Soil secrets to suppress disease

Image of a woman sitting before a microscope

Associate Professor Pauline Mele
from La Trobe University looks for
the soil microorganisms that
suppress disease in grain crops.

A team of 90 researchers working on 15 projects aim to increase yields and reduce input costs in soils across the high-rainfall zone (HRZ) as part of the GRDC’s Soil Biology Initiative.

Associate Professor Pauline Mele from La Trobe University, who is also a principal research scientist at the Victorian Department of Primary Industries (DPI), is leading the five-year project funded by the GRDC.

Associate Professor Mele says better understanding of suppressive soils, monitoring soil to assist with management decisions and improving nutrient availability for plants are major research priorities.

“There are soils across the country where the incidence or severity of disease is suppressed, even in the presence of a pathogen, host plant and favourable conditions,” Associate Professor Mele says.

“We think every soil has the potential to be suppressive – it’s just a matter of working out which management techniques will encourage this.

“We know the effect is due to a diverse range of beneficial microorganisms because upsetting their balance or sterilising the soil can cause disease to strike with a vengeance.”

At this stage, researchers hope to identify which organisms allow soils to suppress disease. In particular, researchers are looking at how the biological composition of soil contributes to grain production.

She says development of new technologies means the research team is poised to “delve deep into the soil’s biological communities and see who is there and what they are doing – not only as individual species, but as highly interactive communities. Soils are habitats and every habitat is different, which usually means that each community it contains is different, with different types of soil biota potentially in different areas.”

Associate Professor Mele says understanding how differences in habitat and soil biota are influencing plant performance could be refined to provide regionally specific information to guide land management.

“The soil biological resource under our feet is seen as the last frontier for the grains industry,” she says.

Once beneficial microorganisms have been identified in suppressive soils, researchers plan to examine paddock histories, including rotations, inputs and soil characteristics, to understand how management practices could enable them.

The research into disease suppressive soil focuses on the following areas:

  • the physical, chemical and biological features of disease suppressive soils, and whether they are regionally specific;
  • determining whether disease suppression in soils is a temporal phenomenon and whether it targets specific pathogens’ potential development of a disease suppression index based on the genetic signature of a soil community; and
  • management of the crop-soil ecosystem, including the physical and chemical environments, to increase disease suppression.

“Using biological suppression to reduce crop losses, with minimal or no chemical inputs, could improve the profitability of growers around the world,” Associate Professor Mele says, adding that root lesion nematodes alone cause crop losses estimated at $250 million a year in Australia.

More information:

Associate Professor Pauline Mele
03 9210 9219

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GRDC Project Code DAV00099