Interseeding with Cover Crops
Integrating livestock and crop systems is not a new concept, but University of Nebraska Extension Beef Systems Specialist Mary Drewnoski is testing a new method of interseeding annual forage cover crops into corn fields with funding from the Nebraska Corn Board. “We have a lot of cropland in our state and there’s potential to use it more effectively,” said Drewnoski.
As an extension staffer, Drewnoski facilitates cattle and crop production roundtable discussions with producers across the state to focus her work on tackling the common issues that arise. Low availability and high cost of pasture is a common issue that has been raised. “One idea that came up was planting cover crop annual forages in conjunction with crop production,” said Drewnoski.
On-farm research led by Jenny Rees, Nebraska Extension Educator in collaboration with several area producers in Eastern Nebraska has found that some cover crop species could be successfully established by early interseeding with a drill into corn.
With drought putting a strain on producers, interseeding could be a way to increase foraging resources and nutrition density to meet cattle’s needs. A common concern, however, is whether interseeding creates significant yield drag and competition to grain crops. “Choosing a cover crop isn’t a one size fits all matter,” says Drewnoski. Interseeding with cool-season species has not resulted in large impacts on the corn yield but also produces less biomass than warm season species.
Research has found that interseeding with the cool season species, such as annual ryegrass, forage collars, and red clover, have had the most consistent success across the board. Interseeding with cool season annuals are relatively low risk, but they don’t produce quite as much added biomass, although the forage quality is expected to be high. There’s little competition of resources between the cover crop and corn because of the low amount of growth. The growers in Eastern Nebraska saw a yield drag of five bushels or less per acre. However, they counted this a wash because they could cut down on herbicide application. “Grower’s also saw that insects were more drawn to the cover crop then the grain crop,” said Drewnoski.
But as with anything, there are advantages and disadvantages. Some producers are willing to take on a bigger yield drag risk by including warm season annuals such as cowpea or mung bean for example. “These species can be a blessing or a curse,” said Drewnoski, “They generate more high protein biomass, and potentially fix more nitrogen but if the canopy opens due to green snap or a hail it can get pretty competitive and chaotic in a field,” said Drewnoski.
There are many possibilities and options with cover crop interseeding, but there’s a lot left to learn. Drewnoski plans to evaluate the extra feed value that may be added to corn residue when these cover crops are grown with the corn. Moving forward Drewnoski will be working with interseeding annual ryegrass, with the legume red clover and the brassicas forage collards and comparing the added feed value to supplementing growing calves grazing corn residue with distillers. Determining if there are significant long-term benefits to soil health will take time as will implications of extending grazing periods by interseeding.
For more information check out the 2022 on-farm research interseeding results at https://on-farm-research.unl.edu/