“We're essentially trying to work out ways in which to measure herbicides in soil before you start a crop,” Mr Rose said.

“In this experiment we have been determining toxicity thresholds for the herbicide fomesafen, which can persist in soil and is relatively toxic to following canola crops. When we look at R0, it’s a healthy-looking plant because there is no herbicide. However, if we look at R1, it looks a little crook, while R5, that has the most herbicide, is essentially dead."

With a growing need to diversify crop rotations, coupled with the need to control herbicide-resistant weeds, Dr Rose said testing could help growers avoid future crop failures.

“Agronomists, farmers and growers are pretty good at knowing when they might have residues, but these systems are getting more and more complex,” he said.

The amount of herbicide residue which can be harmful can vary depending on soil type as well as crop type. “We want to try and work out thresholds for different herbicide-soil-crop combinations, so growers have the tools and the knowledge to ensure a successful crop for their specific soil composition each time.”