GIVE ALFALFA A FALL RESTING PERIOD
What risks are there for cutting alfalfa in the fall? When and how long is the alfalfa fall resting period or winterizing period? The answers to these questions can help you make an informed decision on whether to take another cutting of alfalfa in 2021.
When and how long is the alfalfa fall resting period? Alfalfa needs about 6 weeks of uninterrupted growth each fall to be fully winterized before the first hard freeze. The first fall hard freeze of 28 degrees Fahrenheit for several hours for the most recent 30-year normal (1991-2020) was October 19 for Beatrice and October 21 for Fairbury according to the National Weather Service. Therefore, no cutting or grazing would be recommended after the first week of September (7th) in this area on average.
What risks are there for cutting alfalfa during the fall resting period? If alfalfa is not fully winterized when cut in the fall, it can lead to poor winter survival, reduced stand persistence, reduced spring vigor and reduction in first-cutting yields in the spring. Recent K-State research in Manhattan, KS (https://doi.org/10.5187/jast.2021.e65) where the average first hard freeze during the study years (2015-2018) was November 3, found that stand persistence was decreased in year 2 and year 3 with fall alfalfa cuttings on September 30, October 15, and October 30, compared to September 15. However, the highest total dry matter yield in year 2 and year 3 of production was obtained with cutting on September 30. Other research studies have found that the dry matter yield is increased for the year by extending the last cutting into the fall, but negatively impacted first cutting yields in the spring.
Fields with more stressful growing conditions during the year, with increased number of cuttings per year, and older stands are more at risk of being negatively impacted by cutting during the fall resting period. The risks (stand persistence, less first cutting, etc.) associated with cutting alfalfa during the fall resting period is weighted against your potential hay shortage between now and first cutting and current hay prices. If you may be short of hay, you should consider cutting or grazing after the fall resting period (hard freeze) generally in late October since it poses less risk to alfalfa stand persistence or only cut selected fields with young stands in good condition during the fall resting period.
Overall, alfalfa growers should strongly consider not cutting alfalfa during the important fall resting period starting around September 7 through the first hard freeze in Saline, Jefferson, and Gage counties. For more information on alfalfa production and other agronomic resources from Nebraska Extension, contact me at email@example.com or 402-821-1722. Know your crop, know your tech, know your bottom line.