Robots coming to America's farms help with weeding, tractor driving

Jun 05, 2023

CHUALAR, Calif. – Looking like the ungainly combination of a Transformer and Edward Scissorhands, the robot slowly trundles across the field of tiny plants. It uses three high-resolution cameras to peer down at the ground below.

Lit by synchronized strobe lights, an onboard computer creates a digital image of each seedling as it glides by, comparing them with all the greenery it might reasonably find in a field of rich Salinas Valley farmland two hours south of San Francisco.

In a fraction of a second, there's a match – broccoli – and the computer hones in on the exact center of the plant, creating an on-the-fly chart of its placement.

"It puts a dot on the stem and maps around it," says Todd Rinkenberger of FarmWise, the robot's maker. "Now it knows what's plant. Everything else is a weed."

The robot's circular set of metal blades smoothly move so they’re right in front of the plant, then snick open and shut, precisely digging into the soil one on each side of the broccoli seedling, destroying the weeds while leaving the sprout untouched, ready to grow to harvest size in another month or so.

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This all happens in a fraction of a second as the FarmWise Titan robot rolls down the field at less than 1 mile an hour.

"It's been quite a change," said Luis Vargas, who started out on 20-person weeding crews in high school and now runs a fleet of four robot weeders for Tanimura & Antle, a grower and seller of fresh vegetables in California and Arizona.

"I remember being in the hand crews, it would be 10 hours days walking the fields. When you get into a super weedy field it's slow, it's hard. And it's hot," he said. "These machines, they don't care if it's hot or cold."

The scene in Chualar is being played out in a small but growing number of fields nationwide as robots using machine learning are deployed. Today, automated machines are mostly driving tractors up and down fields, carrying loads and doing thinning and weeding. Other systems deploy precise doses of fertilizer or herbicides. But harvesting, especially delicate fruits and veggies, is further off in the future.

Together, machines are set to help solve a host of problems. The biggest is reducing the need for backbreaking agricultural jobs. Workers will still be needed, but more will be running the robots, fewer doing tedious, physical labor. It's already resulting in a host of new jobs for people who can build, run and repair the systems. Community colleges and universities are busy creating programs to teach these skills to a new generation of agricultural workers.

Experts say agriculture is a rare application of cutting-edge technology that workers, tech companies, the government, and big business are all to varying degrees optimistic about.

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Another perk of robots, nonintuitive for people outside agriculture, is that they’re smaller and lighter than traditional large tractors. This means farmers can get working in fields early, when the ground is still too wet to bear the weight of large tractors and cultivators, giving farmers a longer growing season without worries about compacting and harming the soil.

"This is important especially with climate change because we’re expecting wetter springs and drier summers," said Steven Mirsky, a research ecologist with the United States Department of Agriculture.

Labor is a huge driver of the change, said John D’Arrigo, president of D’Arrigo California. His family has been growing lettuce, broccoli, cauliflower and broccoli rabe in California for three generations, and he sees his workforce aging out.

"We’re cutting 1 million heads of lettuce a day and it's a hard job," he said. "The people walking in the fields, bending over cutting lettuce? Those people are disappearing, they’re retiring," he said.

Where there's caution, it's from unions that want to make sure their workers enjoy the benefits of automation and help decide how it's rolled out. The United Farm Workers of America isn't seeing robots displacing humans in the fields, said communications director Antonio De Loera-Brust.

Its biggest concern is that the technology be deployed to make agricultural jobs better, not make them go away.

"Is this going to be deployed to make farm work safer and take less of a toll on people's bodies?" he said. "Or is this just going to be another tool to maximize profits on the back of farmworkers? We want workers to have a say in how robots get implemented."

D’Arrigo says agriculture has to make its jobs better.

"I’m losing people to construction," he said. "If we’re going to survive as an industry, we’re going to have to make jobs that are more lucrative and interesting."

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That's certainly been the case for Vargas, 27. His mother has worked for more than 14 years in the packing sheds at Tanimura and Antle.

Vargas went to college with the goal of working in criminal justice, but the new tech possibilities intrigued him. He started working on the first demonstration Smart Cultivator robot systems from Stout Industrial Technology in Salinas about four years ago.

Today, the robot crews he manages can weed about an acre an hour.

"For a hand crew it would take about 20 people," he said.

Agricultural robots and automated systems are mostly invisible to people driving by a field, said Emily Duncan, an agricultural technology and innovation researcher at the University of Guelph in Ontario, Canada.

That can be as simple as a tractor or combine that drives itself along a field of corn or wheat or soybeans. Called auto steer, these systems use GPS and only require that the driver turns at the end of the row.

"When you’re out harvesting 12, 13, 14 hours a day, driving for so long is really tiring. Using this, you’re mostly monitoring," said Duncan.

As of this year, such systems are being used in more than 50% of row crops such as corn, soybeans, cotton and winter wheat, according to USDA.

The next level up will be machines that use high-resolution cameras to see each plant and give it a precisely measured squirt of fertilizer, depending on how well the plant is doing. If it's puny, it might get more, if it's nice and robust, then less.

In some cases, ag robots can do things that simply couldn't be done before. One example is small robots that can navigate and weed under the canopy of a cornfield after the plants have grown high. Any weeds, even hidden ones, take nutrients and moisture from the soil that could go to crops.

"Now we just accept those weeds because we can't get to them," said Shadi Atallah a professor of agricultural economics at the University of Illinois Urbana-Champaign, where the robots are being developed.

Robots could also make organic foods cheaper. Today organic crops rely on more cultivation and hand work than conventional crops because herbicides can't be used, which makes them more expensive to grow. Robots offer an alternative.

"Organic can mean having workers bending over the whole day just so somebody who can afford it can buy an organic vegetable," said Atallah.

In addition to mechanical robot weeders, there's the laser weeder from Carbon Robots, which uses 30 lasers to zap weeds or thin seedlings, with no hand labor or chemicals required.

One other place robots can make a big difference is in cover crops, the growing practice of planting things like winter rye, hairy vetch and crimson clover in newly-harvested fields to lock in moisture and strengthen the soil, then cutting them down to enrich the soil before planting again in the spring.

Today such crops have to be sown after a field is harvested, or by airplane, dropping seeds from the sky. But robots can scoot under the canopy of corn, soybeans and cotton and plant cover crop seed before the main crop is harvested.

"This will expand the ability to do cover cropping and take less time. It's not reducing labor intensiveness, it's using artificial intelligence technology to help with the sustainable transition of agriculture," said Atallah.

A stumbling block is finding tech people to apply their knowledge to agriculture. That's one reason the Western Growers Association created its Center for Innovation and Technology in Salinas.

But while it's only an hour south of Silicon Valley, "there's a real disconnect between people who work in tech and people who work in ag," said Duncan.

The problems farmers face are difficult to solve and don't offer the kind of global scale tech firms like. Each crop type can require a new solution.

"I spoke to an audience of venture capitalists a few years ago," said Neill Callis with Turlock Fruit Co., a fourth-generation melon farm in California's Central Valley.

"I was describing the melon-picking problem and they were all ears. Then I said it's really a $30 to $60 million problem space and you could just see the lights go out. There just wasn't enough upside for them to raise the money and innovate to solve our specific problem."

Today, interest is ramping up, as shown by the host of smaller robot startups launching. "Ten years ago, none of these people were here," said D'Arrigo. "Now there's lots of them around but we need lots more to get into it."

Harvesting will be the last problem solved, especially when it comes to fruits and vegetables, said Dennis Donohue, director of the Center for Innovation and Technology.

"It turns out killing weeds is easier than delicately plucking strawberries," he said. "Robot hands are getting better but they’re not there yet."

It's also got to become a whole lot cheaper. "Picking an apple for $20 is a non-starter. It's got to cost 2 cents," said Callis.

In the end, robots could revolutionize farming, making smaller farms more economical and the entire industry more sustainable, changing an agricultural world in which the model has long been "get big or get out."

"Once you work with a scale-neutral technology like robots, you’re no longer saying you can only survive if you have the biggest combine. The question becomes, ‘Are you a one-robot farm or a 30-robot farm?’" said Steven Mirsky, a research ecologist at the Department of Agriculture who's building the public databases of images ag companies can use to jumpstart their systems.

Startups like Farm-ng in Watsonville, California, are now building small, easy-to-configure robot platforms that farmers can add onto for whatever they need, which USDA is experimenting with, he said. Moving away from huge, massive, and massively expensive, equipment to light robots that will be modular and easier to fix can also enhance the kind of technical ingenuity that has long been the hallmark of the American farmer.

One thing Mirsky is sure of – machines will never entirely supplant farmers.

"The farmer is the ultimate multifactor analyses machine," he said. "You can't replace them, you can only add capacity for them to do what they need to do," he said.