Dealing with Winter Injured Forage Stands

April 22, 2019
Winter injury in alfalfa

Author: Mark Sulc

I’ve been hearing more reports from around the state of winter injured forage stands, especially in alfalfa. The saturated soil during much of the winter took its toll, with winter heaving being quite severe in many areas of the state. So, what should be done in these injured stands?

The first step is to assess how extensive and serious is the damage. Review the article posted on March 6 here for guidelines.

If the damage is extensive and signficant stand loss has occurred throughout the entire field, it usually is best to destroy the stand, rotate out, and plant an emergency forage. In these cases, corn silage is the number one choice for an annual forage crop in terms of high yield and overall good nutritive value. But corn silage won’t be an option for all situations. Forage might be needed before corn silage can be ready, or the equipment and storage infrastructure for silage are not available.

Other acceptable short-season forage options include spring oat, spring triticale, spring barley, and Italian ryegrass planted as soon as possible now in early spring and harvested at the proper stage of maturity this summer. For more details on these species, see the Ohio Agronomy Guide and a related article in the latest issue of Buckeye Dairy News.

Other options, particularly for beef cattle or sheep, include the brassicas.

If planting in late May and June, particularly after the first cutting of the damaged stand is harvested, the summer annual grasses will be a good choice. These include sudangrass, sorghum-sudan, forage sorghum, pearl millet, and teff.

If the forage stand is damaged, but still salvageable, here are a few suggestions to increase forage production this year and longer term that I’ve adapted from an article by my colleague Bruce Anderson, the University of Nebraska Forage Extension Specialist:

  • For fields planted last year, try to interseed this spring to thicken up the thin spots. Even in alfalfa, autotoxicity is not a problem until after stands are more than one year old.
  • For older fields, autotoxicity and other problems make interseeding alfalfa risky.  But in other species interseeding is still possible, and older alfalfa stands can also be interseeded with species other than alfalfa. Consider adding red clover for longer term stands, or if shorter term production of legume is desirable for this year, consider interseeding crimson clover or berseem clover (they will not do much after this year though).
  • Annuals like oats and Italian ryegrass can be interseeded right away; or plant summer annual grasses right after the first cutting. Italian ryegrass planted now will establish rapidly and will continue to produce all year and might even continue into next spring. Oats will produce only a single cutting.
  • Perennials like orchardgrass, festulolium, meadow fescue, and red clover can bring long-term help but won’t add much to this year’s production.

If you do interseed damaged stands, the competition by the surviving plants for sunlight could be a serious threat to success. It only takes about one week of shading by a full canopy to kill seedlings below. About the only way to open up that canopy once it develops is to harvest extra early.  This will lower first harvest yield and may further weaken already stressed plants.  But it’s the only way to get enough sunlight to the new seedlings.

In some situations, it might be better to wait until late summer to interseed damaged stands (this of course doesn’t help forage supplies this year though). Forage cut in late August or early September regrows more slowly than in spring, thus causing less competition. Interseeding right after that last harvest has a better chance of succeeding, provided adequate moisture is available.

Winter injury has reduced stands and will reduce forage production in many forage fields this year. Make a careful assessment of the existing stand, but then act quickly and properly to minimize long-term losses.