As U.S. hay growers sort out damage from the Easter weekend cold snap, they may want to consider what Garry Lacefield, University of Kentucky forage specialist, says he has learned from it. "Mother Nature bats last, and forage plants don't read our books; otherwise more would be dead," he notes. Lacefield and his Kentucky colleagues have been amazed at the amount of variation in damage that occurred after seven weeks of unusually warm temperatures and rapid forage growth were followed by four days of record-setting low temperatures. There seems to be very little damage on tall fescue, orchardgrass, Kentucky bluegrass and timothy, with only leaf tip burning in most cases, he reports. Some ryegrass damage was seen, but not as much as expected. Unfortunately, a very high percentage of alfalfa's terminal buds were killed by extreme low temperatures on April 8. Lacefield is optimistic about future growth because crowns and crown buds are still alive.
"We are very encouraged about new alfalfa and clover seedings," he states. "Generally, these plants are tolerant of colder temperatures. Nebraska workers found that seedlings of alfalfa no older than the first-trifoliate growth stage could tolerate temperatures in the low 20s. While we have found a few dying/dead young seedlings, the number is much less than expected." The past few days, he has seen new seedlings emerge. Hay growers should continue to monitor new stands; Lacefield is hopeful they will thicken up. Information on evaluating new stands, plus tips on managing old and new growth after a freeze, are available on the university's Web site: www.uky.edu/Ag/Forage/Freeze%20Damage.htm.
Ohio hay growers aren't likely to see permanent freeze damage to established, healthy alfalfa. "Back in 1992 we had similar conditions of alfalfa breaking dormancy early in March, followed by cold temperatures that killed the shoots back to the crown," says Mark Sulc, Ohio State University extension forage specialist. "Alfalfa re-initiated growth that year, and first-cutting yields were near-normal, although the first harvest was delayed by seven to 15 days." Such a delay may mean three rather than four cuttings for Ohio growers this year. Yet overall yields could still be near-normal, especially if weather conditions favor good alfalfa growth the rest of the season.
Freeze injury to alfalfa varied significantly across Ohio. In the west-central part of the state, alfalfa sustained considerable injury and virtually no green tissue can be found on plants. In the northeast, alfalfa is recovering nicely, with only stem tips showing frost injury. Apparently, dormancy broke later there, so plants were less susceptible.
Red clover suffered less freeze injury than alfalfa while some perennial ryegrass varieties were injured significantly in west-central Ohio. Orchardgrass showed slight injury to the leaf tips. Most annual ryegrass varieties were completely killed by cold weather in February.
Sulc expects only negligible yield loss on mixed grass-alfalfa stands, but the grass will be ready to cut much sooner than the recovering alfalfa. Should grass-alfalfa mixtures be clipped to slow grass growth? "By the time one could get on the field to clip them, some young alfalfa shoots may be growing, especially those deep in the canopy that survived the frost," he notes. "Cutting could remove those stems and potentially do more harm than good to the alfalfa recovery in the stand."
Last year's late August to September alfalfa plantings may have suffered more frost injury than plantings made in late July to early August. Sulc urges growers to check plant roots to assess whether young plants have died. Weak stands, especially those under waterlogging stress, may have a more difficult recovery this spring and yield levels will be lower than normal, he notes.
Illinois alfalfa ranged from less than 6" high in the north to 20" or more in the south at the time of the freeze. If new leaves and shoots appear in the next few weeks, regrowth should be okay, even though it might be slow, according to University of Illinois experts.
Southeastern South Dakota hay producers received the brunt of the state's cold temperatures, particularly in Yankton, Turner and Bon Homme counties, according to Peter Jeranyama, South Dakota State University extension forage specialist. "The alfalfa was advanced, had broken dormancy, and had more than 3" of growth in these areas," he says. He's not expecting yields to be significantly set back as a result of the cold weather, but advises growers to dig up plants and evaluate root health.
Contact Lacefield at 270-365-7541, Sulc at 614-292-9084, and Jeranyama at 605-688-4754.
For a report on the freeze situation in Minnesota, click on hayandforage.com. Type "freeze damage" in the search box for additional stories.