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Precision sprayer cuts chemical use

Using highly refined sensors and powerful plant recognition algorithms, the multi-purpose applicator has numerous characteristics.

WESTERN PRODUCER — Makers of the Ecorobotix ARA claim their sprayer can apply chemical to a crop using one nozzle per row and that it is individually triggered to turn on and off using instructions from a single sensor dedicated solely to reading that specific crop row, on a 20-foot sprayer at 4.7 m.p.h.

Not only that, the company says the sprayer can reduce chemical use by as much as 95 percent.

The first two North American systems are already at work on Quebec vegetable farms. After only one month’s experience with the Ecorobotix ARA, both operators report that a 95 percent chemical reduction is quite realistic.

Using highly refined sensors and powerful plant recognition algorithms, the multi-purpose applicator has numerous characteristics:

  • Apply selective herbicides on weeds in-crop.
  • Apply non-selective herbicides on weeds while avoiding crop contact. A safety zone of 1.5 inches is maintained around each crop plant.
  • Apply insecticides and fungicides on crop only, thus avoiding chemical losses on ground and on weeds that don’t matter.
  • Apply liquid fertilizer.

Accurately applies on a scale down to six by six centimetres.

European environmental standards are stricter than those in North America.

“We reduce the application of plant protection products as much as 95 percent. ARA is a proven solution for complying with stringent environmental regulations,” Ecorobotix states in a news release.

Ecorobotix was calibrated and ground-truthed with a wide range of different types of crops and products: rapeseed, corn, sugar beets, cotton, string beans, spinach, onions, chicory and iceberg lettuce. It is especially efficient managing potato regrowth, prairie dock and thistle, Ecorobotix field rep José Marchetti said.

“Grain crops are not our current focus, though our software is adaptable to any kind of agriculture,” Marchetti said.

“This is not stopping other farmers from doing broad acre crops to start looking into adopting this in their future operations. More algorithms will be added in the future. The technology is now getting the attention from vegetable growers because the ROI (return on investment) on high value crops is really quick. Farmers with high-value crops say their ROI will be one to two years.”

Marchetti said the unique sensing and control system developed by Ecorobotix chief executive officer Simon Aspinall extends far beyond simple green on green recognition.

Tragically, during preparation of this story, Aspinall died in a highway-bike accident. A spokesperson told The Western Producer Aspinall was the instigator behind the technology and played a major role in motivating his staff.

Marchetti said the sprayer has six computerized sensors performing multiple functions. Some take high-definition photos while others take 3D photos. At the same time, other sensors are taking nadir images.

Nadir builds a satellite image or aerial photo of the Earth taken straight vertically from a satellite to avoid angle distortion. It’s like a broomstick sticking perfectly straight up on the surface of a field. These multiple images from different angles allow the computers to detect not only colour but also the size of plants. This data is fed into the algorithms, which tell the controller whether to spray a specific plant with the appropriate chemical for that operation.

“In a very short fraction of time, just one-fifth of a second, we are in real time mapping the field, identifying the soil, crops and weeds,” Marchetti says.

“Yes our ground speed is lower than conventional sprayers. However, our technology allows for a precision that cannot be matched by any other smart sprayer. We can detect a prairie dock leaf of three centimetres to four cm diameter and spot hit it with a spray pixel of six-by-six cm.

“If you are doing a very selective site, you can spray even with almost no distance to the crop. We can include in the type of mission instructions to use a safety zone of four cm, or 1.5 inches.”

The Ecorobotix algorithm recognizes shape and color of the weed but is not highly dependent on colour. Rather, it’s based on the system’s large bank of images.

“Going through a field we take many, many pictures,” Marchetti says.

“Our computers receive the pictures and process the images, identifies them and then does the matching of what is the crop and what is the weed. Based on that, we open the nozzles to spray only where we need to, only on the weed.

“It gets smarter and smarter with time, right. We often mention how we use artificial intelligence and machine learning.”

Marchetti says three large canopies cover the entire perimeter edge of the sprayer to exclude ambient light from entering the eyes of the six sensors. This provides ultimate control of the light source that sensors require to read the leaves. Sunlight entering the cover would have a negative effect on the sensitivity of the highly tuned algorithm. He says algorithms can be created to work with sunlight, but standardized light waves within the cover make leaf reading much more accurate

Extending the cover down all the way around has secondary benefits, he says.

“You can reduce spray drift by 95 percent. You can spray in a fairly windy day, when other sprayers are going to have a lot of trouble. It’s totally enclosed.

“Of course, it’s always easy to spray with the boom down at the one foot level, but you can also spray with the boom all the way up at three feet. Just like any sprayer, you adjust the cone of application by adjusting boom height. The cone can be very tight. With the very small pixel size six cm by six cm, the cone is tighter. You have between 20 to 30 cm from the target to the boom.

“Each nozzle is controlled by an electric solenoid, so there’s pressure in the system all the time. When we open a nozzle, the fluid and the pressure have to be there and be ready. Some broad acre farmers may not yet appreciate the value of the Ecorobotix, but precision application should be considered. We cover 10 acres per hour at 4.7 m.p.h. That’s about 240 acres per day for a very, very precise spray application, which does a better job of managing your rapeseed crop and uses less chemical.”