Natural rubber crops are a possible market for U.S. agriculture
A decapitated field in Colorado is keeping a secret and holding hope of a new crop. Headless sunflower plants trade beauty for brawn, pumping growth energy toward leaves instead of seed. Inside the green biomass hides the muscle of industry and empire: natural rubber.
Could sunflower grown exclusively for rubber become a viable crop for U.S. farmers? The reality is fast approaching farmland, according to Tom Christensen, CEO of Edison Agrosciences. Sunflower cultivated exclusively for natural rubber content is on track for 2019 commercial pilot acreage, and of particular importance to U.S. growers, the market couldn’t be hungrier. Global demand for industrial rubber products is projected to hit $158 billion by 2018, according to a study by Freedonia Group Inc.
The rubber supply is dominated by tropical Hevea trees that bring tremendous profits into Southeast Asian coffers each year and billions of those dollars are pumped in by U.S. manufacturers. It’s a huge opportunity for U.S. agriculture—made all the more alluring because Southeast Asia’s Hevea trees are at the mercy of leaf blight, have a long production cycle and demand massive amounts of cheap labor. The market trade is ripe for emerging sources and Christensen is hot on the trail.
Based on acreage, sunflower is the second largest hybrid crop globally after corn. Compared with other plant sources, sunflower has an advantage: “The agronomics are well understood. Sunflower management practices are already in place,” he says.
Sunflower leaves contain 1% to 2% natural rubber, but there is no fundamental plant physiology barrier to increasing rubber percentages.
Essentially, Edison is using genetic modification to make sunflower leaves produce even more rubber. “Leaves are our focus,” says Thomas Hohn, director of research and development for Edison. “It may be possible to take leaf rubber up to 15% to 20% of dry weight. Our initial milestone is 5% to 6% through biotechnology.”
Because green leaf tissue houses the rubber, Edison wants to produce sunflower with no heads in order to direct plant energy into leaf matter instead of seed production. Hohn has ongoing research plots in Colorado and North Carolina to test the impact of mechanical head removal in fostering rubber concentration, but ultimately head removal will be achieved through genetic means. Hohn is also measuring plant growth regulator effects on rubber production. Growers can raise rubber sunflowers with current management techniques but without the necessity of fighting diseases that affect flowers and seeds, Hohn explains.
At harvest, the sole aim is to capture green matter. “We expect to bale and remove the dried crop from the field, similar to a forage crop,” Christensen says. “We will harvest above-ground biomass.”
Sunflower rubber exists as particles within the plants’ leaves and is not harvestable as latex. Edison expects to use a solvent-based rubber extraction method similar to what is used in oil seed processing.
With a relatively short growing season (85 to 90 days), sunflower rubber offers a wide geographic footprint. Christensen says the crop is an absolute fit for northern states but also sees opportunity in Kentucky, Missouri and Tennessee, and even as a potential second horse in a double-crop system.
Lab work, field plots and rubber extraction validation point to a possible commercial pilot in 2019. “Producers are looking for economic opportunities and they need a return above and beyond current crops,” Christensen says. “Sunflower rubber is going to be very attractive.”