It can be a tough decision: Do you tear up an alfalfa stand and rotate into another crop, do you make one final cutting in spring and then change crops or do you keep the stand for another year?
Two Pioneer livestock experts from opposite sides of the Corn Belt weigh in with their thoughts about how alfalfa growers should go about assessing their stands in spring. The similarities in their suggestions are greater than their differences.
Growers should assess their alfalfa stands every fall, contends Leo Brown, a livestock information manager based in Illinois. “Fall is the best time to judge stand viability,” Brown says. “You’ll have a much better idea what to expect in spring.”
Watch winter’s effect
However, there are times when winter conditions can be milder or harsher than expected. This can change the stand’s viability heading into spring. (See table, “Factors affecting winter injury.”) When this happens, a reassessment in spring is vital.
“Check to see if the plants retained good health,” Brown suggests. “Look for places where ice coating or heavy water levels covered and smothered stems. Look to see if the crown has separated from the plant. A cycle of freezing and thawing can open the plant for damage.”
“If you see winter injury, you may need to revise your plans concerning whether to keep a stand or rotate immediately into another crop such as corn,” agrees Bill Ramsey, a livestock information manager in Nebraska.
Gauging alfalfa stands
“There are two ways to assess alfalfa stands,” Ramsey reports. “You can conduct a plant count at early greenup.” This is a quick-and-dirty way to assess a field.
A good young stand (one to two years old) will contain 10 to 15 plants or more per square foot. An older stand (three to four years old) should contain five to eight or more plants per square foot. Marginal stands may be anywhere from four to 10 plants, depending on stand age.
If plant counts are lower than 10 for year-old, eight for two-year-old, six for three-year-old and four for four-year-old stands, it might be time to move on — depending on stem counts, current forage needs and impacts on planned crop rotations.
The advantage of the plant count is you can perform it early in spring. However, it’s not the most-accurate yardstick.
Being more precise
“Stem counts are more reliable,” Ramsey says. “The downside is you have to wait until the plant grows.”
Brown suggests the earliest you can conduct a viable stem count is after two inches of growth. He says six to 10 inches of growth provides a more reliable estimate of overall stand health. Ramsey suggests conducting stem counts somewhere between four and six inches of growth.
“Stem counts above 55 per square foot indicate good stand health,” Brown notes. “Counts ranging from 40 to 55 are marginal. Consider replacing any stand containing less than 40 stems per square foot.”
What are your choices?
When you’ve assessed the stand’s health, you essentially have three options:
- Tear it up and plant with another crop. Corn is a sound option because alfalfa fixes nitrogen in the soil, potentially lowering fertilizer costs for the corn crop.
- Let the stand grow and get one more cutting before tearing it out. You may be able to come back with a double crop in such a field, particularly if you pick a shorter-season corn hybrid.
- Keep the crop another year and evaluate in the fall.
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