LP29

LP29 Landscape

Soil Profile Morphology

Surface Soil

A1	0-10 cm	Dark brown (10YR3/3); fine sandy clay loam; hardsetting surface condition; moderate coarse blocky structure; strong consistence dry; pH 8.6; sharp change to:	LP29 Profile
A2	10-12 cm	Conspicuously bleached (7.5YR7/2d); fine sandy clay loam; massive structure; sharp change to:
Subsoil
B21	12-30 cm	Reddish brown (5YR4/4); heavy clay; strong coarse prismatic, breaking down to strong coarse blocky structure; strong consistence dry; pH 9.3; clear and wavy change to:
B22k	30-65 cm	Yellowish red (5YR5/6); heavy clay; same structure as above; strong consistence dry; contains a few (5%) soft carbonate in pockets; pH 9.4; gradual change to:
B23	65-90 cm	Reddish yellow (5YR6/8); medium clay; moderate coarse prismatic structure; strong consistence dry; contains very few (<2%) amount of soft carbonate in pockets; pH 9.5; gradual change to:
B3	90+ cm	Yellowish brown (10YR5/4) and yellowish red (5YR5/8); medium heavy clay; same structure as above; strong consistence moist; dark flecks (ferromanganiferous) common (10%); pH 9.3.

• Strong texture contrast between surface (A) horizons and the top of the subsoil (B21) horizon.
• Conspicuously bleached A2 horizon.
• Calcareous and strongly sodic subsoil.

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	strongly alkaline	very low	non-sodic	none1
Subsoil (25-45 horizon)	very strongly alkaline	low	strongly sodic	strong
Deeper subsoil (1 m)	very strongly alkaline	medium	very strongly sodic	complete
1 Slight dispersion with remoulding.

Horizon	Horizon Depth	pH (water)	pH CaCl2	EC 1:5	NaCl	Exchangeable Cations
						Ca	Mg	K	Na
						Meq/100g
A2	10-12	9.3	8.2	0.25		12.7	9.3	1	4.1
B21	12-30	9.4	8.5	0.43		9.2	11.8	1	5.9
B22	30-65	9.5	8.6	0.73		6.2	11.8	1.2	8.4
B23	65-90	9.3	8.7	0.9		5.2	9.7	0.8	8.5

Horizon	Horizon Depth	Ex Al mg/kg	Ex Ac meq/100g	Field pF2.5	Wilting Point pF4.2	Coarse Sand (0.2-2.0mm)	Fine Sand (0.02-0.2mm)	Silt (0.002-0.02mm)	Clay (<0.002mm)
A2	10-12			42.6	33.4
B21	12-30
B22	30-65
B23	65-90

• The strongly alkaline profile suggests that some nutrients (e.g. phosphorus, iron, manganese and zinc) may be poorly available to some plants.

• The surface is non-sodic but disperses slightly after remoulding. Over stocking or excessive cultivation of the soil when wet may result in surface sealing and exacerbate the hardsetting condition.
• The surface also has a high fine sand content (38%). When cultivated in a dry condition, these soils will become "powdery" and subsequent rain may result in a surface seal development. Maintaining adequate organic matter is important to assist in reducing structural degradation (e.g. compaction and exacerbated hardsetting) on such soils. Practices such as minimum tillage, stubble retention and pasture rotation should be encouraged. Organic matter is also important in terms of soil fertility and water holding capacity.

• The top of the subsoil is strongly sodic and disperses strongly in water. This is likely to restrict water and root movement through the profile. Waterlogging is likely to occur after heavy rains. The presence of a conspicuously bleached A2 horizon above the sodic subsoil indicates that periodic waterlogging occurs.
• The subsoil salinity rating is medium at 90 cm depth in the profile. This may restrict the growth of deeper rooted salt sensitive species (eg. linseed, maize, faba beans, chickpeas, and some other legumes). Chloride salts were not measured for the site so it is not possible to get a full estimate of the salinity rating.