PHO99 (Plot 1)

Site: PHO99 (Plot 1)	Land Unit: Strathdownie
*Aust. Soil Class.:*

General Land Unit Description:
This land unit comprises the Quaternary lacustrine geology south of the Glenelg River. The lacustrine deposits include lagoonal, swamp and local colluvial deposits formed in low-lying wetlands and depressions between stranded beach ridges. Parent material in this land unit comprises of sand, silt, sandy clay, peat, marl and freshwater limestone, occurring in relatively unconsolidated forms.

The soils are variable throughout this land unit due to varying depositional environments. A common soil type is a strong texture contrast soil (Chromosol, Sodosol) commonly with a bleached A2 horizon and a mottled subsoil (indicative of impeded internal drainage). The sandy topsoil can be very deep in some soils. Vertosols are also common on the plains and swales in between the dunes. Podosols occur on the flats as well as on the dunes and that may have been mapped as part of this land unit due to restrictions of scale. Many of the soils are poorly drained and exhibit signs of a perched watertable.

1.5 year old Eucalyptus globulus plantation on ex-agricultural land. Remnant roots were observed to 150 cm, the pockets of dark grey sand in the B21 and B22 layers may have arisen due to previous (now remnant) root activity.

Site Description:

Geology: Quaternary lacustrine	Landform pattern: Level plains
Position in landscape: Flat	Internal drainage: Imperfectly drained

Soil Profile Morphology

A1	0-20 cm	Very dark greyish brown (10YR3/2) loamy sand; single grain structure; very weak consistence when dry; common medium roots; clear and smooth transition to:
A2	20-55 cm	Dark greyish brown (10YR4/2) loamy sand; single grain structure; loose consistence when moderately moist; common medium roots; clear and smooth transition to:
A3	55-80 cm	Dark grey (10YR4/1) with many coarse faint dark yellowish brown (10YR4/4) sandy loam; weak subangular blocky structure (20-50 mm); loose consistence when moist; few fine roots; clear and smooth transition to:
	Subsoil
B1	80-100 cm	Grey (10YR6/1) with many coarse distinct yellowish brown (10YR5/6) mottles and dark grey sand (10YR4/1) on ped faces, sandy clay; weak subangular blocky structure (20-50 mm) parting to weak subangular blocky structure (10-20 mm); very weak consistence when moist; many very fine macropores; areal porosity 0.6%; no roots observed; clear and smooth transition to:
B21	100-140 cm	Grey (10YR6/1) with many coarse distinct brownish yellow (10YR6/8) mottles and dark grey sand (10YR4/1) pockets, medium heavy clay (with sand); weak subangular blocky structure (20-50 mm) parting to weak subangular blocky structure (10-20 mm); very weak consistence when moist; few coarse ferruginous nodules; common fine macropores; areal porosity 0.3%; no roots observed; diffuse and smooth transition to:
B22	140-150 cm	Grey (10YR6/1) with many coarse distinct brownish yellow (10YR6/8) mottles and dark grey sand (10YR4/1) pockets, medium clay (with sand); weak subangular blocky structure (20-50 mm) parting to weak subangular blocky structure (10-20 mm); very weak consistence when wet; common extremely coarse calcareous nodules (soft and hard); few very fine macropores; areal porosity 0.08%; no roots observed.
	150-230 cm	Grey medium clay with sand, sand pipes to 300 cm, zones of sand along cracks (50 mm width)
	230-380 cm	Grey clayey sand.
	380-400 cm	Heavy grey/yellow/brown clay.

Sampled by: Ian Sargeant, Paul Feikema and Martin Clark (5 December 2000)

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