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Anderson 2 (A2)

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Anderson2 - geoArea: 392 sq. km (1.9%)

In contrast to Anderson 1, the Anderson 2 land system occurs close to the margins of both the East Victorian Uplands and South Victorian Uplands on the Tertiary fan deposits which, compared with most of the lowlands, are deeply dissected. This dissection is due to the higher than usual elevation and steeper slopes of the deposits, and the coarse and relatively unconsolidated materials. Anderson 2 land system has rounded hills with moderate slopes and a broad dissection pattern. Anderson 1, Stockdale and Salt Creek land systems also occur on unconsolidated sediments with similar topography; however, the latter occur in a drier climate further to the east. Also Stockdale has sandier sediments and Salt Creek has E. tereticornis forests.
A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Anderson2 - imageSteeper open slopes with Eucalyptus obliqua (messmate stringybark) typical of component 2.
The soil parent materials vary over short distances; dominantly silty or clayey, sometimes sandy. Yellowish brown, mottled, duplex soils are typical, but there is some variation within this group, for example, subsoil reaction varies from acidic to slightly alkaline. Where sandy, rather deep horizons overlie clays, iron cementation may occur at the interface of sand and clay. Podzols with coffee-rock occur on the small areas of deep sands, mainly in component 2.

The sandy topsoils of duplex profiles are particularly susceptible to sheet erosion while the neutral to alkaline dispersive subsoils are susceptible to gully erosion. The deeper, sandy horizons present little resistance to leaching.

The native vegetation that remains is mainly open forest II or III, occasionally shrubby. Similar forests probably covered most of the land system prior to clearing.

CLIMATE
Rainfall, mean (mm)
Temperature, mean (C)
Seasonal growth limitations

Annual 700 - 1200; lowest January (40 - 70), highest October (70 - 100)

Annual 12 - 14; lowest July (8 - 10), highest February (19 - 21)
Temperature <10C (av.): June - August
Rainfall < potential evapotranspiration: November – March
GEOLOGY
Age, lithology

Tertiary fan and colluvial apron deposits; gravels, sands, silts and clays
PHYSIOGRAPHY
Landscape
Elevation range (m)
Relative relief (m)
Drainage pattern
Drainage density (km/km2)

Dissected relict coalescing fans marginal to the uplands

40 - 380
40 - 140
Dendritic
1.2
PRESENT LAND USEMostly cleared: grazing of dairy and beef cattle and sheep on improved pastures; some softwood plantations
Minor proportion uncleared: hardwood forestry (minor timber products); small areas in Morwell National Park

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Anderson2 - csA study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Anderson2 - graph

LAND COMPONENT
Percentage of land system
Diagnostic features
1
95
Crests and uneven, gentle to moderate slopes, occasionally steep
2
5
Valley flats
PHYSIOGRAPHY
Slope %, typical and (range)
Slope shape
7 - 15, (0 - 40)
Variable
2, (0 - 5)
Straight
SOIL
Parent material
Very variable: sand, clay or gravel
Variable alluvial material
Description
Dark sandy loam to sandy clay loam topsoil grading into pale subsurface soil of similar texture, generally abruptly overlying brown to yellowish brown mottled clay subsoil; silica cementation common in the subsurface. Minor areas of deep sand with brown, variably cemented rock at depth, locally overlying clay.
No observations – vary with parent materials; probably mainly medium to heavy textured and greyish brown with mottles; possibly sometimes with deep sandy topsoil.
Classification
Mostly Yellow Podzolic Soils, Soloths and Solodic Soils; some Yellow Earths and Podzols
Mainly Dy3.42; some Gn3.85 and Uc2.32, Uc2.34, Uc4.22, Uc4.32
Humic Gleys likely
Surface texture
Mainly sandy loam to sandy clay loam; sometimes sand
-
Surface consistence
Slightly hard to hard when dry, but soft or loose if very sandy
-
Depth (m)
>2.0
-
Nutrient status
Low, very low for sands
>2.0
Available soil water capacity
Generally moderate; very low for sands
Probably low
Perviousness to water
Mostly slow; very rapid for deep sands
Variable
Drainage
Mostly somewhat poor; somewhat excessive for deep sands
Variable
Exposed stone (%)
0
0
Sampled profile number
47
-
NATIVE VEGETATION
Structure of vegetation and characteristic species of dominant stratum
(+ Predominant species)
Open forest II, III:
Composition variable — usually one or more of E. obliqua,
E. bridgesiana, E. consideniana and E. radiata predominant.
E. ovata (on poorly drained sites), E. sieberi and E. cephalocarpa
associated
Open forest II or III:
Variable composition including E. cypellocarpa+,
E. viminalis+, E. obliqua and E. radiata

Disturbance
Affected process and trend
Primary resultant deterioration
Causal activities
Primary off-site process
FormSusceptibility of componentsIncidence within components
Alteration of vegetation:
— reduction in leaf area, rooting
depth and/or perenniality
Reduced transpiration, resulting in:

a) increased deep percolation and leaching



b) increased infiltration and regolith wetness



Nutrient loss




Landslip and/or soil creep



1; low, but high in areas of deep sand



1; low



Not determined




Uncommon



Removal of trees




Usually after the removal of trees from steeper land



Increased movement of water to groundwater; increased base-flow of streams

Increased sediment load

Increased exposure of surface soilIncreased overland flow and soil detachmentSheet and rill erosion1; moderate - highCommonClearing. Logging, burning, overgrazing, road and dam building and other earth-moving activities, rabbit burrowing, trafficking by stock and vehicles.Increased flash flows and sediment load.
Increased physical pressure on soilIncreased compaction

with

reduced infiltration
Structure decline



Sheet and rill erosion
1; low
2; moderate - high


1; moderate - high
Uncommon



Common
Increased trafficking and cultivation, overgrazing, export of organic matter

As for sheet and rill erosion above
-



Increased flash flows
Increased soil disruptionIncreased soil break-up


Increased loosening of sand
Gully erosion


Wind erosion
1,2; moderate - high


1; moderate on sandy soils
Local occurrence


Uncommon
As for sheet and rill erosion above.

Trafficking, overgrazing, rabbit burrowing, cultivating, earthmoving activities.
Increased sediment load.

Encroachment by sand.
Comments: -
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