CRC1

Location: Murroa

Australian Soil Classification: Bleached-Vertic (& Ferric), Mesotrophic, Brown CHROMOSOL

Geology: Tertiary/Quaternary basalt.
General Landscape Description: Gently undulating rise.
Site Description: Cooperative Research Centre (CRC) trial site.

Image: CRC1 Landscape
Site CRC1 Landscape

Soil Profile Morphology:

Surface Soil

A1	0-12 cm	Brown (10YR4/3); fine sandy clay loam; firm surface condition; weak-moderate coarse blocky, parting to medium blocky structure; weak to firm consistence (dry); pH 5.2; clear change to:	Site CRC1 profile.
A21c	12-25 cm	Light yellowish brown (10YR6/4) sporadically bleached (10YR7/3); very fine sandy clay loam; weak to moderate medium blocky structure; weak to firm consistence (dry); ferruginous nodules common (20%); some rusty root channel mottling; pH 5.4; clear change to:
A22c	25-30 cm	Conspicuously bleached; fine sandy clay loam; many (50%) ferruginous nodules (20-10 mm); pH 5.8; clear change to:
Subsoil
B21c	30-60 cm	Yellowish brown (10YR5/6) with brownish yellow (10YR6/6) mottles; light medium clay (subplastic); weak-moderate medium prismatic, parting to strong medium to fine polyhedral structure (shiny-faced peds); weak to firm consistence (moist); ferruginous nodules (2 mm) common (15%); pH 6.3; gradual change to:
B22	60-90 cm	Yellow (10YR7/8) with brownish yellow (10YR6/6) and red (2.5YR5/5) mottles; medium clay; strong medium polyhedral structure (shiny-faced peds); firm consistence (moist); pH 6.1; gradual change to:
B23	90-110+ cm	Yellowish brown (10YR5/4) with brownish yellow (10YR6/6) and red (2.5YR5/8) mottles; shiny-faced peds; some lenticular structure and possibly slickensides; firm consistence (moist); some manganese stains at 100 cm depth; pH 6.2.

Key Profile Features:

Very strong texture contrast between surface (A) horizons and subsoil (B21) horizon.
Conspicuously bleached subsurface (A2) horizons.
Many ferruginous nodules in subsurface (A2) and upper subsoil (B21) horizons.

Soil Profile Characteristics:

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)	Gravel %


A1	0-12	17	10	35	11	7	40	20	21	5
A21c	12-25	16	5.8	27	7	16	42	16	22	23
A22c	25-30	10	5.7	21	9	26	35	13	23	58
B21c	30-60	<10	8.9	34	24	2	8	7	78	12
B22	60-90	<10	11	44	31	2	7	17	70	3
B23	90-110+	<10	11	44	32	8	17	11	61	1

Management Considerations:

Surface (A) Horizons

The surface soil (upper 25 cm) is strongly acid which indicates that aluminium and manganese toxicity may occur. However, the level of exchangeable aluminium measured at this site is not high (<18 mg/kg). A pH/aluminium test is also best performed from samples taken across the paddock and bulked together. Other factors also need to be considered before lime is recommended e.g. pasture species grown, method of application, local trial responses, soil surface structure and likely cost/benefit.

Subsoil (B) Horizons

The upper subsoil is non-sodic and well structured, parting strongly to fine polyhedral shaped aggregates. This will be conducive to root and water movement, although the strong texture contrast will provide some restrictions. Waterlogging may still occur after heavy rains, but the subsoil is likely to be better drained than the soils with sodic subsoil in the region.

Profile Described By: Mark Imhof, Austin Brown, Darren Bennetts and Malcolm McCaskill - March 2003.

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