Victorian Resources Online (archived)
SW78
Location: Yeo
Australian Soil Classification: Bleached-Vertic, Eutrophic, Black CHROMOSOL
General Landscape Description: Gently undulating rises.
Site Description: Flat to gently inclined plain.
Geology: Mapped as Tertiary-Gellibrand Marl
 SW78 Landscape |
Soil Profile Morphology:
Surface Soil
| A1 | 0-10 cm | Very dark grayish brown (10YR3/2 moist), light brownish gray (10YR6/2 dry); fine sandy loam; moderately pedal; pH 5.2; clear change to: |  SW78 Profile. Note: Surface (A1) horizon has been stripped from the soil profile |
| A2e | 10-50 cm | Light brownish gray (10YR6/2 moist), conspicuously bleached (10YR8/1 dry); light fine sandy clay loam; rusty mottles; minor fine gravel and buckshot gravel; apedal; massive; weak consistence; pH 5.8; sharp and slightly wavy change to: | |
| Subsoil | |||
| B21t | 50-80 cm | Black (10YR2/1 moist) with fine, distinct, yellowish brown and red mottles; heavy clay; few, very coarse (>300 mm) prismatic tending to columnar, parting to coarse prismatic and medium angular blocky structure; deep vertical cracks to full depth of trench (>1.7 m); pH 6.4; gradual change to: | |
| B22ss | 80-110 cm | Very dark grayish brown (2.5Y3/2 moist); heavy clay; coarse lenticular structure; slickensides; pH 6.7; diffuse change to: | |
| B23 | 110+ cm | Brown (10YR4/3 moist); distinct, yellowish brown (10YR5/6-5/8 moist) and dark red mottles becoming dominant and prominent at depth; very few (<0.2%) fine rounded buckshot gravel; pH 6.7. |
 |  | |
| Prismatic structure in the B21 subsoil horizon. | Lenticular ped in the B22 subsoil horizon. |
Key Profile Features:
- Strong texture contrast between surface (A) horizons and subsoil (B21) horizon.
Soil Profile Characteristics:
pH | Salinity Rating | |||
Surface (A1 horizon) | Strongly Acid | Low | Non-Sodic | None |
Subsoil (B21 horizon) | Slightly Acid | Very Low | Non-Sodic | None1 |
Deeper Subsoil (at 80-130 cm) | Slightly Acid | Low | Non-Sodic | None |
| 1 Strong dispersion after remoulding. | ||||
| The surface soil is strongly acid. The subsoil is slightly acid. | Salinity rating is low in the surface becoming very low in the subsoil. |
| The clay content increases markedly at the A/B boundary. |
Horizon | Sample Depth (cm) | pH (water) | pH (CaCl2) | EC 1:5 | Exchangeable Cations | |||
Ca | Mg | K | Na | |||||
meq/100g | ||||||||
A1 | 0-10 | 5.2 | 4.6 | 0.14 | 3.6 | 1.1 | 0.26 | 0.29 |
A2 | 25-45 | 5.8 | 5.1 | 0.06 | 2.3 | 1.2 | 0.07 | 0.15 |
B21 | 55-75 | 6.4 | 5.3 | 0.11 | 5.8 | 12 | 0.24 | 1.4 |
B22 | 85-100 | 6.7 | 5.8 | 0.13 | 4.5 | 13 | 0.24 | 1.8 |
B23 | 100+ | 6.7 | 6 | 0.21 | ||||
Horizon | Sample Depth (cm) | Exchangeable Aluminium mg/kg | Exchangeable Acidity meq/100g | Organic Carbon % | Nitrogen % | Field Capacity 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 | 27 | 15 | 7.2 | 0.36 | 30.4 | 10.3 | 9 | 50 | 23 | 10 |
A2 | 25-45 | <10 | 7.4 | 22.2 | 6.1 | 7 | 53 | 20 | 17 | ||
B21 | 55-75 | <10 | 14 | 47.9 | 29.8 | 1 | 12 | 5 | 77 | ||
B22 | 85-100 | <10 | 11 | 48.7 | 29.5 | 2 | 13 | 6 | 79 | ||
B23 | 100+ |
Management Considerations:
Subsoil (B) Horizons
- The subsoil displays vertic features (i.e. slickensides) which indicates that significant shrinking and swelling occurs during wetting and drying cycles. This may have engineering implications and is likely to explain the variability in surface horizon depth across the trench.
- The dense and coarsely structured subsoil will restrict the growth of roots down the profile.
Profile Described By: Richard McEwan (March 1999).
