An array of innovative spraying technology has hit the market in Australia over the past few years.
These systems can cut chemical costs for farmers and more effectively spray persistent weeds.
While the benefits are clear, deducing which will be the right fit for your business can be challenging.
A number of these technologies were discussed in detail at a Grains Research and Development Corporation spray day at Jondaryan, Qld, last Wednesday.
Darling Downs Spray Tech managing director Jeremy Jones works with manufacturers to develop implements that are suitable for use with the Weed-It optical spot spraying system.
He had a SwarmFarm Robotics machine fitted with a Weed-It Quadro system on display at the event.
SwarmFarm Robotics is owned by Andrew and Jocie Bate and the SwarmBots are manufactured on-farm at Gindie in central Queensland.
The machines are fully autonomous, meaning no supervision is required.
Within the confines of your farm, they are able to move from the shed to the paddock, or from paddock to paddock, and then complete their task.
Safety is a top priority and Mr Jones said a lot of work had gone into SwarmFarm's safety features.
The 75 horsepower machine on display had a three metre wheel track, 1500 litre tank and 12m boom.
They are lightweight and nimble, weighing less than three tonnes when fitted with the Weed-It.
"If we do get weather events where things are a bit wet, this is going to be one of the first machines to get back out in the paddock with," Mr Jones said.
The SwarmBots run NovAtel receivers so a base station is not needed and have an onboard weather system.
It is able to map a paddock or you can pull in A-B lines from other machinery.
Mr Jones said everything required for the Weed-It system is able to be controlled through the SwarmFarm app.
"We can see a map of where we've been spraying, we can seen an as applied map and we can control the sensitivity and the margin on the go," he said.
"They are travelling around 10km/h as a maximum spray speed, so that means that the nozzles we're running are still putting out around 100L/ha equivalent."
There are four nozzles per sensor in a 25cm configuration on the Weed-It Quadro.
The near-infrared sensors are looking for chlorophyll in the plants so Mr Jones said it did not matter about the colour of the weed.
Mr Jones said there were four ways to use the system.
"There's normal spot spraying; it drives along and when it comes to a weed, sprays it 200 to 300mm before and after," Mr Jones said.
"It has a built in PWM (pulse width modulation) system at no extra cost; as it comes up to the weed, it pulses, it applies that rate through a 50hz solenoid and it gets the right rate on the weed and it's also speed compensating.
"There a dual spray option; you can apply a light blanket rate but spike to high rates when weeds are actually detected.
"Or it can be turned into a blanket sprayer and set to a target rate."
The robots is are available on a three-year lease, which costs approximately $90,000 per year.
Pricing for the Weed-It system on it varies depending on width.
It ranges from $150,000 including the boom and tank up to approximately $330,000 for a trailing system on a 24m boom.
Mr Jones said the next available delivery spots were around July, so farmers could get their hands on a machine this calendar year.
Richard Weston is the Vnet Precision Ag crop care business development specialist for John Deere dealer, RDO Equipment.
He spoke to growers about John Deere's See & Spray Select system.
It uses cameras in conjunction with machine learning and was developed at the University of Southern Queensland.
Mr Weston said John Deere offered the only fully integrated spraying system on the market - from the nozzles, to the spraying technology and the spray rig itself.
See & Spray Select is a green-on-brown sprayer and uses the ExactApply system.
On a 36m boom there are cameras every metre, which control 72 nozzles.
"See & Spray Select is a selective broadacre sprayer, it's not purely an optical sprayer," Mr Weston said.
"So we can use it similar to a Weed-It for high-cost, high-value, low percentage hot brews to smoke some persistent weeds.
"Or use it right the way through to 99 per cent of the field using a more standard fallow brew to make it more economical.
"It's two machines in one because we can still use it as a standard broadacre sprayer."
The machine has single and overlapping modes available.
It can be set to .4m, which sprays 20cm in front of and 20cm behind the weed, .9m or 1.4m.
There is also a fallback mode so if the machine goes below .5m or above 1.5m the system will automatically turn on.
"When we're using See & Spray we're actually using a pressure-based system, we're not pulsing, we're using the solenoids to turn the valve on and off," he said.
"We do have the option of being able to put a blanket spray out the front and camera spray out of the back nozzle.
"It is very sensitive and because we're using an RGB camera we can get a lot smaller pixel size."
Mr Weston said a full digital spraying record was captured and if a mobile weather station was on the machine this information was also stored.
"In cab we can see a map of where we've been, where we're getting the area covered versus the area applied, and a percentage," he said.
"That also gets sent back up to the cloud to the Operations Center."
See & Spray Select is available on John Deere's 400 and 600 series sprayers.
A model year 2023 system costs $150,000 (excluding the cost of the sprayer), however all of this year's stock is sold.
Pricing for model year 2024 systems will be released next month and the ordering window will open in June.
John Deere is also in the pre-production phase of its green-on-green See & Spray Ultimate product.
McIntosh Distribution Miller east coast sales representative and WeedSeeker 2 national product manager Scott Jameson talked farmers through both the WeedSeeker 2 and Bilberry systems.
Mr Jameson said the sensors used on Trimble Agriculture's WeedSeeker 2 spot spraying system had been completely redesigned since the first version.
The plug-and-play ISOBUS compatible system offers farmers plenty of control and reportability.
Expanded sensor coverage enables a nozzle spacing of 50cm.
Mr Jameson said the sensors used two wavelengths of light - a red light and a near-infrared light.
These sensors detect chlorophyll in the plant, not the colour green.
Mr Jameson said the reflective signature changes significantly when this is detected and a single nozzle is activated behind each sensor to spray the weed.
"We want 100L/ha going to the ground when that sensor fires and we want to get really good coverage on that single plant you're trying it hit," he said.
WeedSeeker 2 is able to produce a weed map so problem areas can be identified and will tell you on the screen the percentage saving you are making with the machine.
It is height adjustable between .5m and 1.2m.
If it goes above that height or there is heavy dust, Mr Jameson said it would switch on and spray continuously to ensure no targets were missed.
The speed range is 15 to 20km/h and while the sensors can work faster, Mr Jameson said it was about the efficacy of chemical at high speeds.
It is designed to be a quick-release system and takes about half an hour to remove from a 36m boom.
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Mr Jameson also spoke about the green-on-green Bilberry spot spraying system.
McIntosh offer this system on Miller Nitro sprayers, which include the Spray-Air and PWM IntelliSpray systems.
The Bilberry system has forward facing cameras every three metres that scan a 3x3m block in front of the boom.
Algorithms have been developed for broadleaf weeds in cereal crops, grass weeds in canola and blue lupins in lupins.
Bilberry is also developing this technology for use in sorghum and cotton crops.
"It detects the plants that are non-crop types and then with the nozzles behind sets it to a 25cm or 50cm spacing, depending on how you want to set it up, then it'll activate that individual nozzle to hit that plant," Mr Jameson said.
It can be used for green-on-brown spraying, however Mr Jameson said the WeedSeeker 2 was more accurate for this.
Mr Jameson said the cost to retrofit a WeedSeeker 2 system to a 36m boom was just above $200,000.
He said they had kits available to suit most major manufacturers' machines.
For a Bilberry system you are looking at similar money and there is a paid subscription required for both devices.
The cereal algorithm for the Bilberry system is about $8/ha but is capped at $40,000 for the year.
Unused hectares can also be banked for the following year.
For the WeedSeeker 2 system it is about $2.5/ha and capped at $11,000.
Once you have paid for that hectare, both systems allow you to go over it as many times as needed.
Another homegrown innovation is the Single Shot system, developed by the Single family.
The Singles farm near Coonamble, NSW, and have developed a drone-based weed detection sensor.
Single Agriculture director Ben Single said farmers were saving $25 to $30/ha on average using the system.
Before flying, a digital boundary is drawn around the field so the drone knows what area to cover.
It is able to map weeds as small as 4cm at 200ha/h.
"The drone sensors are capturing the data as it flies over but it is not doing anything with the data at that stage," Mr Single said.
"It is captured on a high speed USB, which is then plugged into a laptop running our system and then we process that data then and there.
"You need a little bit of internet to process but a mobile hotspot or 4G is enough.
"The processing time is at roughly 1:1 so if you spend an hour flying, it takes about an hour to process."
Once the data is processed, a prescription can be created.
The weed size, location and spray area information is all used to generate this on-off spray plan.
Rather than having to buy a new sprayer, this information can then be used by farmers who have an existing machine with section control.
"Once we know where they are, we can make that plan and we can spray when it is appropriate," Mr Single said.
The drone is manufactured in China but is heavily modified to suit this task.
One set of batteries lasts for 40 minutes and about 160ha can be covered before recharging or swapping for another set.
The Single Shot system is set up for green-on-brown spraying but the Singles are getting into green-on-green.
It is designed for broadacre farmers and contractors and can be bought outright for $145,000.
A smaller, less expensive model is on the cards.
