LP33

LP33 Landscape

Soil Profile Morphology

Surface Soil

A1	0-7 cm	Dark yellowish brown (10YR3/4); fine sandy loam, hardsetting surface condition; massive; strong consistence dry; pH 5.7; sharp and smooth change to:	LP33 Profile
A2	7-10 cm	Brown (10YR4/3) conspicuously bleached (10YR7/1d); fine sandy clay loam; massive; strong consistence dry; abrupt and wavy change to:
Subsoil
B21	10-35 cm	Yellowish brown (10YR5/6); light medium clay; moderate very coarse columnar structure; very strong consistence dry; pH 8.0:
B22	35-70 cm	Yellowish red (5YR5/6); medium heavy clay; moderate coarse angular blocky structure (with shiny faced peds); very strong consistence dry; pH 8.8:
B23	70-105 cm	Dark yellowish brown (10YR4/4) with 25% yellowish red (5YR5/6); medium clay; weakly structured; strong consistence dry; contains many (20-50%) ferromanganiferous nodules with very few (<2%) carbonate (with silica) nodules and a few (2-10%) fine quartz; pH 9.1:
B24	105+ cm	Yellowish red (5YR5/6); light clay; weakly structured; very strong consistence dry; contains very few (<2%) carbonate (with silica) nodules.

• Strong texture contrast between the surface (A) horizons and the clay (B) subsoil.
• Hardsetting nature of the soil surface.
• Conspicuously bleached A2 horizon.
• Coarse columnar structure at the top of the subsoil.

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	moderately acid	very low	non-sodic	none1
Subsoil (B21 horizon)	moderately alkaline	very low	sodic	complete
Deeper subsoil (at 1 m)	very strongly alkaline	low	strongly sodic	__
1Strong dispersion after remoulding.

Management Considerations:

Surface (A) Horizons

• The surface soil has a low-moderate overall nutrient status. Organic carbon and total nitrogen levels are reasonable. Improving 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.
• When dry the surface soil becomes hard and may be difficult to work. The soil disperses strongly when remoulded which indicates that excessive cultivation or over-stocking when the soil is wet may lead to surface crusting and exacerbate the hardsetting condition. A cultivated soil is also likely to suffer structural damage from raindrop action. A cover of plants or stubble will provide some protection.

• The dense and coarsely structured subsoil is sodic and disperses completely in water. This will result in soil structural conditions which limit water and plant root movement through the profile. The presence of a conspicuously bleached A2 horizon indicates that water movement into the subsoil is restricted and that periodic waterlogging occurs.

• Paddock under pasture for the past 2-3 years, prior to this oats wheat and barley were successfully cropped.
• Gypsum has been added in a neighbouring paddock. The soil has responded well and is easier to plough.

• Profile described by Mark Imhof, Paul Rampant and Sonia Thompson (14/2/95).