2005 Year in Review

Forage Strategies Recommended

Northern Illinois producers may be facing winterkill in their alfalfa fields and two University of Illinois Extension specialists recently discussed the problem and strategies for combating it.

"Winterkill in alfalfa has been reported in northern Illinois and can occur any time across Illinois," said Jim Morrison, Extension crops educator based in Rockford. "The extent of injury varies from field to field, and within fields. Factors that contribute to winterkill are lack of snow cover, lack of crop residue, lack of winterhardinesss, low soil fertility, and low soil pH. When alfalfa crowns are exposed to temperatures below 15 degrees F., plants may be killed."

Plants suffering from winterkill have soft and fibrous crowns and taproots and many times a distinct brown line is visible across the taproot two to three inches below the soil surface.

"In assessing alfalfa stands, it is important to dig some plants--include the top six inches of the root--and examine the crown for size, symmetry, and number of shoots. Split the crown and taproot lengthwise and check for the degree of discoloration, which is indicative of disease and/or injury," said Morrison.

Hutjens noted the problem has important implications for dairy producers.

"For high-producing dairy cows, quality is critical to achieve optimal dry matter intake, improve palatability, and maintain milk yield," Hutjens said.

He recommended a number of strategies for dairy producers to consider in case the alfalfa crop is damaged.

“Sorghum-sudangrass hybrids, especially the brown midrib type, or sudangrass hybrids are attractive choices as these crops respond to warm soil and weather and can be planted in May and June. They yield one to two tons of dry matter per acre when cut at 20 to 30 inches in height and additional cuttings can occur every 25 to 30 days, depending on rain,” he said. ‘If harvested in the optimal stage, the forage is similar to grass containing 14 to 17 percent crude protein and below 50 percent NDF. After each cutting, manure can be applied.”

Corn silage is another excellent choice, Hutjens added, as it can be planted in late May to June. Corn silage will provide the highest potential yield of dry matter per acre—five to eight tons of dry matter per acre. It has high-energy values, over 0.70 Mcal of net energy per pound of dry matter, and palatable forage.

“If the damaged stand of alfalfa is one year old or less, the alfalfa may be reseeded,” said Morrison. “However, over seeding with additional alfalfa is the stand is over one year of age is not recommended due to the likelihood of autotoxicity. Red clover is not affected by the autotoxicity of alfalfa, so it can be used to ‘thicken’ an alfalfa stand.”

Small grain, such as oat, spring triticale, and barley, can be seeded solo or in a field pea mixture if planted early in spring or late fall.

“This strategy will be too late for this spring, but could be an alternative next year or if winter wheat is available,” said Hutjens. “Harvest small grain forages in the boot stage—heads beginning to emerge—for higher quality for lactating dairy cows.”

by  Editor, theCity1.com
May 4, 2005