Soil/Landform Unit 177

Undulating plains near Nullawarre

Area:

1043 ha

0.08% of CMA region

This unit of gently undulating plains comprises mounds and shallow depressions known as blow outs in the Nullawarre area. Occurring on the western boundary of the catchment, this unit forms one of many sedimentary landforms within the Western Plains of Victoria. This unit consists of plains with minor dissection where the Neogene sandy sediments cap Neogene limestone, which may explain the limited surface drainage expression. The soils tend to be

acidic

mottled

texture contrast (

Kurosols

) soils on the mounds or very slight rises, with acidic mottled texture contrast soils with sporadic

bleached

subsurface horizons occurring on the flats and shallow depressions (blow-outs between the mounds). Unbleached equivalents occur on the crests with the occasional gradational soil (

Dermosol

). Remnant vegetation includes the Damp Heathland/Damp Heathy Woodland Mosaic and Herb-rich Foothill Forest classes. The high annual rainfall explains most of the soil acidity (due to

leaching

). Dairying is the major land use of this unit. Surface and subsurface soil nutrient decline and local waterlogging are susceptibilities of this unit.

The plains are mainly used for grazing by diary and beef cattle

Component	1	2	3
Proportion of soil-landform unit	20%	60%	20%
CLIMATE Rainfall (mm)	Annual: 910
Temperature (^oC)	Minimum 9, Maximum 18
Precipitation less than potential evapotranspiration	November–March
GEOLOGY Age and lithology	Neogene fluvial-marine sediments, minor marl, calcarenite
Geomorphology	6.2.4 Plains, rises and low hills of the Sedimentary Western Plains
LANDUSE	Uncleared areas: Hardwood forestry for sawlogs, posts and poles; water supply; nature conservation Cleared areas: Dairy farming; beef cattle and sheep grazing; cropping (cereal and horticulture); water supply; softwood plantations
TOPOGRAPHY Landscape	Gently undulating plains
Elevation range (m)	31–124
Local relief (m)	4
Drainage pattern	Dendritic
Drainage density (km/km²)	0.4
Landform	Undulating plains with very slight rises (mounds)
Landform element	Mound crests	Mound slopes	Flats and sinkholes
Slope and range (%)	1 (0–3)	3 (1–8)	0
Slope shape	Straight	Convex	Straight
NATIVE VEGETATION Ecological Vegetation Class	Damp Heathland/Damp Heathy Woodland Mosaic (2.3%), Herb-rich Foothill Forest (0.5%)
SOIL Parent material	Sand, silt and clay	Sand, silt and clay	Marl, calcarenite, sand, silt and clay
Description (Corangamite Soil Group)	Acidic mottled brown, grey or yellow texture contrast soils (15)	Acidic mottled brown, grey or yellow texture contrast soils (15)	Acidic mottled brown, grey or yellow texture contrast soils (15) and acidic black texture contrast soils (23)
Soil type sites	MM5109, SW63, OTR499	MM5109, MM5308, OTR499	MM5109, OTR499, CLRA9
Surface texture	Fine sandy loam	Fine sandy loam	Fine sandy loam
Permeability	Moderate	Moderate	High
Depth (m)	<1.5	< 2	< 2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Texture contrast, occasionally gradational. Heavy clay subsoil. Acidic upper soil. Low nutrient holding capcity in upper soil (depending on organic matter content), higher in subsoil. Surface permeability is moderate to high but low in subsoil. Site drainage is well drained (water shedding).	Texture contrast, occasionally gradational. Heavy clay subsoil. Acidic upper soil. Low nutrient holding capcity in upper soil (depending on organic matter content), higher in subsoil. Surface permeability is moderate to high but low in subsoil. Site drainage is moderately to imperfectly drained (water shedding and receiving)	Texture contrast, occasionally gradational. Heavy clay subsoil. Acidic upper soil. Low nutrient holding capcity in upper soil (depending on organic matter content), higher in subsoil. Surface permeability moderate to high, but low to moderate in subsoil. Site drainage imperfectly to poorly drained (water receiving).

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