Science & Environment

Oregon researchers propose innovative path forward for farming’s water woes

By Jes Burns (OPB)
July 21, 2022 12 p.m. Updated: July 21, 2022 3:48 p.m.
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At 8 a.m., it’s already warm — bordering on hot — at Oregon State University’s Vegetable Research Farm in Corvallis.

The ground is dusty and so is faculty research assistant Matt Davis, who’s on his knees, rooting around in the soil.

“If we were a big commercial operation, we definitely wouldn’t be doing it this way. Research is a little less efficient,” he says.

He pulls out an Adirondack blue potato, one of three varieties he’s harvesting, and hands a bin of them to OSU Extension’s Amy Garrett for sorting and weighing. Garrett examines each potato closely, looking for damage.

“We’re looking for wireworm damage. This variety seems to get these spots that are bad on them. We’re screening varieties for dry farming,” says the Small Farms Program researcher.

Garrett studies dry farming — growing crops without irrigation — which explains the dusty soil.

“I feel like the water issue is definitely real and on the forefront of everybody’s mind,” she says. “A lot of farmers are already on land without water rights and limited water availability.”

But there’s something else out of the ordinary about this particular research plot: The rows of potatoes are planted between rows of solar panels.

“Water is an issue. Our climate is getting hotter and drier and if we want to continue to grow food and eat, we need to look at alternatives,” she said.

Garrett is a member of a growing cadre of researchers testing the viability and showing the untapped potential of what’s been dubbed agrivoltaics.

OSU faculty research assistant Matt Davis harvests potatoes on a research plot located within a solar array.

OSU faculty research assistant Matt Davis harvests potatoes on a research plot located within a solar array.

Brandon Swanson / OPB

Agrivoltaic vision

You may have noticed farm fields in the Pacific Northwest that have been decommissioned and converted to solar installations. It’s usually one or the other.

But agrivoltaics pairs agriculture (including grazing) and solar power production on the same plot of land. OSU agriculture professor Chad Higgins’ research is showing ways of doing both together that could increase the efficiency of that land significantly.

The panels’ shelter could protect from frost and heat and reduce water use.

“What they do is what we do when we’re out in the sun: we sweat. Plants do something similar where they use water to keep their leaves cool enough for photosynthesis,” Higgins said. “So, if you take that stress off them, now they’re using less water.”

With temperatures in Oregon expected to increase by an average of 5 degrees over the next 30 years under the current rate of greenhouse gas emissions and precipitation expected to come more and more when farmers can’t use it, this would be a huge advantage.

“I think the key words are: more food and better food, less water, extra revenue for the farm. It’s a four-way win for farmers,” Higgins said.

It’s a win for everyone else if all that new solar helps move the world away from burning fossil fuels.

A 2020 paper, co-authored by Higgins, calculated that the United States could meet 20% of its electricity demand by converting 1% of the country’s farmland into agrivoltaics.

The upfront investment to do this would be $1.12 trillion over the 35 years of their proposed project — a steep price tag. But those systems would pay back that investment in green electricity production in just 17 years.

“At a national level, agrivoltaics would produce more renewable energy and more food while using less water, fortifying the security of all three of these critical natural resources,” the authors concluded.

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It would also mean an influx of economic resources into rural communities.

“The solution to climate change is rural America,” Higgins said.

Grim water outlook

Oregon and Washington farmers are already feeling the impacts of climate change.

“Climate change, food security, nutrition security — it’s all connected. It’s all interlinked,” said Emory University biogeochemist Debjani Sihi, who studies soil water capacity, but is not part of the Oregon agrivoltaics research.

The West is in the worst period of drought in more than 1000 years and would not be in this extreme situation in the absence of human-caused climate change. Warmer temperatures and drought have prompted battles over limited water supplies in places like the Klamath Basin, Central Oregon and the Yakima Basin. And these challenging conditions are only expected to get worse as we continue to rely on fossil fuels to power our homes, businesses and transportation.

“I think we’re at a point now where we have to focus on adapting, and if you look at that for agricultural communities, one of the most effective ways of adapting is water management,” said Higgins.

While precipitation is actually expected to increase in the Pacific Northwest under human-caused climate change, farmers won’t get that water when they need it. Instead the heaviest precipitation will come in winter and fall as rain instead of snow, according to the 2021 Oregon Climate Assessment.

Lower snowpack in the mountains means less water in the form of spring and summer melt that many farmers rely on for irrigation.

But now researchers in Oregon, led by Higgins, are proposing agrivoltaics – a new way of doing agriculture that could reduce water use while giving farmers the power to lead the green energy revolution.

“We’re working on something that I think can have a huge impact,” Higgins said.

Researchers are also looking at the advantages of grazing livestock around solar panels to maximize the use of agricultural land.

Researchers are also looking at the advantages of grazing livestock around solar panels to maximize the use of agricultural land.

Brandon Swanson / OPB

Combining forces

OSU Extension’s Garrett says agrivoltaics pairs nicely with her dry farming systems. It could be a boon in naturally arid regions as well.

“In the solar setting, there’s definitely not just a shading effect, but a sheltering effect from the wind as well,” Garrett said.

Garrett is seeing that some of the potato varieties are doing better around the panels than in full sun, though the research is ongoing. And not every vegetable would be suitable to grow around panels in the Pacific Northwest.

“Potatoes are more shade tolerant than some other crops that love full sun like tomatoes and squash and melons and dry beans and corn,” she said.

Higgins and the North Willamette Research and Extension Center near Wilsonville are setting up a multi-acre solar array designed to expand agrivoltaics research in Oregon even further.

“At the end of the day, if it’s something that can help the bottom line, that can help a farm survive, then why not go for it?” Higgins said.

Obstacles ahead

Yet despite the promising results, there are substantial obstacles ahead for implementing these types of systems — including upfront costs, insurance questions, questions about the potential transfer of heavy metals from solar arrays into crops, and limited grid access.

And other researchers caution putting too much faith in one single idea to get us through the climate disaster.

“[There’s] not just one solution. You need to do [things] in combination. And I think as a scientist and community, we have to find the best possible solution,” Emory soil researcher Sihi said.

And there are challenges more locally as well. Current land use laws in Oregon prevent or severely limit the installation of solar arrays on high-quality agricultural lands, though it does leave the door open for agrivoltaic-style systems in some cases.

But Higgins remains optimistic about the potential for agrivoltaic systems to transform the way we produce energy and food.

“We don’t have to make it work everywhere, right? We can pick and choose and pick the best spots. It’s our universe to design.”

A map of soil types illustrates areas in orange that will be subject to new restrictions on commercial solar development.

A map of soil types illustrates areas in orange that are subject to restrictions on commercial solar development.

Courtesy of Oregon Department of Land Conservation and Development

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