Marong map unit Osb

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

Map Unit:	Ordovician sediments, steep slope	Map Unit Symbol:	Osb
		% of Study Area:	0.2

Land-form diagram for Marong map unit Osb

General Description:
This unit is located on the steep upper slopes of the metamorphic aureole (Big Hill Range). The soils are very similar to those on the aureole crests; shallow dark grey brown stony loams. The variation being that the soils on the steep slopes tend to be slightly deeper. Surface coarse fragments are common.

Site characteristics:

Parent material age:	Ordovician	Depth seasonal watertable:	> 5 m
Lithology:	Sediments	Potential recharge to groundwater:	Very high
Landform Pattern:	Rolling Hills	Flooding risk:	Nil
Element:	Upper slopes	Drainage:	Rapidly drained
Slope common:	33%	Depth to hardrock:	0.5 m (variable)
Slope range:	30 - 40%
Rock outcrop:	2 - 10%

Major vegetation: Grey Box, Red Ironbark, Buloke, Golden Wattle, Red Stringybark, Hedge Wattle, Cat's Claw Grevillea, Black-anther Flax-lily, Tall Rapswort, Spear Grass, Wallaby Grass, Native bulbs.

Present land use: Native forest, park

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

Soil profile characteristics:

Permeability (measured - average, range):	4705, 1761 - 5904 mm/day
Permeability (estimated):	-
Available water capacity:	95 mm H₂O
Linear shrinkage (B horizon):	1.6%

Soil profile description:

A1	0-17 cm	Brownish black (10YR2/2) fine sandy loam, weak subangular blocky peds less than 2 mm, rough fabric, very weak consistence, abundant angular metamorphic cobbles and stones, pH 5.2. Gradual transition to
B	17-50 cm	Greyish brown (7.5YR4/2) fine sandy loam, weak structure, subangular blocky peds 2-5 mm, rough fabric, moderately weak consistence, less than 2% organic segregations, abundant angular metamorphic cobbles and stones, pH 5.3.
C	50 cm	Rock

Soil classification:

Factual Key (Northcote):	Uc 6.1 (major) Um5.51 (minor)
Australian Soil Classification:	Acidic, Mellic, Grey, Kandosol; moderate, medium, loamy, very gravelly
Unified Soil Group:	GM

Interpretation of soil analyses*

Horizon	pH	Gravel %	E.C. (salts)	Nutrient Status	P	K	Al	Organic Matter	Dispersibility
A	5.2**	68.9	VL	VL	D	S	T	H	L
B	5.3**	57.1	VL	VL	D	S	T	H	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)	C₃T₅S₅	Steep slope, very high gravel/stone/boulder content, very susceptible to sheet erosion
Effluent disposal (septic tanks)	5	Steep slope, excessive permeability – risk of polluting groundwater
Farm dams (earthen)	5	Steep slope, very low suitability of subsoil, shallow depth to hardrock, excessive permeability
Building foundations - slab	5	Steep slope
Building foundations - stumps/footings	4	Steep slope, high risk of slope failure, shallow depth to hardrock
Secondary roads	5	Steep slope
Urban residential	5	Secondary roads, building foundations (slab)
Rural residential	5	Farm dams, effluent disposal, secondary roads, building foundations (slab)

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