Trafalgar (Tr)

	Area: 65 sq. km (0.4%) Alluvial and colluvial outwash material from the South Victorian Uplands has accumulated in a broad apron in the area between Yarragon and Moe and the area is mapped as the Trafalgar land system. The clayey colluvium was derived mainly from soft, Cretaceous sediments and basic volcanics following uplift of the South Victorian Uplands. Surface drainage is often poor but ochreous colours in deeper layers indicate better drainage at depth. Surface wash still occurs but active colluviation now appears to be minimal. The boundary with the Moe land system is indistinct at the more distal parts. The soils have formed mainly on fine-textured colluvium and alluvium under conditions of seasonal wetness, especially in the low-lying areas receiving run-off and seepage water from adjacent hills. The soils of the higher, more-steeply-sloping areas may dry out completely during summer.	The almost flat distal parts of a colluvial apron below the lower slopes of the Strzelecki Ranges from which the material was derived. The more sloping, proximal parts of the apron are just visible.
Mottling is strong in most subsoils and may extend to the surface in places. Moderate nutrient levels are inherited from the source sediments. Erosion hazards are slight but the soils are susceptible to structure decline caused by trafficking and trampling, particularly when wet. The original vegetation, probably dominated by open forest II or III of E. ovata, has been almost entirely cleared.

CLIMATE Rainfall, mean (mm) Temperature, mean (°C) Seasonal growth limitations	Annual 700 - 1200; lowest January or February (40 - 70), highest August or October (90 - 120) 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	Pleistocene — Holocene silty and clayey colluvium and alluvium derived from Cretaceous sediments and Tertiary volcanics
PHYSIOGRAPHY Landscape Elevation range (m) Relative relief (m) Drainage pattern Drainage density (km/km²)	Low-angle outwash fans and aprons 60 - 800 0 - 5 Dendritic 0.8
PRESENT LAND USE	Cleared: grazing of beef and dairy cattle on improved pasture; some apiculture

LAND COMPONENT Percentage of land system Diagnostic features	1 50 Sloping proximal parts of fans and aprons	2 40 Almost flat distal parts of fans and aprons	3 10 Shallow drainage depressions
PHYSIOGRAPHY Slope %, typical and (range) Slope shape	2, (0 - 5) Concave	<1, (0 - 2) Straight to slightly concave	<2, (0 - 2) Concave
SOIL
Parent material	Silty and clayey colluvium and alluvium
Description	Limited observations — probably mainly very dark greyish brown sandy clay loam to light clay topsoil merging into greyish brown strongly mottled subsoil with texture ranging from silty loam to heavy clay; stratified colluvium or alluvium below. Waterlogging during winter and spring common in components 1 and 2
Classification	Wiesenboden; possibly Humic Gleys in component 3 Gn2.81, Gn4.51, Um2.31
Surface texture	Sandy clay loam to light clay
Surface consistence	Friable to firm when moist
Depth (m)	>2.0
Nutrient status	Moderate
Available soil water capacity	Moderate
Perviousness to water	Slow
Drainage	Somewhat poor	Poor to somewhat poor	Very poor
Exposed stone (%)	0	0	0
Sampled profile number	43	-	-
NATIVE VEGETATION Structure of vegetation and characteristic species of dominant stratum (+ Predominant species)	Open forest II: E. ovata + Understorey often includes Melaleuca ericifolia or M. squarrosa Clearing has made it difficult to determine 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 raised watertables	Waterlogging	1; moderate 2,3; high	Common: in low-lying areas	Reduced plant water-use in the catchment	Increased run-on and ponding in low-lying areas
Increased exposure of surface soil	Increased overland flow and soil detachment	Sheet and rill erosion	1; low 2; very low	Uncommon	Overgrazing, cultivating, road and dam building and other earth-moving activities, trafficking by stock and vehicles.	Increased flash flows and sediment load.
Increased physical pressure on soil	Increased compaction With Reduced infiltration	Structure decline Sheet and rill erosion	12,3; low – moderate 1; low 2; very low	Uncommon Uncommon	Increased trafficking, cultivation, overgrazing, export of organic matter As for sheet and rill erosion above	- Increased ponding in low-lying areas
Increased soil disruption	Increased soil break-up	Gully erosion	1,3; low - moderate 2; very low	Uncommon	As for sheet and rill erosion above	Increased sediment load.
Comments: -

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