EGS264

Location: Wiseleigh

Australian Soil Classification: Melacic, Magnesic (and Dystrophic), Brown CHROMOSOL

Map Unit: Tambo (Component 2)
Previous Site Name: EG264

General Landscape Description: Gently undulating plain.
Site Description: Mid south slope, 17% slope
Land Use: Grazing
Native Vegetation: Grassy woodland
Geology: Ordovician sediments



Sequence of soil pits examined at Wiseleigh

Soil Profile Morphology:

Surface Soil

A11	0 – 8 cm	Very dark grey (7.5YR3/1); loam; strong fine granulars structure; firm consistence dry; abrupt change to:	EG264 Profile
A12	8 – 35 cm	Very dark grey (7.5YR3/1); clay loam; weak fine angular blocky structure; firm consistence dry ; clear change to:
Subsoil
B21	35 – 50 cm	Brown (7.5YR5/4) medium clay; moderate coarse (50 -100 mm) prismatic structure; firm consistence dry; few (2 – 10%) angular pebbles (< 60 mm); gradual change to:
B22	50 – 70 cm	Light brown (7.5YR6/4); light clay; moderate coarse (50 - 100 mm) prismatic structure; very firm consistence dry; few (2 – 10%) angular pebbles (< 60 mm); gradual change to:
C	70 – 100 cm	Mottled yellow (10YR7/6) and reddish yellow (5YR6/6); light clay; strong medium (10 – 20 mm) polyhedralstructure; very firm consistence dry; diffuse change to:
R	100 cm+	Weak decomposing rock

• Texture contrast between the surface (A) horizons and the subsoil (B horizons).
• Very high organic matter in the surface soil, which enhances nutrient and water-holding capacity.

	pH	Sodicity	Dispersion
Surface soil (A11)	Very strongly acid	Non-sodic	-
Subsoil (B21 horizon)	Moderately acid	Non-sodic	None
Deep subsoil (C horizon)	Slightly acid	Sodic	Slight1

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	0-8	4.9	4.2	0.12	11	0.59	360	18	3.4	3.2	0.9	0.1	24	23	19	19	53.1	30
A12	8-35	5.0	4.3	<0.05	5.3	0.22	460	20	0.2	0.7	0.2	.1	17	24	23	28	53.0	15.2
B21	35-50	5.8	4.7	<0.05			140	13	<0.1	0.7	0.2	0.1	18	22	13	44	34.4	14.1
B22	50-70	5.8	4.7	<0.05			82	6.1	<0.1	0.7	0.1	<0.1	22	21	27	28	29.3	12.4
C	70-100	6	4.6	<0.05			55	4.2	<0.1	1.3	0.2	0.2	8	16	46	29	35.5	14.7

• Based on a plant root depth of 50 cm, the plant available water capacity is about 62 mm.
• Texture contrast between the surface (A horizons) and the subsoil (B horizon).

• The surface (A11) horizon has a particularly high organic matter content which has greatly added to the nutrient holding and water holding capacity of the soil. By contrast the subsurface soil (A12) horizon has a very low nutrient holding capacity.
• The surface soil is very strongly acidic and the very high levels of exchangeable aluminium are likely to restrict the growth of aluminium sensitive species. A response to lime would be expected, but before it is applied, test strips should be used to evaluate the cost/benefit.

• All of these horizons have a very low nutrient holding capacity (based on the sum of the calcium, magnesium, potassium and sodium cations).
• The deep subsoil (C horizon) is sodic and shows moderate dispersion after 20 hours of wetting. Such a soil would be prone to tunnel and gully erosion.