Genetic engineering may help reverse alfalfa’s decline, says agronomist
Improved traits developed through genetic engineering hold the best promise of reversing alfalfa's acreage decline in the Midwest, believes a University of Minnesota forage agronomist.
“I'm really concerned about the future of alfalfa,” said Craig Sheaffer at the recent Midwest Forage Association annual symposium in Wisconsin Dells, WI. “We have a great environmental crop that can improve the sustainability of agriculture if used in crop rotations, but I think it may well become a minor crop here in the next 10 years.”
He pointed out that Minnesota's alfalfa acreage has dropped by a third since 1990, while corn and soybean acreage has increased. Alfalfa is heavily dependent on the state's declining dairy industry; alternative uses haven't been developed. But corn and soybeans have a diversity of uses as human food and livestock feed.
Alfalfa lags in productivity, too. Its average yield has stayed at 3.3 tons/acre in Minnesota for the last decade, while corn and soybean yields have increased. Some of those gains have come from genetic engineering, and Sheaffer said that alfalfa may need the technology to stay competitive.
“Without genetic engineering, will we lose alfalfa from our landscapes?” he asked.
The crop's significant environmental benefits, like reducing soil erosion, improving water quality and sequestering carbon and nitrogen, should be weighed against the risks associated with genetic engineering as part of the Roundup Ready alfalfa debate, said Sheaffer. He emphasized, however, that if Roundup Ready alfalfa clears legal hurdles, guidelines and oversight must be developed that will protect farmers' rights to grow non-genetically engineered forage or seed.
He worries that, if Roundup Ready alfalfa isn't approved, genetically engineered traits that could increase the crop's value and use may be delayed. In his research, though, the Roundup Ready trait didn't improve the crop's yield or profitability.
In a four-year study, he applied Roundup herbicide to Roundup Ready alfalfa in the seeding year and compared the results with those of conventional varieties treated with another herbicide. Forage yield and quality were similar in the first year and over the life of the stands. But returns were lower for the Roundup Ready system because of the technology fee.
“Although Roundup Ready technology gives producers flexibility to control a diversity of weeds, I really think many Midwestern farmers who have good rotations with several years of alfalfa, corn and soybeans, and have their weed populations under control, may not need it,” said Sheaffer. “They may not need any herbicide.”