Weed Wars: Laser Beam Technology May Fundamentally Change Farming

Is a laser beam the future of farming?

A raised rectangular vehicle, slightly smaller than a compact sedan, rolls across farmland and shoots concentrated bursts of infrared light into the rows. Audible crackles and pops rise above the furrows, followed by the distinct smell of burning vegetation as weeds smolder beside unscathed crops.

Technology enabling farmers to blast weeds with pinpoint lasers would be a fundamental, transformative moment of change for agriculture, akin to the advent of the gin, tractor, or combine. Paul Mikesell believes the moment has arrived, carried into fields by the Autonomous LaserWeeder.

According to Mikesell, founder and CEO of Carbon Robotics, the unmanned Autonomous LaserWeeder covers 15-20 acres per day and kills 100,000 weeds per hour, delivered from eight lasers beneath its undercarriage. No manual chopping crew, no soil disturbance beyond wheel traction, and no herbicide use—a particularly tantalizing detail for an agriculture industry annually spending $15 billion in weed control chemicals.

“Repeatable, consistent, and easy, all while distinguishing weeds from crops,” says Mikesell. “People don’t yet realize how effective laser technology is at killing weeds, but it is incredible.”

Day or Night

In 2018, Mikesell sought a simple, precise means to kill weeds and knew a laser was ideal from an energy and power perspective. However, concise delivery of a laser—ensuring discretion between weed and plant—required extreme engineering. “We (Carbon Robotics) spent almost three years designing a system that targets weeds on its own while rolling through a field,” Mikesell says. “It operates entirely autonomous and separate from any human action.”

James Johnson, a fourth-generation grower and owner of Carzalia Valley Produce in Columbus, New Mexico, has trialed the Autonomous LaserWeeder and intends to use four units in his Luna County specialty crops in 2022. “The robot is incredibly effective, works with a range of crops and can bring overhead costs down,” says Johnson. “The potential for this technology is the highest I’ve seen with any technology as a farmer.”

How does the Autonomous LaserWeeder work? A capsule version: Computer artificial intelligence mimics human sight through 20 cameras used to identify, track, and target weeds. The trained AI recognizes a given crop and then directs eight lasers on any other vegetation in the field—weeds or volunteer crops. Vehicle movement, image processing, and laser firing all happen in real-time, allowing the Autonomous LaserWeeder to blast weeds while moving at average speeds of 1-2 mph. Seek weed; kill weed.

Generated from sealed glass tubes within the machine, the CO2 lasers feature 3mm accuracy and are ready to fire every 50 milliseconds. The lasers decimate weed meristems, according to Mikesell. “Through lysis, we’re exploding the plant cells and delivering a high level of trauma to the weed.”

“Over several seasons of trials, we’ve seen 100,000 weeds killed per hour in our counts,” Mikesell continues. “Depending on water content, the weeds make a great popping noise when the laser hits, and the smell of burning plant matter is even more distinct.”

At 9,500 lb., 80” track width, 110” wheelbase, and roughly 7’ in height, the Autonomous LaserWeeder is diesel-powered with a 74-hp Cummins QSF2.8, and operates on one fill-up approximately every 20 hours (75-gallon fuel capacity). Day or night, it navigates via a combination of GPS and computer vision: The in-field driving process relies on camera detection of furrows, and end-row turnarounds require GPS guidance.

The LaserWeeder functions in crop heights of 3’ or less. “We’ve been in onion fields a week before harvest and had no problems,” Mikesell describes. “The smaller the weed, the more effective the laser and that means hitting them close to emergence. Also, smaller weeds mean less laser energy required and less laser charging time, which means the LaserWeeder moves faster across a field.”

How does the vehicle perform in wind and dust—characteristic elements of many farms? “Very, very well,” Mikesell contends. “By nature, the rows are always very dusty and dirty, but unless the wind and sand would be so extreme as to block a camera lens, there is no problem and we’ve had no issues.”

Time: The Ultimate Judge

Regardless of technological efficacy in weed control, the ROI question looms large for farmers. Cost comparisons of the LaserWeeder versus herbicide application or chopping crews show a major contrast, contends Mikesell. “In the fields we’ve done, we’ve saved farmers 80% on weeding bills versus spraying or manual labor. It also translates to a higher stand count, less erosion, maintenance of soil structure, and an option for organic growers.”

The Autonomous LaserWeeder made its market debut in 2021 in specialty crops—onions and carrots. However, Mikesell has corn, cotton, soybeans, and other traditional row crops on his radar. “We’re starting this in specialty crops, but will push next into other crops. There is no hindrance or issue in the LaserWeeder technology that will prohibit its use in almost any kind of row crop. It will mainly be a matter of adjusting for row spacing and machine height.”

Further, with each pass of the LaserWeeder, Mikesell sees a bounty of opportunity for the execution of other agriculture tasks. “Our roadmap is a machine that performs multiple functions, but right now we’re focused directly on cost-effectiveness and efficiency for the crop.”

Time is the ultimate judge for any new technology, particularly regarding groundbreaking agriculture innovation. However, Mikesell is firm: Laser weed control will become standard on farmland. “This is so effective and efficient like nothing else,” he adds. “Laser weeding is going to be a standard part of all types of farming and there is no better alternative.”