Managing your alfalfa crop following a hectic spring season

Let your alfalfa blossom during the summer to capture some carbohydrates.

The early, warm weather, frost, alfalfa weevils and potato leafhoppers all took their turn during the first part of the growing season to give alfalfa producers some moments of indecision. Michigan State University forage agronomist Kim Cassida has made some recommendations to help producers develop a plan for the rest of the growing season. The two primary areas of focus are:

  • How can producers manage stands to give alfalfa the best opportunity for good stand survival?
  • What cutting schedule should I be using for the rest of the summer growing season?

To recap what the consequences to alfalfa are following environmental stress, producers need to remember that the early spring growth depends on carbohydrate reserves in the roots. When frost kills the stems, photosynthesis is stopped or slowed and the plants begin growing again with a low reserve of carbohydrates, essentially running on a low or empty fuel tank.

To keep the alfalfa stand in production, producers should manage the field to allow plants to regenerate root reserves as much as possible and, therefore, reduce the amount of stand decline.

If the stems of the plants were not killed, but only stunted and slowed, the effect will not be as severe because the plant didn’t have to start over with a low fuel tank.

Recommendations for managing alfalfa stands from Cassida are listed below.

  • Consider delaying second or third cutting until the flower stage to give alfalfa roots a chance to catch up. Harvesting at bud stage will produce the highest quality forage for dairy cattle, but it may be at the expense of the alfalfa stand.
  • Give alfalfa plenty of time to store carbohydrates for the winter by avoiding harvest less than 30 days before the expected killing frost.
  • Make sure soil fertility and pH are at recommended levels. While all nutrients are important, potassium is particularly important in helping plants tolerate stress.
  • Reduce pest stress on stands using an integrated pest management (IPM) strategy program that includes a good scouting program.

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