Soils on Basaltic Terrain

Tbs - Tertiary Basalt - Steep | Tgn - Upper Tertiary Plains | Tgp - Lower Tertiary Sediments - Gentle | Tsc - Upper Tertiary Scarps | Tsp - Lower Tertiary Sediments - Steep

Tgn - Upper Tertiary Plains

Land Capability Study - Ballan - Land Unit - Upper Tertiary Plains - TgnThis unit consists of fairly deep soils on unconsolidated Tertiary sands, clays and gravels in a gently undulating plain scattered throughout the central and southern parts of the Shire. The unit occupies 7.38% of the survey area or 68.4 km2. The main uses of these areas are grazing and sand and gravel extraction. Some of the poorer areas have been left forested with low quality timber. Some extensive flat areas to the south of the Shire are poorly drained (as component 3). Also in the South of the Shire, there are some outcrops of quartzite of pedological origin.

TGN Red Mottled Yellow Duplex Soils

Factual Key Dy 3.41/SL-FSL, 10-40/tertiary sediments, 100-150

Horizon
Depth (cm)
Description
A1
0-10
Dark brown (7.5YR 3/4) when moist; sandy loam; weak sub-angular blocky 10 mm; consistence when slightly moist is firm; pH 5.0; abrupt boundary.
A2
10-20
Dull yellowish brown (10YR 5/4) when moist; sandy loam; apedal & massive; consistence when slightly moist is firm; 50% buckshot concentrated at A/B boundary; pH 6.0; abrupt boundary.
B1
20-35
Yellowish brown (10YR 5/6) when moist; few distinct red mottles; medium clay; strong angular blocky 2 mm; consistence when slightly moist is firm; 4% buckshot; pH 5.5; diffuse boundary.
B2
35-150
Yellowish brown (10YR 5/6) when moist; with abundant distinct red mottles; medium clay; strong angular blocky 2 mm; consistence when slightly moist is firm; 4% buckshot; diffuse boundary.
C
150+
Weathering tertiary sediments.

COMPONENT
Proportion %
1
2
3
4
70
2
15
13
CLIMATE
Rainfall(av.) mm
650 – 900
Temperature(av.) °C
-
Seasonal growth limitations
-
GEOLOGY
Age, rock
Tertiary; gravels, sands and clays
TOPOGRAPHY
Landscape
Plains
Elevation (range) m
400
Local relief (av.) m
3
Drainage pattern
Dendritic
Drainage density km/km2
4.4
Land form
Undulating plain
Undulating plain
Flat plain
Drainage lines
Position on land form
Well drained non-sandy areas
Patches of deep sandy soil
Poorly drained non-sandy areas
Low lying areas
Slope (range) %, slope shape
1 – 3; Convex
1 – 3; Convex
0 – 2; Flat
1 – 3;; Concave
NATIVE VEGETATION
Structure
Low open forest – woodland
Dominant species
Callitris columellaris in lower stratum (south of Shire area)
E. viminalis, E. obliqua, E. radiata, E. rubida, E. ovata, (E. pauciflora – Durdidwarrah area)


Pteridium esculentum,
E. viminalis


E. ovata
E. ovata
SOIL
Parent material
Unconsolidated gravel, sand and clay
Unconsolidated sand
Unconsolidated gravel, sand and clay
Unconsolidated gravel, sand and clay
Description
Red mottled, yellow duplex soil, fine structure
Yellow sand soil, uniform texture
Yellow sodic duplex soil, coarse structure
Mottled yellow duplex soil
Surface texture
Sandy clay loam to loamy sand
Sand
Clay loam
Clay loam, sandy clay loam
Permeability
Moderate
High
Low
Moderate
Depth (range) m
2
2
2
2
LAND USE
Grazing, gravel, extraction, mining
SOIL DETERIORATION
Critical land features
Hard setting surfaces, dispersibility, permeability
Low water holding capacity, low nutrient holding capacity
Hard setting surfaces, permeability
Hard setting surfaces, permeability
Processes
Leaching of salts, overland flow
Leaching
Leaching of salts, overland flow
Some accumulation of salts, overland flow
Forms
Sheet and rill erosion, gully erosion
Fertility decline
Surface compaction, sheet erosion
Sheet and rill erosion, minor gully erosion. Salting, especially when adjacent to ordovician sediments.

Tgp - Lower Tertiary Sediments - Gentle

Land Capability Study - Ballan - Land Unit - Lower Tertiary Sediments - Gentle - TgpThis unit consists of gentle rises and elopes in the Parwon Valley with brown sodic duplex soils derived from Tertiary sands and silt clay. It has been separated from Tsp on the basis of gentler slopes, soil type and vegetation. The unit covers 0.85% of the Shire or 7.9 km2. It is used mainly for grazing although some parts have been cropped for cereals. The erosion hazard is moderately high but is much less than for Tsp.

TGP Brown Sodic Duplex Soils

Factual Key Dy 3.43/FSL, 10-30/tertiary sediments

Horizon
Depth (cm)
Description
A1
0-15
Greyish yellow brown (10YR 4/2) when moist; fine sandy loam; hydrophobic; apedal & massive; consistence when dry is very hard; pH 6.5; clear boundary.
A2
15-25
Greyish yellow brown (10YR 5/2) when moist; with few faint yellow mottles; fine sandy loam; apedal & massive; consistence when dry is very hard & when wet is spewy; pH 6.5; clear boundary.
B1
25-55
Dull yellow (2.5YR 6/4) when moist; with abundant & distinct yellow mottles; sandy clay; weak prismatic 150 mm; breaking down to weak sub-angular blocky 30 mm; consistence when slightly moist is hard; 3% buckshot 5 mm; pH 8.5; abrupt boundary.
B2
55-85
Greyish yellow (2.5YR 7/2) when moist with abundant and prominent yellow mottles; sandy clay; weak prismatic 150 mm breaking down to moderate sub-angular blocky 30 mm; consistence when slightly moist is hard; pH 9.0; clear boundary.
C
85+
Unconsolidated tertiary sediments (yellow mottled white silty clay).

COMPONENT
Proportion %
1
100
CLIMATE
Rainfall(av.) mm
500 – 630
Temperature(av.) °C
-
Seasonal growth limitations
-
GEOLOGY
Age, rock
Tertiary sand & silty clay
TOPOGRAPHY
Landscape
Gentle rises & slopes in the Parwan Valley
Elevation (range) m
240 – 270
Local relief (av.) m
40
Drainage pattern
Dendritic
Drainage density km/km2
0.3
Land form
Undulating plains
Position on land form
-
Slope (range) %, slope shape
3 – 10 ; Convex
NATIVE VEGETATION
Structure
Woodland (?)
Dominant species
E. leucoxylon, E. melliodora
SOIL
Parent material
In-situ weathered rock
Description
Brown sodic duplex soils
Surface texture
Fine sandy loam
Permeability
Moderate
Depth (range) m
1
LAND USE
Grazing, some cereal cropping
SOIL DETERIORATION
Critical land features
Hard setting surfaces, dispersible sub-soils
Processes
Overland flow, movement of salt
Forms
Sheet, gully, tunnel erosion

Tsc - Upper Tertiary Scarps

Land Capability Study - Ballan - Land Unit - Upper Tertiary Scarps - TscThe unit is composed of the level upper surface of late Tertiary sediments which have been partially buried by the Quaternary lava flow and later exposed where streams have cut down through the basalt due mainly to rejuvenation associated with faulting, or where the more recent lava has terminated. The unit is mainly used for grazing and has a high erosion hazard. The unit extends over 17.0 km2 or 1.83% of the survey area.

Soils
Due to the variability of the parent material and, in places, to the influence of the colluvium from the basalt cap there is a wide spectrum of soils. A very strong volcanic influence can be inferred by the very dark clayey, well-structured horizons.

TSC Black Uniform Soils

Factual Key Ug 5.11/Mc, 50-70/Volcanic colluvium over tertiary gravels.

Horizon
Depth (cm)
Description
A110-25Brownish black (10YR 2/2) when moist; medium clay; strong sub-angular blocky 3mm; (self-mulching); consistence when dry is hard; pH 6.5; clear boundary.
A1225-60Brownish black (10YR 2/2) when moist; medium clay; moderate prismatic breaking into moderate sub-angular blocky 3 mm; consistence when dry is very hard; 5% of stones; pH 7.0; clear boundary.
BC60-190Dark brown (10YR 3/3) when moist; medium clay; moderate to angular blocky 3 mm; 70% stones; pH 7.5; clear boundary to tertiary gravels.

COMPONENT
Proportion %
1
2
3
85
5
10
CLIMATE
Rainfall(av.) mm
650 - 900
Temperature(av.) °C
-
Seasonal growth limitations
-
GEOLOGY
Age, rock
Tertiary gravel, sands & clays plus colluvium from basalt
Tertiary ironstone
Tertiary, quartzite
TOPOGRAPHY
Landscape
Original Tertiary plain, partially buried by Quaternary lava flow
Elevation (range) m
243
Local relief (av.) m
10
Drainage pattern
-
Drainage density km/km2
-
Land form
Scarp
Rise
Outcrop
Position on land form
-
-
-
Slope (range) %, slope shape
30 ; Straight – concave
2 ; Straight
1 ; Straight
NATIVE VEGETATION
Structure
Open forest (?)
Dominant species
E. obliqua, E. viminalis, E. radiata
SOIL
Parent material
Alluvial & colluvial basalt and unconsolidated gravels, sands and clays
Ironstone
Quartzite
Description
Black Uniform Soils
Reddish Shallow Uniform Soil
Brown Shallow Uniform Soil
Surface texture
Clay
Loam
Loam
Permeability
Moderate
High
High
Depth (range) m
1
0.10
0.10
LAND USE
Grazing, occasional cropping (market garden)
Grazing
SOIL DETERIORATION
Critical land features
Slopes
Exposure, rooting depth
Processes
Overland flow
Overland flow
Forms
Sheet and rill erosion
Sheet, rill and wind erosion

Tsp - Lower Tertiary Sediments - Steep

Land Capability Study - Ballan - Land Unit - Lower Tertiary Sediments - Steep - TspThis unit is the deeply dissected plain of the Parwan Valley with isolated hills, some of which have volcanic capping. The unit contains some of the most serious soil erosion in Victoria and as it is in a water supply catchment needs special management. The unit covers 32.2 km2 or 3.47% of the survey area. It is used for grazing although some parts should revert to forestry.

Soils
The presence of many active landslips and the influence of colluvium from the basalt cap at the top of the scarp has produced a soil which can be extremely variable over short distances. The soil described is one showing some basalt influence.

TSP Shallow Sodic Gradational Soils, Coarse Structure

Factual Key Gn 3.13/CL-LC, 5-15/Tertiary sediments, 30-50

Horizon
Depth (cm)
Description
A
0-13
Dark brown (7.5YR 3/3) when moist; light clay; moderate sub-angular blocky 5 mm; consistence when slightly moist is firm; 15% of gravel; pH 6.0; clear boundary.
B
13-35
Dark brown (10YR 3/3) when moist; clay; strong angular blocky 25 mm; consistence when moist is firm; 2% weak accumulations of organic matter; pH 8.5; diffuse boundary.
C
35-150+
Dull yellow orange (10YR 6/3) when moist; silty clay; pH 9.0.

COMPONENT
Proportion %
1
100
CLIMATE
Rainfall(av.) mm
500 – 630
Temperature(av.) °C
-
Seasonal growth limitations
-
GEOLOGY
Age, rock
Tertiary sands & silty clays
TOPOGRAPHY
Landscape
Deeply dissected plain with isolated hills, some of which have volcanic capping
Elevation (range) m
240 – 400
Local relief (av.) m
130
Drainage pattern
Dendritic
Drainage density km/km2
1
Land form
Closely dissected plain
Position on land form
Crests and slopes
Slope (range) %, slope shape
15 – 35; Concave
NATIVE VEGETATION
Structure
Woodland (?)
Dominant species
E. leucoxylon, E. melliodora, E. microcarpa
SOIL
Parent material
In-situ weathered rock
Description
Shallow sodic gradational soil, coarse structure
Surface texture
Light clay
Permeability
Moderate
Depth (range) m
1
LAND USE
Grazing
SOIL DETERIORATION
Critical land features
Slope, structure, dispersibility, hard-setting surface
Processes
Leaching, overland flow, sub-surface flow, movement of salt
Forms
Severe landslip, sheet, gully, tunnel erosion

Tbs - Tertiary Basalt - Steep

Land Capability Study - Ballan - Land Unit - Tertiary Basalt - Steep - TbsThis unit consists of the steeply dissected Tertiary basalt plain in the Greendale area and around Pykes Creek Reservoir. The area has quite good black clay soils which are presently used for grazing and in gentler sloping areas, some cereal cropping. The latter could possibly be used more intensively. The unit repre­sents 1.07% of the Shire and covers 9.9 km2.

TBS Black Clay Soils Uniform Texture Coarse Structure,

Factual Key Ug 5.12/LC-MC, 5-20/Basalt, 25-50
Horizon
Depth (cm)
Description
A11
0-5
Brownish black (7.5YR 2/2) when moist; light medium clay; strong angular blocky 3 mm (self-mulching); consistence when moist is friable; pH 5.5; clear boundary.
A12
5-25
Brownish black (7.5YR 2/2) when moist; medium clay; strong angular blocky 5 mm; consistence when moist is friable; pH 6.5; clear boundary.
25+
Weathering basalt.

COMPONENT
Proportion %
1
2
90
10
CLIMATE
Rainfall(av.) mm
685 – 736
Temperature(av.) °C
-
Seasonal growth limitations
-
GEOLOGY
Age, rock
Tertiary basalt
TOPOGRAPHY
Landscape
Deeply dissected plains in the Greendale area
Elevation (range) m
400 – 550
Local relief (av.) m
40
Drainage pattern
Dendritic
Drainage density km/km2
1.8
Land form
Scarps & slopes
Stony areas
Position on land form
-
Localised surface capping
Slope (range) %, slope shape
8 – 50 ; Convex
1 – 3 ; Convex
NATIVE VEGETATION
Structure
Open forest (?)
Dominant species
E. viminalis, E. ovata
SOIL
Parent material
Description
Black clay soils, uniform texture, coarse structure
Red shallow gradational soil
Surface texture
Clay
Clay loam
Permeability
Moderate
High
Depth (range) m
1
<1
LAND USE
Grazing; cropping (cereal)
Grazing
SOIL DETERIORATION
Critical land features
Slopes, permeability
Slopes
Processes
Overland flow – Subsurface flow
Overland flow
Forms
Sheet erosion – Landslip
Sheet erosion
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