NECRC3

Location: North Boorhaman	Australian Soil Classification: Calcic, Mottled-Subnatric, Red SODOSOL
General Landscape Description: Level plain.	Site Description: CRC-PBMDS trial site
Geology: Quaternary alluvial and aeolian deposits.

NECRC3 landscape

Columnar structure in upper subsoil (B21) horizon

Soil Profile Morphology:

Surface Soil

A1	0-12 cm	Very dark greyish brown (10YR3/2); light sandy loam; weak-moderate coarse to medium subangular blocky structure; weak to firm consistence (dry); very few (<1%) coarse (10-15 mm) manganese nodules; pH 6.8; abrupt change to:	NECRC3 profile
A2e	12-17 cm	Brown (7.5YR5/4), conspicuously bleached (10YR7/1 dry); light sandy loam; massive; pH 5.6; discontinuous change to:
Subsoil
B21	17-60 cm	Yellowish red (5YR5/6) with reddish grey (5YR5/2) mottles; medium clay; strong very coarse columnar, parting to coarse prismatic and blocky structure; very firm consistence (dry); sodic caps on columnar structure; pH 7.2:
B22	60-90 cm	Reddish yellow (7.5YR6/6) with pinkish grey (7.5YR6/2) mottles; heavy clay; moderate coarse to medium subangular blocky structure; few (~2%) soft to hard medium-sized (5 mm) carbonate nodules and some manganese staining; pH 9.3:
B23k	90-140 cm	Brown (10YR5/3) with reddish yellow (7.5YR6/6) mottles; medium heavy clay; strong coarse to medium polyhedral structure; fine-earth carbonate accumulations (10-15%) common with some coarse (10 mm) nodules; pH 9.4:

• Strong texture contrast between surface (A) horizons and subsoil (B21) horizon.
• Columnar structure (with hard capping) in upper subsoil.
• Calcium carbonate at depth.

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	Slightly Acid	Very Low	Non-Sodic	None
Subsoil (B2 horizon)	Slightly Alkaline	Very Low	Sodic	Strong-Complete
Deeper subsoil (at 90-140 cm)	Very Strongly Alkaline	Medium-High	Strongly Sodic	Strong- Complete

Horizon	Horizon Depth (cm)	Exchangeable Aluminium (mg/kg)	Exchangeable Acidity (meq/100g)	Field Capacity pF 2.5	Wilting Point pF 4.2	Coarse Sand (0.2-2.0 mm)	Fine Sand (0.02-0.2 mm)	Silt (0.002-0.02 mm)	Clay (<0.002 mm)
A1	0-12			17.7	5.4	34	38	13	9
A2	12-17	18	3.7	14.4	3.7	36	41	12	9
B21	17-60			22.4	13.7	24	27	11	35
B22	60-90			24.2	14.1	27	28	10	32
B23k	90-140			28.4	15.9

• The dense and coarsely structured subsoil is sodic and strongly dispersive. This indicates that root and water movement will be restricted in the subsoil. The columnar structure in the subsoil has a hard capping which will also restrict root movement. Some roots are likely to move between the columns.
• The level of soluble salts become reasonably high in the deeper subsoil – which may restrict the growth of deeper-rooted salt sensitive species.