Site LP112

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Groups: Natte Yallock Landcare group.
Aust. Soil Class.: Eutrophic, Mottled-Mesonatric, Brown SODOSOL (shallow profile depth)

General Site Description: Grazing paddock.
Geology: Ordovician Schist (metamorphic) and Quaternary alluvial deposits (Shepparton Formation).

Site LP112 Soil Landscape

Surface Soil			Site LP112 Soil Profile
A1	0-6 cm	Very dark greyish brown (10YR3/2); fine sandy clay loam; very firm consistence (dry); few (10%) ferruginous gravel (4 mm average diameter); pH 5.8; abrupt change to:
A2	6-12 cm	Dark yellowish brown (10YR4/4) with yellowish red (5YR5/8) mottles; sandy clay loam; strong consistence (dry); few (10%) ferruginous gravel (4 mm average diameter); pH 5.9; abrupt change to:
A2j	12-15 cm	(Discontinuous up to 5 cm thick) Brown (7.5YR5/4); sporadically bleached; fine sandy loam; strong consistence (dry); few (10%) ferruginous gravels (4 mm average diameter); pH 6.3; abrupt change to:
Subsoil
B21	15-20 cm	Yellowish brown (10YR5/8) with reddish yellow (7.5YR6/8) mottles; medium heavy clay; weak coarse blocky structure; very firm consistence (moderately moist); very few (2%) ferruginous gravel (4 mm average diameter); pH 6.2; clear change to:
B22	20-35 cm	Yellowish brown (10YR5/6) with yellowish brown (10YR5/4) mottles; medium heavy clay; weak coarse blocky structure; very firm consistence (moderately moist); very few (2%) ferruginous gravels (4 mm average diameter); pH 6.1; clear change to:
B23	35-45 cm	Yellowish brown (10YR5/6); light medium clay; very firm consistence (moderately moist); very few (2%) ferruginous gravels (4 mm average diameter); pH 6.0; clear change to:
C	45 cm +	Weathered Schist

• Discontinuous and bleached subsurface (A2) horizon.
• Strong texture contrast between surface (A) horizon and the top subsoil (B21) horizon.
• Shallow soil profile (with weathered rock at 45 cm depth).

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	0-6	5.8	4.8	0.13		4.2	4.7	0.99	0.78			25.8	10.9	10	49	13	23
A12	6-12	5.9	4.8	0.13		3.4	4.8	0.4	1.1			22.1	8.8
A2j	12-15	6.3	4.9	0.07		1.3	2.1	0.19	0.51			15.4	4.9	12	61	13	13
B21	15-20	6.2	5.1	0.16		3.9	10	0.49	1.9			32.1	18.2	6	36	10	47
B22	20-35	6.1	5.2	0.24		3.3	12	0.48	2.6			18	15
B23	35-40	6	4.8	0.17		1.6	6.5	0.28	1.7

• 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 cation complex (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 contents can all assist in maintaining soil aggregation and porosity as well as reducing the breakdown of organic matter.
• Plant available water capacity (PAWC) is considered to be low (estimated at 55 mm) for the profile. This is based on available laboratory data and assumes an effective rooting depth of 35 cm. Effective rooting depth will be restricted by the strongly sodic subsoil and presence of weathered rock at 45 cm depth.
• (PAWC) is considered to be low (estimated at 55 mm) for the profile. This is based on available laboratory data and assumes an effective rooting depth of 35 cm. Effective rooting depth will be restricted by the strongly sodic subsoil and presence of weathered rock at 45 cm depth.

• The inherent fertility is moderate (based on the sum of the exchangeable basic cations) which is beneficial for plant growth.
• The level of the organic carbon indicates that the organic matter of the shallow surface soil is moderate. Organic matter is important for reducing slaking and enhancing soil aggregation, fertility and water holding capacity, as well as binding together sandy (60% sand) soils. 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 marginally sodic and slightly 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. Maintaining some pasture or stubble cover will be beneficial.
• The bleached subsurface (A2) horizon indicates that periodic waterlogging occurs on top of the more slowly permeable subsoil.

• The coarsely structured subsoil is sodic (becoming strongly sodic at depth 30 cm) and dispersive with a low calcium to magnesium ratio (<1). 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 above.