You won't catch Barry Fisher confusing anyone about annual ryegrass and cereal rye. Both can be used successfully as cover crops, but who and why you use them, and how you grow and later kill them, are totally different. Fisher, state agronomist with the Natural Resources Conservation Service, believes both have their place as cover crops.
Cover crops have been a hot topic over the past year, replacing no-till as the main focus for getting conservation on the land for some soil and water conservation districts. The innovators who study cover crops know the difference. However, Purdue University weed control specialist Bill Johnson believes some farmers checking out cover corps perhaps for the first time hear the two terms and think they are interchangeable. That's false, he stresses.
Rye is a cereal crop like wheat, and has been grown as a traditional cover crop to prevent soil erosion during the winter for many years. Some are using it now to help trap nitrogen left after a crop instead of letting it wash through the soil profile.
Annual ryegrass is not even in the same family, and instead is a forage grass, Johnson says. The term annual ryegrass refers also to Italian ryegrass, which can become a weed in other crop production systems if it escapes control. Rye is easy to control with glyphosate and other products, but annual ryegrass is not, he says,
Those who have grown annual ryegrass for some time say it can be controlled, but it takes careful attention to detail, spraying at the right time, often morning to mid-day, and not skimping on rates. Then it takes follow-up to make sure plants are dead. If not, they may begin the process of turning into weeds in crops where they are not wanted.
Johnson urges farmers who grew annual ryegrass over winter, and who saw it get a good jump this spring, which is desirable for accomplishing the goal that people plant it for - deep rooting and improvement of the soil, but which also made for larger plants at burndown time, check carefully after applications to make sure that they get adequate control and don't set themselves up for lots of escapes.