Paul R. Peterson, Extension Agronomist - Forages

January 15, 2005

Even though it’s still winter, let’s get serious here – about growing alfalfa. Alfalfa has so much to offer as a feed, soil builder, and profit center within crop rotations on Minnesota dairy farms. But too often, we don’t fully capitalize on opportunities to get the most out of this important crop.

Let’s start with variety selection. All varieties are definitely not created equal. Good varieties cost more. But with alfalfa varieties, as with many things, you get what you pay for. Sometimes cheaper varieties seem to work well, but it’s often a crapshoot. Paying a little extra for more dependable varieties is a much better strategy, especially for the risk-averse. If seed of good varieties costs $2 more per pound than that of “cheap” seed, and alfalfa is seeded at 15 lb/ac, then the good seed costs $30 more per acre than risky seed. If we assume that good-quality alfalfa hay is worth $100 per ton, only 0.3 tons more forage yield per acre is needed to pay for the “extra” seed cost of the better variety. Harvested yield is by far the largest driver of profitability with alfalfa production (see table), so it’s worth our close attention. In most cases, good varieties will easily yield 0.5 to 1.0 ton or more per acre per yearmore than cheaper varieties. This makes the extra seed cost almost trivial.

Producers should also use the Winter Survival Index (WSI) rating when selecting varieties. This is especially important if you want to capitalize on the high quality forage and added profit of harvesting alfalfa in the fall. Alfalfa producers are encouraged to check the results of the University of Minnesota trials as an unbiased, trustworthy source of variety performance information. The 2004 results are now available on the web at www.maes.umn.edu or in printed form (contact your county Extension office).

Consider strategies to increase seeding-year alfalfa yields. Too often we settle for one or two seeding-year harvests. Even in Minnesota , three to four seeding-year harvests are doable in most years. Seeding early (April) and taking the first harvest 60 days after emergence puts the alfalfa producer on pace for good seeding-year production. In addition, first-year stands of winter-hardy alfalfa varieties (WSI ~2 or less) are very tolerant of fall (October) harvesting, so the producer shouldn’t leave a ton of good-quality fall forage standing in spring-seeded fields. Using Italian ryegrass as a nurse crop also offers a means to boost seeding-year yields without reducing nutritional value. Italian ryegrass spring-seeded at 5 lb/ac with alfalfa provides a vegetative forage with high digestibility at every seeding-year harvest. The ryegrass then dies in most winters.

Fall cutting (or grazing) should be considered more often (see table). Fall growth after a late August cut can often exceed 1 ton of dry matter per acre and be the highest quality forage of the season. When this growth is left in the field over winter, the residue can reduce the quality of next spring’s first crop harvest. Fall cutting is most viable (least risky) where modern, winter-hardy varieties are used, where fertility (particularly K and pH) and drainage are good, and where one growth period at some point during the year has been allowed to reach an early flower stage prior to harvest. Younger stands are more tolerant of fall cutting than older stands, but recent data from Wisconsin suggest that we may often try to keep alfalfa stands longer than is profitable.

Univ. of Wisconsin Forage Agronomist , Dan Undersander, recently conducted an economic analysis of the profitability of different rotation lengths in corn-alfalfa rotations on dairy farms. The analysis revealed that three-year stands (including the seeding year) are often more profitable than five-year stands. He cited multiple reasons for this. One reason included declining yield potential of even the best alfalfa varieties after their third year. Another results from reduced fertilizer and pesticide costs due to more opportunities to capitalize on alfalfa’s fixed N and fewer years of corn following corn.

Do you want to take your alfalfa management more seriously? The above alfalfa production strategies will be discussed in greater detail at three University of Minnesota Forage Days to be held February 2-4. The purpose of the Forage Day program is to help alfalfa producers develop productive and profitable strategies to get more out of their alfalfa acres. A panel discussion entitled “21 st Century Alfalfa Production Management” will highlight the program agenda at the three sites. Dr. Dan Undersander, along with NDSU Forage Agronomist Dr. Dwain Meyer, and Univ. of Minnesota Forage Agronomist Dr. Craig Sheaffer will join a team of Univ. of Minnesota Extension Service Forage Team members in delivering the program at each site.

The meeting dates and locations are Wed., Feb. 2 at the St. Charles Community Center (local contact -- Lisa Behnken, lbehnken@umn.edu, 507-280-2867); Thurs., Feb. 3 at the Freeport Community Center (local contact -- Dan Martens, marte011@umn.edu, 800-964-4929); and Friday, Feb. 4 at the Detroit Lakes Holiday Inn (local contacts -- Doug Holen, holen009@umn.edu, 218-998-5787 and Gene Krause, kraus018@umn.edu, 218-463-0295).

The program at all locations will run from 10:00am to 3:00pm, with registration beginning at 9:30am. The registration fee is $30/person which includes lunch, the new edition of the comprehensive North Central region Alfalfa Management Guide, proceedings of all meeting presentations, the Jan. 2005 Minnesota Variety Trials Results, the Winter issue of AFGC’s quarterly publication The Forage Leader, and other handouts.

For further information, contact one of the above local site individuals or me (peter072@umn.edu, 612-625-3747).