Assess Alfalfa Stands To Determine Next Move

Check out how many plants remain before making decisions.

Published on: Nov 22, 2012

If you've got an alfalfa field where the alfalfa is getting thin, or if it didn't come storming back after rains returned in September, you may want to assess whether you want to keep that field in alfalfa for another year or rotate to another crop.

Chris Parker, Morgan County Extension ag educator with the Purdue University Ag Extension Service, says this is a good time to make checks of fields.

"If you decide you need to improve it or rotate, you can begin making those plans now instead of waiting until spring," Parker says.

If you have 40 stems per square foot in pure alfalfa stands, the stand is still productive and good enough to leave, he notes.

Pick your hay: One part to knowing when to redo pastures is understanding what kind of hay you want. How much alfalfa do you want in the windrow when you prepare to bale?
Pick your hay: One part to knowing when to redo pastures is understanding what kind of hay you want. How much alfalfa do you want in the windrow when you prepare to bale?

"There is a distinction between plants and stems that is critical here," he adds. "Those 40 stems may come from four or five plants. Each plant crown can produce multiple stems, up to 10 or so. It's stems that we're worried about."

In other words, if you have 4 to 6 plants per square foot but they have 40 stems or more, the stand is still viable economically. You can make a square foot frame and throw it down in various spots in the field at random to check the counts. Or you can take a coat hanger and throw it down at random within the field. The area within a typical coat hanger is about one square foot, Parker observes.

If there are only three to four plants per square foot, you may want to think about other options. With alfalfa, many recommend rotating to another crop for a year. That gives the field a break, and also reduces any chance of alleopathy, a condition by which decaying alfalfa plants release substances harmful to germinating plants.

The problem with assessing stands is that there are very few pure stands, Parker says. Usually there is orchardgrass present. Often orchardgrass was included in the seeding mix for two reasons: alfalfa seed is much more expensive, and many customers, especially horse customers, prefer hay with some grass in it.

What you have to do in those situations, he says, is determine if there is still enough alfalfa in the mix to make the kind of hay you need for the animals that you are going to feed the hay to. If not, you may need to rotate and renovate.