GL170

Site: GL170	Land Unit: Willaura Basalt
*Aust. Soil Class.:* Vertic, Mottled-Mesonatric, Brown SODOSOL (confidence level 1)

General Land Unit Description:
This land unit occurs on the level to gently undulating plains between Moyston and Willarua. The soils are commonly sodic and exhibit gilgai micro-relief although due to land management gilgais are not always apparent on the surface. The soil description below represents the lighter textured topsoil which is possibly the swale. The hummock generally is black cracking clay with evidence of patchy calcium carbonate. Soil depth is variable due to basalt floaters. On the broad flat crest and level areas, particularly in the southern portion of the land unit, the soils can have a conspicuously bleached A2 horizon. Numerous grey clay swamps and depressions are scattered throughout this map unit. Occasionally Red or Brown Chromosols or Sodosols may be found on banks surrounding these swamps.

Site Description:

Slope: 3%	Geology: Quaternary basalt
Landform pattern: Lava Plain	Position in landscape: Flat
Internal drainage: Imperfectly drained

Soil Profile Morphology

A1	0-15 cm	Dark yellowish brown (10YR4/3) fine sandy clay loam, weak subangular blocky structure (10-20 mm), firm consistence when dry, pH 5.4; transition to:
A2	15-30 cm	Dark greyish brown (10YR4/2) fine sandy clay loam, conspicuously bleached (10YR7/1) when dry, massive structure, firm consistence when dry, pH 5.9; transition to:
	Subsoil
B2	30-90 cm	Brown (10YR5/3) heavy clay, many prominent coarse yellowish brown (10YR5/8) mottles, strong prismatic (50-100 mm) to strong angular blocky structure (20-50 mm), very strong when dry, very few prominent medium soft calcareous segregations (2-6 mm), distinct organic cutans are common, pH 7.8; transition to:
B3	90-150+ cm	Brown (10YR5/3), heavy clay, strong lenticular structure (20-50 mm), very strong when dry, very few medium soft calcareous segregations (2-6 mm), many prominent slickensides present, pH 8.0.
	Notes:
B21	20-55 cm	Very dark grey (2.5Y3/1), heavy clay, many distinct slickensides present; transition to:
B22	55-90+ cm	Black (2.5Y2.5/1), heavy clay, very few distinct medium soft calcareous segregations (2-6 mm), many distinct slickensides present.

Key profile features:

Acidic topsoil
Strong texture contrast between topsoil and subsoil
Mottled subsoil
Sodic subsoil
Subsoil cracks
Topsoil dispersive when worked when wet
Subsoil dispersive when dry

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