Keep Crops Alive In a Warmer, Dryer World

By Paul Tullis

Opti-Harvest’s colored polymer tubes, panels and cones are placed on, above or around trees or other crops to increase photosynthesis, according to the company.
Source: Opti-Harvest

Every week, the University of Nebraska-Lincoln, National Oceanic and Atmospheric Administration and the U.S. Department of Agriculture update America’s Drought Monitor, a map illustrating the parts of the country that are currently experiencing water scarcity, and to what extent.

In the West and High Plains, which comprise 15 states with some of the most productive land in the nation, the news over the past 20 years has not been good. Drought conditions have prevailed in more than 15% of the West for 1,138 of the last 1,144 weeks. California has spent eight of the last 10 years with more than half of its land under stress. As of Feb. 8, 95% of the West was considered “abnormally dry.”

Farmers are bearing the brunt. In California, home to the country’s most profitable agricultural region—the San Joaquin Valley—warm-season temperatures have climbed 1.4ºC (2.5ºF) since the 1970’s, and a projected increase of another 2ºC is baked in for midcentury. For vegetation, an average difference of 1ºC can be significant.

With global warming unlikely to slow any time soon, California’s Fourth Climate Change Assessment (issued in 2019) cited new technology as both a means of mitigation and crop adaptation to persistent water stress.

The opportunity hasn’t been lost on inventors—or investors. Startups from Los Angeles to Switzerland have been rolling out products. Deal value in the agricultural technology industry has increased every year over the past decade, almost quadrupling since 2016. Last year, companies in the sector saw $7.8 billion worth of investment.

But whether the new tech works as advertised, is affordable and sufficiently scalable remains an open question.

Wavelengths in the red part of the spectrum are conducive to growth, says Opti-Harvest Chief Executive Officer Jonathan Destler.
Source: Opti-Harvest

According to the United Nations, some 155 million people faced a food crisis in 2021, up from 135 million the year before. That means (at the very least) that a household is suffering serious malnutrition or can meet basic food needs only by depleting essential assets. Key among the causes are climate shocks including extreme weather conditions triggered by accelerating warming, floods, drought and related population displacement.

Ariel Ortiz-Bobea is an associate professor and fellow at the Atkinson Center for Sustainability at Cornell University. He said recent research by his team shows “anthropogenic climate change has already slowed agricultural productivity growth globally,” losing the last 7 years of growth out of the past 60.

“Global agriculture, while more productive over time, is not growing increasingly resilient to high temperatures,” he said. “A sustainable future of agriculture in a world with growing global population and living standards requires that we improve productivity.” More land, labor and chemicals are not sustainable options, he said. So the answer is to invest in research and development.

Opti-Harvest, which calls itself an “agricultural innovation company,” said it’s taken that lesson to heart. Its products seek to make up for less available water by speeding plant growth. The Los Angeles startup produces specially colored polymer tubes, panels and cones that are placed on, above or around trees or other crops. The aim is to get more sunlight to leaves that wouldn’t otherwise see any, at least not directly. Moreover, the mechanism also manipulates the spectrum toward wavelengths more geared toward growth, the company said.

Accelerated growth may mean crops need less water. “We’re basically irrigating with photons,” said Opti-Harvest Chief Executive Officer Jonathan Destler.

Opti-Harvest’s “canopy unit” looks like an enormous mixing bowl sitting atop a garbage can. The device focuses light into a red tube, which has small holes to allow the reflected light to reach beneath the tree’s canopy, where it’s normally shaded. Wavelengths in the red part of the light spectrum are conducive to growth, Destler explained. So Opti-Harvest said it collaborated with chemical giant BASF to come up with just the right pigment of red, tweaking the geometry to collect and disperse the light (too much, and the plant overheats).

Experts in plant physiology, horticulture and optical physics from Israel’s ministry of agriculture and the Weizmann Institute of Science, an ag-tech hub outside Tel Aviv, were also involved in its development, Destler said. Randomized trials on an experimental farm in California showed the mechanism spurred more and larger fruit from citrus trees and increased nut yield by as much as 24%, according to Opti-Harvest.

John Bushoven is department chair of horticultural science at Fresno State University. When he first heard what the company was doing, he said his first reaction was “it’s about time someone brought the greenhouse outdoors.”

Bushoven spoke from a pistachio orchard on Fresno State’s 36-acre research farm, where he’s conducting research into root development as part of a contract with Opti-Harvest. His expertise is using ground-penetrating radar to measure root systems. Pistachio and almond trees—high-value crops requiring years of investment and lots of land and water—are especially vulnerable to temperature fluctuation and drought. Roots that reach deeper can access more water, in turn requiring less irrigation, he said.

Vivent’s PhytlSigns product consists of electrodes that poke into the plant and uses machine learning to determine how the plant is reacting to the agricultural input.
Source: Vivent

While there’s not enough water to go around (especially for crops like almonds and pistachios), there’s also far too much fertilizer being used. Among other downsides, ammonium nitrate, a commonly used synthetic fertilizer, brings with it negative greenhouse-gas effects. While there are already devices used to read nutrient levels in soil to better target fertilizer use, Switzerland-based company Vivent contends it can do them one better.

The company’s product, PhytlSigns, consists of electrodes that poke into a plant, measuring electrical signals. Sensors and machine learning determine how a plant is reacting to agricultural inputs—fertilizer, nutrients, water, pesticides—or even if it’s under attack from pests, according to Vivent.

“We are guilty,” said Vivent sustainability manager Marina Martin Curran, “of torturing a lot of tomato plants.”

Algorithms can tell users what kind of stress the plant is experiencing and what to do about it—add or lower fertilizer input, apply more water or pesticide. Lack of nitrate produces a different kind of signal than does lack of water, for instance. “Those signals vary according to the health status of the plant,” Curran said. Whatever the stressor, “you’ll see useful data well before the leaves start to droop.”

The company said it has focused on high-value crops such as tomatoes and cannabis because of the high cost of developing the technology. But Curran added “we are very keen to support staple crops.”

Vivent said it has tested PhytlSigns on maize in the lab, and on soy and potatoes in the field. Outdoors, however, signals are harder to read, creating an obstacle to scalability. Maize “is more subject to wind and other physical stimuli, which can affect the signal,” said Daniel Tran, a researcher with Agroscope, an arm of the Swiss Federal Office for Agriculture that conducts research and development for the food industry.

And the bigger the field or farm, topography makes it more difficult to choose a plant to “read” that represents the entire area. Nevertheless, Tran said his research shows PhytlSigns has the potential to work on all crops, regardless of scale.

In November 2021, the company received €1.8 million ($2 million) in venture funding from
ePlant Inc., a self-described plant technology startup, and impact investor Astanor Ventures. Vivent said that much of the money will go toward developing a wireless system to deploy its technology, which the company hopes will make it cost-effective and scalable.

“We’re hopeful we can offer farmers the opportunity to dramatically reduce their fertilizer inputs or give them more information about the specific nutrients a plant needs,” Curran said.

Pivot Bio says it has developed a way to reprogram microbes to produce nitrogen regardless of
what’s going on around them.
Source: Pivot Bio

While growers need to become more resilient to global warming, an expanding segment of the industry is focused on reducing greenhouse gas emissions by employing microbes to do the job of fertilizer. It’s called nitrogen fixation.

Certain microbes that live in soil can produce nitrogen, reducing the need for added fertilizer. But if the microbes detect nitrogen in their environment, they stop making it. Legumes have evolved what is essentially a safe house for microbes, where they live shielded from the surrounding environment and thus continue to manufacture it. (This is one reason soy is a popular cover crop—not needing fertilizer, it’s cheap to grow.)

Berkeley, California-based Pivot Bio said it’s developed a way to reprogram microbes to produce nitrogen regardless of what’s going on around them. The company led the ag-tech industry’s investment rankings last year with $430 million, according to PitchBook.

As synthetic fertilizer prices rose in 2021 to more than double their five-year average, Pivot said its products have become more attractive (though it declined to disclose how much they cost). Other companies in the microbial agriculture space include New Leaf Symbiotics of St. Louis and Joyn Bio, a Boston-based joint venture of Gingko Bioworks and Bayer AG.

“Nitrogen fixation is the holy grail for cereal grains,” said Pivot Chief Executive Officer Karsten Temme.

Cornell’s Ortiz-Bobea said technologies like those proposed by Opti-Harvest, Vivent and Pivot Bio—even if successful and scalable—aren’t a panacea. They’re just new tools among many, all of which must be used if the climate crisis’s effect on global food production is to be mitigated.

“What is most critical is that investors have incentives to invest,” he said. “Governments and international organizations have a role to play in fostering a framework to catalyze this.”