Maffra 2 (M2)

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Maffra2- geo

Area: 78 sq. km (0.4%)

The highest parts of the modern flood plains with a less active flood regime and with relatively uniform materials are mapped as Maffra 2 land system. The plains arc almost flat, with few channels or levees, and the alluvium tends to be clayey and relatively pervious.

Generally the length of time since deposition of alluvium and the high organic matter production due to high moisture availability and nutrient-rich parent materials have allowed the development of two different soil types; those with good drainage and those with poorly-drained subsoils. Both of these have friable, black to very dark greyish brown topsoils, rich in organic matter. Soil development has been similar to that in Maffra I land system. but the lower frequency of the poorly-drained soils in Maffra 2 may he explained by the better permeability and/or deeper ground water.

The soils are generally fertile and have a low erosion hazard, but are susceptible to compaction, particularly when wet.

As in Maffra 1, the native vegetation has been almost completely cleared. It was probably also an E. tereticornis grassy open forest II.

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Maffra2- image

A broad. almost flat flood plain without active or relict channels. typical of Maffra 2 land system.

CLIMATE Rainfall, mean (mm) Temperature, mean (°C) Seasonal growth limitations	Annual 500 - 800: lowest July (30 - 50). highest October (50 - 80) Annual 12 - 14; lowest July (8 - 10), highest February (19 - 21) Temperature <10°C (av.): June - August Rainfall < potential evapotranspiration: November – March
GEOLOGY Age, lithology	Holocene alluvium of clays and silts
PHYSIOGRAPHY Landscape Elevation range (m) Relative relief (m) Drainage pattern Drainage density (km/km²)	Almost flat, partly active alluvial plains 20 - 40 0 - 5 Irregular and braided 1.3
PRESENT LAND USE	Cleared: grazing of beef and dairy cattle on improved, often irrigated pastures; some cropping: apiculture

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Maffra2- cs

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Maffra2- graph

LAND COMPONENT Percentage of land system Diagnostic features	1 10 Fans and aprons	2 80 Broad, almost flat flood plains	3 10 Mainly relict flat bottomed channels
PHYSIOGRAPHY Slope %, typical and (range) Slope shape	4, (3 - 5) Straight to concave	1, (0 - 2) Straight	<2, (0 - 3) Concave
SOIL
Parent material		Clayey and silty alluvium
Description	Mostly clayey and silty colluvium from adjacent land systems	Probably mainly black to very dark friable silty loam to clay loam grading into greyish brown to reddish brown clay loam to light clay subsoil	Probably mainly greyish brown topsoil merging into grey. strongly mottled subsoil; textures similar to component 2
Classification	Probably mainly greyish brown loam to clay loam changing abruptly to mottled yellowish brown blocky alkaline clay subsoil	Prairie Soils, some Wiesenboden Um5.52. Uf6.12	Wiesenboden/Humic Gleys Gn3.53
Surface texture	Solodic Soils, sometimes strongly gleyed Dy3.13, Dy3.23	Silty loam to clay loam	Fine and medium textures
Surface consistence	Loam to clay loam	Friable when moist	Friable to firm when moist
Depth (m)	Firm when moist	>2.0	>2.0
Nutrient status	>2.0	Moderate to high
Available soil water capacity	Moderate	Moderate to high
Perviousness to water	Moderate	Slow to moderate
Drainage	Slow	Moderately good to good	Very poor to poor
Exposed stone (%)	Poor to somewhat poor	0	0
Sampled profile number	0-	-	-
NATIVE VEGETATION Structure of vegetation and characteristic species of dominant stratum (+ Predominant species)	Grassy open forest II: E. tereticornis+ Clearing has made it difficult to determine if any other predominant or associated tree species

Disturbance	Affected process and trend	Primary resultant deterioration			Casual activities	Primary off-site process
Disturbance	Affected process and trend	Form	Susceptibility of components	Incidence with components	Casual activities	Primary off-site process
Alteration of vegetation: - reduction in leaf area, rooting depth and/or perenniality	Reduced transpiration, resulting in increased deep percolation and leaching	Nutrient loss	Not determined	Not determined	Reduced plant-water use	Increased movement of water to groundwater; increased base-flow of streams
Increased exposure of surface soil	Increased overland flow and soil detachment	Sheet and rill erosion	2,3; very low 1; low	Uncommon; localised occurrences	Cultivating, overgrazing, road and dam building and other earth-moving activities, trafficking by stock and vehicles.	Increased flash flows, sediment load and turbidity of streams.
Increased physical pressure on soil	Increased compaction With Reduced infiltration	Structure decline Sheet and rill erosion	1.3; moderate 2; moderate-high 2,3; very low 1; low	Not determined Not determined	Increased trafficking cultivation, overgrazing, export of organic matter. As for sheet and rill erosion above	- Increased flash flows
Increased soil disruption	Increased soil break-up	Gully erosion	1,3; very low 2; low	Uncommon	As for sheet and rill erosion above	Increased sediment load.
Comments: Disturbances on adjacent land systems do contribute to sheet, rill and gully erosion.

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