Soil/Landform Unit 15

Undulating to gently undulating hillslopes at Pittong

Area:

1519 ha

0.11% of CMA region

The undulating low granitic hills south of Pittong are part of the granitic landscapes within the Midlands of the Western Uplands. This

Devonian

granite unit is located south of Pittong in the north of the catchment. The undulating slopes graduate into the prominent footslopes, drainage depressions and

alluvial

fans of Unit

. Remnant vegetation on the granite is sparse with the Grassy Woodland, Heathy Dry Forest and Riparian Woodland among the major classes. The soils consist of an association of

mottled

texture contrast soils and deep brown sands. Areas of rocky outcrop occur on the upper slopes and crests with deep sands. Minor mottled

sodic

texture contrast soils occur on the mid to lower slopes. Unbleached mottled texture contrast soils with lighter textured surfaces may also occur on some of the lower crests. Land use is restricted to grazing and cropping due to the low available water holding capacity and ready leaching of nutrients from these soils. Gully erosion occurs to a moderate extent and is difficult to control on the steeper slopes and valleys of these hills. Salting is also expressed at the surface as evidenced by the presence of spiny rush.

Ferruginised Cainozoic deposits of a cutting overlooking the Pittong clay works
	Weathered granite exposed in the cutting south of Pittong

Component	1	2	3
Proportion of soil-landform unit	15%	30%	55%
CLIMATE Rainfall (mm)	Annual: 740
Temperature (^oC)	Minimum 7, Maximum 18
Precipitation less than potential evapotranspiration	October-March
GEOLOGY Age and lithology	Devonian granite
Geomorphology	2.1.2 Dissected Western Uplands associated with granitic rocks and aureoles
LANDUSE	Uncleared: Nature conservation Cleared: Sheep grazing; limited cropping (cereal)
TOPOGRAPHY Landscape	Low granite hills
Elevation range (m)	268-470
Local relief (m)	60-100
Drainage pattern	Dendritic
Drainage density (km/km²)	2.3
Landform	Hillslopes
Landform element	Crest and upper slopes	Mid slopes	Lower slopes
Slope and range (%)	4 (1-9)	6 (3-12)	3 (1-8)
Slope shape	Convex	Convex	Concave
NATIVE VEGETATION Ecological Vegetation Class	Gassy Woodland (6.6%), Heathy Dry Forest (0.7%), Riparian Woodland (0.1%)
SOIL Parent material	Granite	Granite	Granite
Description (Corangamite Soil Group)	Deep brownish sands (4)	Acidic mottled brown, grey or yellow texture contrast soils (3)	Sodic mottled brown, grey or yellow texture contrast soils (2)
Soil type sites	MM236, BD8	MM5150	MM162, MM411
Surface texture	Loamy sand	Coarse sandy clay loam	Sandy clay loam
Permeability	Very high	Moderate to high	Moderate
Depth (m)	<2	<2	>2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Uniform sand, deep texture contrast, very low nutrient holding capacity and water holding capacity in sandy soils, high in underlying clays. Susceptibility to deep seepage, nutrient decline and sheet erosion.	Moderate slope, low permeability and hardsetting surfaces with overland flow common. Rapid subsurface flow associated with deep seepage, leaching of salts, rill and gully erosion, and sheet erosion.	Moderate slop, low permeability and hardsetting surfaces may cause overland flow. Rapid subsurface flow associated with deep seepage, leaching of salts, rilly and gully erosion, and sheet erosion.

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