Scalping the soil to restore grasslands
I’ve been quite inspired by the Woorndoo Land Protection Group and their work to restore the grasslands of the Victorian Volcanic Plains in south-western Victoria. Incredible stuff. Scalping the land to remove topsoil full of nutrients and weed seeds and then introducing grassland species, mainly via direct-seeding, with some tube-stock planting. The results are splendid and from the photos I’ve seen, well worth a drive to visit the roadsides.
The concept of “scalping” is pretty confronting for many of us who have been taught to avoid soil disturbance as much as possible, but the results speak for themselves. I recommend “Land of Sweeping Plains” to anyone with grassland restoration questions.
We have a native grass paddock near our house which is fenced from kangaroos and is lavished with much attention (endless weeding, thanks dad). We have about twelve species of native grasses, as well as herbs and forbs, but in one part the Barley Grass has defeated us. So, in November 2019, we decided to try scalping. I cried when Phil lowered the tractor bucket and carted away a load of topsoil. Into the bare earth I planted half with Purple Plume Grass (Triraphis mollis) tubestock and direct seeded the other half with Bottlewashers (Enneapogon avenaceus). There was a bit of native Purple Lovegrass (Eragrostis lacunaria) and Silky Umbrella Grass (Digitaria ammophila) in the mix too.
The grasses all grew and looked great. All the species I planted were summer-growing perennial (C4) species, and they die back in winter. So in Spring, I slipped in some Spear Grass (Austrostipa scabra) tubestock, which is a winter growing C3 grass. I’m hoping to have year-round cover of native grasses.
I watched the little grass patch carefully for signs of Barley Grass invasion. Initiallythere were only a few plants, easily plucked out. Such a contrast to the adjoining areas which I decided to treat by mowing and brush-cutting the Barley Grass before it set seed, dodging around any native grass tussocks. Five times I mowed it and the seed heads just kept coming! I don’t think it is possible to stop Barley Grass from seeding by cutting it. (Yes, I know you told me so, Phil)
In subsequent years, the Bottlewashers and Purple Plume Grass tussocks re-sprouted from the winter-dormant tussocks and were lush and seeding long before any other tussocks in the paddock. I think this was because there was no competition from the Barley Grass.
But after several years the weeds returned to my tiny scalped area. This patch was just too small to stay weed-free for long.
March 2020
November 2020
Although I am a scalping convert in areas where weeds can’t be managed. I don’t think I’ll ever be able to afford a large-scale scalp like Woorndoo, Euroa Arboretum or some of Paul Gibson-Roy’s or Flora Victoria’s sites.
Jazz in the Spear Grass and Long-tails (Ptilotus polystachyus). This is a rare plant in Victoria and I can remember when I found the first plant on Raakajlim in 2009. Now look at it!
First published 27 November 2020