Can Lasers Solve Michigan Vegetable Growers' Weed Problems?

By Andi Anderson

Weed control could become a little more high-tech for Michigan vegetable growers as researchers explore whether precision lasers can reduce labor costs and make organic production more profitable.

A new $1 million USDA grant will support Michigan State University researchers studying precision laser weeding for vegetable growers transitioning to organic production.

The four-year project is funded by the U.S. Department of Agriculture's National Institute of Food and Agriculture through its Organic Transitions Program. MSU researchers will partner with scientists at Oregon State University as well as growers in Michigan and Oregon.

The project is led by Joshua Miranda, assistant professor and MSU Extension specialist in MSU's Department of Horticulture. His research focuses on specialty crop weed management, precision weed control technologies, agricultural robotics, non-chemical weed control and herbicide resistance.

Tackling an expensive problem

Weeds represent a significant challenge for all crop producers, but organic vegetable growers face additional hurdles because synthetic herbicides aren't part of their weed-control toolbox.

Instead, growers may depend on cultivation, mulches, organic herbicides and hand weeding. Those approaches can increase labor and management costs.

"Organic growers rely heavily on cultivation and hand weeding, but repeated cultivation can disturb soil structure, reduce surface residue and stimulate additional weed emergence, while hand weeding is costly, labor intensive and increasingly difficult to sustain," Miranda said.

The researchers want to determine whether precision laser weeding can become part of a broader organic weed-management strategy.

"The overall goal is to better understand how laser weeding can help overcome weed management and labor challenges during the transition to organic production, reduce dependence on hand weeding, improve profitability, and make organic vegetable production more competitive, practical and scalable," Miranda said.

How do laser weeders work?

Precision laser weeders use machine vision to identify individual weeds and then target them with a laser.

The technology, however, comes with limitations. Current systems can be expensive and may lack the operating speed necessary for efficient use on many farms.

Researchers also need to establish when and how the technology works best, including the crop growth stages, weed sizes and application timing that provide the greatest benefits.

Those questions will be examined in carrots, lettuce, onions and spinach.

Researchers will initially evaluate crop safety, weed control, accuracy and operating thresholds. They will then develop integrated organic weed-management strategies combining precision laser weeding with other control methods for weeds both within and between crop rows.

Could the technology pay for itself?

One of the most important questions for growers will be economics.

Researchers will compare the costs and benefits of laser weeding with standard organic weed-management practices to identify the production conditions under which investing in the technology could make financial sense.

That's particularly relevant for Michigan's vegetable sector.

"Vegetables, especially onions, have serious weed issues in Michigan," said Greg Bird, executive director of the Michigan Vegetable Council and Michigan Onion Committee. "There are not enough labels for conventional sprays, and organic sprays just can't manage the weeds."

Bird said growers are aware that advanced technologies are emerging, but questions remain over whether they are ready for commercial vegetable operations.

"With Dr. Miranda's grant, we hope to answer that question to get the technology ramped up and ready to zap down some Michigan weeds," he said.

Michigan growers will participate

The research team will work directly with growers in Michigan and Oregon and collaborate with agricultural organizations including the Michigan Vegetable Council and Michigan Onion Committee.

On-farm demonstrations and field days are planned as the research progresses.

The team will also create fact sheets, videos and decision-support tools designed to help producers determine whether and how the technology could fit their operations.

"Collaborating closely with growers in Michigan and Oregon is an essential component to this work," Miranda said.

Ultimately, researchers hope the project provides farmers with another tool for tackling one of organic vegetable production's most persistent and expensive challenges.

"We hope this can help growers successfully transition more acres to organic production and improve the viability and profitability of organic vegetable production in these regions," Miranda said.

Photo Credit: Carbon Robotics