A PhD student funded by the Grains Research and Development Corporation (GRDC) is analysing soils from dryland farming grain cropping systems in order to answer questions about the soil biota.
The University of Adelaide’s Sjaan Davey is focusing her research on soils that are disease-suppressive for Rhizoctonia root rot.
“Rhizoctonia root rot is caused by the fungus Rhizoctonia solani,” Ms Davey said.
“It can have a devastating impact on crops in dryland areas, but very little is known about the disease.”
“Research has shown that disease-suppressive soil from Avon, in South Australia’s mid-North, is able to host Rhizoctonia, but the disease symptoms aren’t showing in the crop.
"Research by Roget and Wiseman in 1995 showed the Avon soil became suppressive to soil-borne diseases after 10 years of retaining crop residues.”
Ms Davey is now conducting experiments to see if the Rhizoctonia-suppressive soil biota, present in the Avon soil can be found in soils from South Australia’s Eyre Peninsula, where Rhizoctonia is an important management issue for grain growers.
“We are seeing if the beneficial characteristics of the Avon soil can be found on Eyre Peninsula,” Ms Davey said.
“It would be hugely beneficial to Eyre Peninsula growers if the disease was suppressed over there too.”
Ms Davey is working in conjunction with the South Australian Research and Development Institute (SARDI) root disease testing unit.
"There, they are using DNA testing to measure populations of beneficial micro-organisms in the Eyre Peninsula soils.
Although Ms Davey is still in the early stages of her research, she said early results have provided lots of new information about the Rhizoctonia-suppressive soil biota.
“This research will be applicable to dryland farming systems right across the southern Region,” she said.
“These areas are afflicted by Rhizoctonia every year.
“The fact that Avon suppressive rhizobiota were not transferable to Eyre Peninsula soils poses many questions.
"For example, what exactly is hindering the development of biological disease-suppression within these soils?
“My results so far, highlight how little is known about the complex interactions between the physical soil abiotic matrix and the soil biology, despite the importance of such interactions.
"My research will now focus on answering these questions.”
Ms Davey’s PhD is supported by growers and the Australian Government through the GRDC, with further funding support from the South Australian Grain Industry Trust (SAGIT) and the Eyre Peninsula Farming Systems project.