Alfalfa Killed by Floods or Winter Conditions March 22, 2019
Following ice, historic snow, and historic floods, it’s natural to wonder if your alfalfa survived.
It’s nearly impossible to predict how much damage this past winter’s weather did to existing alfalfa fields. While alfalfa usually comes through winter in pretty good shape in our area, I’m sure this year there could be plenty of exceptions.
It will be a couple weeks at least before you might expect to see the beginnings of spring growth. However, it’s important that you determine the amount of damage as soon as possible so you have time to respond in the best way possible.
Flooded fields may be the most difficult to evaluate, especially if much sediment was left behind. Alfalfa that went into winter in good shape might tolerate up to a couple weeks of flooding; however, alfalfa will have a difficult time emerging through more than two inches of sediment. Expect poor stands any place where you have thick deposits. In areas with lighter sediment levels, expect some delayed emergence. Removing sediments mechanically may help in some situations. Also, be sure to remove any debris that might interfere with mowing or could contaminate your hay.
For both winter- and flood-damaged alfalfa, older, dryland fields that have fewer than 30 new shoots per square foot coming from two or three plants may need to be replaced soon. Very productive sites, such as irrigated and sub-irrigated fields, should have at least 40 shoots per square foot from four to six plants. Check for these densities in several areas of your fields when the early shoots are 4 to 6 inches tall.
No one knows for certain how much damage might be expected in alfalfa fields so check your fields early, just in case.