GL166

Site: GL166	Land Unit: Ararat Marine Siltstone
*Aust. Soil Class.:* Sodic, Mesotrophic, Red CHROMOSOL (confidence level 1)

General Land Unit Description:
The dominant landform of this land unit is dissected undulating rises (GL171), although there are some rolling low hills (represented by this site) and some undulating plains that are mainly at the footslopes of the rises. The major land element is the gentler footslopes of the undulating rises and plains. The major soil type found on these slopes tend to be reddish and well structured strong texture contrast soils (Chromosols) (GL171). The subsoil can be quite acidic and there may be high aluminium levels in some soils. There is evidence of an occasional bleach horizon. The soils are often quite shallow. The topsoil and subsoils tend to be acidic. The soils on the dissected rolling low hills are generally shallow, although they can be quite well structured. They are commonly sodic red Chromosols (GL166). Banded sedimentary rock outcrop is common on these soil types, especially on the exposed westerly aspects. Gully erosion on the plains below these hills and on the drainage depression is quite severe.

Site Description:

Slope: 13%	Geology: Cambrian marine sediments
Landform pattern: Low hills	Position in landscape: Mid-slope
Internal drainage: Moderately well drained

Soil Profile Morphology

A1	0-20 cm	Brown (10YR4/3) clay loam, weak subangular blocky (10-20 mm) to moderate subangular blocky structure (2-5 mm), weak consistence when dry, many medium angular coarse quartz pebbles (6-20mm), pH 5.7. Clear transition to:
	Subsoil
B2	20-50 cm	Yellowish red (7.5YR4/6) medium clay, strong prismatic (20-50 mm) to strong polyhedral structure (10-20 mm), medium angular quartz pebbles are common (6-20 mm), pH 6.5. Gradual transition to:
B3/C	50-80 cm	Strong brown (7.5YR5/6) light clay, distinct medium yellowish red (5YR4/6) mottles are common, weak polyhedral structure (10-20 mm), pH 7.0. Clear but wavy transition to:
C	80-100 cm

Key profile features:

Many coarse fragments above the B2 horizon
Sodic at depth
Strong texture contrast between topsoil and subsoil
Subsoil dispersive when worked when wet

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