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Things to consider when buying alfalfa seed

Dan Undersander
When buying alfalfa seed some growers tend to be pennywise and pound foolish. The most important consideration for profit is yield potential, not seed price.

When buying alfalfa seed some growers tend to be pennywise and pound foolish. The most important consideration for profit is yield potential, not seed price.

In an analysis conducted by researchers at the University of Wisconsin over a 30-year period, significant performance differences were found between the lowest-yielding and highest-yielding entries.

As the graph below shows, the difference between the highest-performing and lowest-performing variety, planted side by side, averaged 2.3 DM tons per acre per year for the second to fourth years of the stands.

In an analysis conducted by researchers at the University of
Wisconsin over a 30-year period, significant performance
differences were found between the lowest-yielding and highest-yielding entries.

Each stand age involves 75 to 100 comparisons. With alfalfa averaging $198 per DM ton* for prime hay or $144 per DM ton* for grade 1 (125 to 150 RFQ), any additional seed cost for a premium variety is recovered with increased yield each year.

The comparisons included every year in the 31-year time period, including some drought years when yields were low and yield differences minimal.

Return on Investment

Further, the high-yielding alfalfa varieties yielded 1.3 DM tons per acre more than the low-yielding varieties in the seeding year (68 comparisons). This data demonstrates it is advantageous to buy premium seed even if the intent is only to keep the stand one or two years.

Thus, it pays to look at yield potential of the variety first and seed cost second. While little public yield trial data is available, one can discern yield potential from company trials (most include competitor varieties). More importantly, one can look at traits that promote high yield, such as winterhardiness and disease resistance.

High-yielding varieties will have a winter survival score of 2 or less. This high winter survivability means not only that the varieties will more likely survive the winter, but that the crowns and fall-developed shoots will survive winter better to increase first-cutting yields.

Disease resistance is also a valuable indicator into variety performance. The premium varieties have high resistance to Aphanomyces races 1 and 2, as well as enhanced resistance to a novel strain of Aphanomyces which is still being tested for. Additionally, high resistance to Anthracnose race 5 is also imperative for survivability and high performance in many areas. Both diseases can be significant alfalfa yield limiters if present.

Some regions will benefit from additional traits of some varieties including nematode resistance, aphid resistance, and salt tolerance.

Additionally, pure alfalfa stands planted without a cover crop will benefit from the Roundup Ready® trait. I have come to believe that this trait is beneficial whenever spring is not “normal,” and “normal” does not happen often. In a cool spring, weeds can get too big before the alfalfa is big enough to spray, and when weeds are a problem, glyphosate is the best broad-spectrum control.

Producers that take time to do their research and choose wisely, should be able to achieve a healthy stand of alfalfa for several years.

Considerations

After you have selected premium seed it is important to consider the fields you want to seed and whether or not they are ready for alfalfa.

Soil - The first big consideration is to have the soil tested and ensure that the soil pH is at least 6.8. This generally means that any lime should have been applied about one year ahead of planting. The lime particles benefit from incorporation and need time to dissolve and raise soil pH.

Nutrients - Check other nutrients to see what may need to be added next spring for good, vigorous establishment and yield. NAFA News – November 19, 2020.

Herbicide - You will also want to consider the herbicide history of the field, i.e., what herbicides were applied to the preceding crop. Note that a number of corn and soybean herbicides have an 18-month or up to two-year cropping season recommended interval before planting alfalfa. Failure to follow the recommended planting interval has resulted in a number of stand failures across the Midwest. Similarly, some 9- and 10-month planting restrictions occur for herbicides labeled for wheat which would prevent using those herbicides for spring applications to wheat and fall alfalfa seedings. We generally need to plan herbicide applications on the preceding crop if intending to plant alfalfa.

Equipment - Think about the equipment you will use to seed the alfalfa. A very high percentage of stand failures that are blamed on seed quality are actually due to poor equipment and seeding techniques. Do you have a new, wellmaintained drill or are you planning to use granddad’s drill that has been out in the rain since the last use? I have seen individual row meters putting out twice as much seed as adjacent row meters. Are the seed drop tubes clear or blocked? Are the discs adjusted for proper depth (¼ to ½ inch)? Are press wheels properly adjusted?

Note that newer designs of drills maintain seeding depth more accurately when crossing a valley or depression in the field. If the drill is old and worn, it is likely poorly placing seed; it may be more economical to have a custom operator seed the field. The cost of seeding alfalfa is now about the same as seeding corn (though alfalfa should last more than one year). Most would not plant corn with a seeder in poor condition.

Consider investing in a good seeder or hiring a custom operator since the alfalfa stand is expected to last 3-4 years. Well-planted premium seed to establish a good stand will produce return for several years.

Conclusion

Planting alfalfa is a longer-term commitment than other crops such as corn and soybeans. Choosing your variety wisely, based on private and third-party variety trials, known field history, and your management needs, is critical for a successful stand. Ensuring the seedbed is prepared correctly, nutrients are available and in adequate amounts, and the correct equipment is used when seeding are all important parts of the seeding process.

If you do your research and choose wisely, you should be able to achieve a healthy stand for several years.

*(Hay prices from Wisconsin Team Forage Hay Market Report https://fyi.extension.wisc.edu/forage/h-m-r/ Oct 12, 2020.)

Dan Undersander

Dr. Dan Undersander is a Professor Emeritus with the University Wisconsin