Marong map unit Qa2

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

Map Unit:	Quaternary alluvium, terrace (Loddon River lower)	Map Unit Symbol:	Qa2
		% of Study Area:	0.1

Land-form diagram for Marong map unit Qa2

General Description:
The lower terrace of the Loddon River occurs intermittently between Newbridge and Laanecoorie. The soil is young and consists of two separate layers representing different periods of river deposition. The top layer is a greyish yellow silty loam. The buried layer is a brownish grey silty loam over a silty clay loam. Mottles are common at depth.

Site characteristics:

Parent material age:	Quaternary	Depth seasonal watertable:	>2 m
Lithology:	Alluvium	Potential recharge to groundwater:	Low
Landform Pattern:	Alluvial terrace	Flooding risk:	High
Element:	Flat	Drainage:	Moderately well drained
Slope common:	0 %	Depth to hardrock:	> 2.0 m
Slope range:	0 - 1 %
Rock outcrop:	0 %

Major vegetation: Red Gum, Yellow Box, Round-leaf Wattle, Wallaby Grass, Variegated Thistle, Clover, Onion Grass, Nettles

Present land use: Recreational area, grazing

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

Soil profile characteristics:

Permeability (measured - average, range):	22, 8 - 29 mm/day
Permeability (estimated):	-
Available water capacity:	220 mm H₂O
Linear shrinkage (B horizon):	8.5

Soil profile description:

A	0 - 26 cm	Greyish yellow brown (10YR5/2) silty loam, moderately weak structure, subangular blocky peds 10-20 mm, rough fabric, moderately weak consistence, moderate organic matter, pH 6.8. Abrupt transition to
B	26 - 39 cm	Greyish yellow brown (10YR5/2) silty loam, a few faint yellow mottles, moderately weak structure, subangular blocky peds 10-20 mm, rough fabric, moderately weak consistence, pH 7.2. Abrupt transition to
2A	39 - 71 cm	Brownish grey (10YR/4/1) silty loam, weak structure, angular blocky peds 10-20 mm, smooth fabric, moderately weak consistence, pH 7.2. Gradual transition to
2B21	71 - 89 cm	Brownish grey (10YR4/1) silty clay loam, weak structure, subangular blocky peds 10-20 mm, smooth fabric, moderately weak consistence, moderate organic matter, pH 7.2. Clear transition to
2B22	89 - 140 + cm	Brownish grey (10YR4/1) silty clay loam, common distinct yellow/brown mottles, weak structure, angular blocky peds 10-20 mm, smooth fabric, moderate organic matter, pH 7.2.

Soil classification:

Factual Key (Northcote):	Um 6.14
Australian Soil Classification:	Haplic, Eutrophic, Grey, Dermosol; very deep, medium, silty, non-gravelly
Unified Soil Group:	CL

Interpretation of soil analyses*

Horizon	pH	Gravel %	E.C. (salts)	Nutrient Status	P	K	Al	Organic Matter	Dispersibility
A	6.8	< 1	VL	M	D	S	S	M	M
B	7.2	< 1	VL	M	D	S	S	M	M
2A	7.2	< 1	VL	M	S	S	S	M	M
2B21	7.2	< 1	VL	M	S	S	S	L	H
2B22	7.2	< 1	VL	M	S	S	S	L	H

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)	C₃T₁S₃	Moderately dispersible topsoil, climate
Effluent disposal (septic tanks)	5	High risk of flooding
Farm dams (earthen)	5	Low suitability of subsoil, highly dispersible subsoil
Building foundations - slab	5	High risk of flooding
Building foundations - stumps/footings	5	High risk of flooding
Secondary roads	5	High risk of flooding
Urban residential	5	Secondary roads, building foundations
Rural residential	5	Effluent disposal, secondary roads, building foundations

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