Cup plant can't match corn silage or alfalfa haylage for yield or feed value, and at this point its seed is very expensive. But it potentially offers a few advantages over those other forages.
For example, cup plant, a perennial silage crop, loves wet soil, says Ken Albrecht, a University of Wisconsin agronomist who's studied the plant since the 1990s.
“It's a good choice for smaller acreages of flood-prone land — where alfalfa won't survive or corn can't be planted until mid-June when the soil dries out,” says Albrecht.
Cup plant is persistent, too. “We've had cup plant plots that were 15 years old and still going strong,” he says. “The plants survive winters very, very well. Cup plant stands would be a good place to dispose of manure, too.”
In dairy-feeding trials, researchers replaced up to 25% of the forage in TMRs with cup plant silage without a drop in milk production, he says.
It fared less favorably in beef trials where growing steers were fed either corn silage or corn silage and cup plant silage, with no grain supplement added in either treatment. Results showed that, for every additional percentage of cup plant fed, animal performance dropped.
“The drop was associated with the lower intake and digestibility of cup plant silage compared to corn silage,” says Albrecht.
He's gotten hundreds of calls from producers interested in cup plant. It has also garnered interest from environmentalists and good reviews from the Audubon Society.
“It's a good plant to include in prairie restoration projects because it benefits wildlife. The plant's large, cupped leaves hold water for birds and insects.”
Cup plant is actually native to Midwestern prairies, but researchers saw it used as cattle feed in the former Soviet Union in the 1980s and brought seed back for evaluation. Native Wisconsin lines yield better than the imported line, says Albrecht.
Cup plant can grow up to 8' tall and has square stems. Although the stems are quite thick, they're digestible if cut before the crop blooms.
Best-suited for making silage vs. haying or grazing, it can be harvested once or twice. With a single harvest, yields range from 3 to 5 tons of silage dry matter/acre; with two harvests, 4-8 tons/acre.
Crude protein ranges from 16% to 18% in first-cutting cup plant; in the mid-20s in the second cutting. ADF and NDF percentages run a little higher than those of alfalfa.
In a two-cut situation, Albrecht recommends harvesting it in mid-June and late August in Wisconsin. For a single harvest, he suggests cutting around July 15, just as the crop is starting to flower. Conditioning is necessary to facilitate dry-down of the thick stems.
An air seeder can be used to plant the crop at a rate of 3 lbs of seed/acre. It's sowed in rows with the goal of having plants spaced 12-18” apart the first year.
Cup plant seed is available, but costs about $200/lb, says Albrecht, who collects and saves his own seed to cut costs.
“Right now the seed is produced in quantities to support prairie restoration and the ornamental plant industry,” he says. “Before it can be used widely as an agronomic crop, seed production has to be ramped up. Producers can't justify paying $200/lb, even though the stands last for several years.”
Albrecht developed a line that produces 10-20% more forage than other lines.
“If interest in commercial development of cup plant seed production on a large scale for agricultural use develops, I've got the seed ready to go,” he says.