Location: Clydebank Landcare Group. | Australian Soil Classification: Hypocalcic, Mottled-Subnatric, Brown SODOSOL. |
Great Soil Group: solodic. | Geology: Pleistocene flood plain. (Early Pleistocene torrent gravels occur at 10 m depth). |
General Landscape Description: Level plain above present flood plain. | Mapping Unit: Montgomery [This soil is equivalent to Bundalaguah clay loam as mapped by Skene and Walbran (1948)]. |
Site Description: Dairy grazing paddock. |
Site GP70 Landscape |
A1 | 0-10 cm | Very dark greyish brown (10YR3/2); fine sandy clay loam; weak coarse blocky structure; strong consistence dry; pH 5.4: | Site GP70 Profile |
A21 | 10-30 cm | Very dark greyish brown (10YR3/2) with a slight sporadic bleach; rusty root channel mottling present; fine sandy clay loam; weak coarse blocky structure; strong consistence dry; pH 5.1: | |
A22 | 30-40 cm | Light brown (7.5YR6/4) with very dark brown (10YR3/2) and very faint yellowish brown (10YR5/6) mottles; fine sandy clay loam; moderate coarse prismatic, parting to moderate coarse blocky structure; strong consistence dry; pH 5.9; sharp change to: | |
Subsoil | |||
B21 | 40-80 cm | Strong brown (7.5YR5/8) with brown (7.5YR5/2) mottles; light medium clay; strong coarse prismatic, parting to strong coarse blocky structure; strong consistence dry; dark stains on ped faces; pH 6.9; gradual change to: | |
B22 | 80-120 cm | Brown (7.5YR5/4) with brownish yellow (10YR6/8) mottles [and dark greyish brown (10YR4/2) infill]; dark stains along root channels; light medium clay; strong coarse prismatic structure; strong consistence dry; pH 8.8; gradual change to: | |
B23 | 120+ cm | Reddish grey (5YR5/2) with reddish yellow (7.5YR6/8) and light brownish grey (10YR6/2) mottles; dark stains along root channels; light clay; strong coarse prismatic structure; strong consistence dry; pH 9.3. |
Horizon | pH | Salinity Rating | ||
Surface (A1 horizon) | Strongly Acid | Moderate | Non-Sodic | None1 |
Subsoil (B21 horizon) | Slightly Acid | Low-Moderate | Sodic | Strong2 |
Deeper subsoil (at 1 m) | Strongly Alkaline | Low- Moderate | Strongly Sodic | Complete |
The surface is strongly acid. The subsoil is slightly acid becoming strongly alkaline at 90 cm depth. | The surface is non-sodic. The subsoil is sodic becoming strongly sodic at 75 cm depth. | ||
The surface salinity rating is moderate. The subsoil rating is low to moderate. | The clay content increases significantly at the A/B horizon interface. |
Horizon | Horizon Depth (cm) | pH (water) | pH (CaCl2) | EC 1:5 | NaCl | Exchangeable Cations | |||
Ca | Mg | K | Na | ||||||
meq/100g | |||||||||
A1 | 0-10 | 5.4 | 4.8 | 0.45 | 0.08 | 6.8 | 2.5 | 0.3 | 0.5 |
A21 | 10-30 | 5.1 | 4.5 | 0.26 | 0.06 | 5 | 1.8 | 0.2 | 0.3 |
A22 | 30-40 | 5.9 | 4.8 | 0.19 | 2.9 | 3 | 0.15 | 1.3 | |
B21 | 40-80 | 6.9 | 6 | 0.35 | 3.6 | 6.6 | 0.2 | 1.2 | |
B22 | 80-120 | 8.8 | 7.8 | 0.36 | 2.3 | 7 | 0.2 | 3.4 | |
B23 | 120+ | 9.3 | 8.1 | 0.32 | 1.7 | 5.4 | <0.1 | 3.1 |
Horizon | Horizon Depth (cm) | Exchangeable Aluminium mg/kg | Exchangeable Acidity meq/100g | 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 | 22 | 15.4 | 5 | 30 | 34 | 22 | ||
A21 | 10-30 | 29 | 11.7 | 3 | 34 | 34 | 25 | ||
A22 | 30-40 | <10 | 10.1 | 4 | 36 | 33 | 26 | ||
B21 | 40-80 | <10 | 16.8 | 1 | 29 | 27 | 43 | ||
B22 | 80-120 | 16.5 | 2 | 23 | 37 | 40 | |||
B23 | 120+ |