USA
May 17, 2023
Globally considered the “Queen of Forages,” alfalfa is the third most valuable field crop in the United States, with an estimated economic value of $8.7 billion a year, according to USDA’s National Agricultural Statistical Service. The United States grows about 23 million acres of alfalfa each year. It is highly valued by organic and conventional farmers for its soil health-building characteristics and is the premiere forage for dairy cows.
Several Land-grant Universities conduct research and Extension projects with funding from USDA’s National Institute of Food and Agriculture (NIFA) that supports the nation’s alfalfa industry. Learn more about some of these projects, including those funded through NIFA’s Alfalfa Seed and Alfalfa Forage System Program. The application deadline for this grant program is May 25.
Developing New Alfalfa Cultivars
An increasing number of bermudagrass growers across the Southeast have been incorporating alfalfa into suppressed or closely clipped bermudagrass pastures. Most growers were attracted to alfalfa because they have seen enormous improvement in the quality of their hay, and they were able to save on the application of nitrogen fertilizer. Alfalfa competes well with bermudagrass, even in drought conditions. The major challenges to alfalfa production in the Southeast are low pH soils and aluminum toxicity.
University of Georgia crop and soil scientists in the forage breeding program are conducting direct field evaluation and selection in low pH and high aluminum soils, with the goal to develop low pH tolerant alfalfa varieties. The project will enable expanding the adoption of alfalfa in Georgia and the Southeast. With the shrinking acreage of alfalfa in California and the Western U.S. due to competition for water from almonds, the Southeast offers the biggest opportunity for expanding alfalfa acreage nationally, whether as a pure crop or as a companion in bermudagrass pastures and hayfields.
Keeping Moisture at Bay
Properly storing hay is a logistical challenge for farmers. Hay that is baled and stored too moist — at moisture levels above 15% to 20% — can lead to the growth of molds that reduce bale weight and nutritional value, and impact animal health. Improper hay storage can even cause so much microbial activity that the bales will heat up and combust. New research from the University of Maine and Virginia Tech shows that certain preservatives are more helpful than others to keep high-moisture hay mold-free — and that grass hays are more responsive to these treatments, compared to alfalfa.
Researchers found that organic acid-based preservatives, buffered organic acids and other organic acids were effective at reducing dry matter loss (also known as “bale shrink”), moldiness, bale heating and indigestible protein. They were also, to different extents, effective at preserving hay sugars and dry matter digestibility. Meanwhile, microbial inoculants—microorganisms applied to either soil or plants to improve productivity and crop health—had only small effects on the prevention of hay spoilage and were negatively affected by the increase of hay moisture.
Perhaps most significantly, the researchers found that legume hay, including alfalfa, was less responsive to the effects of preservatives than grass hay during storage. Legume hay typically has a higher nutritional value than grasses due to its higher protein and pectin concentrations and higher rate of fiber digestion. Alfalfa alone represents half of the hay production in the United States.
Current guidelines for preservative application are the same for both alfalfa and grasses, but this will likely change thanks to the study’s findings.
Controlling Alfalfa Weevils
Alfalfa weevils cause the most damage and loss to Wyoming’s number one crop commodity—hay. In the last three years, alfalfa hay has been 70% of Wyoming’s hay production and provides an annual revenue of approximately $300 million. Wyoming alfalfa producers have been dealing with alfalfa weevils for decades. However, producers say the alfalfa weevil has become more difficult to control since the mid-1990s.
As a result, University of Wyoming Extension conducted research on alfalfa weevil populations to assist producers with monitoring and insecticide application timings to control the pest. In partnership with Montana State University, researchers identified the first documented account of insecticide resistant alfalfa weevil populations in Wyoming and Montana.
As a result of the education programs, crop advisors, commercial applicators and producers are changing their pest management strategies for alfalfa weevil. This change includes increasing monitoring efforts to determine timing for insecticide applications to identify resistant populations and changing to effective insecticides.
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