EGW30

Location: W Tree

Australian Soil Classification: Haplic, Eutrophic, Black DERMOSOL

Map Unit: W Tree (Component 1)
Previous Site Name: EG30

General Landscape Description: Dissected plateau
Site Description: Upper hill-slope, W aspect 7% slope
Land Use: Grazing
Native Vegetation: Valley grassy forest
Geology: Tertiary basalt

Surface soil
A11	0 – 15 cm	Dark brown (10YR3/3); clay loam; moderate medium polyhedral structure; weak consistence moist; few sub-rounded basalt pebbles; pH 6.9; clear change to:
A12	15 – 20 cm	Dark greyish brown (10YR4/2); clay loam; moderate medium polyhedral structure; weak consistence moist; few sub-rounded basalt pebbles ; clear change to:
Subsoil
B1	20 – 30 cm	Very dark greyish brown (10YR3/2); light clay; moderate medium prismatic structure parting to medium polyhedral; very firm consistence moderately moist; few (2 - 10%) sub-rounded basalt pebbles ; pH 6.1; gradual change to:
B21	30 – 75 cm	Very dark greyish brown (2.5Y3/2); heavy clay; strong medium prismatic structure parting to medium polyhedral; very firm consistence moderately moist; few sub-rounded basalt pebbles; pH 6.6; gradual change to:
B22	75 – 85+cm	Very dark greyish brown (2.5Y3/2); heavy clay; strong medium prismatic structure parting to medium polyhedral; very firm consistence moderately moist; many sub-rounded basalt fragments.

• Lack of strong texture contrast between the surface (A11 and A12) and subsoil (B1).

Horizon	Horizon Depth (cm)	pH (water)	pH (CaCl2)	EC dS/m	Organic Carbon %	Total Nitrogen %	Free Fe2O3 % w/w	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
A11	0-15	6.9	6.3	0.12	2.3	0.18		11	25	15	0.9	0.2	14	31	16	24	41.1	24.1
B1	20-30	6.1	5.2	0.11			3.15	15	12	10	0.33	0.47	4	19	36	34	45.8	24.0
B2	30-75	6.6	5.7	0.09			3.77	13	19	21	0.26	0.89	20	11	14	54	49.7	29.7

• The profile is slightly acid throughout.
• These soils are very well drained due to their strongly developed subsoil structure.
• Plant available water capacity is considered to be moderate to high (estimated at 108 mm) based on the laboratory data and an effective rooting depth of 100 cm.

• The soil has a low organic matter content. Organic matter will be better maintained under rotational grazing, which enables stronger pasture recovery, rather than set stocking.
• The nutrient holding capacity of the soil is high (based on the sum of the exchangeable basic cations).
• Although the soils are fairly high in iron oxide, the pH is high enough to minimise phosphorus fixation.
• Potassium levels are high and no response to potassium fertilisers would be expected.

• The friable nature of the subsoil allows deep penetration of plant roots.
• The friable nature of the subsoil, together with the shallow depth to rock, can lead to problems with sealing of earth dams.