A great stand starts with a good bounce

Managing alfalfa fields in the spring is vital whether it be checking the vigor of an established stand of alfalfa or properly preparing the seed bed when it comes to planting a new seeding.  The importance of evaluating an existing stand of alfalfa in the spring is crucial to make the determination if the plant has succumb to winterkill or damage.  Because the alfalfa plant goes dormant, but it still alive through the winter, it can incur damage when spring comes, resulting in the death of the plant. Seed bed preparation is imperative to get right because it is the first step to ensuring the alfalfa stand will be successful for the duration of the alfalfas life.

Winterkill damage occurs when the crown of the plant is subjected to temperatures under 5-15 degrees Fahrenheit; this causes cells in the plant to burst. In years where there is little to no snowfall, alfalfa is subjected to extremely cold temperatures.  Snow is an insulator for alfalfa; since it is porous the plant can still breath or respirate under snow cover. Even with sufficient snow protection, alfalfa can still be damaged if the snow is blown off fields.  The likelihood of winter damage to alfalfa increases if there is not sufficient alfalfa residue left in the field, or if a cutting is taken beyond the recommended September 15th deadline.  Also, if the fertility levels on the farm are not sufficient a field could be more susceptible to winterkill. In the winter plants are not able to acquire energy through photosynthesis, so in the fall the plants store extra sugar as their energy for the entire winter. The sugar in the plant acts like an “anti-freeze”. Improper pH also makes plants more likely to fall victim to winterkill. The optimum pH for alfalfa is above 6.6, but preferably over 6.8. Another common cause of winterkill is ponding in fields, especially when ice freezes and melts repeatedly; the ponded water seals off the air flow to the crown.

Winterkill is most common in older stands. These fields have already incurred damage because of years of regular field activities, like driving over the field and causing compaction. Often this damage can be seen with satellite imagery, tools like Winfield United’s R7 and FMT can be helpful when looking for possible damage. To check for winterkill, ask your local Centra Sota Crop Advisor to do a health check on alfalfa fields as soon as the frost is gone.

Whether you are re-seeding a poor or damaged stand or doing a new seeding a proper seedbed is one of the best ways to ensure a successful, quality and high yielding crop. Alfalfa seeds must have very close contact with the soil and soil moisture to ensure a rapid emergence. A firm seed bed helps prevent seed from being planted too deep which will hurt emergence and later stand. There should be just enough loose soil left on the surface to cover the seed after planting. On a properly prepared firm seedbed, you should be able to bounce a basketball and have it and sink in no more than a quarter inch.

Contact your local Centra Sota Crop Advisor to get an alfalfa health check and to talk about seeding preparation and options. Click below to get in contact with you Crop Advisor.
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