It is that time of year when alfalfa seed is generally purchased for seeding in the spring. However, the choice of which variety “is best” for a particular farm is not that easy.
Over the past 10 years, more than 150 alfalfa varieties or experimental lines have been evaluated by Penn State University in research trials in Pennsylvania. A large number of varieties for which adequate data are available have performed satisfactorily in these research trials. The results of these variety evaluation trials appear in the Forage Trials Report. The 2016 edition of this annual publication is available free at county offices of Penn State Cooperative Extension or online at http://extension.psu.edu/plants/crops/forages/species/forage-variety/reports.
With all of these varieties available, how can you choose the “best” variety? First of all, there is no “best” variety for all situations. In fact, there probably is not one “best” variety for a single Pennsylvania farm because of the extreme variability in soils across the state. The key to selecting varieties is to identify the two or three varieties that are best suited for a particular situation. The following steps may help identify those suitable varieties.
• Select varieties that have adequate resistance to the diseases prevalent in your area, on your farm, or in the exact field where the alfalfa will be planted.
• From these varieties, select those that have persisted well in environments or situations similar to the farm where they will be planted. This information is given in the Penn State Forage Trials Report.
• From the list of varieties that you have identified as acceptable, select the highest yielding varieties. This can be done by selecting the highest yielding variety at one location over several years or by selecting the varieties that were among the highest yielding at all locations for several years. The first method will provide a small list of varieties that yield well under a narrower range of conditions, while the second method provides a limited list of varieties that yield well under a wider range of conditions.
• From the list, select two or three varieties to plant and “test” in the field.
The varieties selected in this manner, when properly fertilized and managed, will be the highest yielding available and normally persist for three or more years. By planting a couple varieties, you are testing the “best” varieties to see which is truly best on your farm or in a particular field. This information should help when selecting an alfalfa variety in the future.
Unfortunately, there are varieties marketed in Pennsylvania that have not consistently shown improved quality or yield over traditional varieties. Once again, select varieties based on disease resistance, winter hardiness and yield, not because they are “new and improved.”