SFS 19

Location: Teesdale-Inverleigh Road
Aust. Soil Class.: Vertic (& Ferric), Mottled-Subnatric, Brown SODOSOL

General Landscape Description: Level Plain
Site Description: "Leigh Road South Paddock”
Landform: Level plain
Element: Plain
Slope: 0-1%
Aspect: 0
Geology: Moorabool Viaduct

SFS 19

Surface Soil			SFS 19
Ap	0-10 cm	Dark brown (10YR 3/3); light sandy loam; weakly pedal structure tending to platy at bottom of Ap; weak consistence; pH 6.3; clear change to:
A2c	10-30 cm	Yellowish brown (10YR 5/4 moist) conspicuously bleached (10YR 6/3 dry); gravelly loam; apedal structure; weak consistence; very many (>50%) medium to coarse (5-20 mm) irregular sub-rounded gravel - mostly cemented ferruginous nodules (remnants of Moorabool Viaduct sand) but also minor component of rounded quartz alluvial gravel; pH 5.1; sharp and smooth change to:
Subsoil
B21t	30-60/70 cm	Brown (10YR 5/3) clay ped exteriors (thick cutans) surrounding brownish yellow (10YR 6/8) matrix with reddish yellow (7.5YR 6/8) mottles; medium clay; coarse (<60 mm) prismatic, parting to medium to coarse blocky (10-40 mm) and fine to medium (<15 mm) polyhedral and lenticular structure; strong consistence; slickensided appearance to most of the ped fractures; pH 6.7; clear change to:
B/C	60/70+ cm	Mottled dark red (10R 3/6) to red (10R 5/8) with reddish yellow (7.5 YR 6/8) and grey (2.5Y 7/1) coarse mottling; weathered ferruginised Moorabool Viaduct Formation sediments with clay accumulation; rigid ferruginised masses of sandier material than B21 above but with reticulate structure defined by thick bands of illuviated clay; pH 7.6.

• Strong texture contrast between surface (A) horizon and subsoil (B21) horizon.
• Conspicuously bleached subsurface (A2) horizon with ferruginous nodules.

	pH	Salinity Rating	Sodicity	Dispersion
Surface (A1 horizon)	Slightly Acid	Low	Non-Sodic	None
Subsoil (B21 horizon)	Slightly Acid	Very Low	Marginally Sodic	Moderate-Strong
Deeper subsoil (at 1 m)	Slightly Alkaline	Very Low	Sodic

Horizon	Horizon Depth (cm)	pH (water)	pH (CaCl2)	EC dS/m	NaCl	Exchangeable Cations
						Ca	Mg	K	Na
						meq/100g
AP	0-10	6.3	6.1	0.22		3.3	0.7	0.5	<0.1
A2	15-30	5.1	4.5	0.05		0.88	0.25	0.24	0.24
B21+	40-60	6.7	6.2	0.15		5.4	7.9	1.4	1.4
C/B	80+	7.6	6.8	0.12		2.8	5.7	0.45	0.45

Horizon	Horizon Depth (cm)	Exchangeable Aluminium mg/kg	Exchangeable Acidity meq/100g	Field Capacity pF2.5	Wilting Point pF4.2	Coarse Sand (0.2-2.0 mm)	Fine Sand (0.02-0.2 mm)	Silt (0.002-0.02 mm)	Clay (<0.002 mm)
AP	0-10	<10	6.9	10.4	6.4	60.4	23.8	3.0	7.5
A2	15-30	18	3.7	7.0	2.6	58.7	28.5	4.0	6.0
B21+	40-60	<10	8.8	50.4	30.3	6.4	2.6	2.5	86.0
C/B	80+			30.2	19.9	23.4	10.2	6.0	58.5

• The three profiles shown here represent well the variation over short distances (within farm or paddock) for soils developed on the Moorabool Viaduct formation sediments.
• The texture contrast and the sodic subsoil restricts drainage and the soils readily become waterlogged in winter.
• The sandy topsoils are very susceptible to soil structure decline; the weak aggregation is readily destroyed by cultivation and the soils are prone to compaction. Bare soil is vulnerable to structural breakdown by rain (slaking and sealing) and to erosion by water. In dry conditions these soils are known to be vulnerable to wind erosion.
• Plough pans are common in these soils. Disruption of pans by tillage is short lived unless controlled traffic is deployed in cropping situations. Raised beds have been used with some degree of success in these soils but the unstable topsoils do not lend themselves well to bed survival.

• Two additional sites were excavated in the vicinity.
  SFS19a, “Top Paddock” - Variant with less gravel, thicker and sandier A1+A2 horizon. More prone to wind erosion and waterlogging
  SFS19b, “Outside North Paddock” - Variant with shallower profile and greater (80%) and coarser (10-40 mm) gravel content
• Soil profile described by Richard MacEwan & Mark Imhof, June 2000.