Can 'Carbon Farming' Limit the Environmental Impact of Beef Production?

Jul 28, 2009

Fact: Eating less beef is good for the health of our bodies and the health of the planet.

Fact: Beef production is one of the world's major sources of carbon emissions.

Footnote: Some scholars and farmers think beef-production can be re-jiggered to be carbon-negative.

Carbon-negative? Is that possible? The basic framework is familiar—carbon sequestration in soil. As soil science professor Chuck Rice of Kansas State University notes,

"There is more carbon stored in the soil than in the atmosphere. If we can make a small change in managing that carbon in the soil, it would make a big difference in the atmosphere."

The method is the oddly named "carbon farming," or raising grazing animals on grass and roughage, but rapidly cycling them through multiple pastures, letting them gnaw the vegetation to just before the point on no-return, then pushing them onto the next patch of land.

The animals will trample the loose vegetation into the top of the earth, the root structures remain, allowing vegetative cover to re-grow fairly quickly, which it does by drawing upon carbon dioxide from the atmosphere. Ad infinitum. It's a nice idea, supported by common sense and natural history, merely awaiting experimental verification. As Nebraska farmer Chad Peterson explained to the High Plains Journal,

"If you repeatedly graze the new shoots, you are pulling from the carb reserves. ... When it runs out of carb reserves, the plant dies or it is a weak plant. Weak plants don't have deep roots. Shallow rooted plants die when it gets dry."

But by quickly shuffling the animals through multiple fields, the cattle graze for such a short period of time that the plants' root structures remain undamaged.

Prevailing methods of livestock rearing involve, first, growing feed using input-intensive, high-irrigation, carbon-leaching processes and second, stuffing those cereal crops into caged or movement-restricted animals that defecate into manure pits, which, as they decompose, emit tons of greenhouse gases. It leads to livestock production generating 18 percent of global greenhouse gas emissions, according a report from the UN Food and Agriculture Organization.

Even most grass-fed cattle are allowed to eat a patch of vegetation nearly down to the roots, damaging the plant sufficiently that re-growth is delayed, while making the soil more prone to erosion.

Pushing animals through different lots enables them to both expel waste as natural fertilizer directly onto the land that will produce their feed, and then trample it into the ground, building soil organic matter quickly and naturally. Grasslands are also perennials, building root-systems that reach meters-deep into the earth, in a kind of mirror-image of a tree—invisible to the naked eye, but still storing more and more carbon, day by day. As farmer Joel Salatin told a grazing conference,

"First, the animals become less selective. They don't have the time or opportunity to be picky about which plants they eat. The result is more even mowing and a tremendous reduction in normally ungrazed plants. This pushes succession of the good species ahead."

Some evidence from trials of controlled sheep-grazing supports this idea. The cattle also stomp seeds from grasses deep into the ground, where they're more likely to find water. This also works to the nutritional benefit of the cattle. Tall grass has a far higher starch-to-protein ratio than young, fresh grass. Cows needs more starch than protein—a fact often ignored by those who promote feeding cows on fresh re-growth.

So one obvious benefit of continuous vegetative cover is that it nearly eliminates soil erosion. But grasslands are an enormously under-appreciated carbon sinks, too.

That the meters-high prairie grass that grew in the American plains for centuries sat atop jet-black carbon-rich soil, cultivated by bison and buffalo—that was no coincidence, and is precisely the type of ecosystem that "managed rotational grazing," or in its more cutting-edge form, Ultra High Stock Density (UHSD) grazing, seeks to imitate.

There is little evidence that grazing beasts contributed substantially to increasing the level of atmospheric greenhouse gases then, and so it seems prudent and reasonable to try to emulate natural processes.

Beef-production as it's currently done must be reduced, but that doesn't mean other models can't work, or that they shouldn't be tried.

 

See also:

Land Use Offers Valuable Solutions for Protecting the Climate

Beef: What's Not for Dinner in a Sustainable World

Beef: The Prime Cause of Deforestation in the Amazon

 

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