TUCSON, Ariz. — Bridgestone Americas Inc. is committing $35 million to help fund research at the University of Arizona into the viability of the guayule shrub as a potential natural rubber source.
The funding — Bridgestone's contribution plus a $35 million grant from the U.S. Department of Agriculture (USDA) — will help the university's Department of Chemical and Environmental Engineering conduct research over the coming five years into the development and refinement of growing guayule with "climate-smart" practices, according to Kim Ogden, head of the department.
The research project and the funding were disclosed May 8 by Robert Bonnie, USDA undersecretary for farm production and conservation, at a news conference held at the University of Arizona's Controlled Environment Agriculture Center.
A hardy, perennial shrub that matures in two years, guayule is native to the Chihuahuan Desert, which covers northern Mexico and parts on the southwestern U.S.
Bridgestone and others consider guayule to be a domestic alternative to para rubber trees, which are susceptible to disease, particularly leaf fall disease, leading potentially to precarious supply and market volatility.
In addition, the price of rubber is affected by increasing labor costs, and there is the potential for geopolitical disorder, Ogden said,
"There is a big risk, as well as supply-chain problems, when you have all the natural rubber coming from one region of the world," Ogden said. "The goal for Bridgestone and for the other tire companies is to find reliable, domestic sources of rubber."
Additional partners on the project include the Colorado River Indian Tribes, Colorado State University, regional growers and OpenET, a public-private partnership that facilitates responsible water management.
Bridgestone has been working with guayule in Arizona since 2012 at the company's 280-acre farm in Eloy, about halfway between Phoenix and Tucson. Bridgestone plans to expand the farm to 20,000 acres in the next several years by working with Native American farmers to grow guayule on tribal lands, and with other area farmers.
"Eventually, we hope to have plantings of around 100,000 acres, spread out across 15 or 20 facilities across the Southwest," David Dierig, section manager for agro operations at Bridgestone, said.
The company said it has invested more than $100 million to date in its efforts to commercialize guayule and committed $42 million more last August to establish commercial operations in the U.S. Southwest toward that goal.
The USDA grant is part of the agency's Partnerships for Climate-Smart Commodities Initiative. It was awarded last fall to Bridgestone, which now is redirecting it to this research project.
Scientists have considered guayule as an alternative source of latex for over a century, Dierig said.
"People had looked at this plant as far back as World War I, and during World War II there was a ton of research because our rubber supply got cut off," Dierig said, referring to Japan's control of most of Southeast Asia at that time.
The Emergency Rubber Act, passed by Congress in 1942, directed scientists to find alternative sources for rubber, Dierig said, and guayule was in the mix.
"They probably had around 30,000 acres of it planted here in Arizona, and they found a lot of facets to it that were advantageous," Dierig said.
Once access to rubber plantations in Southeast Asia was restored, interest in guayule faded, and the para rubber tree remained essentially the sole source of industrial rubber.
The research partners pointed out that while synthetic rubber is suitable for many uses, it does not have the resilience of natural rubber and has limited use in demanding applications, such as airplane tires or tires for large agricultural vehicles.
"Reducing the amount of rubber we are importing from Southeast Asia is also going to help with biodiversity and climate change," Dierig said.
"We want to use less water, install irrigation systems to avoid flood irrigation, use less fertilizer and educate the growers," Ogden said. "If you're looking at a big system life-cycle assessment, this is going to cut down on greenhouse gases."
Unlike annual crops, which require tilling the land every time the crops are planted or harvested, guayule is perennial, which makes no-till and low-till farming a viable practice, the project's backers said.
It's also a method of storing carbon dioxide in the soil rather than the air — i.e., carbon sequestration — and has natural properties that deter insects, so no insecticides are needed once the plants reach early maturity.
Ogden and the team at the University of Arizona also are working to find additional products that could be derived from guayule and marketed to supplement the revenues from manufacturing rubber products.
In addition to a rubber content of about 5%, guayule also has a resin content of 7% to 9%, which could be used to make natural adhesives and insect repellents. The rest of the plant is woody biomass that could be converted into biofuel or used to make particle board.
"Finding research-based solutions that have a global impact is an ideal expression of the University of Arizona's mission," University of Arizona President Robert Robbins said.
"I am grateful to our partners at Bridgestone and the USDA for their investment in Dr. Ogden's expertise. I look forward to seeing new, sustainable tires on the road soon, knowing the University of Arizona helped get them there."
