GL172a

Location: Dobie

Australian Soil Classification: Vertic, Mottled-Mesonatric, Red SODOSOL (confidence level 1) (shallow soil depth)
General Landscape Description: Plain
Site Description: Mid-slope (2.5%)
Land Unit: Hillside Basalts
Geology: Quaternary basalt
General Land Unit Description: This land unit represents the gently undulating to undulating basalt plains around Ararat. The plains are often dissected with very slight rises. This site represents the lighter textured basalt soils on the slight rises, predominantly Red Sodosols. The soil indicates that there is some gilgai micro-relief although it is not that evident on the surface. Rock outcrops can occur, particularly on the crests of the small rises. Ferromanganiferous nodules can occur above the clayey subsoil. This often occurs as a thin band. The soils on the plains are commonly Brown Vertosols (GL173). There are commonly large cracks on the surface when the soil is dry and the soils themselves indicate significant movement.




Soil Profile Morphology:

Surface Soil
A1	0-10 cm	Dark brown (10YR3/3); fine sandy clay loam, weak medium subangular blocky structure; weak consistence, dry; contains very few medium subrounded ferruginous and manganiferous nodules; pH(field) 5.0; clear change to:
A2	10-25 cm	Yellowish brown (10YR5/5),conspicuously bleached (10YR7/2d), with many distinct medium strong brown (10YR5/6) mottles; fine sandy clay loam,; massive structure; very weak consistence, dry; contains abundant medium subrounded ferruginised and manganiferous nodules; pH 5.8; abrupt and wavy change to:
Subsoil
B21	25-45 cm	Yellowish red (5YR5/6), with many faint medium red (2.5YR4/8) mottles; heavy clay; strong very coarse polyhedral, parting to strong coarse angular blocky structure; very firm consistence, dry; a few distinct slickensides evident, pH 7.9; diffuse but wavy transition to:
B22	45-55 cm	Yellowish brown (10YR5/4), with a few fine faint mottles; heavy clay; strong very coarse prismatic parting to strong coarse angular blocky structure, very firm consistence when dry, few distinct slickensides evident; pH 9.0; changes to:
C	55+ cm	Weathered basalt

• Strong texture contrast
• Strongly sodic top of subsoil
• Alkaline at depth
• Cracking subsoil
• Impeded internal drainage
• Bleached A2 horizon
• Ferromanganiferious nodules in A2 horizon
• Shallow soil
• Topsoil dispersive when worked when wet
• Subsoil dispersive when dry

Horizon	Horizon Depth (cm)	pH (water)	pH (CaCl2)	EC dS/m	Organic Carbon %	Total Nitrogen %	Exchangeable Aluminium ppm	Exchangeable Acididty meq/100g	Exchangeable Cations				Coarse Sand (0.2-2.0 mm) %	Fine Sand (0.02-0.2 mm) %	Silt (0.002-0.02 mm) %	Clay (<0.002 mm) %	Field Capacity % w/w	Wilting Point % w/w
									Ca	Mg	K	Na
									meq/100g
A1	0-10
A2	10-25	5.8	4.6	0.06	0.74	0.07	16	5.5	1.7	0.83	0.31	0.39	15	50	23	10	19.3	8.8
B21	25-45	7.9	6.9	0.27					10	14	0.6	6.3	2	20	9	65	44.3	31.0
B22	45-55	9.0	8.6	0.23					14	19	0.52	0.05	2	16	18	60	57.1	34.0
C	55 +