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0308 FG: Managing windrow disease in alfalfa

Bruce Anderson Published on 16 June 2008

When rain occurs in windrowed alfalfa fields, problems often develop. Sometimes referred to as “windrow disease,” these problems can be noted by stripes in the field where alfalfa windrows remained so long that some smothering occurred underneath the hay.

Windrow disease presents special challenges. Weeds often invade, requiring spraying to maintain quality and protect stands. And during the next growth period, plants that were not smothered regrow rapidly, while plants underneath the windrow suffer delays. Part of the field often will begin to bloom while windrow-stressed plants are still short and tender.

So, given these variances, when do you harvest – when the first plants begin to bloom or do you wait until injured plants are ready? I suggest using two factors to tell you when to cut:

•the health and vigor of your stand
•the nutrient needs of your livestock

For example, is your alfalfa healthy and regrowing well? If not, wait to cut until stunted plants begin to bloom so you can avoid weakening them even more. If your alfalfa is in good shape, cut when it will best meet the needs of your animals. Dairy cows need alfalfa that is cut early, so harvest when the first plants begin to bloom. Regrowth of injured plants may be slow after cutting, but this sacrifice is needed for profitable milk production.

In contrast, beef cows do not need such rich hay, so let stunted plants recover, and then cut when they are ready to bloom. By the next cut, production should be able to return back to normal.  FG

—From University of Nebraska – Lincoln Extension Crop Watch newsletter

Bruce Anderson, Extension Forage Specialist, University of Nebraska – Lincoln