GP85

Site GP85 Landscape

Soil Profile Morphology:

Surface Soil

A1	0-10 cm	Dark greyish brown (10YR4/2); loamy sand; quartz gravel; pH 4.7:	Site GP85 Profile
A2	10-30 cm	Light yellowish brown (10YR6/4) conspicuously bleached (10YR8/2 dry); loamy sand; quartz gravel common (5-50 mm in size); pH 4.7:
Subsoil
B21	30-50 cm	Yellowish brown (10YR5/4) with yellowish red (5YR5/6), yellow (10YR7/8) and red (2.5YR5/8) mottles; medium clay; strong very coarse prismatic, parting to strong very coarse to strong coarse blocky structure; quartz gravel (2-10 mm); pH 4.8:
B22	50-90 cm	Yellowish brown (10YR5/6) with dark red (2.5YR4/6) mottles (30%); light clay; pH 5.1.

• Strong texture contrast between sandy surface (A) horizons and clayey subsoil (B21) horizon.

Horizon	Horizon Depth (cm)	pH (water)	pH (CaCl2)	EC 1:5	NaCl	Exchangeable Cations
						Ca	Mg	K	Na
						meq/100g
A1	0-10	4.7	4.0	<0.05		0.35	0.21	0.37	0.08
A2	10-30	4.7	4.3	0.08		0.12	0.41	0.17	0.16
B21	30-50	4.8	4.2	0.19		0.06	4.4	0.43	0.88
B22	50-90	5.1	4.4	0.10		<0.05	4.8	0.18	0.66

Horizon	Horizon Depth (cm)	Exchangeable Aluminium mg/kg	Exchangeable Acidity meq/100g	Field Capacity pF2.5	Wilting Point pF4.2	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	0-10	44	8.3			33	47	11	4
A2	10-30	42	2.8			32	46	12	6
B21	30-50	230	10			21	22	5	51
B22	50-90	87	5.6			32	26	5	35

• The soil profile has large amounts of quartz fragments throughout.

• The sandy and strongly leached surface horizons have a very low inherent fertility.

• The coarsely structured (and marginally sodic) subsoil may restrict root and water movement to some degree.
• The subsoil has very low levels of exchangeable calcium compared to exchangeable magnesium (i.e. magnesic). This indicates that nutrient imbalances (e.g. calcium deficiency) may occur.
• The very strongly acid upper subsoil has a high level of exchangeable aluminium – that may restrict the growth of aluminium-sensitive species.