Soil/Landform Unit 21

Plateaux of the dissected landscape near Happy Valley in the Western Uplands

Area:

3709 ha

0.28% of CMA region

This hills and plains unit is a member of the dissected Western Uplands. This unit of only two occurrences predominantly consists of a Neogene plain (plateau) which has been dissected and some moderately steep

Palaeozoic

low hills in the Pitfield, Cape Clear area. This unit is either close to or forms a boundary between the Western Uplands and the Western Plains. The soils are sodic often acidic, mottled brown texture contrast soils (Sodosols, Kurosols) on the plains, and shallow mottled red and yellow gradational soils (Dermosols) on the hills. The lighter surface soils are prone to nutrient decline and sheet and rill erosion. Sheet, rill, gully and minor mass movement are concerns on the steeper slopes. Nutrient levels are low in this unit and most of the soils are dispersible, the Neogene clays particularly so (due to sodicity). The predominant land use is grazing, with some mineral extraction on the plains and some hillslopes, while forestry, recreation and conservation are confined to the hills.

The main land use of these plains and slopes includes grazing and cropping (cereal)
	Gully and tunnel erosion is common on slopes and roadsides near Cape Clear

Component	1	2	3	4	5	6
Proportion of soil-landform unit	1%	12%	1%	11%	74%	1%
CLIMATE Rainfall (mm)	Annual: 660-720
Temperature (^oC)	Minimum 8, Maximum 19
Precipitation less than potential evapotranspiration	October-March
GEOLOGY Age and lithology	Neogene fluvio-marine sand, Orodivician marine sandstone and shale and minor Quaternary basalt
Geomorphology	2.1.3 Dissected Western Uplands associated with Cainozoic gravel and sediments
LANDUSE	Uncleared areas: Hardwood forestry; nature conservation Cleared: Sheep and beef cattle grazing; gravel extraction; mining
TOPOGRAPHY Landscape	Moderate steep low hills and gently undulating plain
Elevation range (m)	185-324
Local relief (m)	5-35
Drainage pattern	Dendritic
Drainage density (km/km²)	2.5
Landform	Low Hill			Plain
Landform element	Southern slope	Northern slope	Drainage line	Creast	Non-sandy areas	Patches of deep sandy soil
Slope and range (%)	15 (10-25)	15 (10-25)	4 (2-10)	7 (0-15)	1 (1-3)	2 (1-3)
Slope shape	Straight	Straight	Concave	Convex	Convex	Convex
NATIVE VEGETATION Structure	Tall open forest	Open forest	Open forest	Open forest	Low open forest-woodland	Low open forest-woodland
Dominant species	E. obliqua, E. ovata, E. radiata, E. viminalis	E. dives, E. obliqua, E. viminalis, E. radiata	E. viminalis, E. radiata, E. obliqua	E. obliqua, E. dives, E. viminalis, E. radiata	E. viminalis, E. obliqua, E radiata, E. rubida, E. ovata, E. pauciflora	Pteridium esculentum, E. viminalis
SOIL Parent material	In situ weathered rock	In situ weathered rock	Unconsolidated sediments	In situ weathered rock	Unconsolidated gravel, sand and clay	Unconsolidated clay
Description (Corangamite Soil Group)	Mottled brown, grey or yellow gradational soils, fine structure (25)	Mottled brown, grey or yellow gradational soils, fine structure (25)	Black gradational soils (34)	Shallow stony red gradational soils (40)	Mottled brown, grey or yellow texture contrast soils, fine structure (15/13)	Bronw, grey or yellow sand soils (8)
Soil type sites	BD10, CLRA53, MM168	BD10, CLRA53, MM168	SW39, CLRA15, CLRA1	BD10, CLRA53, MM168	OTR499, 5109, SW67	CLRA5, OTR608, OTR740
Surface texture	Fine sandy loam	Fine sandy loam	Clay loam	Gravelly loam	Sandy loam, sandy clay loam	Sand
Permeability	High	High	Moderate to low	High	Moderate	High
Depth (m)	1	1	1.5	0.5	2	2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Overland flow across the steeper slopes encourages sheet and rill erosion. Potential for minor mass movement.	Hardsetting surface soils on steep slopes can lead to compaction and are subject to overland flow and sheet and rill erosion.	Drainage lines are subject to seasonally high watertable and periodic waterlogging with some gully erosion. Hardsetting surface soils lead to surface compaction.	Hardsetting surface soils can lead to compaction and are subject to overland flow and sheet and rill erosion on moderate slopes.	Hardsetting surface soils lead to overland flow and sheet and rill erosion. Moderate permeable, leaching of salts and dispersive subsoils lead to gully erosion.	Hardsetting surface soils with low fertility lead to minor wind erosion. Highly permeable, leaching and dispersive subsoils with low fertility are common.

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