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Munro (Symbol: Mu)

EG220 | Profile No. 8

Geology
Wind-blown sands derived from Neogene (late Tertiary) alluvial sediments. These Late Tertiary sediments form the oldest ‘terraces’ and outwash fans from the uplands. These sand deposits have been mapped as the Munro map unit and form a complex with the Stockdale map unit which is shown on the map as Sd/Mu.

These sediments have been strongly dissected over time and sands were probably derived from windblown material from the many drainage lines. The sands occur over about 30% of the area delineated by the Stockdale/Munro map unit. The soils of the Stockdale map unit are texture contrast soils, with a variable depth of sand or sandy loam overlying clay subsoil whereas the Munro soils are deep sands.

Landform
Rolling low hills. In the late Tertiary it is most likely the area was an alluvial plain but since then has been dissected and subject to periods of aridity, resulting in areas of deep sand cover.


Munro Map unit north-west of Stockdale. These dunes become covered in bracken if the lowland forest is cleared.

Original vegetation
Lowland forest

Soil
The soils of the Munro map unit are deep sands generally with very dark grey acidic sand surface soils overlying paler sands at about 50 cm. These sands may mantle mottled clay but if the sand is sufficiently deep, cemented sands known as ‘coffee rock’ occur in the deeper subsoil, generally around 70 to 90 cm.

Previous maps and reports
This map unit is included within the Stockdale Land System as described by Aldrick et al. (1992).

Land use
Some of the land is cleared, mainly for grazing, but there are large areas of the original vegetation west of the Tambo River and north-west of Lakes Entrance.
These soils may be used for specialised crops (for example, horticulture and floriculture, such as Proteas) if sufficient water is available. As the soils are generally low in organic matter and clay, nutrients will be leached down the soil profile. Wind erosion may also be a problem if the soils are left bare. For crops to be grown, organic matter needs to be maintained or enhanced to improve water retention and regular applications of fertiliser, including dolomitic lime, phosphorus and potassium need to be added.

Site EG220

Location: Lake Tyers	Geo. Ref.: 0597130E 5813020N
Australian Soil Classification: Melacic, Humosesquic, Aeric PODOSOL	Uniform textured deep sand
General landscape description: Rolling low hills
Geology: Tertiary sediments
Site description: Simple mid slope 3% north east
Land use: Grazing
Native Vegetation: Lowland forest
Map unit: Stockdale with Munro

Soil profile morphology

Surface soil

A1	0 – 25 cm	Very dark grey (10YR3/1); sand; apedal, single grain structure; diffuse change to:
A2	25 – 60 cm	Dark grey (10YR4/1); sand; apedal, single grain structure; clear change to:
A3	60 – 75 cm	Greyish brown (10YR5/2); sand; apedal, single grain structure; diffuse change to:
Subsoil
Bhs	75 – 95 cm	Greyish brown (10YR5/2); sand; apedal, single grain structure; with pockets of a mainly very dark brown (10YR3/2) weakly cemented organic pan; clear change to:
C	60 – 90 mm	Light brownish grey (10YR6/2); sand; apedal, single grain structure

Key profile features

• Deep sandy surface.
• Accumulation of iron-organic matter compounds (coffee rock) in the subsoil.

Soil profile characteristics

	pH	Salinity rating	Sodicity	Dispersion	Slaking
Surface soil (A1 horizon)	Strongly acid	Very low	Non-sodic	Minimal aggregation	Minimal aggregation
Subsurface (A2horizon)	Strongly acid	Very low	Non-sodic	Minimal aggregation	Minimal aggregation
Deeper subsoil (70-95 cm)	Moderately acid	Very low	Non-sodic	Minimal aggregation	Minimal aggregation

Horizon	Depth cm	Field texture	pH water	pH CaCl2	EC dS/m	Coarse sand %	Fine sand %	Silt %	Clay %	Field cap. % w/w	Wilt. point % w/w	PAW* water % w/w
A1	0-25	S	5.3	4.2	<0.05	69	20	1	2	10.6	5.4	5.2
A2	25-60	S	5.5	4.3	<0.05	68	24	1	2	8.4	1.5	6.9
A3	60-75	S	5.9	4.8	<0.05	64	27	1	3	6.7	1.2	5.5
Bhs	75-95	S	6.0	5.0	<0.05	58	30	4	4	9.2	2.4	6.8

* PAW refers to plant available water. This is the difference between the soil’s water content at field capacity and wilting point.

Depth	OrgC#	Total N	Free Fe2O3	Exch. Al	Exchangeable cations cmol (+) /kg							Ca:Mg	ESP
cm	%	%	% w/w	ppm	Ca	Mg	K	Na	Total	H	CEC
0-25	1.8	0.085		<10	2.2	0.77	0.18	0.1	3.2	7.1	10.3	2.8
25-60	0.66	<0.05		20	0.76	0.22	<0.05	0.057	1.1	4.0	5.1	3.4
60-75	<0.30	<0.05		<10	0.55	0.38	<0.05	0.077	1.1	1.4	2.5	1.4
75-95	0.5	<0.05		<10	1.1	1.4	<0.05	0.18	2.6	4.9	7.5	0.8

# Organic carbon

Management considerations

• If the soil was under pasture with an effective rooting depth of 70 cm the plant available water capacity is considered to be low estimated at 52 mm. Because of the low wilting points throughout the profile, plants will be able to use very light rains when the soil is dry. Due to the low water storage capacity of the soil, plants will suffer water stress unless further rains occur.
• These strongly acid sandy soils have a low nutrient holding capacity and are considered to be infertile. They are naturally deficient in nitrogen, phosphorus, sulphur and potassium. Nitrate and sulphate are readily removed by leaching. Deficiencies of trace elements such as copper, zinc and molybdenum are likely to occur. The trace element boron (B) leaches rapidly through acid sandy soils and deficiencies are also likely to occur.

Profile No. 8 (Aldrick et al, 1992)

Location: Swan Reach	Geo. Ref.: 0579100E 5812700N
Australian Soil Classification: Melacic, Humosesquic, Aeric PODOSOL	Uniform textured deep sand
General landscape description: Undulating rises
Geology: Tertiary aeolian sediments
Site description: Simple mid slope, N aspect, 8% slope
Land use: Not specified
Map unit: Stockdale with Munro

No photo available but profile would have a similar appearance to EG220.

Soil profile morphology

Surface soil

A11	0 – 20 cm	Black (10YR2/1); loamy sand; single grain; very weak dry; clear smooth change to:
A12	20 – 45 cm	Very dark grey (10YR3/1); loamy sand; massive; very firm moist; clear wavy change to:
A2	45- 87 cm	Pale brown (10YR6/3) conspicuously bleached (10YR7/2); clayey sand; very firm moist; clear wavy change to:
Subsoil
Bhs	87 – 120 cm	Brownish yellow (10YR6/8) with prominent grey mottles; sandy clay loam; weak fine angular blocky structure; very firm moist; clear smooth change to:
C	120 – 140 cm	Brownish yellow (10YR6/8); clayey sand; massive; firm moist.

Key profile features

• Deep sandy profile.
• Leached iron and organic compounds have been precipitated on the sandy clay loam layer below the A horizons.

Soil profile characteristics

Horizon	Depth cm	Field texture	pH water	EC dS/m	Gravel %	Coarse sand %	Fine sand %	Silt %	Clay %	Field cap. % w/w	Wilt. point % w/w	PAW* water % w/w
A11	0-10	LS	5.9	0.05	4	51	24	7	15
A12	30-45	LS	5.2	<0.05	4	63	24	6	4
A2	60-87	CS	6.2	<0.05	6	65	26	3	8
Bhs	90-115	LS	5.8	0.17	14	52	19	7	21
C	120-140	CS	5.4	0.18	16	55	23	8	12

Depth	OrgC#	Total N	Free Fe2O3	Exch. Al	Exchangeable cations cmol(+)/kg							Ca:Mg	ESP
cm	%	%	% w/w	ppm	Ca	Mg	K	Na	Total	H	CEC
0-10	1.8	0.092	0.2		2.3	1.3	0.2	0.1	3.9	7.4	11.3	1.8
30-45	0.73	0.029	0.1		0.2	0.4	0.06	0.1	0.8	5.7	6.5	0.5
60-87	0.13	0.006	0.1		<0.01	0.15	0.03	0.05	0.23	0.83	1.06
90-115	0.11	0.015	1.3		0.1	3.2	0.09	1.2	4.6	5.5	10.1	0.03	12
120-140	0.06	0.011	1.9		0.09	2.0	0.06	1.0	3.2	3.1	6.3	0.05	16

# Organic carbon