Your gateway to a wide range of natural resources information and associated maps

Victorian Resources Online

SW87

Australian Soil Classification: Epihypersodic-Endocalcareous, Self-Mulching, Black VERTOSOLGeneral Landscape Description: Basalt plains, gently undulating plan/rises
Site Description: Gently simple slope, easterly aspect (lunette?)Geology: Quaternary-Newer Volcanics


Soil Profile Morphology:


Surface Soil


A10-15cmVery dark grey (10YR3/1 moist and 10YR4/1 dry); light medium clay; thin self-mulching surface; (note: in trench spoil this material had self-mulched to <5 mm peds); smooth-faced coarse blocky structure below surface; strong consistence, deep cracks to surface; pH 5.7; gradual change to:
South West Gasp Pipeline GP87 Profile
SW87 Profile
Subsoil
B21ss15-50/70 cmBlack (2.5Y2.5/1 moist, dry); heavy clay; strong, coarse (>100 mm) irregular lenticular structure, prominent slickensides increasing in size with depth; pH 8.0; clear and wavy change to:
B22k50/70 cm+Olive brown (2.5Y4/3 moist) and dark yellowish brown (10YR4/6 moist) mottles; white soft calcium carbonate (CaCO3); medium clay to light medium clay; vertic; fine, pH 8.3.


South West Gasp Pipeline GP87 Lenticular
Lenticular peds (B22ss)


Key Profile Features:

  • Shallow self-mulching surface.
  • High (>35%) clay content throughout the soil profile.
  • Vertic features (i.e. slickensides and lenticular peds) in subsoil.
  • Calcium carbonate in deeper subsoil.

Soil Profile Characteristics:

pH
Salinity Rating
Sodicity
Dispersion
Surface
(A1 horizon)
Moderately Acid
Low
None
None1
Subsoil
(B21 horizon)
Moderately Alkaline
Medium - High
Strongly Sodic
Strong
Deeper subsoil
(at 50+ cm)
Strongly Alkaline
Very High
Strongly Sodic
None2
1 complete dispersion after remoulding
2 Possibly due to level of soluble salts.

South West Gasp Pipeline GP87 Graphs

Horizon
Horizon Depth
(cm)
pH
(water)
pH
(CaCl2)
EC
1:5
NaCl
%
Exchangeable Cations
Ca
Mg
K
Na
meq/100g
A1
0-10
5.7
5
0.24
16
12
1.4
1
Bss
35-55
8
7.3
0.76
0.15
15
15
0.8
5.5
Bk
60+
8.7
8.3
1.6
0.35
12
16
0.4
7.2

Horizon
Horizon Depth
(cm)
Ex Al
mg/kg
Ex Ac
meq/100g
Field
pF2.5
Wilting Point
pF4.2
Coarse Sand
(0.2- 2.0 mm)
Fine Sand
(0.02- 0.2 mm)
Silt
(0.002- 0.02 mm)
Clay
(<0.002 mm)
A1
0-10
<10
16
48.5
28.2
9.2
19.6
14
44
Bss
35-55
54
25.6
4.8
19.4
15
55.5
Bk
60+
44.3
23.1
1.8
12.2
9
41


Management Considerations:

Surface (A) Horizon

  • The very high wilting point (i.e. 28%) indicates that plants will be unable to fully utilise light rains, when the soil is dry.
  • Tillage of cracking clay soils should be avoided if the soil is wet (i.e. wetter than the plastic limit). At such moisture conditions, excessive tillage, trafficking or over stocking could result in structural damage (i.e. compaction, smearing) occurring. Ideally tillage and trafficking should take place when the soil is drier than the plastic limit.
  • When the soil is dry, heavy rains will move from soil cracks. This rapid recharge can be valuable for the survival of plants near wilting. When wet, the soil will swell and further infiltration of water will be relatively slow.

Subsoil (B) Horizons
  • The subsoil displays vertic features (i.e. slickensides and lenticular peds) and will therefore experience shrinking and swelling during wetting and drying cycle. This may disturb the roots of some plant species and has engineering implications (e.g. disturbance to building foundations).
  • The dense and coarsely structured subsoil is strongly sodic and disperse strongly in water. This will result in restricted root and water movement into the subsoil.

Notes
  • Bk becomes thicker to the west, of this site whilst immediately to the east the profile is shallow and rocky and has a thick calcium carbonate (CaCO3) layer.


Page top