27 Brown, red and black sodic and non-sodic texture contrast soils on Palaeogene sediments

These texture contrast soils are found on Palaeogene sediments around the foothills of the Otway Range. An organic fine sandy loam (about 15 cm) clearly overlies a bleached massive sandy loam subsurface horizon often to a depth of 50 cm, abruptly overlying a coarse to medium strongly structured brown mottled (red and yellow) medium to heavy clay, which grades at about 100 cm into a sandy clay and/or cemented sandstone or calcareous deposits.

Notable characteristics include: variable depth of bleached subsurface horizon, abrupt texture contrast between surface soils and mottled subsoil, deep weathered profiles (sometimes vertic with depth), acidic profiles bordering on strongly acidic, some profiles are acidic but alkaline (calcareous) at depth depending on lithology and climate. The sodic soils are subnatric, other soils may be sodic in the deep subsoil only.

Soil Sites

Site Code	Soil-landform unit	Component	ASC	FK	1:100 000 mapsheet
CLRA414	73	Crest	Mesotrophic, Mottled-Subnatric, Brown Sodosol	Dy3.41	T7621 - Colac
MM104	180	Crest	Eutrophic, Mottled-Subnatric, Brown Sodosol	Db2.42	T7621 - Colac
MM5083	169	Upper slope	Vertic, Calcic, Black Chromosol	Gn3.43	T7721 - Geelong
MM5122	158	Upper slope	Calcic, Mesonatric, Red Sodosol	Dr2.13	T7721 - Geelong
OTR490	89	Mid slope	Calcic, Mesonatric, Brown Sodosol	Dy3.12	T7721 - Geelong
SW73	92	Upper slope	Bleached-Mottled, Mesotrophic, Brown Sodosol	Db2.31	T7621 - Colac
SW76	92	Upper slope	Vertic, Mottled-Subnatric, Brown Sodosol	Dy3.41	T7621 - Colac

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