Our landscapes look and feel like concrete most of the time, so it is no wonder that the subsoil soup phase ( A2 horizon ) is not easily seen.
Tragic for so many valleys where a drain might cut into that old layer and send the whole drainage line into meltdown, This gully on land south of Adelaide has only a small catchment, but the power of salt to start the underground movement to start a rejuvenation cycle is evident .
Are the rocks necessary ?
The usual problem is that during over grazing phases both sheet and rill erosion would have carried away the original topsoil in main drainage area .( isn't late winter spring a great time to sell grass?)
What would you do to fix it ? It looks to me that rocks seem to do little and create a nuisance. IF , sown with lime , and well grazed this paddock will have a chance of being a useful if precarious piece of pasture.
Summary : Rework , compact and resow with fertilizer but without rock
Equipment : Small excavator to save topsoil , mixin a bit of the B horizon especially and lime and compact .
Leave the trees ? better to rework soils or leave them ? and plant new / standalone trees only where they make sense .
Not if the catchment is small .?
