Automated technology fills the labor gap

SALINAS, Calif. -- It smelled a bit like freshly fried chicken with the oil starting to burn. A tractor-like machine rolled slowly over rows of carrots in a field near Salinas, Calif., spraying canola oil onto the weeds but sparing the small, tender carrot leaves.

The device was one of many that showed new ways to manage weeds during the recent Automated Technology Field Day in Salinas. The equipment is being developed by companies here and around the world to confront a shortage of field labor, rising costs of labor and energy, and ever-fewer options for chemical treatment of weeds, fungus, insect pests and soil-borne threats.

Responding to those needs is innovation riding the wave of new technology: robotics, machine learning, artificial intelligence – even video games.

“It’s about best management practices,” said event co-organizer Steve Fennimore, a professor of Cooperative Extension in the University of California, Davis, Department of Plant Sciences. Weeds burden farmers with more than $900 million in annual costs, according to a UC Davis study. “Growers tell me, ‘The only way I can make a profit is to cut my expenses.’ So this is, basically, making the best use of your existing crop management tools.”

For seven decades, farming has relied on chemicals to solve many pest control problems, but environmental regulations have narrowed their use. “The easy chemistry has already been discovered, and the regulatory requirements now are much more strict,” Fennimore observed. “The pesticides that are making it through the regulatory gauntlet now are safe and have minimal effect on the environment, but they are quite fewer.”

But for the relatively small-scale crops that are planted here, such as lettuce, spinach, frisee and bok choy, there isn’t enough acreage to make it worth a chemical company’s while to develop a product compared to, say, an herbicide for corn or soybeans. “There’s 1,500 acres of bok choy in all of California,” Fennimore pointed out.

Growers traditionally have sent field crews to manage weeds, but labor is growing scarcer and more costly for a variety of reasons. 

Solutions that spray cooking oil, root out weeds and zap them with lasers are filling that gap. For starters, they are not regulated. As a result, “the technology is being pushed as far as it can go, as fast as it can go,” Fennimore said.

The event here showed just how far in how little time -- and how much of it is based in and near Salinas. Fennimore hosted along with Paramveer Singh, of UC Agriculture and Natural Resources in Monterey County, and the United States Department of Agriculture’s Agriculture Research Station in Salinas.

Equipment demonstrates various approaches

During Automated Technology Field Day, companies offered a range of new equipment for visitors to inspect and puzzle over: large and expensive, small and less-capital-intensive, modular to adapt to crop and acreage. Some devices offered more-efficient, fine-scale ways to deliver conventional herbicides. Some used mechanical, rotating arms to dig up weeds while skirting crop plants. Some took a non-tillage approach, using oil, laser or heat to suffocate weeds or burn them to a crisp. 

Light flashed from beneath the boxy LaserWeeder onto the crop rows below, zinging weeds while avoiding the tender greens. Pioneered by Seattle-based Carbon Robotics, Fennimore called it “the most significant” among the growing field of machines that use lasers to kill weeds – “vastly more impactful,” he said.

Tensorfield Agriculture, based on the San Francisco Peninsula, developed the Jetty, the device that micro-sprayed hot canola oil through 232 nozzles arrayed along an 80-inch-wide rack at the back of the machine. After watching it roll slowly along the rows of carrot seedlings, visitors knelt down, touched the oily weeds, rubbed their fingers together and took a sniff.

The Weed Spider, in contrast, used 36 bladed arms to uproot weeds, and the same mechanism can be switched over to thin crops. It’s been impressing growers at demonstrations across the West, Fennimore said. “It’s a complex mechanism, but it works well,” he explained. Pioneered by Sutton Agricultural Enterprises Inc., of Salinas, the device is billed as able to replace 20 people and reduce labor costs by 95 percent, according to the company website.

Over rows of young lettuce, the Sharpshooter let loose a targeted stream through pinky-finger-sized nozzles as it rolled along. Water, fertilizer and weed-killing liquid both conventional and organic can be held in its tanks, but its accuracy can reduce chemical use by as much as 96 percent, according to the website of manufacturer Verdant, based in Hayward, Calif. “It has very sophisticated weed-spraying technology,” Fennimore said. “It is quite a significant machine.”

Anything that reduces the labor input is what the growers need,” Fennimore added. “It has to be dependable, and it has to have service support.”

Growers shaping the technology

The Smart Cultivator, built by Salinas-based Stout Industrial Technology, is a tractor with an array of boxes, tubes and wires that connect to thin arms that dance around lettuce, spinach and other leafy crops to uproot weeds. Fennimore called it “very effective at cultivation.”

Stout is the ag technology offshoot of Tanimura & Antle Inc. The Salinas-based produce grower and packager ships around the world, according to the company website. It’s an example of how growers themselves are shaping the technology, Fennimore added.

Perceive, then act: Robot brains and the video game connection

Nearly all the devices shown here used high-resolution cameras to “see” where the robotic arms or twirling discs or ultra-fine sprayers were going, and super-fast processors to tell the machinery, “this one’s lettuce” and “that one’s purslane.”

Chris Laudando, of Laudando & Assoc. based in Chico, Calif., described the scene as the result of “enabling technologies” built on the latest in graphics processing units. Pioneered for use in video games by companies such as Silicon Valley giant Nvidia, GPUs process high volumes of information at high speeds. That makes them ideal for use in machine learning and artificial intelligence, which lie at the heart of the weed-whacking tech on display here.

In action: Laudando & Assoc. engineer Jaggenath Hari moved a squat, robot-looking device dubbed along rows of tender carrot sprouts, while watching a monitor set into one side. Spectators lined up to see what would happen.

Laudando pointed to the camera of his company’s machine, dubbed L&Aser, and explained. “It takes a picture, sends it to the onboard computer, runs an AI model, then sends an answer to a gimble that’s steering the laser beam,” he said. Laser pulses, guided by two large mirrors, beam down onto the kill zone on the ground – but only onto the weeds, inflicting something akin to a combination of sunburn and heat stress. Each zap takes about 10 milliseconds.

“The perception-actuation loop,” Laudando added – the process of detecting the weed, discerning it from the carrot sprout and beaming the laser – “is at the core of everything that’s new and exciting” in the world of automated weed control. And Nvidia’s processors, he said, have ushered in this new era.

“You take all these enabling pieces and marry them together – the financial viability, the user desirability,” Laudando said. Through events like this one, growers and others in the agricultural sector are seeing in-person what such innovation can do for their bottom line. “It’s slowly happening,” he said.