Alfalfa Assessment Key with Increased Winterkill Risk

Across the Dairyland Seed territory, alfalfa stands are at an increased risk of winter injury and winterkill. Widespread drought conditions during the 2021 growing season and increased fertility costs led to less-than-ideal conditions heading into a winter that brought limited snow cover, high winds, and low temperatures. Alfalfa will be entering spring excessively vulnerable to additional stress meaning the risk for reduced yield will be there.

To ensure you have the quality and quantity of alfalfa necessary for a successful 2022, start by evaluating the health of current alfalfa stands as soon as they break dormancy in order to immediately implement the best plan for moving forward.

Suggested plans of action based on observations and alfalfa field conditions. Source: Rebecca Vittetoe, Field Agronomist, Iowa State University & Extension

Assess the extent of the damage

• Dig below the soil surface to evaluate roots for potential health issues
• Check the crown of alfalfa plants for asymmetrical or uneven growth that would indicate partial winterkill
• Note any slowed growth that isn’t green when other fields or areas of the same field are green

Calculate potential yield loss to determine best course of action

• Count the number of plants and the number of stems per square foot
• Between 40-55 stems correlate with a lower yield potential and will need to be monitored closely
• Less than 40 stems indicate severe winter injury and replacement is recommended
• In older stands, you’ll have fewer overall plants that contribute to the total number of stems so making sure each plant is symmetrical in its growth will also be key to estimating yield potential.

Evaluate additional options to replace lost quantity and/or quality

• Delay first cutting to allow plants to store more reserves for subsequent cuttings
• Increase cutting height to put less stress on an already stressed plant
• Don’t cut past September 1st if stand will not be removed prior to winter
• Use fertilizers and/or herbicides to allow plant to use its energy for growth and production instead of fighting off weeds, diseases, and pests. With the increased input costs, doing a partial budget analysis will help support the addition of key nutrients

Work with your trusted Dairyland Seed Dealer, Agronomist, or District Sales manager to help make these important alfalfa stand health determinations.