An ice storm currently threatening the central part of the U.S. is causing deaths, black-outs and, very likely, damage to hay fields. A state of emergency has been declared for the entire state of Oklahoma, and the National Weather Service has posted ice and winter storm warnings for parts of Missouri, Kansas, Nebraska, Iowa and Illinois.
Ice-covered alfalfa fields first covered with snow may not have the damage some growers fear, says Dan Undersander, University of Wisconsin extension forage specialist. Undersander recently commented on the Midwestern freezing rains that followed snowfall the weekend of Dec. 1, reassuring growers that the ice may not be damaging alfalfa fields as much as they fear.
"A lot of people are asking what they can do to help minimize damage from ice that is covering fields from Nebraska, up across Iowa, southern Minnesota and Wisconsin and into Illinois," Undersander says. "I don't think the threat is as bad as ice damage has been in the past because the ice occurred over a sheet of snow."
Ice can create a surface barrier that prevents oxygen from getting to the soil and suffocates plant roots. "People want to be able do something and are asking me about everything from spreading fertilizer across the top of the ice so the salt melts holes in the ice, to disking," says Undersander. "There are several reasons why those are not good ideas right now."
He says spreading fertilizer doesn't work because growers couldn't apply enough to make a difference. In most cases, the salt doesn't melt all the way through the ice, plus pollution issues arise because the fertilizer runs off. Disking can damage fields and doesn't provide much benefit. An additional reason for growers and plants to breathe easier comes from alfalfa residue. "Those who left residue in their fields have stems sticking through the ice, providing a hole for air to get through," Undersander points out.
Contact Undersander at 608-263-5070, or email djunders@wisc.edu.