MM770

Site: MM770	Land Unit: Kororoit Marl
*Aust. Soil Class.:* Bleached-Mottled, ?, Brown CHROMOSOL (confidence level 3)

General Land Unit Description:
This unit is a complex one consisting of gently undulating to level plains with numerous small depressions in the Heywood-Bessiebelle-St. Helens area. In the eastern or more undulating portion of the unit, the very slight rises with broad level crests consist of Mottled Brown Chromosols with minor occurrences of sandy Brown Chromosols and Sodosols dominant locally. There are also minor occurrences of sand hills or dunes consisting of deep uniform sands (Podosols). The numerous small depressions are Grey or Black Vertosols, while some shallower depressions have very little depth to the substrate. Sporadically Bleached Brown Chromosols are predominant on the level areas. In the western portion of the unit, poorly drained soils (Vertosols, Sodosols and Chromosols) are more common with minor occurrences of sand sheets with deep uniform sands (Podosols). Grey Vertosols and Sodosols occur in the swamps and depressions in this portion of the unit.

Site Description:

Geology: Marl	Landform pattern: Gently undulating to level plains
Position in landscape: Flat	Internal drainage: Imperfectly - poorly drained

Soil Profile Morphology

A1	0-25 cm	Very dark brown (10YR3/2) sandy loam, structureless, pH 5.3. Clear transition to:
A2	25-35 cm	Pale brown (10YR6/3) sandy loam, bleached (10YR7/3) when dry. Sharp transition to:
	Subsoil
B21	35-55 cm	Yellowish brown (10YR5/4) medium clay, yellowish brown mottles (10YR5/8), medium blocky structure (10-20 mm), pH 5.5. Gradual transition to:
B22	55+ cm	Yellowish brown (10YR5/6) medium clay, red mottles (2.5YR4/6), strong blocky structure (10-20 mm), pH 5.3.

Key profile features:

Strong texture contrast between topsoil and subsoil
Bleached A2 horizion
Mottled subsoil
Strongly acidic topsoil
Strongly acidic subsoil

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