INFORMATION is power and a new laser technology system which could identify where weeds have dropped their seeds in a paddock is aiming to use that knowledge to help growers apply increased weed control diversity.
The system was the innovation of the Australian Herbicide Resistance Initiative (AHRI) and works using light detection and ranging technology, known as LiDAR, to detect where weeds are in a paddock at harvest time and report that back to farmers.
Certain weeds - such as wild oats, brome grass, sowthistle and wild radish - often grow taller than the crop at harvest time, but some of them drop their seeds beforehand and are therefore less well suited to harvest weed seed control.
The idea of the laser system was that it could be fitted to a header at harvest to identify where the weeds are and where their seeds will likely have fallen, allowing growers a greater chance of knowing where weeds are going to germinate in the next year.
AHRI research agronomist Michael Ashworth, who was the mastermind behind the project, said one of the biggest problems with weed control was that it was inherently reactive - a weed is spotted, a herbicide purchased and the weed is sprayed.
"Because of herbicide resistance that scenario is now less effective as well and we end up developing high density weed patches with high levels of herbicide resistance," Mr Ashworth said.
"If we have an idea where weed seeds fell, we're able to predict where the next generation of weeds are going to come from.
"That means we can apply integrated weed management to those herbicide resistance patches, instead of just re-actively changing up a herbicide mode of action."
By knowing where the weeds are going to be, growers have tools in their arsenal and could double the seeding rate, use a cultivar on that patch that has a higher biomass, use a different pre-emergent herbicide package or use a different application rate.
The laser technology, which was also contributed to by AHRI and The University of Western Australia research agronomists Ken Flower and Nik Callow, is able to be used in tandem with variable rate technology that pre-exists within seeders, as well as precision ag which has predominantly been used for fertiliser use.
AHRI teamed up with RCT, a firm which develops and designs autonomous vehicles for the mining industry, to build a prototype of the system.
"Lidar is now a really cheap technology that is used in a lot of cars to mark where the car in front of it is, as well as in the vast majority of autonomous vehicles, so agriculture is way behind mining when it comes to this sort of technology," Mr Ashworth said.
"We did a lot of static tests looking at different sized targets and found out the LiDAR was fantastic at picking that up from a distance, then we strapped it to a header with Chris Syme out at Cunderdin and ran it over a fairly droughted crop.
"We had quite a reasonable success rate, roughly 97 per cent, which indicated that in situations with bad weed problems, this LiDAR was relatively effective."
AHRI is in the early phases of working with a technology based start-up, Stealth Technologies, to further refine the technology and get protypes out to growers and see what they think of it.
"When dealing with weeds, they're the symptom and the real cause is the seed in the soil, so weed control is actually about dealing with the seeds first, then the weeds won't exist in the first place," Mr Ashworth said.
"We don't expect the cost point to be particularly high on it and I think it would pay for itself extremely quickly in herbicide use."
With it being early days, the laser technology is still years away from being commercially available in Australia.
