GP53

GP53 Landscape

Soil Profile Morphology:

Surface Soil

A1	0-25 cm	Very dark greyish brown (10YR3/2); medium clay; hardsetting surface condition parting to self mulching; moderate coarse polyhedral, parting to strong fine polyhedral structure; strong consistence dry; pH 5.5; clear to abrupt change to:	GP53 Profile
Subsoil
B21	25-70 cm	Very dark grey (10YR3/1) with brownish yellow (10YR6/8) mottles at depth; heavy clay; moderate coarse prismatic, parting to strong coarse blocky structure; strong consistence dry; pH 6.3; gradual change to:
B22	70-120 cm	Grey (10YR5/1) with brownish yellow (10YR6/8) and very dark grey (10YR3/1) mottles; medium heavy clay; moderate coarse prismatic, parting to moderate coarse blocky structure; pH 7.2:
B23	120+ cm	Grey (10YR5/1) with yellow (10YR7/6) mottles; moderate lenticular structure; pH 7.8.

Key Profile Features:

• Hardsetting surface condition breaking down to self-mulching.???Mark??
• Vertic properties present within the subsoil.

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	Strongly Acid	Low	Non-Sodic	None
Subsoil (B21 horizon)	Slightly Acid	Very Low	Sodic	None1
Deeper subsoil (at 1 m)	Slightly Alkaline	Moderate	Sodic	None

The surface soil is strongly acid. The upper sub-soil is slightly acid becoming slightly alkaline at depth.

The salinity rating in the surface soil is low. The upper subsoil is very low becoming moderate at depth.

The surface soil is non-sodic. The subsoil is sodic.

The clay content increases abruptly at the A/B boundary.

Horizon	Horizon Depth	pH (water)	pH CaCl2	EC 1:5	NaCl	Exchangeable Cations
						Ca	Mg	K	Na
						Meq/100g
A1	0-25	5.5	5	0.23		13	5.4	0.66	0.58
B21	25-70	6.3	5.4	0.14		11	11	0.47	2
B22	70-120	7.2	6.7	0.69	0.13	11	12	0.2	4
B23	120+	7.8	7.3	0.95	0.17	9.6	9.8	0.2	4.5

Management Considerations:

Surface (A) Horizon

• The surface soil (A1) is strongly acid. As a result, deficiencies in molybdenum, potassium and phosphorus may occur. Manganese toxicity may also occur in strongly acid soils, particularly when poorly drained (as waterlogging may bring manganese into solution).
• The inherent fertility of the surface (A1) horizon (based on the sum of the exchangeable calcium, magnesium and potassium cations) is high. The nitrogen levels are also high.
• The high wilting point value (i.e. 30%) indicates that plants will be unable to utilise light rains when the soil is relatively dry.

• The dense and coarsely structured upper subsoil (B21) horizon is sodic, however, strong dispersion only occurs after remoulding. The deeper subsoil becomes strongly sodic at 105 cm. The subsoil is dense and coarsely structured which will restrict root movement down the profile.
• The subsoil has vertic properties which indicates that significant shrinking and swelling occurs during wetting-drying cycles. This can disrupt the roots of perennial plants and may have implications for engineering applications (eg. building foundations and fence lines).
• The presence of mottling throughout the subsoil indicates that the profile is seasonally waterlogged.
• The level of soluble salts increases with depth and the salinity rating is moderate in the deeper subsoil (ie. from 1 m depth). This is only likely to restrict the growth of deeper rooted salt sensitive species.