- New research found that the greenhouse gases sequestered in one grass-fed system balanced out those emitted by the cows, but some meatless advocates are skeptical.
There’s no denying Americans eat a lot of meat. In fact, the average U.S. citizen eats about 55 pounds of beef a year, including an estimated three hamburgers a week, and the United States Department of Agriculture (USDA) expects that amount to increase by about 3 percent by 2025. This heavy reliance on animal protein carries a big environmental footprint—livestock production contributes about 14.5 percent of global greenhouse gas (GHG) emissions, with beef constituting 41 percent of that figure, thanks to the methane cattle produce in the digestion process and the fact that overgrazing can release carbon stored in soils.
….A new five-year study that will be published in the May 2018 issue of the journal Agricultural Systems suggests that they can. Conducted by a team of researchers from Michigan State University (MSU) and the Union of Concerned Scientists (UCS), the study suggests that if cattle are managed in a certain way during the finishing phase, grassfed beef can be carbon-negative in the short term and carbon-neutral in the long term….
….“it is possible that long-term [adaptive multi-paddock grazing] AMP grazing finishing in the Upper Midwest could contribute considerably more to climate change mitigation and adaptation than previously thought.”
Rather than using the common method of continuous grazing, in which cattle remain on the same pasture for an entire grazing season, the researchers used the more labor-intensive method of AMP, which entails moving the cattle at intervals ranging from days to months, depending on the type of forage, weather, time of year, and other considerations. A herd of adult cattle on MSU grazing land served as their test population.
Though the study’s finding that strategic grazing can make a dent in the overall environmental impact of cattle runs counter to the widespread opinion among other researchers and climate activists, it is welcome news for advocates of regenerative agriculture.
…. Tara Garnett, a food systems analyst and the founder of the Food Climate Research Network (FCRN) at the University of Oxford in England, calls the MSU work “a really useful study,” but also observes that it is “unclear how far this approach will lead to the same results elsewhere.” The study authors, too, are careful to stress that their results apply to Upper Midwestern conditions, and using a similar method in other ecosystem types will require further tailored study. They also acknowledge that while degraded land properly managed can take up large amounts of carbon, the soil will eventually reach equilibrium (meaning it will reach its carbon limit), and estimates of how long that takes vary widely.
In addition, soil types and the many other aspects of climate and ecosystems in different regions require detailed understanding and granular management of grazing—something many beef producers may be unwilling to undertake. And grazing requires twice as much land as feedlots….
…. One very promising practice, she said, is for ranchers to enlist farmers in the beef finishing phase. One farmer was initially very skeptical, but after he had grown a series of cover crops to rest his wheat fields and used cattle to “harvest” them, leaving the residue on the fields, he discovered that the soil was improving rapidly, Carman said. Reduced fertilizer and pesticide inputs, together with the income from the pasturage fees, makes the next wheat crop less expensive to grow.
…. said Rowntree, “I hope our paper can give our industry, combined with policymakers, a lens that can potentially help. We’re not trying to pit one group against another.”
Carman also acknowledges the complexity at hand, but feels the benefits to the soil she has seen are important to take into account. “Livestock are partly to blame for a lot of ecological problems we’ve got,” she said. “But we couldn’t repair these problems without livestock.”
Paige L. Stanley, Jason E.Rowntree, David K.Beede, Marcia S.DeLonge, Michael W.HammImpacts of soil carbon sequestration on life cycle greenhouse gas emissions in Midwestern USA beef finishing systems. Agricultural Systems Volume 162, May 2018, Pages 249-258 https://doi.org/10.1016/j.agsy.2018.02.003
And related NPR story:
April 9 2018 America’s farmers are digging soil like never before. A movement for “regenerative agriculture” is dedicated to building healthier soil and could even lead to a new eco-label on food.