Site GN21

Location: East Shepparton Landcare Group.

Australian Soil Classification: Sodic, Calcic, Brown CHROMOSOL
Northcote Factual Key: Dy 2.33
Great Soil Group: red-brown earth

General Landscape Description: Lower lying position on a level plain. This soil has been mapped as Congupna Clay Loam by Skene and Freedman (1944). Site GN21 Landscape

Soil Profile Morphology:

Surface Soil

A1	0-15cm	Brown (7.5YR4/2); fine sandy clay loam, hardsetting surface condition; weakly structured; very strong consistence dry; rusty root channel mottling present; pH 6.4; sharp change to:	Site GN21 Profile
Subsoil
B21	15-30cm	Strong brown (7.5YR5/6) with pale brown (10YR6/3) mottles; medium heavy clay; moderate coarse blocky structure; strong consistence moist; pH 6.1; gradual change to:
B22	30-50cm	Brownish yellow (10YR6/6); medium heavy clay; moderate coarse blocky structure; very strong consistence moist; pH 5.4; clear change to:
B23	50-80cm	Yellowish brown (10YR5/6); medium heavy clay; moderate coarse blocky structure; very firm consistence moist; contains a few (5-10%) dark manganese flecks; pH 6.8; clear change to:
B24	80-95cm	Similar to above, but structure becomes moderate medium polyhedral; contains very few (2%) soft carbonates; pH 7.8:
B31	95-120cm	Pale brown (10YR6/3) with brownish yellow (10YR6/6) and strong brown (7.5YR5/6) mottles; light medium clay; moderate medium polyhedral structure; firm consistence moist; contains very few (1%) soft carbonates and some dark manganese stains; pH 7.8; gradual change to:
B32	120-160cm	Light brownish grey (10YR6/2) with brownish yellow (10YR6/6) mottles; clay loam (fine sandy); moderate medium polyhedral structure; firm consistence moist; contains patches of sand; pH 8.2:
B33	160cm+	Light medium clay; pH 8.2.

Key Profile Features:

• Strong texture contrast between surface (A1) horizon (26% clay) and subsoil (B21) horizon (54% clay).

Soil Profile Characteristics:

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	slightly acid	very low	non-sodic	none
Upper subsoil (15 - 30 cm)	slightly acid	very low	non-sodic	none
Deeper subsoil (95 - 120 cm)	slightly alkaline	high	strongly sodic	-
Deep subsoil 160 cm +	moderately alkaline	low-medium	-	-

Management Considerations:

Whole Profile

• Plant available water capacity (PAWC) is considered to be medium (estimated at 135 mm) for the top metre of this profile. This is based on available laboratory data and should be considered as a potential capacity since root movement will be restricted by the coarsely structured subsoil. Also, the level of soluble salts becomes high between 80 -120 cm in the profile.

Surface (A) Horizon

• The surface soil has a high combined fine sand and silt content (i.e. 65%) and sets hard when dry. Organic matter is important for soils such as these in order to maintain soil aggregate stability.

Subsoil (B) Horizons

• The coarsely structured upper subsoil is non-sodic but disperses moderately in water. This will result in some restriction to root and water movement through the subsoil. The presence of rusty root channel mottling in the surface horizon indicates that some waterlogging occurs above the relatively slowly permeable subsoil.
• The deeper subsoil becomes sodic and the calcium:magnesium ratio is low (<1), suggesting that root and water movement will be more restricted at depth.
• The level of soluble salts becomes high in the 80-125 mm zone. This is likely to restrict the growth of deeper-rooted salt sensitive species.

Comments from Landholder:

• This is the lowest part of the property.
• Managed similarly to site GN20.
• Pears have been grown here for 60 years.

Profile Described By: Mark Imhof, Paul Rampant, Sonia Thompson (1996).

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