Victorian Resources Online (archived)
CRC3
Location: Murroa
Australian Soil Classification: Vertic, Mottled-Subnatric, Brown, SODOSOL
General Landscape Description: Undulating rises
Site Description: Lower slope of a gently undulating rise.
Geology: Tertiary/Quaternary basalt.
Soil Profile Morphology:
Surface Soil
| A1 | 0-15 cm | Dark brown (10YR3/3); very fine sandy clay loam; hardsetting; firm consistence (dry); pH 5.2; clear change to: |  CRC3 Profile |
| A21 | 15-25 cm | Brown (10YR5/3); sporadically bleached; very fine sandy clay loam; weak consistence (moist); ferruginous nodules (1-10 mm) common (10%); pH 5.5; clear change to: | |
| A22c | 25-40 cm | Brown (10YR5/3); very fine sandy clay loam; many (40%) ferruginous nodules (1-10 mm); pH 6.2; clear and wavy change to: | |
| Subsoil | |||
| B21 | 40-75 cm | Brown (10YR5/3) with a common amount of yellowish brown (10YR5/8) and red (2.5YR5/8) mottles; medium clay; strong very coarse to coarse prismatic, parting to moderate to strong medium to fine blocky structure; very firm consistence (moist); ferruginous nodules (2-10 mm) common (15%); pH 6.6; wavy and irregular change to: | |
| Note: Some parts of the soil pit have brownish yellow (10YR6/8) with brown (10YR5/3) and strong brown (7.5YR5/6) mottles; medium clay; pockets of strong fine polyhedral structure; firm consistence (moist); many (30%) ferruginous nodules (2-10 mm); pH 7.0: | |||
| B22 | 75-140 cm | Light yellowish brown (10YR6/4) and brownish yellow (10YR6/6) with many dark red (2.5YR4/8) mottles; medium clay; strong very coarse prismatic, parting to strong coarse to very fine lenticular structure; few (5%) ferruginous nodules; manganese stains; pH 7.4: | |
The variability in depth of the bleached surface horizon across the soil pit is the result of gilgai microrelief.
Key Profile Features:
- Very strong texture contrast between surface (A) horizons and subsoil (B21) horizon.
- Conspicuously bleached subsurface (A2) horizon.
- Many ferruginous nodules at the base of the subsurface horizons.
- Vertic properties i.e. slickensides and lenticular peds in the deeper subsoil.
Soil Profile Characteristics:
pH | Salinity Rating | |||
Surface (A1 horizon) | Strongly Acid | Medium | Non-Sodic | None |
Subsoil (B21a horizon) | Slightly Acid | Very Low | Marginally Sodic | None1 |
Deeper subsoil (at 75-140 cm) | Neutral | Low | Sodic | None |
 |
Chemical and Physical Analysis:
Horizon | Horizon Depth (cm) | pH (water) | pH (CaCl2) | 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 | 5.2 | 4.8 | 0.40 | 13 | 15 | 6.4 | 1.8 | 0.5 | 0.2 | 8 | 37 | 23 | 17 | 39 | 15 | ||
A21 | 15-25 | 5.5 | 4.7 | 0.06 | 12 | 8.2 | 3.1 | 1.5 | 0.15 | 0.15 | 18 | 36 | 24 | 18 | 26 | 9 | ||
A22c | 25-40 | 6.2 | 5.2 | <0.05 | <10 | 4.1 | 1.5 | 0.96 | 0.11 | 0.11 | 33 | 32 | 18 | 12 | 19 | 8 | ||
B21 | 40-75 | 6.6 | 5.6 | 0.08 | 10.7 | 6.5 | 8.9 | 0.25 | 1.5 | 4 | 12 | 11 | 72 | 43 | 29 | |||
B22 | 75-140 | 7.4 | 6.6 | 0.21 | 7.4 | 7.2 | 13 | 0.27 | 3.0 | 4 | 14 | 8 | 72 | 50 | 29 | |||
Management Considerations:
Surface (A) Horizons
- The surface soil (upper 25 cm) is strongly acid which indicates that aluminium and manganese toxicity may occur. However, the level of exchangeable aluminium measured at this site is quite low (<13 mg/kg). To confirm this finding, a pH/aluminium test is best performed from samples taken across the paddock and bulked together. Other factors also need to be considered before lime is recommended e.g. pasture species grown, method of application, local trial responses, soil surface structure and likely cost/benefit.
- The dense and marginally sodic upper subsoil is likely to restrict root and water movement more than the subsoils of sites CRC1 and CRC2. Waterlogging is also more likely to occur here as these soils occupy the lower parts of the landscape.
