Alfalfa Assessment 7-24-09
July 24, 2009
Evaluate and Replace Thinning Alfalfa Stands
An established alfalfa stand faces stress from weather as well as harvest, insects, leaf diseases, weeds, and natural aging. 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. Now is a good time to check these fields to learn if they need to be replaced with a new seeding this August or next spring.
Evaluate Your Stands
Older, dryland fields with less than 25 shoots per square foot coming from 2 or 3 plants should be replaced. Very productive sites, such as irrigated and sub-irrigated fields, should have over 40 shoots per square foot from 4 to 6 plants.
Dig and examine the plant 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 yet, but it could develop into a serious disease in another year or two. Roots that are discolored in one-third to one-half of the tissue might survive this coming winter, but plants will not yield well next year. If crowns and taproots show extensive brownish discoloration or are becoming mushy and partly rotted, these plants probably won’t survive another winter.
Observe and anticipate declining alfalfa stands now so you can plan for reseeding.
Extension Forage Specialist