On Tocal Dermosol soils like this one are formed on lower slopes from colluvium (material that has been moved downslope) or alluvium (material deposited by stream flow).
The dark loamy soil in this example has formed from basalt colluvium over shale and you can see the change in profile from the A horizon to the structured B horizon of Dermosol soils. During tertiary times great basalt flows poured out over the sedimentary rocks in the Hunter Valley. Colluvium (material that has weathered and moved downslope) derived from this basalt forms highly productive soils.
Dermosols on Tocal are moderately well to imperfectly drained and have a deep acidic topsoil which is rich in humus (pH increases with depth).
These soils are highly productive if phosphorous levels are kept high.
They lend themselves to pasture improvement due to the slight slope and open nature of the landscape. They are among the most intensively-used soils for beef grazing at Tocal.
Profile description
- 0cm: A1 horizon. Darkish grey-brown clay loam. Abundant plant roots, well drained, pH 5.6
- 20cm: B horizon. Dark grey-brown clay. Strong angular blockystructure, plant roots common, pH 6.4
- 90cm: C horizon. Dark brown and dark greyish brown light clay with a trace of gravel. Well drained
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