Soil/Landform Unit - Darragan rolling rises

Rolling rises to the north-east across a corridor to a former stranded beach ridge

Area: 9491 ha

0.40% of CMA region

Rolling rises south of Horsham represent a sequence of ferruginised Neogene sediments (Parilla Sand) as part of the prominent ridges with eroded ferruginised northern spurs of the North Western Dunefields and Plains (5.5.3). Comprising rolling rises and defined drainage lines, major soils include sodic red and brown texture contrast soils (Sodosols) with cracking clays (Vertosols) confined to lower drainage depressions and flats. Soils are prone to compaction due to hardsetting surfaces that benefit from organic matter contributions to improve soil structure. Land use is variable between dryland cereal cropping, sheep and cattle grazing and occasional intensive industries (e.g. viticulture). Dominant woodland remnant vegetation includes Heathy Woodland, Riverine Chenopod Woodland, Grassy Woodland, Creekline Sedgy Woodland, Plains Woodland and Shallow Sands Woodland. Sandstone Ridge Shrubland is also found along ridges and rises in the landscape.

Ferruginised Parilla Sand cutting
	Looking southwards across cropped plains towards a rolling rise

Component	1	2
Proportion of soil-landform unit	10%	90%
CLIMATE Rainfall (mm)	Annual: 500

Temperature (^oC)	Minimum 8, Maximum 21
Precipitation less than potential evapotranspiration	October–April
GEOLOGY Age and lithology	Neogene marine sand and silt (Parilla Sand); Quaternary alluvium, gravel, sand and silt

Geomorphology	5.5.3 Prominent ridges with eroded ferruginised northern spurs of the North West Dunefields and Plains
LANDUSE	Uncleared areas: nature conservation Cleared areas: dryland cropping; sheep and beef cattle grazing; gravel extraction

TOPOGRAPHY Landscape	Rolling rises

Elevation range (m)	117–193
Local relief (m)	10–15
Drainage pattern	Parallel
Drainage density (km/km²)	0.5
Landform	Rises
Landform element	Creek/drainage line	Rolling to undulating rise
Slope and range (%)	4 (1-7)	6 (3-10)
Slope shape	Convex	Concave
NATIVE VEGETATION Ecological Vegetation Class	Grassy Woodland (35.0%), Plains Woodland (32.5%), Creekline Sedgy Woodland (13.3%), Sandstone Ridge Shrubland (12.6%), Other (6.1%)

SOIL Parent material	Alluvial gravel, sand and silt	Marine sand and silt

Description (Corangamite Soil Group)	Grey and brown cracking clay soils (37)	Sodic red and brown texture contrast soils (40)
Soil type sites	LS3, LSWW9, LSWW5	HOR1, HOR2
Surface texture	Medium clay	Loamy sand
Permeability	Slow	Moderate
Depth (m)	> 2	< 2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS Critical land features, processes, forms	Susceptible to inundation and waterlogging in lower areas. Slightly susceptible to surface sheet erosion where soils are exposed. Surface soils are friable and only slightly susceptible to wind erosion. Soils are susceptible to compaction at critical moisture contents.	Weakly structured or hardsetting upper soil susceptible to sheet and rill erosion especially where significant slopes occur. Sandy surfaces can be susceptible to wind erosion. Dispersive and deep subsoils susceptible to gully erosion on steeper slopes. Ferricrete occurs at depth.

Page top