ALFALFA SEED DORMANCY AND WINTER HARDINESS

Understanding geography and climate will help you select a variety with the proper dormancy rating to match alfalfa harvest management and cutting expectations. If the alfalfa is cut every 35 to 40 days, select a variety with low fall dormancy. If you are on an aggressive cutting schedule, such as 26 to 30 days, select a variety with a higher fall dormancy rating.

DORMANCY BY REGION

In the Pacific Northwest and Upper Midwest, alfalfa dormancies will typically range from a 2 to 5 rating. Central Plains can range from fall dormancy rating of 2 to 6. California and the Southwest will plant fall dormancies from a range of 4 to 10. Higher fall dormancy varieties tend to green-up faster in the spring and continue growing later in the fall. This extra growth period could make the difference when attempting to gain one additional cutting during the growing season. Higher fall dormancy varieties tend to have the highest yields, while lower fall dormancy ratings are associated with higher forage quality.

PERSISTENCE AND WINTERHARDINESS

Persistence – a key trait for a wide range of environments such as wet or saturated soils – and winterhardiness are two other important characteristics in variety selection. Previously, lower fall dormancy varieties were thought to provide the best winterhardiness. While fall dormancy may have an impact on winterhardiness, other factors such as disease and pest resistance ratings also play a role. Through advanced breeding techniques in recent years, researchers have separated the correlation between fall dormancy and winterhardiness. Today, growers can plant later fall dormancy varieties without sacrificing the winterhardiness and persistence that can lead to longer stand life.