A mechanical weed chipper could hold the answer to reducing chemical use

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Aptly named the Weed Chipper it is billed as a break through for the first mechanical system capable of site-specific weed control

Weeds don’t stand a chance once the Weed Chipper finds its target with photon technology and then mechanically sets about removing the weed

The Weed Chipper has been plodding away across vast cropping ground in WA for the past few seasons and is now modified to become a machine that can kill weeds with one single swipe.

This unique mechanical system that will soon provide an alternative to using herbicides for weed management in large-scale cropping operations.

The Weed Chipper uses specifically-designed rapid response tines that behave like mechanical hoes, coupled with commercially-available sensing technology to detect and chip out weeds in fallow paddocks.

It is the first mechanical system capable of site-specific weed control in our local grain production chain.

UWA’s inaugural agricultural engineer Dr Andrew Guzzomi from the UWA School of Engineering and The UWA Institute of Agriculture, has led the ongoing engineering design of the Weed Chipper.

“I’m excited by the prospect of seeing these machines being put to use by grower who need alternatives to herbicidal weed control,” Dr Guzzomi said.

The Weed Chipper has been recognised with an award at the Weed Science Society of America’s virtual 2021 Annual Conference.

Project leader, USYD Associate Professor Michael Walsh, accepted the award and said, “Receiving the award from such a prestigious body spoke volumes for the technology and the work of the team involved.

The mechanical Weed Chipper is readying for its commercial release and is expected to appeal to large-scale growers who want to cut back on chemical usage and cost

“It demonstrates the merit of the innovation and the potential impact that mechanical non-chemical approaches could have in helping combat the persistence of tough-to-kill herbicide resistant weeds,” he concluded.

The award is the most recent accolade for the weed chipper, which also won the Rio Tinto WA Innovator of the Year emerging category award in 2019.

The next milestone for the weed chipper will be its commercial release onto the market, expected later in 2021.

From the time it was first taken under the wing of the UWA and USYD in 2019 the mechanical weeding Weed Chipper has been expected to change the face of fallow weed control across our broadacre grains industry.

The Weed Chipper is backed by a host of researchers and engineers who expect it to be the next answer in the fight against herbicide-resistant weeds.

The machine has been designed using a cultivator bar where tines are raised above the ground in a standby position, ready to chip the weeds out of the ground the moment they are detected with weed-sensing technology.

While the design is simple in its application, it is also ground breaking technology that will allow grain growers to control weeds in summer and winter fallows as it can be used in situations that restrict the use of herbicide treatments, such as wind, humidity, heat and resistance.

The Weed Chipper has been designed and built in response to grower concern about the difficulties associated with summer weed control.

This weed-chipping machine has been designed to adapt seamlessly and quickly into grain-cropping systems, with WEEDit sensors installed across the bar to detect a green plant.

Once a weed it detected it activates the appropriate tines to rapidly engage with the soil and, by using a hoeing action, they chip out the weed with minimal soil disturbance.

The bar has been designed to run at 10kph and, while this may be slower than a sprayer, the weed chipper can work around the clock in a wider range of environmental conditions.

In terms of the technology involved, the Weed Chipper operates in a similar way as a weed-seeking spray boom. Weeds are sensed, though instead of spraying them, they are chipped out.

This is the six-metre wide pre-commercial prototype mechanical Weed Chipper that was trialled by growers over the summer season in 2019 – photo UWA

According to Project leader, USYD Associate Professor Michael Walsh, who has led testing prototypes in paddock trials, the weed control success rate has so far been 100% effective.

“The real value is its ability to chip out weeds across a wide range of sizes and growth stages with minimal soil disturbance,” he says.

“Using this approach takes the pressure off herbicides and removes the need to plan your herbicide treatments according to plant growth stages, weed species and resistance.”

Dr Walsh says the initial concept for the machine goes as far back as 2012, when it was developed on a tour through the northern grain-growing region of NSW and Queensland.

“WA growers Ray Harrington, Andrew Messina and Lance Turner and I were travelling through northern NSW and southern Queensland, where we were delivering workshops on harvest weed-seed control,” Dr Walsh says.

“On a farm visit where we were walking through a fallow, Ray noticed the grower was kicking out the weeds with his boots and remarked “Why can’t we get a tine to do that.”

The pre-commercial rig has hydraulic break-out tines with a three-point linkage frame system to aid manoeuvrability between farms and the heavy-duty design allows it to handle a significant workload in tough conditions.

Dr Walsh is hesitant to place a price point on the machine but believes it will be affordable for growers compared with current spray equipment.

“It is difficult to compare the regular seasonal cost of herbicides with a capital investment of the weed chipper,” he says.

“But given this system requires little ongoing maintenance or inputs, we can see significant long-term cost savings for those growers using this system.” Dr Walsh concluded.

The Weed Chipper is also expected be a perfect fit for automated technology, particularly since there is no requirement to fill the machine with any chemicals.

Once this robust and simple mechanical solution gets its final design approval over the next few months it is the first step in commercialising the Weed Chipper, and ultimately get this cost saving technology into the hands of growers.