Site LP114b

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Site 114a

Groups: Natte Yallock & Timor West Landcare groups.
Aust. Soil Class.: Vertic (& Hypercalcic), Mesonatric, Brown SODOSOL

General Site Description: Plains near small tributary of Bet Bet Creek.
Geology: Basalt (Quaternary)

Site LP114 Soil Landscape

Soil Profile Morphology:

Surface Soil			Site LP114b Soil Profile
A1	0-10 cm	Dark yellowish brown (10YR3/4), fine sandy clay loam; moderate medium sized blocky structure; very firm consistence (dry); pH 6.1; abrupt change to:
A2	10-25 cm	Dark reddish brown (5YR2.5/2) conspicuously bleached (5YR7/1), fine sandy clay loam; moderate medium sized blocky structure, parting to strong fie blocky structure; pH 6.3; clear change to:
A3	25-40 cm	Dark brown (10YR4/3) with 25% strong brown (7.5YR5/8) and 10% greyish brown (10YR5/2), fine sandy clay loam; very firm consistence (moist); pH 8.4; clear change to:
Subsoil
B21	40-60 cm	Dark yellowish brown (10YR4/4), medium clay; firm consistence (moist); slickensides present; pH 8.4; abrupt change to:
B22	60-80 cm	Strong brown (7.5YR4/6), medium heavy clay; strong consistence (moderately moist); few (2%) hard carbonate nodules; occasional basalt cobbles (up to 100 mm diameter); pH 8.7; abrupt change to:
B23	80-140 cm	Greyish brown (10YR5/2), medium clay; firm consistence (moderately moist); moderately calcareous; pH 9.1.

Key Profile Features:

• Strong texture contrast between surface (A) horizons and upper subsoil (B21) horizon.
• Conspicuously bleached subsurface (A2) horizon.

Soil Profile Characteristics:

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	Slightly Acid	Very Low	Marginally Sodic	None 1
Subsoil (B21 horizon)	Moderately Alkaline	Slight	Strongly Sodic	Strong
Deeper subsoil (at 85+ cm)	Very Strongly Alkaline	Medium	Strongly Sodic	Slight

¹ Strongly dispersive when remoulded.

Horizon	Horizon Depth	pH (water)	pH CaCl2	EC dS/m	NaCl %	Exchangeable Cations				Ex Al mg/kg	Ex Ac meq/100g	Field pF2.5	Wilting Point pF4.2	Coarse Sand (0.2-2.0mm)	Fine Sand (0.02-0.2mm)	Silt (0.002-0.02mm)	Clay (<0.002mm)
						Ca	Mg	K	Na
						meq/100g
A1	10-25	6.1	4.9	0.08		6.2	4	0.67	0.61			32.7	13.8
A2	25-40	6.3	4.9	0.1		4.9	5.1	0.47	1.3			27.8	12.6	5	45	21	28
A3	40-60	8.4	7.1	0.29		9.4	13	1.1	5.3			45.2	23.9	3	30	11	53
B21	60-80	8.7	7.8	0.53	0.13	10	16	1.2	7
B22	80-140	9.1	8.4	0.92	0.08	19	25	1	13

Management Considerations:

Surface (A) Horizons

• 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 level of the organic carbon indicates that the organic matter of the surface soil is low. Organic matter is important for reducing slaking and enhancing soil aggregation, fertility and water holding capacity. 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 are dispersive after remoulding. This indicates that the surface soil will disperse when worked in a moist condition even though it may not disperse in its natural state. The action of rain impact on the soil surface may also cause dispersion; by maintaining some pasture or stubble cover this may be prevented. Tillage or over-stocking should be avoided when the soil is in a moist to wet condition.

Subsoil (B) Horizons

• The dense and coarsely structured subsoil is sodic and dispersive (and has a low calcium:magnesium ratio). This will result in restricted root and water movement in the subsoil. Water is likely to build up on the top of the subsoil after heavy rains causing waterlogging of the more porous surface horizons.
• The salinity rating is of the soil from 60 cm is medium to high. This may affect the growth of some deeper-rooted salt sensitive plant species.

Profile Described By: Mark Imhof,

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