PVI 11

Site: PVI 11	Land Unit: Basalt Alluvium
*Aust. Soil Class.:* Mottled, Epipedal, Black VERTOSOL (very gravelly surface)

General Land Unit Description:
This land unit consists of the smaller swamps and depression which occur on the basalt plains. Grey Vertosols tend to dominate the smaller swamps and depressions on the plains. On the other hand, Black Vertosols are commonly found in the swamps and depressions associated with the stony rise landscapes and the larger alluvial plains. Both soil types are typically sodic at depth and imperfectly drained. There are minor occurrences of Sodosols. In some areas of the basalt plain, this land unit would have been incorporated into the basalt land units.

Site Description:

Geology: Recent alluvial over Quaternary basalt	Landform pattern: Plain
Position in landscape: Drainage depression	Internal drainage: Imperfectly drained

Soil Profile Morphology

A11	0-10 cm	Very dark greyish brown (10YR3/2); gravelly clay; weak consistence (dry); many (40%) ferruginous nodules (2-5 mm); rusty root channel; pH 5.7; clear change to:
A12	10-20 cm	Very dark brown (10YR2/2); gravelly clay; moderate strong blocky structure; weak consistence (dry); very many (60%) ferruginous nodules (2-5 mm); pH 6.5; rusty root channel mottling; abrupt change to:
	Subsoil
B21	20-90 cm	Very dark grey (2.5Y 3/0) with few (10%) faint brownish yellow (10YR6/6) mottles; heavy clay; moderate very coarse prismatic, parting to strong coarse blocky structure; slickensides; strong cracking; very strong consistence (dry); pH 7.1; gradual change to:
B22	90-120 cm	Dark grey (10YR4/1) with faint brownish yellow (10YR6/6) mottles; heavy clay; strong medium to coarse lenticular structure; very firm consistence (moist); pH 5.9; gradual change to:
B23	120+ cm	Grey (10YR5/1) with faint brownish yellow (10YR6/6) mottles; heavy clay; strong medium to coarse lenticular structure; slickensides; very firm consistence (moist); pH 6.0.

Key Profile Features

Large amount of ferruginous nodules in surface (A) horizons
Clay texture throughout soil profile
Significant cracking when profile is dry
Prominent slickensides in subsoil

Soil Profile Characteristics

	pH	Salinity Rating	Sodicity	Dispersion
Surface soil (A1 horizon)	Moderately Acid	Low	Non-Sodic	None
Upper subsoil (20-90 cm)	Near Neutral	Low	Marginally Sodic	None¹
Deeper subsoil (at 120+ cm)	Moderately Acid	High - Very High	Non-Sodic	None

¹ strong dispersion after remoulding

Soil pit PVI 11 graphs

Horizon	Horizon Depth	pH (water)	pH CaCl2	EC dS/m	NaCl %	Exchangeable Cations				Ex Al mg/kg	Ex Ac meq/100g	Field pF2.5	Wilting Point pF4.2	Coarse Sand (0.02-0.2mm)	Fine Sand (0.02-0.2mm)	Silt (0.02-0.02mm)	Clay (<0.002mm)
						Ca	Mg	K	Na
						meq/100g
A11	0-10	5.7	5.2	0.17		14	11	1.1	0.50	12		33.0	26.4	35.4	7.8	12.5	27.5
A12	10-20	6.5	5.9	0.12		12	14	1.1	0.73			34.5	21.4	36.6	8.4	10.5	36.5
B21	20-90	7.1	6.4	0.13		14	25	1.3	2.4			60.4	32.6	0.8	8.3	14.5	68.5
B22	90-120	5.9	5.6	1.7	0.32	13	20	0.4	1.7	11	12	63.3	33.1	0.3	8.6	17.0	71.0
B23	120+	6.0	5.8	1.9	0.31	12	20	0.5	1.6	11

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