July 25, 2008

Have you taken a good look at your alfalfa stands lately? After several years of drought, some tough winters, and this spring's freeze, some alfalfa plants that managed to survive the harsh weather finally are showing the accumulated effects of all that stress. This isn't unusual because harvesting alfalfa also causes stress. Add in any insect damage or leaf diseases and plants that were old or weak starting out this spring may simply have too much root disease and not enough healthy root to keep going. If weeds are becoming a problem, that suggests replacement.

Now is a good time to check fields to learn if they need to be replacedwith a new seeding this August or next spring. Also evaluate your stands. Older, dryland fields with less than 25 shoots per square foot coming from two or three plants should be replaced. Very productive sites, such as irrigated and sub-irrigated fields, should have over 40 shoots per square foot from four to six plants.

Then dig up and look at some roots. Healthy roots are solid and white, with a firm texture. A little browning in the top couple inches of the crown may not be much of a problem, but it could develop into a serious disease in another year or two. Roots that are discolored in a third to one-half of the tissue might survive this coming winter, but will not yield well next year. If crowns and taproots show extensive brownish discoloration or are becoming mushy and partly rotted, plants will not survive another winter.

Check your alfalfa stands now so you can replace them on your terms instead of Mother Nature's.

Bruce Anderson
Extension Forage Specialist