Why Does Snow Cover Matter When It Comes To Alfalfa?

While it may not be true for the entire state, those of us in Eastern NY have left our snowmobiles parked due to the lack of snowfall, but ample freezing rain, lately. But how does this affect our alfalfa stands? I’m sure most of you know that snow provides abundant insulation. But, if you’re noticing ice sheets on your alfalfa fields, keep reading, and check out these two articles from the University of Wisconsin – Madison: Ice on Alfalfa and Managing Alfalfa Stands for Winter Injury.

Heavy ice coverage often leads to alfalfa winter injury or even kill as the crowns are damaged and the roots are not receiving the oxygen they need for survival. Alfalfa covered by a thick layer of ice for three + weeks will likely see injury or death. While there is not much you can do now to keep the ice off your dormant crop, make sure you take the time in the spring to assess the damage and call upon your local CaroVail Certified Crop Advisors to help determine the yield potential of an injured alfalfa crop.

A few signs to look for include slow green up, asymmetrical growth, and root damage. Of course, many factors contribute to your yield potential, such as soil factors, nutrient deficiency, insects, and disease. The number of stems in a square foot can also be a useful tool to determine your yield potential. Come spring, it’ll be time to get your frisbee out and start counting.

• Over 55 stems – Stem density is not limiting yield
• Between 40 – 55 stems – Stem density is limiting yield 
• Under 40 stems – Stem density is severely limiting yield, Consider replacing

Factors that may influence your level of winter injury include:

• Stand Age: the younger the stand, the more resilient against winter injury
• Variety: the level at which it is winterhardy
• Soil pH: a pH lower than 6.6 is more likely to experience higher levels of winter injury
• Soil fertility: stands may experience less winter kill if they are properly fertilized. Potassium is especially important!!
• Soil moisture: stands that enter winter with a high soil moisture will likely experience more winter kill
• Cutting management: the longer the interval between cutting, the less risk of winter injury. Be mindful of cutting height and maturity, as well. The longer you allow a stand to mature, make sure you do not mow off the new shoots – so pay attention to mowing height

Your plant health is of great importance to us at CaroVail, so please reach out with any winter injury concerns. Stay warm and think spring – it will be here before you know it.