Soil/Landform Unit 165

View north-west over the former Heytesbury Soldier Settlement

Area:

11 654 ha

0.87% of CMA region

Rolling hills of the Heytesbury region (often referred to as the Heytesbury Soldier Settlement) are formed from Miocene marine clay, marl and limestone. Included are the catchments of Scotts Creek and Cooriemungle Creek. Faulting and slumping of the landscape has led to occasional steep scarps, but most slopes are long, gentle and straight, separated by broad drainage lines. The soils on these Miocene sediments are typically brown, grey and black texture contrast soils, with heavier textured cracking clays lower in the landscape. Soils on these sediments are significantly more fertile than the soils formed on the Neogene sediments in adjacent units (Unit 86). Free lime is often preent at depth in the soil profile. Nearly all native vegetation has been cleared as part of the soldier settlement, apart from a significant remnant stand in the centre of the Heytesbury region. Dairy farming is the main land use. Subsoils are dispersible and gully erosion has occurred along some drainage lines. Landslip and slumping is a major engineering issue that escalates when soils are waterlogged. Drainage lines and lower slopes remain waterlogged for most of the year and are prone to soil compaction (pugging) by stock.

Gentle slopes of the highly dissected remnant plain in the Heytesbury region
	Overlooking the remnant vegetation of the Heytesbury Soldier Settlement from Cowleys Creek

Component	1	2	3	4	5
Proportion of soil-landform unit	4%	65%	20%	8%	3%
CLIMATE Rainfall (mm)	Annual: 900-1000, lowest January (40), highest August (120)
Temperature (^oC)	Annual: 14, lowest July (9), highest February (18)
Seasonal growth limitations	Temperature: less than 10^oC (av.) June-August Precipitation: less than potential evapotranspiration November-March
GEOLOGY Age and lithology	Miocene marine marl. Recent clay, sand and gravel
Geomorphology	6.2.2 Dissected plains, rises and low hills of the Sedimentary Western Plains
LANDUSE	Cleared areas: Dairy Minor uncleared areas: Nature conservation
TOPOGRAPHY Landscape	Rolling hills
Elevation range (m)	20-170
Local relief (m)	120
Drainage pattern	Dendritic
Drainage density (km/km²)	2.6
Landform	Hills			Valley floor
Landform element	Upper slope and crest	Mid slope	Lower slope	Low rises	Alluvial flats and fans
Slope and range (%)	5 (0-12)	5 (0-10)	4 (1-7)	1 (0-3)	0 (0-1)
Slope shape	Convex	Concavo-Convex	Convex, linear	Convex	Linear
NATIVE VEGETATION Ecological Vegetation Class	Open forest	Woodland	Woodland	Closed scrub	Closed scrub
Dominant species	E. obliqua, E. ovata, E. aromaphloia	E. ovata, E. radiata	E. obliqua, E. ovata	Melaleuca squarrosa, Leptospermum lanigerum	Melaleuca squarrosa, Leptospermum lanigerum
SOIL Parent material	In situ marl	Colluvial marl	Colluvial/alluvial marl and sand	Colluvial/alluvial sand and marl	Alluvial sand and clay
Description (Corangamite Soil Group)	Brown, grey or yellow texture contrast soils (calcardous subsoils), coarse to fine structure (20)	Mottled brown, yellow and grey texture contrast soils, coarse to fine structure (20)	Mottled yellow and grey texture contrast soils (20)	Grey sandy soil with weakly cemented pan over mottled clay (22)	Yellow grey texture contrast (31) and grey uniform clay soils (33)
Soil type sites	SW53, (SW59)	SW53, SW77, SW82	SW53, SW77, SW82	SW55, SW56	SW56, SW57
Surface texture	Clay loam to clay	Sandy loam to clay	Sandy loam to clay	Sandy loam	Clay loam
Permeability	Very low	Very low	Very low	Low	Very low
Depth (m)	>2	>2	>2	>2	>2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Heavy textured soils are very prone to pugging damage by cattle. Acidic surface.	All slopes are subject to periodic saturation are prone to severe waterlogging and pugging by cattle. Landslips and slumping of road batters are a major hazard. Soils respond well to subsurface drainage including mole drainage.	Soils are prone to severe waterlogging and pugging by cattle. Saline discharge occurs at toe slopes of landslides and in some drainage lines. Soils respond well to subsurface drainage including mole drainage.	Better draned surface soils of this element render it less prone to pugging by cattle.	Soils are prone to severe waterlogging and pugging by cattle. Soils respond well to subsurface drainage including mole drainage.

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