Victorian Resources Online (archived)
EGC207
Location: Doctors Flat
Australian Soil Classification: Eutrophic, Subnatric, Red SODOSOL
Map Unit: Dargo (Component 1)
Previous Site Name: EG207
General Landscape Description: Rolling low hills
Site description: Mid north-west facing slope (8% slope)
Land Use: Grazing on annual pasture
Native Vegetation: Grassy woodland
Geology: Palaeozoic granite
Soil Profile Morphology:
| Surface soil |  | ||
| A1 | 0 – 15 cm | Dark brown (10YR4/3); sandy loam; weak fine (2 – 5 mm) granular structure; weak consistence dry; clear change to: | |
| A2 | 15 – 20/25 cm | Very pale brown (10YR7/4) conspicuously bleached (10YR8/3d); sandy loam; apedal; very weak consistence dry; many (20 – 50 %) coarse (6 – 20 mm) ferruginous concretions; sharp wavy change to: | |
| Subsoil | |||
| B21 | 20/25 – 45 cm | Yellowish red (5YR5/6); medium clay; moderate medium (10 -20 mm) angular blocky structure; strong consistence dry; diffuse change to: | |
| B22 | 45 – 75 cm | Reddish brown (10YR5/4); medium clay; weak medium (10 -20 mm) angular blocky structure; strong consistence dry; few (2 – 10 %) manganiferous veins; diffuse change to: | |
| B23 | 75 – 110 cm | Light reddish brown (10YR6/4); medium clay with sand; very strong consistence dry; very few (<2 %) manganiferous veins |
Key Profile Features:
- Strong texture contrast between the surface (A) horizons and the subsoil (B) horizons.
Soil Profile Characteristics:
- | pH | Salinity | ||
Surface soil (A1 horizon) | Strongly Acid | Very Low | Non-sodic | None |
Subsoil (B21 horizon) | Slightly Acid | Very Low | Sodic | Slight |
Deeper subsoil (75-110cm) | Strongly Alkaline | Low | None |
Chemical and Physical Analysis:
Horizon | Horizon Depth (cm) | pH (water) | EC dS/m | Organic Carbon % | Total Nitrogen % | Exchangeable Aluminium ppm | Exchangeable Acididty meq/100g | Exchangeable Cations | Coarse Sand (0.2-2.0 mm) % | Fine Sand (0.02-0.2 mm) % | Silt (0.002-0.02 mm) % | Clay (<0.002 mm) % | Field Capacity % w/w | Wilting Point % w/w | |||
Ca | Mg | K | Na | ||||||||||||||
meq/100g | |||||||||||||||||
A1 | 0-15 | 5.1 | 0.1 | 1.6 | 0.12 | 16 | 6.3 | 1.3 | 0.52 | 0.48 | 0.11 | 43 | 37 | 9 | 4 | 11.8 | 3.6 |
A2 | 15-20/25 | 5.5 | <0.05 | 0.66 | <0.05 | 19 | 4.6 | 0.79 | 0.52 | 0.24 | 0.07 | 41 | 38 | 11 | 6 | 11.5 | 2.5 |
B21 | 20/25-45 | 6.5 | 0.08 | 0.54 | 2.5 | 4.8 | 9.1 | 1.1 | 0.82 | 12 | 26 | 12 | 47 | 31.1 | 18.2 | ||
B22 | 45-75 | 7.6 | 0.14 | 0.41 | 3.6 | 11 | 0.39 | 1.5 | 20 | 28 | 13 | 36 | 26.9 | 14.8 | |||
B23 | 75-110 | 8.7 | 0.33 | 0.3 | 21 | 23 | 12 | 40 | 33.7 | 17.4 | |||||||
Management Considerations
Whole profile
- Plant available water content for this profile is considered to be low, as the effective rooting depth is largely limited to the surface horizons due to the dense and coarsely structured nature of the subsoil.
- The low wilting points (3.5 and 2.5 %) of the surface soils indicates the plants are able to utilize very light rains when the soil is dry. However, due to the low water storage capacity, plants will soon suffer moisture stress unless further rains occur.
- The surface soil is strongly acid. However the level of exchangeable aluminium is reasonably low (16 mg/kg) and is unlikely to affect the growth of aluminium sensitive species, except the most sensitive. Lime can be used to increase soil pH but a pH/aluminium test is best performed by taking samples across the paddock and bulked together. The use of test strips to observe lime response could be used as an aid in evaluating its cost/benefit. For this soil a response to lime (about 1-2 tonnes/ha) would be expected.
- The organic matter content of the soil is low. Such levels result in a poor to moderate structural condition and low to moderate structural stability.
- Potassium is at a moderate level for pastures and no response to potassium fertilisers would be anticipated.
- Salinity is not a problem in the surface soil.
- The nutrient holding capacity of the surface (A1 and A2) horizons is very low (based on the sum of the exchangeable calcium, magnesium, potassium and sodium cations).
- Root and water movement is likely to be restricted in the dense and coarsely structured subsoil although the red colour of the subsoil indicates the soil is generally well drained.
- The roots tend to follow cracks between the soil aggregates and can only extract part of the soil water.
- The subsoil and the deep subsoil are slightly dispersive but slake considerably. If the subsoil is exposed, for example by a gully head, headward erosion is highly likely.
Profile Described By: Heather Adams, Julieanne Sargant and Ian Sargeant, June 2009.
