Winterkilled alfalfa: Think through your options

By Chris Wacek-Driver The past year’s weather has presented challenges in some areas as we look to this season’s forage crops.  To create the best-fit forage plan for your farm, make sure you have a good handle on the extent of winterkill in your fields and your forage needs for the upcoming months as well as the year ahead. Evaluating winterkill alfalfa Dr. Dan Undersander, an extension forage agronomist with the University of Wisconsin, said the first step is to make sure the “dead spots” are actually dead and not just delayed.  Dig up a few plants.  Look at the top 4 inches of the tap root.  If the plant is delayed but alive, the taproot will be off-white in color and turgid (not ropy).  Do the same check for fields that are putting out small shoots.   Some dying plants will produce 1- to 2-inch shoots and then die.  Again, dig up the plants and look for healthy taproots. If only a small percentage of the field is affected by winterkill, Undersander recommends going over the affected areas with a drill as soon as possible and seeding 10 pounds per acre with a 50/50 mix of Italian ryegrass and perennial ryegrass. Other alternatives for interseeding include red clover (6 to 10 pounds per acre) orchardgrass (5 to 10 pounds per acre), tall fescue (6 to 12 pounds per acre) or oats/barley (50 to 75 pounds per acre). If the stand is less than a year old, alfalfa can be interseeded at 6 to 10 pounds per acre.  If the stand is older than one year, the new seedlings will die from autotoxicity. If a higher percentage of the field is affected, the best strategy for reducing your losses depends on the time of need and the intended use. Considering forage inventory If a moderate percentage of the field is affected and you want to take a first cutting, Undersander recommends immediately interseeding Italian ryegrass at 10 pounds per acre, take the first cutting and then seed corn for maximum yield. Producers with low forage inventories and a high percentage of winterkill will need tonnage quickly to replace the first cutting.  In this case, Undersander reports that a small grain is the best option as it can be harvested at the middle to end of June.  Oats are likely the best choice (followed by barley and triticale, based on yield).  Planting small grains with peas will increase crude protein and palatability, but not yield. If you have a high percentage of winterkill, but your forage inventory can carry you through the next few months, maximum yield should be the goal.  Corn is the best high tonnage option for silage.  An alternative is sorghum-sudangrass if you expect dry conditions or above-average temperatures.  For haylage, Undersander says seeding Italian ryegrass with alfalfa or solo-seeding alfalfa is the best strategy. Finally, if forage is not needed immediately and you want to get high yields on new seeding, direct-seeding Roundup Ready® alfalfa will produce the highest yield and quality.  The added cost for seed should be recovered during the first crop due to higher yields and higher RFV. Spray the Roundup Ready alfalfa when it is 12 inches tall. Use your resources Work with your nutritionist and agronomist to evaluate your options and pick the best strategy.  The following University of Wisconsin resources contain additional information about winterkilled alfalfa and emergency forages.

• Alfalfa stand assessment:  Is this stand good enough to keep?
• Maximizing Forage in Winter Injured and Killed Stands, Spring of 2013
• Forage Options Following Alfalfa Winterkill
• Pea and Small Grain Mixtures
• Emergency Forages

About the author:  Chris Wacek-Driver is the Vita Plus forage program manager.  She grew up on a farm outside of Denmark, Wis. and attended the University of Wisconsin-River Falls where she earned her bachelor’s degree in dairy science with an ag business minor.  She went on to receive her master’s degree from UW-Madison.  She conducted her research focusing on forage quality at the USDA Forage Center under Dr. Larry Satter.  In particular, she studied forage fermentation, the role of microbial and enzyme additives, and their effects on dairy animal performance.  Wacek-Driver has been a Vita Plus employee owner for the past 21 years and worked in dairy technical services prior to her current role.  She has a passion for working with dairy producers to help them with on-farm feed inventory, feed management, forage fermentation and production, and dairy nutrition.  She resides on a 240-acre farm along the bluffs of the Mississippi River in western Wisconsin.