Soil/Landform Unit 32

Lower slopes and depression (most likely a former swamp) now supporting blue gums in belts

Area:

1469 ha

0.11% of CMA region

This unit falls predominantly within the Dissected Uplands associated with volcanic landforms of the Western Uplands, between Garibaldi and Grenville. There is a minor occurrence on the Western Plains adjoining the Western Uplands, east of Maude. The northern occurrence is surrounded by sedimentary terrain (Unit

) and connected to a basalt flow (Unit

). The soils are predominantly neutral and

acidic

mottled

brown texture contrast soils (

Chromosols

and

Sodosols

) with more

friable

red gradational (earth) soils (

Ferrosols

) on the upper and mid slopes (associated with the eruption point) and black

self mulching

soils (

Vertosols

) in the depressions and occasionally on lower slopes. Rainfall is higher to the north, the southern occurrence is drier. The low-lying areas are prone to waterlogging with slow site drainage and some

compaction

. The sloping areas are more susceptible to sheet and rill erosion though moderately rapid site drainage and some soil friability. Depth and stoniness may vary enough to affect permeability and land use; mainly grazing.

Soils of the mid and upper slopes offer potential for cropping or other intensive agricultural enterprises
	Steep gullies near Hardies Hill

Component	1	2	3	4	5	6
Proportion of soil-landform unit	18%	18%	23%	2%	28%	11%
CLIMATE Rainfall (mm)	Annual: 730
Temperature (^oC)	Minimum 7, Maximum 18
Precipitation less than potential evapotranspiration	October-March
GEOLOGY Age and lithology	Pleistocene basalt			Recent sands, silts and clays	Pleistocene basalt	Quaternary river deposits (gravels, sands and clay)
Geomorphology	2.1.4 Dissected Western Uplands associated with volcanic landforms and 6.1.3 Volcanic Western Plains with poorly developed drainage
LANDUSE	Uncleared: Nature conservation Cleared: Grazing; occasional cropping (cereal); softwood and hardwood plantations
TOPOGRAPHY Landscape	Low hills
Elevation range (m)	79-443
Local relief (m)	45
Drainage pattern	Dendritic
Drainage density (km/km²)	1.9
Landform	Scarps with local rock outcrop	Creek bed	Volcanic cone	Swamps and depressions	Gently undulating plains	Depressions and terraces
Landform element	Slope	Floodplain	Slopes and crest	Long gentle upper slopes
Slope and range (%)	13 (8/25)	2 (0-3)	17 (5-40)	1 (0-1)	1 (1-3)	1 (1-2)
Slope shape	Convex	Straight	Straight	Flat	Straight	Straight
NATIVE VEGETATION Structure	Open forest	Open forest	Open forest	Woodland		Woodland
Dominant species	E. viminalis, E. ovata	E. viminalis, E. ovata	E. viminalis, E. radiata	E. ovata	E. ovata, E. viminalis, E. rubida, E. obliqua	E. viminalis, E. radiata
SOIL Parent material	In situ weathered rock	Unconsolidated sedimentary and in situ weathered rock	In situ weathered rock	Unconsolidated sands, silts and clays	In situ weathered rock	Unconsolidated gravel, sand, silt and clay
Description (Corangamite Soil Group)	Shallow brown texture contrast (37) or gradational soils (41)	Black clay soil, coarse structure (31)	Stony red gradational soil (40)	Mottled dark grey, brown, yellow gradational soil and black clay soil, coarse structure (34)	Mottled brown, yellow or grey sodic texture contrast soil, coarse structure (35)	Dark brown soil - variable (34)
Soil type sites	SFS5b, SW48, BD2	CLRA15, SW37. CLRA48	BD5, SW96, SW26	SW39. CLRA15, CLRA1	SW86, CLRA49, MM178	SW39, CLRA15, CLRA1
Surface texture	Clay loam	Clay	Clay loam	Light clay/clay	Clay loam	Fine sandy clay loam
Permeability	High	Low	High	Low	Moderate to low	Moderate to low
Depth (m)	1	1.5	1	2	1.5	2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Scarp slopes combined with hardsetting surfaces results in overland flow. Soils are vulnerable to sheet and rill erosion.	Poorly drained soils with a low permeability. Overland flow and waterlogging may cause compaction and streambank erosion where exposed.	Steep slopes result in overland flow. Leaching of nutrients and rill and sheet erosion occur where soils lack ground cover.	Slowly permeable soils experience waterlogging and compaction.	Hardsetting surfaces with slowly permeable subsoils cause overland flow and waterlogguing may cause compaction as well as sheet erosion.	Low-lying areas receiving drainage experience severe waterlogging. Gully erosion may occur where subsoils are sodic.

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