Soil/Landform Unit 86

View north towards Fergusons Hill

Area:

6851 ha

0.51% of CMA region

Most outcrops of Neogene sediments to the west of the Otway Range are either steeply dissected or have deeply weathered soils. However, some ridges and spurs are only mildly dissected and their soil profiles are only weakly developed. These areas are found at Ferguson Hill, just south of Simpson, along Pipeline Road and in an additional small area near Cape Otway. The parent material is Neogene sand, silt and clay, with some minor areas of ferricrete. The soils vary according to the nature of the outcropping beds, but in general their structure is weak and often the A and B horizons are not clearly differentiated. Profile drainage is good on all but those areas with hardpans, and these are the only areas prone to waterlogging despite the high annual rainfall.

Eucalyptus obliqua

and

E. baxteri

colonise most areas and often reach heights in excess of 30 m on the better drained soils. However, these stands are decreasing in area as much of the land is being cleared for agriculture. The soils are naturally quite stable and the major problems are likely to arise from nutrient decline.

Slopes with devined dendritic drainage on southern slopes of Ferguson Hill
	Woodlands of the broad ridge of Ferguson hill

Component	1	2	3	4	5	6	7	8
Proportion of soil-landform unit	15%	20%	25%	5%	8%	15%	10%	2%
CLIMATE Rainfall (mm)	Annual: 1000-1100, lowest January (4), highest August (130)
Temperature (^oC)	Annual: 13, lowest July (7.5), highest February (9)
Seasonal growth limitations	Temperature: less than 10^oC (av.) June-August Precipitation: less than potential evapotranspiration mid November-March
GEOLOGY Age and lithology	Paleogene marine carbonaceous clay to sand, Neogene fluvio-marine sand and marine marl.
Geomorphology	3.3.2 Dissected low hills rolling hills of the Southern Uplands
LANDUSE	Uncleared areas: Hardwood forestry for sawlogs, posts and poles; water supply; nature conservation; gravel extraction Cleared area: Sheep and beef cattle grazing; dairy farming; water supply
TOPOGRAPHY Landscape	Undulating hills and ridges
Elevation range (m)	30-230
Local relief (m)	40
Drainage pattern	Dendritic
Drainage density (km/km²)	1.7
Landform	Hills				Drainalge lines	Broad ridges		Scarps
Landform element	Lower slope	Slope	Crest	Midslope	-	Crest and upper slope	Crest	-
Slope and range (%)	4 (1-7)	14 (5-37)	5 (2-9)	11 (3-15)	4 (2-9)	4 (0-11)	4 (0-7)	29 (25-37)
Slope shape	Straight	Straight	Convex	Straight	Concave	Convex	Straight	Concave
NATIVE VEGETATION Structure	Open forest	Open forest	Low woodland (variable)	Open forest	Open forest	Open forest	Tall woodland	Open forest
Dominant species	E. obliqua, E. ovata	E. baxteri, E. nitida, E. obliqua	E. nitida, E. baxteri	E. baxteri, E. radiata, E. obiqua, E. cypellocarpa	E. obliqua, E. baxteri	E. baxteri, E. obliqua	E. baxteri, E. obliqua	E. obliqua, E. baxteri, E. ovata, Acacia malanoxylon
SOIL Parent material	Clay and silt	Clay, silt and sand	Sand	Sand, silt and clay	Alluvial sand, silt and clay	Clay and silt; some lateritic remnants	Clay and silt; some lateritic remnants	Colluvial lateritic ironstone
Description (Corangamite Soil Group)	Grey-brown gradational soils (29)	Yellow gradational soils, weak structure (29)	Grey sand soils with hardpans (29)	Red sandy loam soils (29)	Grey gradational soils (17, 34)	Mottled brown, grey, yellow or red gradational soils (17)	Red gradational soils, weak strcture (17)	Stony red gradational soils (17)
Soil type sites	SW24	OTR497, CLRA13	OTR608	-	OTR733, SW23	OTR782	OTR749	-
Surface texture	Fine sandy loam	Sandy loam	Loamy sand	Sandy loam	Sandy loam	Sandy loam	Sandy loam	Gravelly loamy sand
Permeability	Moderate	High	Very low	Very high	Low	Moderate	High	Very high
Depth (m)	>2	>2	>2	>2	>2	>2	0.9	>2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Minor hazards	Weakly structured surfaces on steeper slopes are prone to sheet erosion. Low inherent fertility and high permeability lead to nutrient decline.	Weakly structured sands on hardpans are prone to sheet erosion and seasonal watrlogging. Permeable surface sands of high acidity and low inherent fertility are prone to nutrient decline.	Low inherent fertility and high permeability lead to nutrient decline.	High seasonal watertable leads to soil compaction.	Low inherent fertility, phosphorus fixation and permeable surfaces lead to nutrient decline.	Low inherent fertility and high permeability lead to leaching of nutrients.	Steep slopes with weakly structured surface soils of low water holding capacity are prone to sheet erosion.

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