Victorian Resources Online (archived)
LP57
| Property: Mitiamo | Group: Pine Grove Farm Advance |
| Australian Soil Classification: Vertic (& Calcic), Mesonatric, Red SODOSOL | Northcote Factual Key: Dr 2.13 |
| Great Soil Group: red-brown earth | General Landscape Description: General Landscape Description: Old alluvial plain. |
| Geology: Quaternary (Shepparton Formation) alluvial and aeolian deposits. | |
 LP57 Landscape |
Soil Profile Morphology
Surface Soil
| A1 | 0-10 cm | Strong brown (7.5YR4/6); fine sandy clay loam; hardsetting surface with 1-2 mm wide cracks extending into the B horizon; weak coarse blocky structure; firm consistence moist; pH 6.4; clear change to: |  LP57 Profile |
| Subsoil | |||
| B21 | 10-30 cm | Reddish brown (5YR4/4); light medium clay; strong medium polyhedral structure; very strong consistence dry; pH 7.6; gradual change to: | |
| B22 | 30-60 cm | Yellowish red (5YR5/6); light medium clay; strong coarse blocky structure; very strong consistence dry; contains a few (5%) fine-earth carbonates and a very few (1%) hard calcareous nodules, as well as a few (2-5%) fine gypsum crystals in the 50-60 cm zone; pH 8.5; gradual change to: | |
| B23 | 60-80 cm | Strong brown (7.5YR5/6) and yellowish red (5YR4/6); heavy clay; strong coarse polyhedral structure; strong consistence dry; contains very few (2%) hard calcareous nodules; pH 8.0; gradual change to: | |
| B24 | 80 cm+ | Light yellowish brown (2.5Y6/4) and yellowish red (5YR5/8); light medium clay; strong medium polyhedral structure; strong consistence dry; pH 8.6. |
Key Profile Features
- Strong texture contrast between surface horizon (clay content 26%) and subsoil (B21) horizon (clay content 56%).
- Hardsetting surface soil - with a high fine sand (46%) and silt (27%) content.
Key Profile Characteristics:
pH | Salinity Rating | |||
Surface (A1 horizon) | slightly acid | low | marginally sodic | none1 |
Subsoil (B21 horizon) | slightly alkaline | low | strongly sodic | strong |
Deeper subsoil (at 1 m) | strongly alkaline | medium - high | strongly sodic | strong |
| 1 Complete dispersion with remoulding. | ||||
 |
Horizon | Horizon Depth | pH (water) | EC 1:5 | NaCl | Exchangeable Cations | |||
Ca | Mg | K | Na | |||||
meq/100g | ||||||||
A1 | 0-10 | 6.4 | 0.18 | 3.2 | 3.6 | 0.6 | 0.5 | |
B21 | 10-30 | 7.6 | 0.19 | 4.8 | 7.5 | 0.9 | 3.2 | |
B22 | 30-60 | 8.5 | 0.99 | 0.16 | 5.7 | 11 | 0.9 | 6.8 |
B23 | 60-80 | 8 | 3.68 | 0.2 | 6.8 | 10 | 0.8 | 8 |
B24 | 80+ | 8.6 | 1.12 | 0.17 | 3.7 | 9.1 | 0.6 | 6.7 |
Horizon | Horizon Depth | Ex Al mg/kg | Ex Ac meq/100g | Field pF2.5 | Wilting Point pF4.2 | Coarse Sand (0.2-2.0mm) | Fine Sand (0.02-0.2mm) | Silt (0.002-0.02mm) | Clay (<0.002mm) |
A1 | 0-10 | 24.2 | 8.7 | 1 | 46 | 27 | 26 | ||
B21 | 10-30 | 32.4 | 18.5 | 1 | 26 | 18 | 56 | ||
B22 | 30-60 | ||||||||
B23 | 60-80 | ||||||||
B24 | 80+ |
Management Considerations:
- In general, management strategies for all soils should aim to increase organic matter levels in the surface soil; minimise the degradation of soil aggregates and porosity; promote the development of stable biopores; improve the calcium status of the ion exchange complex (particularly when sodium is a significant part – i.e. sodic), and break up any hardpans. Less frequent tillage; using less aggressive implements, and working the soil at optimum moisture conditions can all assist in maintaining soil aggregation and porosity as well as reducing the breakdown of organic matter. Practices such as residue retention, minimum tillage and including pasture rotations could be utilised if cropping takes place in order to build up organic matter, reduce erosion risk and increase fertility.
- Plant available water capacity (PAWC) is estimated to be low (estimated at 65 mm) for this profile - based on the laboratory data available. Effective rooting depth will be limited by the strongly sodic.
Surface (A) Horizons
- The surface soil has a low overall nutrient status (based on the sum of the exchangeable basic cations).
- The surface horizon is hardsetting when dry and has a high fine sand and silt content. Upon wetting and drying, the surface sets hard and may become "powdery" when worked in a dry condition. Tillage should be minimised and stubble retention/pasture rotations practised to build up organic matter.
- The organic carbon level is moderate for the surface soil. Soils such as those with high fine sand and silt levels depend on organic matter for monitoring structure. Improving soil organic matter levels will assist in minimising structural problems such as surface sealing and hardsetting as well as improving soil fertility and water holding capacity.
- The surface horizon is maginally sodic and disperses completely after remoulding. This indicates that excessive cultivation or over stocking of the soil in a wet condition may result in dispersion and surface sealing. Gypsum is usually an effective ameliorant on such soils.
Subsoil (B) Horizons
- The coarsely structured subsoil is strongly sodic (together with a low calcium to magnesium ratio) and disperses strongly in water. This is likely to result in restricted water and root movement through the profile.
- The salinity rating becomes medium at a 30 cm depth in the profile. This may restrict the growth of salt sensitive species (e.g. maize and many legumes).
