After corn silage comes off, dairy farmers will often consider seeding fields to winter rye as a cover crop. It’s an easy, familiar option that establishes reliably in the fall and helps take up residual nitrogen from the soil.
However, that heavy nitrogen uptake can sometimes contribute to a yield drag in the following corn crop. This limitation has prompted growing interest in a lesser-known alternative. Camelina sativa, also sometimes referred to as false flax, is an oilseed researchers are evaluating as a cover crop that could bring added flexibility to dairy rotations.
While much of the crop’s earlier production has occurred in western dryland regions, winter camelina is now generating interest in the upper Midwest as an overwintering cover crop that can fit into rotations with corn and soybeans. And for dairy producers who are working with a continuous corn, camelina could be a useful option after corn silage to help with disease, weeds and nutrient loss.
A Smart Choice for Corn-Heavy Fields
Camelina belongs to the Brassicaceae family, like canola and mustard, which makes it different from grasses such as corn and rye. Because it’s not a grass, camelina can fit into rotations in ways that help break pest and disease cycles. Agronomists say this also means it can provide many of the same environmental benefits as rye, like reducing nitrate loss and protecting soil, without some of rye’s potential drawbacks.
“A lot of people are concerned with using rye because it might cause yield drag,” says Anastasia Kurth, a University of Wisconsin Extension agronomist and educator. “Rye takes up a lot of nitrogen, which is great for reducing nitrates in our groundwater. But if you’re planting corn silage afterward and really want high tonnage, camelina might be a better option.”
Kurth notes camelina also generally produces less biomass than rye, which can make spring management simpler.
“I would say it’s a pretty easy entry cover crop,” Kurth adds. “There’s little-to-no yield effect on the corn following the cover crop.”
Termination is also straightforward.
“It’s very easy to kill,” Kurth notes. “With rye or winter wheat, you often have a lot of biomass that’s hard to manage and can make planting difficult. Camelina doesn’t have that issue, so I’d call it a low-risk entry cover crop for someone looking to try something new.”
However, camelina doesn’t have to replace rye entirely. For farms that rely on rye for spring forage, the two crops can potentially be grown together.
“It definitely could be [a sweet spot], because if you want to take that rye for any forage, that could be an option as well,” Kurth says. “I think that could be a really great mix for folks.”
Recommended rates in a mixed stand include roughly 30 lb. per acre of rye with 3 lb. to 5 lb. per acre of camelina.
A Natural Fit After Corn Silage
According to Kurth, corn silage harvest provides one of the best opportunities for getting camelina established.
“Silage gives us a great opportunity to get the crop in,” she says. “It comes off earlier than grain corn, which provides plenty of time for establishment.”
In Wisconsin and other northern states with similar climates, camelina is typically planted from September through early October. The crop establishes quickly and forms a small rosette before going dormant over the winter.
Kurth says silage harvest also leaves conditions that favor camelina establishment.
“Silage removes more of the residue, and camelina really likes good seed-to-soil contact,” Kurth says. “So, when there’s a little less residue left after a silage harvest, it’s more beneficial for establishing the crop.”
Seed size is also an important consideration. Camelina seed is extremely small, with roughly 400,000 seeds per pound, meaning proper seeding depth and seed-to-soil contact are essential. Kurth notes drilling is generally recommended at about 6 lb. to 8 lb. per acre, though broadcasting can also work with slightly higher seeding rates.
A Natural Option for Managing Weeds
Another reason camelina is drawing interest is its potential role in weed suppression.
“Leaving corn silage ground bare is obviously a risk for weeds popping up,” Kurth says.
As a brassica crop, camelina produces compounds called glucosinolates. Kurth notes these compounds are known for their biofumigant properties and may help suppress certain weed species.
“Just that chemical compound being in the soil reduces some of those smaller seeded weeds,” she adds.
Early field observations hint that the effect could be meaningful in some situations.
“Some farmers struggle with heavy waterhemp pressure in their fields,” Kurth says. “But in fields planted with camelina, they didn’t see any waterhemp emerge — only large ragweed. It looks like camelina may be helping suppress the waterhemp.”
A Cover Crop Ready for Its Turn in the Field
While still in the early adoption phase, camelina is steadily moving from research plots into real farm rotations. As more dairy producers look for ways to reduce nutrient loss, manage weeds and protect soil without sacrificing corn silage yield, the ancient oilseed may offer a practical new option. For many farms, the next step may simply be trying camelina on a few acres after silage and seeing how it performs in their own system.
