LP51

Property: LP51 Mitiamo	Group: Pine Grove Farm Advance
Australian Soil Classification: Calcic, Mottled-Mesonatric, Red SODOSOL	Northcote Factual Key: Dr 2.33
Great Soil Group: red-brown earth
General Landscape Description:

LP51Landscape

Soil Profile Morphology

Surface Soil

A1	0-12 cm	Dark brown (7.5YR3/4); fine sandy clay loam; hardsetting and massive; strong consistence dry; pH 5.9; abrupt change to:	LP51 profile
A2	12-15 cm	Yellowish red (5YR4/6) sporadically bleached; coarse sandy clay loam; massive; strong consistence dry; contains a few (5%) quartz fragments; pH 6.6; sharp change to:
Subsoil
B21	15-30 cm	Dark reddish brown (2.5YR3/4) and yellowish red (5YR5/8); medium clay; strong coarse blocky structure (with smooth-faced peds); strong consistence dry; pH 8.1; gradual change to:
B22	30-60 cm	Yellowish red (5YR4/6); light medium clay; strong coarse blocky structure (with smooth-faced peds); strong consistence dry; pH 8.8; gradual change to:
B23	60-85 cm	Yellowish red (5YR5/8); light medium clay; moderate medium to coarse polyhedral structure; very firm consistence dry; pH 9.0:
B24k	85 cm+	Yellowish red (5YR5/6); light medium clay; strong medium polyhedral structure; very firm consistence dry; fine-earth carbonate common (10%); pH 9.0.
NOTE: This soil corresponds to Sylvaterre Sandy Clay Loam as mapped by Skene (1971). It has developed on both colluvial and aeolian (parna) materials.

Key Profile Features

Strong texture contrast between surface (A) horizons (clay content 15%) and subsoil (B21) horizon (clay content 48%).
Hardsetting surface horizon (with high fine sand content of 46%).
Coarsely structured (strongly sodic) subsoil.

Key Profile Characteristics

Management Considerations:

In general, management strategies for all soils should aim to increase organic matter levels in the surface soil; minimise the degradation of soil aggregates and porosity; promote the development of stable biopores; improve the calcium status of the ion exchange complex (particularly when sodium is a significant part – i.e. sodic), and break up any hardpans. Less frequent tillage; using less aggressive implements, and working the soil at optimum moisture conditions can all assist in maintaining soil aggregation and porosity as well as reducing the breakdown of organic matter. Practices such as residue retention, minimum tillage and including pasture rotations could be utilised if cropping takes place in order to build up organic matter, reduce erosion risk and increase fertility.
Plant available water capacity (PAWC) is relatively low (estimated at 60 mm) for this profile - based on the laboratory data available. PAWC is limited by the strongly sodic subsoil.

Surface (A) Horizons

The surface horizon is hardsetting and has a high fine sand content (i.e. 46%). Upon wetting and drying the surface soil sets hard and will be difficult to work and may become “powdery” when worked in a dry condition. Cultivation of such soils when wet may result in surface sealing upon drying. Tillage should be minimised and stubble retention/ pasture rotations practised.
The organic carbon value is low for the surface soil. Soils such as these with high fine sand and silt levels depend on organic matter for maintaining structure. Improving soil organic matter levels will assist in minimising structural problems such as surface sealing and hardsetting as well as improving soil fertility and water holding capacity.
The subsurface (A2) horizon disperses strongly after remoulding. This indicates that it may disperse if excessively cultivated or overstocked when wet. This may lead to the development of a cultivation pan.

Subsoil (B) Horizons

The coarsely structured subsoil is strongly sodic and disperses completely in water. This is likely to result in restricted root and water movement through the profile. The presence of a sporadically bleached subsurface (A2) horizon above the sodic subsoil indicates that water movement is restricted.
From 60 cm depth, the soil salinity rating is medium, and increases with depth. This is likely to restrict the growth of deeper-rooted salt sensitive species.

Landholder Comments:

Notes:
Profile described by Mark Imhof, Paul Rampant and Karen de Plater (2/3/95).

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