Class	Grassy Woodland (5.5%), Calcarenite Dune Woodland (2.1%), Damp sands Herb-rich Woodland (1.0%), Other (1.9%)
SOIL Parent material	Ferruginised sand, silt marl, minor limestone	Silt, marl, minor limestone, ferruginised sand
Description (Corangamite Soil Group)	Brown and red texture contrast soils, often with a ferric horizon and brown calcareous gradational soils (14, 24)	Brown calcareous gradational soils and brown texture contrast soils, often with a ferric horizon (24, 14)
Soil type sites	CLRA33, CLRA32, CLRA3	CLRA32, CLRA33
Surface texture	Caorse sandy loam, clay loam	Clay loam, coarse sandy loam
Permeability	Moderate	High
Depth (m)	<1	<1
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Large texture contrast between surface soil and subsoil, low nutrient holding capacity and water holding capacity in surface soils, much higher in subsoil. Light surface soil susceptible to nutrient decline, sheet and rill erosionand wind erosion. Restricted drainage where slow site drainage. Site drainage generally very rapid.	Gradational, shallow, strongly structured soil. Low water holding capacity (shallow) but high nutrient holding capacity. Site drainage is very rapid, less at slope base. Susceptibility to sheet erosion on steep slopes.

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