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Annual Ryegrass – A Double-edged Sword

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Annual ryegrass (Lolium multiflorum) is a cool-season grass that originated in southern Europe. It is sometimes called Italian ryegrass. Although an annual, ranchers in the southeast U.S. depend on it for its reseeding ability, resulting in "volunteer" stands of annual ryegrass from year to year once the seed bank is established. The greatest use of ryegrass in the Noble Research Institute service area within 100 miles of Ardmore, Okla., is either as a component of a winter pasture mix to be grazed out by stocker cattle or as an early-season forage overseeded into bermudagrass (Cynodon dactylon) to provide 30-45 days of grazing prior to bermudagrass breaking dormancy.

Annual ryegrass is not a perennial plant or a cereal grain. There are perennial ryegrasses (Lolium perenne L.), but they are not adapted to the Southern Great Plains. Rye (Secale cereal L.) is a common winter annual that, because of the name, is sometimes confused with ryegrass.

Why Producers Like Annual Ryegrass

Annual ryegrass is easy to establish since it doesn't require a prepared seedbed. A broadcast seeding of 20-30 pounds of seed per acre over a wheat/rye/oats pasture or a shortly grazed bermudagrass pasture is all that is needed to produce a stand of annual ryegrass. Some producers will lightly disk their bermudagrass pastures in the fall to encourage the annual ryegrass to germinate. When overseeded into bermudagrass sod, most of the production occurs from early April through June. Planting time for annual ryegrass is late August through early October, but can be as late as February. Annual ryegrass will germinate in the fall, but there is usually not sufficient top growth to support much fall grazing except in a clean-tilled situation. In Noble Research Institute variety trials using a clean-tilled seedbed, ryegrass has been shown to out-produce wheat or rye plantings in terms of total production, and the seed is usually less expensive than small grains seed.

Management Challenges With Annual Ryegrass

The biggest challenge for managing annual ryegrass when overseeding is to manage the growth so that it doesn't impede the early growth of the bermudagrass. It is not uncommon in Texas and Oklahoma to have good precipitation in the early spring followed by a dry summer. Early spring rains allow ryegrass to produce an abundance of forage. Annual ryegrass will use the available moisture and then shade the bermudagrass just as it is trying to break dormancy. The result is a severely weakened, suppressed stand of bermudagrass.

To manage the annual ryegrass growth spurt before the bermudagrass greens up, high stock densities of livestock are necessary to keep up with the growth. In some years, haying is the best or only means to adequately remove the ryegrass to allow the bermudagrass to start its growth cycle. Ryegrass hay is usually of high quality if cut and baled properly.

Other Management Considerations

Do not overseed all of your bermudagrass with annual ryegrass. Designate certain pastures as ryegrass pastures, and leave your best bermudagrass pastures as monocultures. Allocate approximately 1 acre per cow to provide you with 30-45 days of grazing in early spring, provided you fertilize in February or March with 50 pounds of nitrogen per acre.

Early production of bermudagrass will be lost if the ryegrass growth is not removed by grazing or haying no later than May 15. For some producers, however, that 30-45 days of grazing prior to May is worth it to be able to quit feeding hay.

Overseeding annual ryegrass into bermudagrass does not provide a free lunch. You will lose some early production of bermudagrass in a normal year, and, if it is dry for the rest of the summer, you could lose your entire stand of bermudagrass.