Marong map unit Osf

Back to: A Land Capability Study of the Rural City of Marong

Map Unit:	Ordovician sediments, very gentle slope	Map Unit Symbol:	Osf
		% of Study Area:	11.4

Land-form diagram for Marong map unit Osf

General Description:
The very gentle sedimentary slopes are a common unit within the Rural City. The associated soils are dominantly red duplex with red brown fine sandy loam top soils, sporadically bleached, hardsetting A2 horizons and whole coloured, red brown medium clay subsoils. Minor soil variations include non existent to fully bleached A2 horizons and yellow mottling in the subsoil. Angular sedimentary rock fragments are found throughout the profile and occasionally on the soil surface.

Site characteristics:

Parent material age:	Ordovician	Depth seasonal watertable:	> 2 m
Lithology:	Sediments	Potential recharge to groundwater:	Low
Landform Pattern:	Undulating rises	Flooding risk:	Nil
Element:	Slope	Drainage:	Moderately well drained
Slope common:	2%	Depth to hardrock:	0.8 m
range:	1 - 3%
Rock outcrop:	0%

Major vegetation: Grey Box, Red Box, Yellow Gum, Golden Wattle, Round-leaf Wattle, Gold Dust Wattle, Hedge Wattle, Black-anther Flax-lily, Spear Grass, Drooping Cassinia, Onion Grass

Present land use: Native forest, grazing, residential (major) cropping (minor)

Land degradation:	Water erosion		Wind erosion	Salting	Acidification
Land degradation:	Sheet/rill	Gully	Wind erosion	Salting	Acidification
Susceptibility	Moderate	High	Low	Moderate	Moderate
Incidence	Low	Moderate	Nil	Low	Low

Soil profile characteristics:

Permeability (measured - average, range):	37, 15 - 88 mm/day
Permeability (estimated):	-
Available water capacity:	112 mm H₂O
Linear shrinkage (B horizon):	14.6%

Soil profile description:

A1	0-13 cm	Dull reddish brown (5YR4/3), fine sandy loam, weak structure, subangular blocky peds 2-5 mm, smooth fabric, moderate firm consistence, a few subangular sedimentary and quartz gravel fragments, moderate organic matter, contains a small sporadically bleached A2 horizon, pH 6.2. Clear transition to
B2	13-54 cm	Dull reddish brown (5YR4/4) medium clay, weak structure, subangular blocky peds 10-20 mm, smooth fabric, very firm consistence, pH 7.3. Clear transition to
B3	54-80 cm	Dull reddish brown (5YR4/4) medium clay, moderate structure, subangular blocky peds 5-10 mm, smooth fabric, moderately firm consistence, many subangular sedimentary gravel fragments, pH 9. Clear transition to
C	80 cm	Rock

Soil classification:

Factual Key (Northcote):	Dr 2.33 (major) Dr 2.13, Dr 3.41 (minor)
Australian Soil Classification:	Subnatric, Red, Sodosol; moderate, medium, loamy, non-gravelly
Unified Soil Group:	CH

Interpretation of soil analyses*

Horizon	pH	Gravel %	E.C. (salts)	Nutrient Status	P	K	Al	Organic Matter	Dispersibility
A1	6.2	2.6	VL	M	D	S	S	H	L
B2	7.3	2.9	M	H	D	S	S	L	VH
B3	9.0	62.9	H	H	D	S	S	VL	L

VL : Very Low; L : Low; M : Moderate; H : High; VH : Very High; D : Deficient; S : Satisfactory; T : Toxic; **: Acid * See Appendix 4 for analytical results

Land capability assessment

Land Use	Class	Major limiting feature(s)/ landuse
Agriculture (CTS values)	C₃T₂S₄	Shallow depth to hardrock, highly susceptible to gully erosion, high gravel/stone content
Effluent disposal (septic tanks)	4	Slow permeability
Farm dams (earthen)	5	Shall depth to hardrock, very dispersible subsoil
Building foundations * slab * stumps/footings	3 3	Moderate drainage Moderate drainage, moderate linear shrinkage
Secondary roads	3	Moderate linear shrinkage, moderate drainage, Universal Soil Group
Urban residential	3	Secondary roads, building foundations
Rural residential	5	Farm dams

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