EGW110

Location: Limestone Road, Benambra

Australian Soil Classification: Acidic, Bleached-Orthic TENOSOL

Map Unit: Cobungra (Component 1)

General Landscape Description: Rounded low hills
Site description: Upper mid slope
Land Use: Grazing on annual pasture
Native Vegetation: Montane grassy woodland
Geology: Palaeozoic granite

Surface soil
A1	0 – 10 cm	Dark greyish brown (2.5YR4/2); coarse sandy loam; weak blocky structure; very weak consistence dry; pH 6.2; clear change to:
A2	10 – 50 cm	Light yellowish brown (7.5YR6/4), conspicuously beached (10YR8/4d); coarse sandy loam (light); apedal; very weak consistence dry; pH 5.0; gradual change to:
A3	50 – 70+ cm	Yellowish brown (10YR5/6); coarse heavy sandy clay loam; apedal; pH 5.0.

• The sandy and hard setting nature of the soil profile.

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	0-10	6.2	0.07	4.0	0.1	<10	4.8	5.6	1.0	0.31	0.05	38	31	18.0	9	23.9	6.0
A2	10-50	5.0	<0.05			83	4.8	0.94	0.26	0.16	0.06	33	36	22.0	8.0	18.2	3.6
A3	50-70	5.0	<0.05			83	3.7	0.81	0.42	0.18	0.07	38	31	22.0	10	17.5	4.4

• Plant available water is considered to be quite low estimated to about 34 mm based on an effective rooting depth of 25 cm. This is due to the dense and hard-setting nature of the soil below this layer.
• The apedal deep subsoil nature of the subsoil could lead to tunnel and gully erosion in the wetter parts of the landscape.

• The surface soil is moderately acid. However, given the nature of the strongly acidic nature of the subsoil, its higher pH may be due the proximity of the profile to Limestone Road and be elevated by dust originating from the road. Soil tests are best performed by taking samples across the paddock and bulked together. The aluminium is low (<10 mg/kg) and is unlikely to affect the growth of aluminium sensitive species
• Potassium levels are bordering on deficient but plant responses to potassium fertiliser are unlikely given the present grazing management practices.
• Salinity is not a problem in the surface soil.
• The nutrient holding capacity of the surface (A1 and A2) horizons are low (based on the sum of the exchangeable calcium, magnesium, potassium and sodium cations).

• Root growth would be severely restricted because of the dense and hard nature.
• The soil is strongly acid and moderately high in exchangeable aluminium. This may affect the growth of aluminium sensitive pasture species.
• The subsoils are likely to slake when wet, making them prone to tunnel and gully erosion.