What happens to all the charcoal after a bushfire?
Bushfires have a big impact on the environment, but maybe less obvious is the impact on the soil in the devastated area. This year's Leeper Memorial Lecture at the University of Melbourne sets out to answer the question. The build-up of burnt and partially burnt organic matter after a bushfire changes the nature of the organic matter in soil, and increases its potential to capture carbon.
Taken overall, the effects on soil quality are probably more good than bad. The build-up increases the soil carbons aromaticity – and therefore stability – which decreases the rate of decomposition. That means the charcoal can remain much longer in the subsoil – centuries in some cases – and so acts as a sink for atmospheric carbon.
The carbon helps also helps with soil structure, and improves water holding capacity, making the soil less drought prone and therefore more productive. Fraser Island, the world's largest sand island, is a common example of a place where the build-up of organic matter in the sandy subsoil allowed enormous forests to grow.
The Leeper Lecture, named for pioneering Australian agricultural chemist Geoffrey Leeper, will be presented by Professor Heike Knicker, a German biologist specialising in physical biochemistry at the Institute of Natural Resources and Agrobiology of Seville, Spain.
Her main research interests are in the field of soil biochemistry, the carbon and nitrogen cycle in soils and the impact of vegetation fires and biochars on soil organic matter. She has published approximately 160 publications in the field of soil science and NMR spectroscopy in peer-reviewed journals
The lecture, presented by the Victorian branch of Soil Science Australia and the University of Melbourne's Faculty of Veterinary and Agricultural Sciences, will be held in the Agar Lecture Theatre of Melbourne University's Zoology building in Parkville from 5-6:30 Friday 21 November. Followed by free drinks and nibbles!