The power of carbon + coexistence struck me while visiting a farm in New South Wales, Australia, a few years ago. It hit when I learned that the number of native grass species on the farm had increased from seven to 130 in only seven years! The key? Using cattle and sheep managed together as one herd.

The man responsible for this accomplishment was Eric Harvey, a gregarious former wool trader who had decided to try his hand at the other end of the supply chain by purchasing a 7000-acre farm called Gilgai, located a few miles from the crossroads city of Dubbo. Shortly after buying Gilgai in 2004, however, Eric nearly “bought the farm” himself when he had a massive heart attack, as he explained to me on the drive in from Dubbo. After recovering, Eric was astonished to learn from his doctor that his body was almost completely devoid of minerals, which are essential to human health. He knew there weren’t many minerals in rainwater – due to water scarcity Australians collect and drink a lot of rainwater – but he assumed he was getting enough minerals from the plants and animals he ate, which in turn get their minerals from the soil. Ninety-five tests showed he wasn’t. This was a huge eye-opener, he said.

Eric had soil tests conducted at Gilgai, discovering that it too was depleted of essential minerals, including carbon. This meant that the farm and Eric’s health were now one and the same – both had to recover. But where were the minerals going to come from, he wondered? A mine? A factory? That didn’t sound very practical or economical. And what about carbon? Was he supposed to spread compost over all 7000 acres of land? That didn’t sound economical either.

A chance conversation with a neighbor provided Eric with an unexpected answer: the sky. Carbon was freely available in the air, his neighbor said, in the form of carbon dioxide, and all Eric had to do was get it into the soil via photosynthesis, livestock, and planned grazing practices. The goal, he told Eric, was to grow native grass –diverse and copious amounts of it.

So that’s what he did. First, he studied the principles of planned grazing and then, after deciding to put them to work, he made another unconventional decision: to run cattle and sheep together as one grazing unit. It’s called a flerd – a flock of sheep and a herd of cattle, comingled. Years ago, he saw sheep and cattle grazing on a farm in Africa and thought “that makes sense.” Maybe to Eric – but not to many others. To say that it is not traditional to run cows and sheep together would be a huge understatement. It’s hardly done anywhere. Not only do many in agriculture consider the two types of herbivores to be incompatible with each other from a grazing perspective, most sheep and cattle farmers consider each other to be incompatible as well. In fact, Australia endured its share of range wars between sheepmen and stockmen over the decades, much like America did in the nineteenth century.

Eric ignored all that and in 2005 he put together his first flerd, eventually comingling 5000 sheep and 600 cows. His goal was to use the different grazing behaviors of sheep and cattle to benefit plant vigor, diversity, and density. Nature likes mixed-species grazing, Eric said, because animals often complement each other in what they will eat, the composition of their manure and the way their hooves interact with the soil. As Eric described it, herbivory creates an organic “pulse” below the ground surface as roots expand and contract with grazing. This feeds carbon to hungry fungi, protozoa, and nematodes, which in turn feed grass plants. The manure “pulse” aboveground helps too, especially with nutrient cycling. His plan with the flerd was to make both “pulses” beat stronger and more steadily.

To accomplish this goal, Eric divided the 7000-acre farm into 196 paddocks, mostly with electric fencing, creating an average paddock size of 140 acres (the smallest is six acres). The flerd moves from paddock to paddock every few days, giving each paddock plenty of time to grow more grass. And with only one “mob” to watch, Eric is often back home by 10 am. As further work reduction, Eric monitors the watering troughs remotely via sensors linked to the computer in his office, as he showed me, which supply up-to-the-minute data. He also pays for a service that provides aerial infrared images of his farm daily, which allows Eric to monitor the growth rate in his paddocks at a 7-acre scale. He calls this service “pastures from space” and says it gives him an invaluable snapshot of forage conditions, which helps adjust his grazing schedule.

Eric also ground-truths the monitoring data he receives. That’s how he knows he has been able to expand the number of plant species on Gilgai from seven to 130. This improvement in diversity has substantially enhanced the mineral content of the plants, since they can now access nutrients more widely, as well as deeper in the soil profile, and process them more effectively. And when these plants are eaten by animals, which are in turn eaten by us, the minerals enter our bodies, as Eric can personally attest (his physical health has improved dramatically). That’s why Eric and his family grow and sell only grassfed products from their farm. By definition, grassfed means an animal has spent its entire life on grass or other green plants, from birth to death. This contrasts with the feedlot model in which an animal finishes its life in confinement, fattened on grain and assorted agricultural by-products and pumped full of medication and other chemicals.

Thanks to a lot of digging in the scientific literature over two decades by Jo Robinson, an independent researcher (, the health benefits of grassfed over feedlot meat have become widely known. They include:

  • More omega-3 fatty acids (“good” fats) and fewer omega-6 (“bad” fats)
  • Lower in the saturated fats linked with heart disease
  • Much higher in conjugated linoleic acid (CLA), a cancer fighter
  • Much more vitamin A
  • Much more vitamin E
  • Higher in beta-carotene
  • Higher in the B-vitamins thiamin and riboflavin
  • Higher in calcium, magnesium, and potassium
  • Enhanced immunity, increased bone density, and suppression of cancer cells
  • Does not contain traces of added hormones, antibiotics, or other drugs

As Jo Robinson says, “If it’s in their feed, it’s in our food” – which means if you’re a meat-eater, it’s in us.

Here is a photo of Eric’s flerd in action at Gilgai:

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As for the flerd itself, Eric Harvey has hardly had any trouble running sheep and cattle together. The key is to raise them as one family, he said, especially the lambs. Sheep will bond with cows at a young age and remain bonded for the rest of their lives. As a result, the sheep follow the cattle wherever they go, which means they’ll move from paddock to paddock with the herd without much fuss. This is great news for a multi-paddock farm like Gilgai. It also means Eric doesn’t have to train any sheep to electric fencing, only the cattle. “Needless to say, moving one herd of livestock is a lot easier than moving two,” he said. “You just make to make sure there’s enough forage and water ahead of them.”

The only trouble he’s had, other than an occasional grumpy cow who doesn’t like sheep – quickly culled – happens during calving, when mama cows become highly protective and might kill a ewe that comes too close. Eric solves this by separating the cattle from the sheep during their respective birthing seasons. “The only other conflict I’ve ever seen is over shade,” says Eric. “And that’s been minor. Otherwise, they get along great.”

We went to see for ourselves. After quick stop for a look inside a sheep-shearing shed (which I had only seen in Australian movies), Eric and I walked down a dirt lane, crossed through a gate, and entered a grassy field. The cattle saw us coming. A number of them jogged hopefully towards us until it became clear that we weren’t going to open a gate so they could move to fresh grass. They drifted off, followed closely by small flocks of sheep. We stopped in the middle of the paddock. Looking around, I saw cattle and sheep everywhere. “Look how they spread themselves out,” Eric said. “Cattle prefer grass over forbs [broad-leaf plants], but it’s vice versa with the sheep. If you keep them in a paddock just the right amount of time, everything gets a nibble. That’s good for the plants and the soil.”

“They’ll all be out of here tomorrow,” he added.

Although Eric doesn’t run goats as part of the flerd, he said there’s no reason it couldn’t be done. Not only do goats get along with sheep and cattle just fine, but, if bonded properly, goats prefer brush and weeds over grass and forbs, which means they would add another level of grazing diversity to a pasture – also good for the soil.

According to some research I had done prior to my trip, another benefit to a flerd is protection from predators, such as coyotes. In the American West, coyotes are the scourge of sheep, lambs especially, which is one reason why sheep-only ranching has declined steadily over the decades as predator populations rebounded, wolves especially. Experiments, however, have shown that when sheep are bonded to cattle they are protected from predation by coyotes, which are reluctant to take their chances with a closely packed herd of bovines. Experiments have also demonstrated that sheep gain weight faster when grouped with cattle compared with sheep that are managed as a separate flock. Wool production was also greater with the flerd than with sheep foraging alone – a fact that Eric said he could confirm.

He attributed both improvements to the healthier soil and increased diversity of plants on Gilgai – a result of his careful stewardship.

Excerpted from Soil, Grass, Hope: a Journey Through Carbon Countryby Courtney White