Niemand hier kann Savorys Behauptung ueberpruefen, aber nach 20 Jahren auf trockenem Land, machen seine Behauptungen fuer mich absolut keinen Sinn.
Im wesentlichen benutzt er nur Anekdoten, die nicht bewiesen werden koennen. Ueberweidung ist der Hauptgrund fuer Wuestenbildung. Damit empfiehlt er genau die falsche Methode. Wuesten entstehen nicht durch das Fehlen von Weidetieren. Intensive Beweidung verdichted die Erde und ist schaedlich. Seine Behauptungen zur CO2 Sequestrierung sind frei erfunden. Alle, die versucht haben seine Methoden zu untersuchen, kommen zu einem negativen Ergebnis.
Ich hab im folgenden Text die wesentlichen Punkte fett markiert fuer die, die keine Lust haben den ganzen Text zu lesen.
Allan Savory's Holistic Management Theory Falls Short on Science
On the Savory Institute's website, there are links to ample testimonials from ranchers who claim benefits from using the Savory method. "We are excited to share the simple yet effective tools of holistic management with our community," reads one typical statement, from a California rancher named Kelly McGarva. "It has made all the difference in our management practices, and the results can be seen on the land." The attraction for ranchers is Savory's promise that they can double, even triple, stocking rates while improving soil and vegetation cover. But the tales of success are self-reported and anecdotal. When scientists have conducted the rigorous evaluation suggested by the University of Natal researchers, the results have not been favorable.
In 1969, the Charter Estate, a London-based company, donated land, funding, and cattle to conduct a seven-year study of Savory's "short-duration grazing" on 6,200 acres in Zimbabwe. Savory stated in 2000 that the Charter Trials, as the experiment was called, was "the only trial ever conducted" about his work and that it "proved what I have always advocated and continue to advocate when livestock are run on any land."
But a 2002 review of the Charter Trials concluded that the Savory grazing method "failed to produce the marked improvement in grass cover claimed from its application." The study's authors found "no definite evidence in the African studies that short-duration grazing . . . will accelerate plant succession." The re-greening from cattle didn't happen. (Savory has since disavowed short-duration grazing, saying that it was flawed and that holistic management, despite its similarities to the short-duration model, now offers the best option.)
Since that initial study was conducted, Savory has faced a new wave of scrutiny. A group of United States-based rangeland scientists, led by David Briske, a professor in the Department of Ecosystem Science and Management at Texas A&M University, stated flatly that the Savory method "can not green deserts or reverse climate change." Savory's claims "are not only unsupported by scientific information, but they are often in direct conflict with it." Briske's study, published in the journal of the Society for Range Management in 2013, concluded: "We find all of Mr. Savory's major claims to be unfounded."
The Briske team found that Savory misrepresented the photos of landscapes he presents as evidence of the alleged desertifying effect of removing cattle. One of the photo series he often uses features Chaco Culture National Historical Park in New Mexico. But the land, the Briske report said, was not desertified from lack of cattle. Instead, the landscape was slowly recovering from decades of abusive overgrazing. (I emailed Briske for an interview, but he declined to talk. "Frankly, I have grown weary of the grandiose and unsubstantiated claims of Mr. Savory," Briske replied.)
Andres Cibils, a professor of range science at New Mexico State University, looked at Savory's claims of rangeland regeneration in Patagonia, among the highlights of the TED Talk. "In the case of Patagonia," Cibils told me, "there are no credible data to support Savory's success assertions."
Before coming to the United States, Cibils lived and worked in Patagonia for 13 years. Many of the region's ranchers, hard-hit by desertification that had resulted from decades of overgrazing, were worried for their future. "They were hungry for a miracle," said Cibils, who is familiar with several of the ranches where the Savory system was attempted. "They were willing to try this thing. But it's the same old story. I visited ranchers in New Mexico where Savory has consulted. These are people who tried it and who either modified or abandoned it because the results were a train wreck."
One of the tenets in Savory's argument is that soil becomes unhealthy—less carbon-rich—without the concentrated hoof action of cattle. By increasing the number of cattle on the land, ranchers can boost soil carbon sequestration. But this claim also founders under close inspection.
Briske and his colleagues looked at Savory's assertion that revitalized rangelands could help reduce atmospheric carbon to preindustrial levels. This would be a 30 percent drop, from 400 parts per million of CO2 to 280 PPM. The idea, the researchers concluded, is fantastical, amounting to "an enormous misrepresentation of the global carbon cycle and climate change science."
With global greenhouse gas emissions at roughly 50 billion metric tons a year, rangelands would have to sequester 13.6 billion tons annually, the report concluded. There are 5 billion hectares of rangelands; the most widely accepted estimate of potential soil carbon sequestration is less than 0.25 tons of carbon per hectare per year. That's eightfold less than Savory's claims would require.
Rattan Lal, a leading authority on soil carbon sequestration who teaches at Ohio State University, also expresses skepticism. "When a climate is drier and warmer, as on most rangelands, the rates of sequestration are generally lower," Lal said. "The question with Savory is the rates."
According to some researchers, Savory appears to misunderstand the intricate processes of soil carbon sequestration and nutrient cycling. I called up Kelsey Brewer, a one-time organic farmer who is now a staff researcher at the University of California, Davis, and who is studying whether livestock grazing alone can improve sequestration. "Carbon is central to his argument," Brewer said. "But he gives no specifics in his TED Talk. And no data. He makes claims, and shows pictures."
In Savory's universe, ungrazed land, known as "rested" land, will always wither away. "It's just wrong," said Brewer. A substantial number of studies on desert grassland have found that with rest, grass cover "increases dramatically," while "intensive grazing delays this recovery."
A study of grasslands in China found that 20 years of grazing exclusion increased soil carbon storage by more than 35 percent. Another study there of semiarid grasslands reported that carbon levels, variously measured in aboveground biomass, belowground biomass, and grass litter, were as much as 157 percent higher in livestock-free grasslands than in grazed grasslands. In Australia, researchers concluded that destocking shrublands for a period of 20 years resulted in net carbon sequestration.
Well-managed grazing, Brewer emphasized, can in some cases increase soil carbon content. It's based on how you do it. "His claim is that grazing density doesn't matter, and that it's only a matter of the speed with which the grazers move through the land," he said. "But grazing density totally matters." Savory says that fast-moving, densely packed livestock loosen soil. "This is the exact opposite of correct," Brewer said. High-density grazing can result in compaction. The very top layer of the soil—a fraction of the soil, the top 10 centimeters—might be loosened, but ultimately there is a net compaction. "There's just too much evidence supporting increased compaction for Savory to make this claim without more concrete proof."
An increase in carbon content is almost always associated with the beneficial things we want from soil: more porosity, more water penetration and retention, an increase in microbial biomass, and an overall increase in nutrient cycling, which means that fungi and bacteria are transforming nutrients back into plant-available forms while also gobbling up atmospheric CO2. But as a stand-alone strategy, animal grazing results in a metabolic gap in the nutrient cycle. The cycle becomes open instead of closed—especially in a market-based grazing model, which Savory advocates. The moment a rancher puts an animal onto rangeland, the animal is removing nutrients from the soil and converting them into muscle and fat. The moment the animal leaves the land to head to slaughter, those nutrients leave the system, and the net total productivity of the land decreases. A dead animal remaining in the system rots back into the soil, its carcass closing the nutrient loop. But that doesn't happen in the system advocated by Savory, whose sales pitch to ranchers includes the prospect of selling more cattle on the market.
This is exactly the complex analysis one doesn't hear from Savory. "And that's my point," Brewer said. "You can't be reductive. Savory's claims are so reductive. I study integrated crop-livestock systems, in which we have grazing coupled with co-management and the inputs of additional fertilizers, like nitrogen and phosphorus, and we do see increases in carbon. The problem is that very often animal grazing alone does not increase carbon. It's just not true what Savory says."
♦
In March 2016, while traveling in the high desert of southern Utah, I was invited to a local presentation about rotational grazing that included a screening of Savory's TED Talk. About 20 people showed up at the community center in the remote farming village of Boulder, population 226. We sat in the dark and listened to Savory's stirring words and watched his slideshow. The event, designed to inspire area ranchers, was organized by a group of self-described progressive agrarians.
Following the video, Ron Johnson, who runs an organic farm and lodge, led a discussion. Johnson is an optimistic 56-year-old who made a small fortune investing in Utah's Great Salt Lake brine shrimp industry and is now interested in getting into livestock using holistic management. There was mostly praise and admiration for Savory.
A lone voice in the audience demurred. It was Dennis Bramble, a fit-looking, silver-haired evolutionary biologist and professor emeritus at the University of Utah. Bramble, who was profiled in the best-selling book Born to Run, upended the field of evolution with his groundbreaking studies tying the physical development of modern Homo sapiens to our species' ability to run. He is also a self-taught ecologist who has schooled himself in the ecology of grazing in arid lands.
"I think claiming that you're going to reverse climate change by running cattle across the dry lands of the earth doesn't make sense," Bramble told the crowd. "And I would caution you all not to leap on the Savory bandwagon, especially in these parts. This is very dry country. And you need to consider some evolutionary history. There were no large ungulates grazing in this region. The grasses did not coevolve with grazing."
He said that on his own property, inside the nearby national forest, there had been a remarkable recovery of the landscape—and this was because, he quietly added, grazing had been curtailed as opposed to increased.
There was a moment of silence. "Why not give it a try?" said one of the attendees. That was the consensus in the room. After the event ended, Bramble and I talked. He was saddened by having to throw cold water on the hopeful meeting of local citizens. "The whole Savory thing," he sighed, shaking his head.
A few months later, Bramble took me on a tour of his property, which had been fenced off from cattle. The 160-acre parcel has been cattle-free for six years, and it exhibits a profusion of grasses and forbs and flowers. Before that, the property experienced only light, monitored grazing. Bramble has counted about 50 grass species that have recolonized the space, 80 percent of them native varieties. Rest from grazing, contrary to Savory's claims, did not result in desertification. Instead, minimal grazing and then a complete respite from cattle produced a healthy, self-sustaining ecosystem.
I asked him about the controversies surrounding Savory. "If I had most of the credible range scientists getting together to write papers saying I was full of crap, I'd do some real soul-searching," he replied. "As a scientist, that's what you'd have to do. But I don't know if he is a scientist."
Die Observationen zu Savorys Methoden in diesem Text decken sich mit dem Eindruck, den ich selbst hatte.
Ich hab dieses Gerede schon vor ueber 20 Jahren gehoert. Da gab es die Yeoman Brueder in Australien, die behaupteten, das Waelder schlecht sind fuers Klima weil einjaehrige Pflanzen schneller wachsen. Und das wir deshalb besser Weideland anlegen. Das ganze nur um ihren Tiefenpflug zum Auflockern von Weideland zu vermarkten.
Dann gab es die Carbon Farmers of America und die Carbon Farmers of Australia, die versucht haben, einen Handel mit Emissionsgutschriften zu betreiben fuer Farmer, die durch ihre besondere Methoden mehr CO2 sequestrieren. Dabei wurde nur das Ziel dargestellt zusammen mit Interviews von Farmern, die sich ein Einkommen von dieser Firma erhofft hatten und dementsprechend gluehend ueber ihre Methoden geredet haben. In all den Jahren habe ich nicht erfahren, ob jemals ein Gramm zusaetzlich an CO2 sequestriert wurde. Savory kommt offensichtlich aus derselben Ecke.
Es ist schade, dass sich Menschen jahrelang solche Videos reinziehen. Geht besser auf die Wiese und fuettert die Kuehe.