Ferguson Hill Land System

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Most outcrops of Tertiary sediments to the west of the Otway Range are either deeply dissected or 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 Tertiary sand, silt and clay, with some minor areas of lateritic ironstone. 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 colonize most areas and often reach heights in excess of 30 m on the better-drained soils. However, these stands are decreasing in areas 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.

A Study of land in the catchments of the Otway Range and adjacent plains - ferguson hill

Along Pipeline Road the dissection is only mildly developed
on these comparatively youthful soils. In the foreground E. nitida
grown on grey sand soils, while in the distance tall open woodlands
occur on red gradational soils with weak structures.

Area: 52 km²	Component and its proportion of land system
Area: 52 km²	1 15%	2 20%	3 25%	4 5%	5 8%	6 15%	7 10%	8 2%
CLIMATE Rainfall, mm	Annual: 1,000 – 1,100, lowest January (40), highest August (130)
Temperature, 0^oC	Annual: 13, lowest July (7.5), highest February (19)
	Temperature: less than 10^oC (av.) June - August
	Precipitation: less than potential evapotranspiration mid November – March
GEOLOGY Age, lithology	Paleocene marine sand, clay and silt; some Pleistocene lateritic ironstone
TOPOGRAPHY Landscape	Undulating hills and ridges
Elevation, m	30-230
Local relief, m	40
Drainage pattern	Dendritic
Drainage density, km/km²	2.4
Land form	Hill				Drainage line	Broad ridge		Scarp
Land form element	Lower slope	Slope	Crest	Midslope	-	Crest, 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. obliqua, E. cypellocarpa	E. obliqua, E. baxteri	E. baxteri, E. obliqua	E. baxteri, E. obliqua	E. obliqua, E. baxteri, E. ovata, Acacia melanoxylon
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	Grey-brown gradational soils	Yellow gradational soils, weak structure	Grey sand soils with hardpans, uniform texture	Red sandy loam soils uniform texture	Grey gradational soils	Mottled yellow and red gradational soils	Red gradational soils, weak structure	Stony red gradational soils
Surface texture	Fine sandy loam	Sandy loam	Loamy sand	Sandy loam	Sand 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 USE	Uncleared areas: Hardwood forestry for sawlogs, posts and poles; water supply; nature conservation; gravel extraction. Cleared areas: Sheep and beef cattle grazing; dairy farming; water supply
SOIL DETERIORATION HAZARD Critical land features, processes, forms	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 pone to sheet erosion and seasonal waterlogging. 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 water table lead 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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