Soil/Landform Unit 87

Irrigation and cropping of undulating plains and rises for dairy farming is common throughout the landscape

Area:

10 427 ha

0.78% of CMA region

From Princetown, stretching northwards, an undulating plain can be found extending up into the catchment of Kennedys Creek. The southern parts consist of a series of northnorth- west and south-south-east orientated ridges, but the major part of the unit is a plain with a dendritic drainage pattern. The higher parts of the landscape have deeply weathered soils with yellow and red

mottles

. Most slopes, however, carry heavier textured soils with dark coloured and coarsely structured subsoils. They extend up to the crests ridges in many areas; less weathered profiles occupy the lower parts of the landscape. This pattern resembles that found in many other soil-landforms on Paleogene sediments. The distinguishing features here are the dominance of the coarsely structured soils in the landscape, and the absence of ferruginised cappings. Dairy farming is the main land use with pine and blue gum plantations; with only small areas remain under native forest. The coarsely structured subsoils are dispersible and gully and tunnel erosion have occurred. On recently cleared areas, particular care is needed to prevent active gullies from being initiated. Landslips also occur on these soils.

Blue gum and pine plantations are dominant with dairy farming across this landscape
	Soils on gentle rises here are particularly prone to pugging by dairy cattle

Component	1	2	3	4
Proportion of soil-landform unit	20%	65%	6%	9%
CLIMATE Rainfall (mm)	Annual: 950-1050, lowest January (40), highest August (130)
Temperature (^oC)	Annual: 13, lowest July (8.5), highest February (18)
Precipitation less than potential evapotranspiration	Temperature: less than 10^oC (av.) June-August Precipitation: less than potential evapotranspiration November-March
GEOLOGY Age and lithology	Neogene marine marl and calcarenite; Paleogene marine carbonaceous marl, siltstone, sandstone and minor			Recent clay, sand and gravel
Geomorphology	3.3.2 Dissected rolling low hills of the Southern Uplands
LANDUSE	Cleared areas: Dairy farming; beef cattle and sheep grazing; pine and blue gum plantations; water supply Uncleared areas: Water supply; hardwood forestry; nature conservation
TOPOGRAPHY Landscape	Undulating plain
Elevation range (m)	15-150
Local relief (m)	70
Drainage pattern	Predominantly dendritic with some trellis
Drainage density (km/km²)	3.0
Landform	Gentle rises			Alluvial terraces
Landform element	Upper slope and crest	Middle slope	Lower slope
Slope and range (%)	9 (4-15)	10 (4-20)	10 (7-35)	5 (1-9)
Slope shape	Convex	Straight	Concave	(Varialbe - mostly straight)
NATIVE VEGETATION Ecological Vegetation Class	Open forest	Open forest	Open forest	Woodland
Dominant species	E. obliqua, E. viminalis, occasionally E. ovata	E. aromaphloia, E. viminalis, E. obliqua, E. raidata, E. ovata	E. obliqua, E. radiata occasionally E. viminalis	E. ovata, E. obliqua, E. viminalis
SOIL Parent material	Clay and silt	Clay and silt	Clay and silt	Alluvial clay, silt and sand
Description (Corangamite Soil Group)	Mottled brown, grey, yellow and red gradational soils (17)	Yellow-brown gradational soils, coarse texture (22/21)	Grey-brown gradational soils (22/21)	Mottled brown, yellow and grey gradational soils (34)
Soil type sites	OTR746, OTR41	CLRA9, OTR750	CLRA10	-
Surface texture	Fine sandy loam	Fine sandy loam	Fne sandy loam	Sandy loam
Permeability	Moderate	Low	Moderate	Low
Depth (m)	>2	>2	>2	>2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Low inherent fertility phosphorus fixation and steep slopes lead to sheet erosion and nutrient decline.	High dispersible clay subsoils are prone to gully and tunnel erosion. Periodic saturation leads to landslips. Steeper slopes are prone to sheet erosion of nutrient-rich surface horizons.	Steeper slopes are prone to sheet erosion. Dispersible clay susbsoils on moderately steep slopes are prone to gully erosion.	Dispersible clay subsoils of low permeability are prone to gully erosion. high watertables lead to seasonal waterlogging and soil compaction.

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