Site-specific cultivator targets herbicide resistance

Australian researchers developed a cultivator that tills only areas where weeds are detected, and dubbed it the Weed Chipper.

“It’s an existing cultivator (John Shearer) that had a hydraulic break out or hydraulic release system that has been re-engineered so that the (shanks) are held out of the ground, and when a weed is detected a specific (shank) is quickly engaged to chip the weed and then disengage in the stationary standby position out of the ground,” said Michael Walsh.

Walsh is the University of Sydney’s director of weed research and he designed the prototype cultivator with University of Western Australia agricultural engineers Andrew Guzzomi and Carlo Peressini.

Walsh calls the Weed Chipper a target tillage implement set up for site-specific weed control.

The sensors installed on the cultivator are the WeedSeeker sensors used on the WEEDit spraying systems, which is most commonly used for spot spraying weeds in a fallow situation.

“They (sensors) work on reflectance. They have a light source and so there are different reflectance pattern coming from green material compared to bare earth or dry residue. So when the reflectance from a green plant is detected with the sensors then it actuates either a spray nozzle, or in this case a tillage (shank),” Walsh said.

He said the cultivator is used for the same field activities and targets the same weeds the WEEDit spraying system does.

“The reason why we developed it as a non-herbicide option is obviously in response to the issues we’re having with herbicide resistance,” Walsh said.

He said a benefit of Weed Chipper is that it can be used under conditions that make spraying impossible.

“This machine can be used in all sorts of climatic conditions. It’s not restricted by wind or rain, or high temperature. It can be used around the clock,” Walsh said.

The Weed Chipper is set up to work at 10 km-h.

The John Shearer cultivator the Weed Chipper is built upon uses 1960s’ technology, common in Australia.

“One of the reasons for choosing that system, other than they had a hydraulic breakout, was because they were so popular and potentially growers already had an existing machine that could be retrofitted for the purposes of targeted tillage,” Walsh said.

He said the cultivator might have a fit with organic and possibly row-crop production systems.

“With dedicated rows, you can get your tine spacing up to make sure the tines wouldn’t make contact with the row when they are activated. It would have applications between the rows, as long as you could focus the sensing so that it only senses the weeds between the rows,” Walsh said.

The site-specific cultivator, or retrofit kits are not yet on the market, however a commercial scale evaluation is underway for the six-metre-wide prototype.

“At the moment we’re trying to identify a commercial partner who can take this to market. But we think there should be a range of options available to meet producer’s needs. Some producers might want to retrofit their existing machines others will just want to buy a complete rig,” Walsh said.

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