Cover crops are an investment in soil health, but what if they paid off as a cash crop as well?
Researchers at the University of Minnesota are aiming for just that as they shape pennycress into a suitable food and fuel product that can fit in with the typical upper Midwest crop rotation.
Pennycress grows wild in the Midwest. It could be harnessed as a beneficial winter cover crop that uptakes excess nitrogen in the soil, and its seeds could be used for oil. Planted in rotation with corn and soybeans, it would keep the ground green after harvest and be an opportunity for double cropping – growing two cash crops in one season. However, the wild plant has some qualities that make harvest challenging and its oil unfit for food.
The U of M research is changing that – making way for pennycress to be a viable option in the field and on your dinner plate.
“We have a set of agronomists, economists and food scientists looking to see how we can use this material to make it successful,” said Ratan Chopra, researcher at the university’s department of plant and microbial biology and lead author of a recently published study on the pennycress progress.
Since 2013, University of Minnesota plant and microbiology professor David Marks and his team in St. Paul have been using modern gene sequencing technology combined with decades-old breeding techniques to select for desired traits.
They hope to have a commercial line of pennycress available for farmers in the next four to five years. A recent $10 million grant will go a long way to making that happen. The U.S. Department of Agriculture grant was awarded last year to a working group called the Integrated Pennycress Research Enabling Farm and Energy Resilience, which includes U of M and four other universities.
Undergraduate students put in hard work in the field, and they’ll be tending to the first generation domesticated pennycress as it’s field tested in coming years.
“We are very passionate about this research, what it can do for the environment and what it can do for the economy for the farmers,” Marks said.
Already, the university has licensed a trait for a St. Louis based company that’s doing similar research with hopes to commercialize pennycress. But it’s not competition, Marks pointed out. The company, Covercress, is focused more on the lower Midwest including southern Iowa, Missouri, Indiana and Illinois.
“It’s good for them to succeed in order to drive demand,” Marks said.
One of the traits Marks’ team focused on had to do with the timing of harvest. As a winter cover crop, pennycress could be interseeded in standing corn and left to grow after corn harvest and through the winter before planting soybeans the following spring. But most wild pennycress doesn’t mature in time to harvest its seeds before the window for planting soybeans. Gene selection allowed researchers to combine early maturing varieties with other desirable traits in a single line that flowers a week early.
“We don’t want to compete with soybeans or corn for their resources,” Chopra said, noting that extensive testing of those lines is underway.
Harvesting was another issue. Pennycress seeds are susceptible to shatter. Wild varieties lost as much as 70% of the seed to damage during harvest, but genetic selection changed that. Now most of the loss comes from blowing out of the combine, a minimal issue that happens with any harvest, Chopra said.
A major part of making pennycress a viable cash crop is making its oil usable. The seed carries a fatty acid that’s good for making biofuels but not for humans or animals to eat. Gene selection allowed researchers to get rid of one compound in the oil and improve the oil quality for storage and biodiesel industry.
Marketing to the human food industry would provide for even more opportunities for the crop, so the team set the goal of giving pennycress an oil profile like that of canola with a nutty flavor.
“The whole idea is, ‘how can we create some marketable opportunities for this crop?’” Chopra said.
That’s where another Minnesota organization comes in. The Agricultural Utilization Research Institute (AURI) has been working on processing techniques and product applications for pennycress.
Using an oilseed press at its facility in Waseca, AURI researchers are analyzing the product for qualities like protein content and comparing its performance for a fit in niche markets.
Along with the oil, the meal that’s left from processing the seed could be a protein feed used in the livestock or aquaculture industries.
“What we’re doing with pennycress is not a whole lot different than what the soy industry does,” said Rod Larkins, director of research at AURI.
Facilities that crush soybeans would be able to handle the seed.
The oil has unique properties that lend itself well to bioplastics and aviation fuel. The meal could be concentrated to make protein for human food, and the carbohydrates left over could be fermented and turned into ethanol.
“We try to develop ideas for turning that seed into as many high-value products as we possibly can,” Larkins said.
While pennycress has some challenges, research is helping optimize the crop for growing in northern climates and finding its place in the market.
The journal article can be accessed here:
Chopra, R., Johnson, E.B., Emenecker, R. et al. Identification and stacking of crucial traits required for the domestication of pennycress. Nat Food 1, 84–91 (2020). https://doi.org/10.1038/s43016-019-0007-z