Soil/Landform Unit - Nurcoung plains

Plains surrounding West Wimmera wetlands near Minimay

Area: 13 861 ha

0.59% of CMA region

This unit of consists of many small occurrences from Minimay in the west to Mitre in the east and also south of the Wimmera Highway east of Miga Lake. This plains complex unit is part of the North West Dunefields and Plains; ridges with sands and flats (5.5). These plains, depressions and

lunettes

Quaternary

sediments occur between the NNW/SSE orientated ridges between the Little Desert (5.2) and amongst more open sand plains and low ridges to the south. Dominated by the plain/open depression, dune slopes (lunettes) also occur. Site drainage is slow to very slow, but moderate on the dune slopes. Predominantly soils are grey and brown cracking clay soils (

Vertosols

) on the plains with sodic yellow, brown and grey texture contrast soils (

Sodosols

) on the dune slopes. Topsoils are often

hardsetting

and shallow, occasionally

self-mulching

. Soil

compaction

is also a susceptibility factor with these heavier soils and soils that are

hardsetting

. Broadacre dryland cropping is the major enterprise with some grazing (sheep, some cattle) depending on climate.

Remnant vegetation consists of a number of vegetation communities including Plains Savannah, Shallow Sands Woodland, Plains Woodland, and Heathy Woodland for example.

Sequence of swamps and plains near Minimay between rises
	Bean crop on lower slopes

Component	1	2
Proportion of soil-landform unit	85%	15%
CLIMATE Rainfall (mm)	Annual: 515

Temperature (^oC)	Minimum 8, Maximum 21
Precipitation less than potential evapotranspiration	September–April
GEOLOGY Age and lithology	Quaternary paludal silt and clay; Quaternary aeolian dune sand (Lowan Sand); Neogene marine sand and silt (Parilla Sand)

Geomorphology	5.5.2 Low ridges and oriented swales of the North West Dunefields and Plains
LANDUSE	Uncleared areas: nature conservation; water supply Cleared areas: dryland cropping; sheep grazing

TOPOGRAPHY Landscape	Plains

Elevation range (m)	123–195
Local relief (m)	3–4
Drainage pattern	Dendritic
Drainage density (km/km²)	0.6
Landform	Gently undulating plains
Landform element	Plain/open depression	Dune slope
Slope and range (%)	2 (1-6)	5 (2-9)
Slope shape	Straight	Convex
NATIVE VEGETATION Ecological Vegetation Class	Plains Woodland (47.8%), Shallow Sands Woodland (14.9%), Plains Savannah (12.1%), Red Gum Wetland (8.9%), Other (16.3%)

SOIL Parent material	Marine sand and silt, paludal silt and clay	Aeolian sand

Description (Corangamite Soil Group)	Grey and brown cracking clay soils (37)	Sodic brown, yellow and grey texture contrast soils (38)
Soil type sites	LS3, LSWW9, LSWW5	LSWW11, LSWW17, LSWW13
Surface texture	Medium clay	Loamy sand
Permeability	Very slow	Moderate
Depth (m)	> 2	> 2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS Critical land features, processes, forms	Susceptible to inundation and waterlogging in depressions. Surface soils friable and only slightly susceptible to wind erosion. Soils susceptible to compaction at critical moisture contents.	Susceptible to wind and sheet erosion where surfaces are exposed. Susceptible to compaction where hardsetting and restricted drainage. Upper soil is susceptible to acidification.

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