Fall Management of Alfalfa

Fall is a critical time of year to manage alfalfa to ensure maximum productivity and stand longevity. Unlike annual crops such as corn and soybean, fall is when the alfalfa plant begins to store additional sugar, protein, and nutrient reserves in the crown and root system, which will provide protection from the cold winter weather and facilitate vigorous growth next spring. In a year such as this one, where hot and dry weather this summer was especially stressful to the plant, it is crucial to allow the alfalfa crop to prepare for the cold months ahead.

One of the most important management practices involves timely harvest. Final cuttings should be made early enough in the fall to allow the crop to regrow adequately and replenish necessary reserves before a killing frost, and should generally be completed by early to mid-September, depending on your location and local climate. More guidance on the exact timing can be obtained from state Extension publications or your local Extension agent. This is also a good time of year to assess the overall health and quality of an alfalfa crop, including evaluating stand density and root and crown health, allowing you to address any problems before they become serious.

Also critical for maintaining a successful alfalfa stand is managing the fertility of the crop. Fall is a good time of year to make fertilizer and lime applications. Low levels of nutrients, particularly potassium (K), can also lead to reduced stand health and vigor. In addition to the other essential functions of K in the plant, K plays an important role in the plants’ ability to resist subfreezing temperatures, and low levels of K in the plant can lead to increased winterkill if conditions are favorable. In addition, maintaining a proper pH with liming is critical for a number of reasons, including maximizing the availability of other nutrients and ensuring successful nitrogen fixation. Since lime requires adequate soil moisture and time in order to affect soil pH, making lime applications in the fall allows the liming material time to react and can have a greater effect on next year’s crop.

Careful management of your alfalfa crop this fall can mean a stronger, more vigorous crop next year. Therefore, taking some time to care for your alfalfa crop today can mean better results tomorrow and beyond.