An automated weed chipper could be the key to controlling hard to kill and herbicide resistant weeds in the near future.
Speaking at the Grains Research Development Corporation Update at Goondiwindi, Queensland, last month, University of Sydney director weed research Dr Michael Walsh said the idea for the automated weed chipper came about in 2012 when a group of growers from Western Australia were on a farm tour near Goondiwindi on the Queensland border.
"Invariably when you get these guys together they talk about opportunities for targeting weeds," he said.
"We were walking through a fallow paddock and the observation was made by the growers that the farmer was walking weed to weed and kicking them out with his boot."
Dr Walsh said in subsequent conversations the group discussed how the process could be automated using existing equipment.
"The idea was to use the hydraulic break-out system on the Shearer trash worker and re-purpose it into a weed kicker," he said.
"GRDC heard about the idea and funded a project."
Dr Walsh said the prototype was developed by agricultural engineers and researchers from the University of Sydney University of Western Australia (UWA).
The retro-fit involved raising the location of the tynes so they were held out of the soil, above the ground, when in stand-by position.
"When it is actuated it engages with the soil to target the weed before it returns to its resting position," Dr Walsh said.
"It still has it's breakout function so if it does hit a rock it will break out."
Dr Walsh said the automation was achieved using precision Weedit sensors, however the system could work with other commercial sensors and pre-determined weed maps.
Dr Walsh said the prototype automated weed chipper worked by fitting springs on either side of the tyne which held the tyne out of the soil, while hydraulic solenoids and an accumulator drove the tyne into the soil under hydraulic pressure. "The process happens quite quickly, it occurs within 0.3 seconds," he said.
Dr Walsh said the system had been tested at Narrabri, NSW, on four key winter weeds, being wild oats, turnip weed, sow thistle and ryegrass of various growth stages and found precision was important.
"We targeted a low weed density of approximately one plant per 10 square metres, the sort of density you would use a weed seeker for," he said.
"We targeted them with the actuated tyne, the idea being to get direct contact for the point of the tyne with the base of the weed.
"When we did it was 100 per cent control, regardless of weed size.
"If we didn't get direct contact, and only got partial contact with the wing of the sweep, it was 100pc survival."
Dr Walsh said the system had also been tested on summer weeds at Gatton, Qld, focusing on barnyard grass, feathertop Rhodes grass and windmill grass with similar results.
"Its not built for weed patches, we think we would build in an over-ride system where it maps a patch so you can come back to it," he said.
Dr Walsh said now the project was completed.
"We are talking about this opportunity in the hope it will generate grower interest, and grower interest will generate manufacturer interest," he said.
"We need a manufacturer to come on board so product development can be finished under their banner."
Dr Walsh said while the trash worker had worked as a prototype, engineers working on the device felt starting from scratch would deliver an even better product.
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