GL92

Site: GL92	Land Unit: Merino Tablelands
*Aust. Soil Class.:* Ferric (Reticulate), ?, Brown CHROMOSOL (confidence level 4)

Soil pit GL92 landscape

General Land Unit Description:
This unit consists of the Cretaceous non-marine sandstone of the dissected Merino Tablelands. The tablelands were thought to have formed under swamp conditions and a warm climate. As a result, the soils tend to be high in clay and there tends to be carbon rich seams of charcoal deposits at depth in some of the profiles. The main soil type used to represent this land unit is black cracking clays (Vertosols) that can be sodic at depth. This soil type, along with Black Sodosols, Chromosols and Dermosols, are commonly found on the broad crests or drainage lines. The slopes often consist of Brown Chromosols, Sodosols or Dermosols, although black soils can also occur on the slopes. The lower slopes commonly have Grey Vertosols or Sodosols as the major soil type. The reasonably deep sodic soils on short steep slopes tend to be prone to landslips. The grey soils, in particular are prone to water erosion.

Site Description:

Geology: Cretaceous non-marine sandstone	Landform pattern: Undulating rises
Position in landscape: Broad crest	Internal drainage: Imperfectly drained

Soil Profile Morphology

A1	0-5 cm	Black (10YR2/1) loam, strong subangular blocky structure (2-5 mm), firm consistence when dry, pH 5.4; transition to:
	Subsoil
B21	5-50	Black (10YR2/1) heavy clay, strong lenticular (5-10 mm) to strong angular blocky structure (10-20 mm), strong consistence when dry, pH 6.0; transition to:
B22	50-95 cm	Black (10YR2/1) heavy clay, strong lenticular to strong angular blocky structure (10-20 mm), strong consistence when dry, pH 6.8; transition to:
B23	95-120 cm	Olive brown (2.5Y4/3) light clay, strong angular blocky structure (10-20 mm), consistence strong when dry, few soft calcareous segregations, strong consistence when dry, weathered sedimentary fragments present, pH 8.2; transition to:
B24	120-140 cm	Olive brown (2.5Y4/3) heavy clay, lenticular structure, strong consistence when dry, calcareous segregations are abundant, pH 8.4; transition to:
B25	140-170 cm	Olive brown (2.5Y4/3) heavy clay, many faint yellow mottles, lenticular structure, strong consistence when dry, many soft calcareous segregations, pH 8.6; transition to:
B3	170-220+ cm	Light yellowish brown (2.5Y6/3), many faint yellow and orange mottles, lenticular structure, strong consistence when dry, pH 8.7.

Key profile features:

Acidic topsoil
Calcium carbonate at depth
Mottled subsoil
Sodic subsoil
Cracking soil
Topsoil dispersive when worked when wet
Subsoil dispersive when worked when wet

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