LP118

LP118 Landscape

Soil Profile Morphology

Surface Soil

A1	0-7 cm	Dark brown (10YR3/3), sandy loam; firm consistence when dry; few (<2%) ferruginous gravels; pH 6.2; clear change to:	LP118 Profile
A2e	7-15 cm	Dark brown (10YR4/3) conspicuously bleached (10YR7/3d), fine sandy clay loam; strong consistence when moderately moist; few (5%) ferruginous gravels; most roots stop in the 10-15 cm zone; pH 6.7; gradual change to:
Subsoil
B21	15-40 cm	Dark brown (10YR3/3), light clay; moderate coarse blocky structure; very strong consistence when moderately moist; few roots (probably tree) reach 40 cm; pH 8.3; gradual change to:
B22	40-70 cm	Yellowish brown (10YR5/6) with yellowish brown (10YR5/4) mottle, light clay; moderate coarse polyhedral structure, breaking to strong fine polyhedral structure; strong consistence when moderately moist; few (2%) hard carbonate nodules; pH 9.5; clear change to:
B23	70-110 cm	Reddish brown (5YR4/4) and yellowish brown (10YR5/6), light clay; strong medium sized polyhedral structure, breaking to moderate very fine polyhedral structure; very firm consistence when moderately moist; carbonates (hard in tubules and soft in patches) common (15%); pH 9.7; gradual change to:
B24	110-140 cm	Yellowish brown (10YR5/6) and reddish brown (5YR5/4), clay loam; strong medium sized polyhedral structure, breaking to moderate very fine polyhedral structure; strong consistence when moderately moist; very few (< 2%) carbonate nodules; pH 9.5; gradual change to:
B25	140-170 cm	Dark brown (7.5YR4/4) and light yellowish brown (10YR64), light clay, with 10% sand in pockets (10YR5/8 and 10YR5/4); weak coarse prismatic structure, breaking to moderate medium sized polyhedral structure; strong consistence when moderately moist; few (5%) manganese stains; pH 9.6; clear and tongued change to:
B26	170-190 cm	Dark yellowish brown (10YR4/6) and yellowish brown (10YR5/8 and 10YR5/4), fine sandy clay loam; very firm consistence when moderately moist, pH 9.1.

• Strong texture contrast between surface (A) horizons and subsoil (B) horizons.
• Conspicuously bleached subsurface (A2) horizon.

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	slightly acid	very low	sodic	slight1
Subsoil (B21 horizon)	moderately alkaline	low	strongly sodic	complete
Deeper subsoil (at 110 cm)	extremely alkaline	low (medium at 170 cm)	strongly sodic	complete
1 Strong when remoulded.

Management Considerations:

Surface (A) Horizons

• Organic carbon levels indicate that organic matter content is relatively low for the surface soil from this pit. Organic matter is important for enhancing soil aggregation, fertility and water holding capacity on soils such as these with high fine sand content. Organic matter levels will build up under pasture but will decline if cultivation takes place. Practices such as residue retention, minimum tillage and including pasture rotations should be utilised if cropping occurs.
• The surface horizons have a low inherent fertility (based on the sum of the basic exchangeable cations).
• The bleached subsurface (A2) horizon indicates that periodic waterlogging occurs on top of the more slowly permeable subsoil. This horizon is likely to become 'spewy' as a result.
• The surface horizon is dispersive, especially when disturbed in a moist condition. This will reduce permeability so water will remain on the surface. This condition may be ameliorated with the application of gypsum. Test strips should be trialed to assess the likely benefits.

• The deeper subsoil (from 40 cm depth) is strongly alkaline which indicates that some nutrients (eg. copper, iron, manganese, and zinc) may be poorly available to deeper rooted plants.
• The subsoil is sodic and dispersive which will result in restricted root and water movement in the soil. Water is likely to build up in the surface horizons (as they are more porous) after heavy rains causing waterlogging and surface runoff.
• The deep subsoil (below 140 cm) is slightly saline and is moderately saline below 170 cm.

• Short distance from site of old sand pit (now filled with water).
• River red gums (Eucalyptus camaldulensis) are the most common tree.

• Profile described by Paul Rampant and Ruth Lourey (22/5/96)