GP59

GP57-GP60 Landscape

Soil Profile Morphology:

Surface Soil

A1	0-10 cm	Dark brown (10YR3/3); light clay; moderate coarse polyhedral parting to medium structure; strong consistence dry; subplastic; pH 6.1:	GP59 Profile
Subsoil
B21	10-40 cm	Very dark greyish brown (10YR3/2); medium heavy clay; moderate coarse prismatic, parting to moderate coarse blocky structure; very strong consistence dry; dark staining on prism faces; slickensides from 30 cm depth; pH 6.0:
B22	40-90 cm	Very dark greyish brown (10YR3/2) with faint yellowish brown (10YR5/6) mottles; medium heavy clay; moderate coarse prismatic, parting to coarse blocky structure; strong consistence dry; dark staining on prism faces; strong slickenside development; pH 5.1:
B23	90+ cm	Greyish brown (10YR5/2) with yellowish brown (10YR5/6) and red (2.5YR5/8) mottles; heavy clay; strong consistence moist; pH 4.8.

Key Profile Features:

• High fertility throughout the profile.
• Vertic properties present within the subsoil i.e. slickensides.

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	Slightly Acid	Moderate	Non-Sodic	None1
Subsoil (B21 horizon)	Moderately Acid	Very Low	Non-Sodic	None2
Deeper subsoil (at 90 cm)	Very Strongly Acid	Moderate	Sodic	Strong

The surface horizon is slightly acid. The subsoil is moderately acid becoming very strongly acid at 90 cm.

The salinity rating is low to moderate in the surface. The subsoil is very low becoming moderate at 90 cm.

The exchangeable aluminium levels are low in the surface becoming very high in the subsoil.

The clay content increases markedly 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	0-10	6.1	5.4	0.2		10	11	1.6	1.6
B21	10-40	6	5	0.12		9.6	16	1.5	2.1
B22	40-90	5.1	4.2	0.27	<0.03	5.1	17	0.3	3.7
B23	90+	4.2	0.72	0.11		3.7	20	0.2	6

Management Considerations:

Whole Profile

• The high to very high inherent fertility of this soil makes it very beneficial to root development and plant growth.

• The surface (A1) horizon is non-sodic but has a low exchangeable calcium to magnesium ratio (0.9) and disperses slightly after remoulding. This indicates that tillage or over-stocking of the soil whilst in a moist to wet condition may result in structural degradation (e.g. surface sealing, increased cloddiness) occurring. Raindrop action on bare soil may have a similar effect, so it is important to maintain surface cover. Gypsum application may assist in improving surface soil structural condition on such soils.
• The level of soluble salts in the surface is low to moderate and may restrict the growth of salt sensitive species (e.g. faba beans, linseed, chick peas and lupins).
• Organic matter and nitrogen levels are high throughout the surface soil which is beneficial to plant growth.
• The high wilting point value (i.e. 28%) indicates that plants will be unable to utilise light rains when the soil is relatively dry.

• The upper subsoil (B21) has vertic properties i.e. slickensides which indicates that significant shrinking and swelling occurs during wetting-drying cycles. This can disrupt the roots of perennial plants and will have implications for engineering applications (e.g. building foundations and fence lines).
• The subsoil below the B21 horizon is sodic with a low exchangeable calcium to magnesium ratio (0.3), strong dispersion and an exchangeable aluminium content of 270 mg/kg. Root development will be considerably effected by these factors.
• The presence of mottling within the subsoil (B22) horizon indicates that some waterlogging may occur.
• At 90 cm the subsoil becomes very strongly acid, with moderate salinity and high exchangeable sodium and magnesium levels but these factors would only effect very deep rooted species.