Site LP9

Group: Middle Creek Landcare Group

Australian Soil Classification: Hypercalcic, Subnatric, Red SODOSOL
Northcote Factual Key:Dy 2.43
Great Soil Group: solodized solonetz

General Landscape Description: Upper slope on western side of a sedimentary (lower Ordovician) hillslope. Yellow Gum (E. leucoxylon) and Grey Box (E. microcarpa) association is the typical native vegetation.

LP9 Landscape

Soil Profile Morphology

Surface Soil

A1	0-5 cm	Dark brown (10YR3/3) light fine sandy clay loam; weakly structured; firm consistence dry; contains occasional shale fragments; pH 5.5; sharp and irregular change to:	LP9 Profile
A2	5-10 cm	Light brown (7.5YR6/4) conspicuously bleached fine sandy clay loam; weakly structured; strong consistence dry; contains a slight (10%) amount of ferruginous nodules (buckshot); pH 6.5; sharp and irregular change to:
Subsoil
B21	10-25 cm	Yellowish Red (5YR5/8) heavy clay; moderate coarse columnar, breaking down to strong coarse blocky structure (with smooth faced peds); very strong consistence moist; contains occasional shale fragments; pH 7.1; sharp and wavy change to:
B22	25-40 cm	Red (2.5YR4/8) heavy clay; strong medium blocky structure; very strong consistence moist; contains occasional shale fragments; pH 8.6 :
B3k	40-100 cm	Strong brown (7.5YR4/6) medium clay; with a heavy (>50%) amount of soft carbonate together with weathered shale; pH 9.3; gradual change to:
C	100+ cm	Laminated soft shale.

Key Profile Features

Key Profile Characteristics

Management Considerations:

Surface (A) horizons

The surface horizon has high levels of organic carbon and total nitrogen and a moderate overall nutrient status. However, being very shallow (i.e. 5 cm deep) it provides a limited rooting environment above the sodic subsoil.
The high organic matter levels ensure that the surface aggregates are water-stable and will not readily break down when wet.
Aluminium and manganese toxicity can occur in strongly acid surface soils, although exchangeable aluminium and manganese levels appear relatively low at this site. A lime test (sampled at the paddock level) may be appropriate to determine whether lime is needed to raise the pH levels.
The conspicuously bleached A2 horizon indicates that periodic waterlogging may occur. This horizon has low fertility and is likely to become "soupy" when worked in a wet condition (as is evident by strong dispersion occurring after remoulding).

Subsoil (B) Horizons

The coarsely structured and dense subsoil (i.e. B21 horizon) is sodic and becomes strongly sodic with increasing depth down the profile. Strong dispersion occurs as a result, creating conditions which will restrict water and plant root movement.
Effective plant rooting depth is shallow due to the coarsely structured sodic subsoil being encountered at 10 cm depth. Plant available water capacity for the profile is also low as a consequence.
At a depth of 40 cm the soil becomes strongly alkaline which may result in nutrients such as phosphorous, iron, manganese and zinc becoming poorly available to plants.