A carbon-neutral burger? It’s not impossible.

By treating cows as part of the grassland ecosystem, some ranchers are already farming sustainable beef.


By Ula Chrobak, Popular Science  

October 7, 2019


Beef has become one of the central villains of the climate crisis. Many environmentalists limit their cow consumption or eat entirely from lower levels of the food chain. But though it's true that global figures on beef's carbon hoofprint are worrisome, they perhaps also gloss over the complex system that these cows are a part of. There are many, many ways of producing burgers and steaks—and some ranchers argue cattle can actually be a force for good. In fact, cattle might play a surprising role in mitigating climate change. If done right, grazing can heal grasslands and enable them to stow away more carbon from the atmosphere, even becoming carbon-negative systems.


At Ranney Ranch in central New Mexico, the cattle herd moves between about 33 smaller pastures within a larger 18,000-acre ranch on rocky mesa grassland. The cows graze down one pasture at a time for a period of a few days to three weeks in what’s called adaptive multi-paddock (AMP) grazing. Then, the ranchers move the ruminants to the next patch, and the just-grazed area has at least six months to rest. In the 16 years since she adopted this grazing plan, Nancy Ranney says she’s increased the number of cattle while at the same time building soil carbon and increasing the biodiversity of native grasses sprouting across the ranch. “Not only is it a viable alternative,” she says, “it’s a necessary management practice if you want to keep grasslands healthy and you want to have healthy soils.”


Cattle production is inseparable from grasslands. Most beef cows—both grass- and grain-fed—start their lives on a pasture, explains Ermias Kebreab, a professor of animal science at the University of California, Davis. After about a year to a year and a half, cows are either sold to a feedlot or continue grazing until slaughter. Feedlot cows are fed a high-calorie, often grain-based, diet on which they fatten quickly. Finishing cows on grass takes about three to six months longer, since grass is less calorie-dense.


Often during the pasture stage, cattle are free to roam about entire ranches, nibbling on whatever patch of grass they like, whenever they want. But especially with large numbers of animals, this continuous grazing can erode the grassland ecosystem. Uninterrupted trampling can reduce a once-vibrant prairie to patches of scraggly, weedy plants and bare, compacted soil. And with that erosion and loss of plants goes the ability of the soil to store carbon in organic matter, a key function of grassy regions.


This bleak picture might lead you to question beef’s sustainability. But the grazer-grassland relationship is not inherently destructive; native ruminants and plants evolved together, and they have a mutually beneficial relationship in natural ecosystems. Millions of bison once roamed the United States, and they instinctively moved between pastures, giving plants and soil a chance to recover.


If done carefully, Kebreab says livestock grazing can mimic this natural function. Additionally, he notes, "the thing that people might not consider is that a lot of these cattle occupy land that's considered to be marginal—you can't really do anything apart from growing grass." So, when considering the amount of land used to produce beef, which many environmentalists cite as a negative impact, it's important to realize that that grazing land can support way more than cows. As long as the operation takes places on a natural rangeland—as opposed to the destructive practice of chopping down a forest to produce pasture—there's potential to foster a healthy ecosystem and store carbon in addition to producing beef.


Rotational grazing, including the AMP approach Ranney uses, seeks to mimic those historic herds of bison and other grazers that once trod the land, creating a microcosm of this ecological relationship...


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