A 2-lb/acre rate of Italian ryegrass seeded with the standard 12 lbs/acre of alfalfa will keep the companion crop from overtaking the legume, says Dan Undersander, University of Wisconsin Extension forage specialist.
After winterkill had wreaked havoc on Upper Midwestern alfalfa this past spring, growers with thinned stands scrambled to decide what to interseed into them.
Some were able to plant oats, a cereal grain traditionally used as a companion crop during alfalfa establishment. But, as the oat seed supply grew scarce, an increasing number of producers turned to Italian ryegrass.
That, says Dan Undersander, was a good move.
“Oatlage is not very palatable and not really in favor with the dairy industry,” says the University of Wisconsin (UW) Extension forage specialist. “Italian ryegrass, on the other hand, has about the same quality as alfalfa, we can plant it in the spring and harvest the ryegrass about the same time we’re taking the first cutting on our established stands.”
Dave Robison also advises producers to choose Italian ryegrass over oats, and that’s not just because his company, Legacy Seeds, sells the ryegrass.
“Italian ryegrass does not head out during the first year at all, so, therefore, it’s present in each cutting (of alfalfa),” says the forage and cover-crop manager.
“With oats, you have a big flush of oats and then you have nothing but straight alfalfa afterward. Your quality of your alfalfa-Italian ryegrass, your digestibility, your milk production, will be considerably higher than where you have straight alfalfa.
“The biggest issue with Italian ryegrass in the Upper Midwest is it’s a one-year proposition. But oats is a one-cut proposition,” Robison says.
Yield comparisons of alfalfa-Italian ryegrass mixes to alfalfa-oats were made by Mark Sulc as part of his doctorate work at Wisconsin in the mid-1990s. He found that an alfalfa-Italian combination yields more than alfalfa alone but less than an alfalfa-oats combination.
Even so, the Italian ryegrass did yield more consistently through the growing season, says Sulc, now Ohio State University Extension’s forage specialist.
Although largely grown as an annual and often confused with annual ryegrass, Italian ryegrass is, in fact, a perennial, says Michael Casler, a UW grass breeder. It was developed more than 1,000 years ago from a meadow grass in northern Italy that began being harvested for hay.
“Gradually, over many hundreds of years, they selected a type that would grow faster and taller and would head out earlier and produce a lot of seeds and reseed itself. That became what we call Italian ryegrass.”
The next part of the story, he says, places the grass in the U.S. South around the 1950s. It was fall-seeded into bermudagrass pastures to provide winter grazing for beef cattle, gradually dying out in April and May, when bermudagrass would again take over.
Then Southern breeders developed new varieties “even more productive with this kind of system and started calling them ‘annual ryegrasses.’ But annual ryegrass is really a term that describes the way it’s used,” Casler says. “Commercially available annual ryegrass is a special type of Italian ryegrass that will head out in the seeding year and is a very weak perennial.”
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Casler also sees the value of using Italian ryegrass with alfalfa instead of oats, especially in alfalfa’s establishment year.
Italian ryegrass can add 1-2 tons/acre of forage to alfalfa’s seeding-year yield, says Undersander. He’s been growing plots at various seeding rates of the legume-grass mix to show growers only 2 lbs/acre of Italian are needed. “Any more than that will cause competition for the alfalfa, and we’ll get a poor stand.”
The forage specialist recommends true Italian types, which don’t head out. “They’ll normally provide some growth on the first two cuttings of the season, be reduced in growth the rest of the year and then winterkill unless we have a lot of snow cover.”
But because Italian ryegrass is a cool-weather, high-moisture crop, it shouldn’t be seeded on sandy soils.
“We wouldn’t want to expect much from it under droughty conditions,” Undersander warns. “But in many cases, it’s a worthwhile risk."
University yield and quality testing of Italian and annual ryegrass varieties can be found online for the following states.
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