Herbicides battle it out in trials

Haidee VandenbergheCountryman
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Pre-emergent herbicides were under the microscope in a trial held by WATFA executive director David Minkey.

New herbicides Sakura and Boxer Gold were investigated alongside Trifluralin in plots of wheat dry seeded and with delayed seeding.

"We chose a weedy site on purpose to demonstrate that dry sown you've got to choose the right herbicide and get the crop emerging really early," Dr Minkey said. "Otherwise if you don't get the crop emerging early it just doesn't compete with the weeds."

Growers have been dry sowing canola and pulses with confidence for years, but weed burden with dry sown wheat remains a concern.

"The modelling is showing that the last decade has had more dry seeding opportunities for wheat than any other decade we've had on record," Dr Minkey said.

"That's because our weather systems are changing slightly.

"We're getting early summer rainfall, then the soil profile dries, then with forecasts of mid-late May rains farmers can get in early, sow their wheat and have the opportunity to also sow a bit later."

The trial yielded some surprising results.

"Basically the results were that in this soil type Trifluralin didn't work at all under dry seeding because it just didn't incorporate at seeding," Dr Minkey said.

"It's a loamy soil type, so it just turned over clods rather than incorporating.

"The Sakura probably worked the best followed by Boxer Gold.

"All three of those performed better under dry seeding than delayed seeding, which is a bit of a surprise.

"The reason why we think that happened is because it was really cold when it germinated, so the wheat didn't compete with the ryegrass, but where the wheat got away early it outcompeted the weeds.

"It shows that if you get it right with good pre-emergent you can manage your weeds pretty well."

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