PROTECTING pasture and crops from damaging insect pests is the focus of a new research initiative which provide a godsend to farmers battling root-eating grubs and beetles.
“I am increasingly being contacted by farmers who are frustrated by herbivore insects, such as chafer grubs and scarab beetles, that are destroying pastures from the ground up,” said Dr Scott Johnson.
He heads the Western Sydney University team that is investigating the potential of adding silicon to soil for plants to use as a defence against root herbivores.
Working within the Hawkesbury Institute for the Environment, Dr Johnson has received $900,000 for the initiative from the Australian Research Council.
“I have been sent photographs from farmers and agronomists, showing that they can grab their grass and roll it back like a doormat because these insects have completely severed the roots from the stems,” Dr Johnson said.
Plants draw silicon from the soil to coat their tissue, build cellulose and lignin in their cells, and protect against insect attack, Dr Johnson said.
“For insects, grasses that contain large amounts of silicon are unpleasant to eat. It would be similar to eating an ice-cream with a thick outer coating of sand.”
The research will also investigate the impact of elevated atmospheric carbon dioxide (CO2) on Australian grasses, which could compromise plants natural defences.
Elevated CO2 makes carbon more available to plants. This can cause them to switch to ineffective carbon defence mechanisms to ward off insects. It is also widely reporeted to supress the Jasmonic Acid (JA) signalling pathway, which grasses use to mount a silicon defences against root attack.
“This research will explore the benefits of counteracting the rising levels of CO2 by introducing the natural, environmentally-friendly supplement to the soil. We will also introduce root herbivores to the environments to test their impacts.”
The research could pave the way for beneficial reuse of a plentiful and potentially cheap industrial waste product.
The silicon will be introduced to the soil in granular form, using slag, a by-product from steel making furnaces.
“Slag is a rich source of silicon and it's in plentiful supply. A single Australian still mill can produce more than a million tonnes of slag every year, making it an easy resource to come by,” Dr Johnson said.
The research will determine the safety of deploying silicon in food crops
Four metre wide open-top chambers will be built to house the grass. The chambers will be enriched with CO2 and silicone to test how they interact.