11 July 2019
On Saturday 6th July 2019, over 50 landholders from the Western Port catchment and Bunyip fire affected area attended a workshop focusing on biological approaches to soil and pasture recovery after a fire.
At the event, renowned soil microbiologist, Dr Mary Cole, explored how landowners can think of the emerging post-fire weed burden as ‘mulch potential’.
Dr Cole explains that although ‘weeds’ such as capeweed are quick to colonise after fire, they support the soil as groundcover, which prevents soil erosion while perennial pastures recover and re-grow.
“Soils immediately following fire are bacterially dominated partly because of the loss of the fungal biomass and increase in pH, but also because of the ability of bacteria to better use the soluble organic compounds released by the heat,” said Dr Cole.
“A post-fire environment benefits weedy species as the primary colonisers of the burnt soil. Weedy species are taking advantage of the bare soil and bacterially dominated soil biomass.
“It is important that the weedy species be allowed to grow because they are stimulating the nitrogen-fixing soil biota to replace nitrogen lost in burning. But it is important that weeds are not allowed to flower as they will produce more seed and spread.”
The landholders at the event learnt that by slashing these ‘mulch potential’ species and applying a remedial biological amendment to the soil, they can greatly hasten the recovery of the fungal biomass. This will support pasture species and reduce the ‘weedy’ species over time with a non-herbicide approach.
The event was organised by the Bunyip Fire Natural Environment Recovery Committee. The committee includes representatives from local councils, the Victorian Government, the Port Phillip & Westernport CMA, Landcare and the Victorian Farmers Federation and meets fortnightly to ensure that fire affected landholders have access to relevant information and services to support their recovery from the March bushfire.
The committee is hosting another workshop on Saturday 3 August in Bunyip North focusing on post-fire shelterbelt design, fire ecology and managing environmental weeds without chemicals.