EGS265

Location: Wiseleigh

Australian Soil Classification: Sodic, Magnesic (and Dystrophic), Brown DERMOSOL

Map Unit: Tambo (Component 3)
Previous Site Name: EG265

General Landscape Description: Gently undulating plain.
Site description: Lower south-south east slope, 12%
Land Use: Grazing
Native Vegetation: Shrubby dry forest
Geology: Colluvium derived from further up-slope


Sequence of soil pits examined at Wiseleigh

Soil Profile Morphology:

Surface Soil

A11	0 – 10 cm	Very dark grey (7.5YR3/1); loam; moderate fine subangular blocky structure; firm consistence dry; clear change to:	EG265 Profile
A12	10 – 55 cm	Dark brown (7.5YR3/2); fine sandy light clay; moderate fine subangular blocky structure; firm consistence dry; clear change to:
A2	55 – 65 cm	Light yellowish brown (10YR6/4); fine sandy clay loam; massive; very firm consistence dry; few (2-10%) angular quartz gravel (6-20 mm); clear change to:
Subsoil
B2	65 – 85 cm	Yellowish red (5YR4/6); fine sandy clay loam; moderate coarse (50 – 100 mm) angular blocky structure; strong consistence dry; few (2-10%) angular quartz gravel (6-20 mm); clear change to:
C1	85 – 120 cm	Yellowish red (5YR4/6); fine sandy light clay; weak fine angular blocky structure; very firm consistence dry; few (2-10%) angular quartz gravel (6-20 mm); gradual change to:
C2	1.2 – 1.9 m	Pale brown (10YR6/3); light clay; strong medium (10 – 20 mm) polyhedral structure; very firm consistence dry; diffuse change to:
C3	1.9 – 2.4 m	Dark reddish grey (5YR4/2); light medium clay; few (2-10%) angular quartz gravel (6-60 mm).

• Deep dark coloured surface horizons indicate a high organic matter content and high water retention properties.
• It is likely much of the surface soil has been derived from further upslope post-clearing.

	pH	Sodicity	Dispersion
Surface soil (A11)	Very strongly acid	Non-sodic	-
Subsoil (B2 horizon)	Slightly acid	Non-sodic	Moderate1
Deep subsoil (C2 horizon)	Slightly alkaline	Sodic	Strong

Horizon	Horizon Depth (cm)	pH (water)	pH CaCl2	CE dS/m	Organic Carbon %	Total Nitrogen %	Exch. Al	Exch. 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 cap. % w/w	Wilt. point % w/w
									Ca	Mg	K	Na
									meq/100g
A11	0-10	5.1	4.4	0.08	9.2	0.54	26	21	3.6	3.2	0.1	0.5	23	24	21	18	44.7	23.2
A12	10-55	5.4	4.5	<0.05	3.5	0.16	230	21	0.6	0.9	0.3	0.1	18	28	7	39	42.9	12.5
A2	55-65	6	4.8	<0.05			63	6	<0.1	0.9	<0.1	0.1	25	34	21	18	21	8.1
B2	65-85	6.2	4.9	<0.05			36	4.6	<0.1	1.9	<0.1	0.3	24	30	21	23	20.3	9.2
C1	85-120	6.6	5.1	0.05			210	3.5	<0.1	2.3	0.4	0.2	21	27	19	33	25.9	11.5
C2	120-190	7.7	6.1	0.06			<5	2.1	<0.1	2.9	<0.1	0.7	23	29	18	30	22.8	9.6
C3	190-240	8	6.8	0.2				3.4	0.3	4.9	0.2	1.9	18	21	14	45	30.1	15.4

• On the assumption the roots can extract the water in the top 65 cm of the soil, the plant available water capacity is estimated at 68 mm. The high amounts of organic matter in this surface soil have added to the soil’s ability to retain water.

• The surface soil is very strongly acidic and the high levels of exchangeable aluminium occurring in the subsurface soil are likely to restrict the growth of aluminium sensitive species. A response to lime may be expected, but before it is applied, test strips should be used to evaluate the cost/benefit.
• Potassium is deficient and a response to potassium fertiliser is likely. This would particularly apply if the pasture was removed and baled.
• The nutrient holding capacity of the immediate surface soil is low to moderate (based on the sum of the basic cations) largely due to its high organic matter content. The immediate subsurface soil has an extremely low nutrient holding capacity.

• Based on the sum of the basic cations, the subsoil has an extremely low nutrient holding capacity.

• The deep subsoils are sodic and strongly dispersive. If the soil becomes saturated there is the risk of deep tunnels and subsequent gully erosion.