Soil/Landform Unit 74

Landform Unit Description

Vegetation regeneration on dissected hills after fire north-east of Chapple Vale

Area:

10 593 ha

0.79% of CMA region

Low woodlands of

Eucalyptus nitida

with understoreys of

Leptospermum continentale

L. myrsinoides

and

Xanthorrhoea australis

characterise these hills on the western periphery of the Otway Range. The soils are mainly deep, infertile and excessively drained sands, which contrast sharply with the adjacent gradational profiles of the Lower

Cretaceous

outcrops. Thus, although rainfall is high, moisture stress and soil infertility severely restrict plant growth. Some attempts have been made to clear tracts of this land and establish pastures for cattle grazing. Trial plots of pine species have also been established. Given sufficient fertiliser and soil ameliorants (such as lime), pastures or even intensive crops could be successfully grown. However, the rates of such chemicals needed to achieve satisfactory production are high and most of the land remains in its natural state. The main activity has been the opening up of numerous soil and gravel extraction pits, most of which have failed to regenerate naturally and now remain as scars on the landscape.

Hills on the margin of the Gellibran River near Devondale
	Remnant closed scrube of the valley floor

Component	1	2	3	4	5
Proportion of soil-landform unit	15%	15%	55%	10%	5%
CLIMATE Rainfall (mm)	Annual: 1000-1350, lowest January (45), highest August (130)
Temperature (^oC)	Annual: 12, lowest July (7), highest February (18)
Precipitation less than potential evapotranspiration	Temperature less than 10^oC (av.) June-September Precipitation less than potential evapotranspiration mid November-late March
GEOLOGY Age and lithology	Paleogene unconsolidated marine glauconitic to carbonaceous sand and mudstone
Geomorphology	3.2.2 Dissected upland ranges of the Southern Uplands
LANDUSE	Uncleared areas: Gravel and sand extraction; nature conservation; water supply; active and passive recreation.
TOPOGRAPHY Landscape	Dissected hills in the western part of the Otway Range
Elevation range (m)	30-270
Local relief (m)	60
Drainage pattern	Dendritic with some radial areas
Drainage density (km/km²)	2.3
Landform	Hills				Valley floors
Landform element	Crest and slope	Broad, slightly depressed area of impeded drainage	Crest and slope	Steep lower slope	-
Slope and range (%)	25 (10-35)	15 (5-20)	20 (5-45)	40 (25-50)	8 (2-12)
Slope shape	Convex	Linear	Convex	Linear	Concave
NATIVE VEGETATION Structure	Tall shrubland	Closed heath	Low woodland	Woodland	Closed scrub
Dominant species	E. nitida, Acacia suaveolons, E. baxteri, Leptospermum juniperinum	Cassuarina littoralis, Anthorrhoea australis, L. continentale, L. myrsinoides, Melaleuca squarrosa, Aotus ericoides, Dillwynia glaberrima, Epacris impressa, Epacris lanuginosa	E. nitida, E. radiata, E. baxteri, E. viminalis, close to valley floor	E. baxteri, E. radiata, E. nitida	M. squarrosa, L. continentale, Casuarine littoralis, Gleichenia circinnata, Bauera rubioides, Sprengelia incarnata
SOIL Parent material	Quartz sand and gravel	Quartz sand	Quartz sand	Quartz sand	Alluvial sand, plant remains
Description (Corangamite Soil Group)	White sand soils (29)	Grey sand soils with hardpans (29)	Grey sand soils (29)	Yellow sand soils (29)	Black sand soils (29)
Soil type sites	OTR426	OTR608	OTR742	OTR740	OTR609, OTR739
Surface texture	Coarse sand	Sandy loam	Loamy sand	Loamy sand	Silty loam
Permeability	Very high	Very low	Very high	Very high	Low
Depth (m)	>2	0-1	>2	>2	>2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Very low inherent feritlity and high permeability leads to leaching of nutrients. Steeper slopes with compacted soils are prone to sheet, rill and gully (scour) erosion.	Hardpans restrict drainage leading to seasonal waterlogging. Very low inherent fertility with leaching of permeable acidic surface horizons leads to nutrient decline.	Very low inherent fertility and high peremability lead to nutrient decline. Steeper slops with compacted soils are prone to sheet, rill and scour gully erosion.	Steeper slopes with weakly structured soils of low water holding capacity are prone to sheet erosion. Low inherent fertility and high permeability lead to nutrient decline.	High watertables lead to waterlogging and soil compaction. Rapid runoff from adjacent hills leads to flooding and siltation.

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