Cattle and the Fate of the Earth, Part II

In last week's post on how livestock grazing will destroy or save the earth, I took a look at the widely ranging field of opinion on climate change and domestic grazing--from the selective truths of Cowspiracy to Tim Flannery to George Monbiot, Hunter Lovins, and Alan Savory.

I ended that post with a promise to provide a bit more insight on Savory's system, which we will get to in short order.

But I want to apologize off the top to anyone who is looking for an unqualified endorsement of Holistic Management (HM). You won't find it here. But neither will you find an out of hand dismissal of it as a viable method of managing grassland. From what I have read on the topic, any management system--continuous, all-season grazing, short-duration intensive grazing, or other forms of rest-rotation--can, in the right hands and with the right stocking rates for the site, produce good results for both beef production and ecological conservation values.

As for the larger claims made by Savory and HM enthusiasts, I am going to lean a little to the skeptic's side of the fence. I am neither a grassland biologist nor a range ecologist nor a rancher. Though I do share some native prairie that we let the neighbour's cattle graze from time to time, I cannot claim any personal experience or knowledge of grazing systems.

I took this photo in the ditch just outside the fence where the cattle in the top photo were grazing--there were lots of lady slippers outside the fence but none inside. Grazing is an important element of grassland management, but there are species that do not do well under intense grazing pressure.

So why am I skeptical of Savory's claims? First, because it just sounds too good to be true and that always makes me suspicious. I can readily believe that in the right landscape with the right soil and climate, a skillful and hard-working grass manager may well increase her production by using HM methods. But I have trouble believing that any system--especially one that has never been proven by independent studies to work on a wide range of grassland eco-types--will sequester as much carbon, and improve water infiltration as Savory claims it will in his Ted talk.

Second, I worry because I do not hear many HM enthusiasts distinguishing between native and non-native grasslands--a vital distinction from a biodiversity conservation perspective. And I worry about people using HM on native grasslands, especially in areas where the land is not terribly productive or resilient.

HM and other methods of "mob grazing" or "short duration grazing," may well be effective for restoring cropland to perennial grasses--if you have the right watering infrastructure and enough labour and skill to make it work the way Neil Dennis has in Saskatchewan. But I have yet to hear of any reports showing that it improves the range condition or biodiversity of native prairie. Until we see at least one independent, peer-reviewed study showing increased biodiversity on native range, increased carbon retention, and improved range condition, I am not sure why we should get enthusiastic about the Savory method and its offspring.

Finally, I am skeptical because people I respect are skeptical. Chris Helzer, whose Prairie Ecologist blog is always even-handed and fair, had this to say about HM and Savory.

Closer to home, I asked Sue Michalsky, Eastend rancher with an MSc in range management, and a director of Ranchers Stewardship Alliance Inc. (RSAI), what she thought of Holistic Management. Here is her response:

"There are several peer-reviewed studies, including a Canadian study with Darcy Henderson as one of the authors, that demonstrate no benefits to biodiversity, carbon storage or even grass productivity associated with high intensity, short duration grazing. To my knowledge (and I watch for these), there are zero peer-reviewed studies that demonstrate a benefit to any of these factors from the use of high intensity, short duration grazing. Despite this lack of evidence, there is an ever-increasing number of people including ranchers, agrologists and environmentalists who are believers. 

What is strange is that the holistic followers view it as a panacea. That is unusual among livestock producers and agrologists. Some of my peers think that holistic grazing may be having a positive effect in severely overgrazed, tame grasslands further south where winter dormancy is not such a huge issue. But not for the reasons that Savory and HMI advertise. Simply because a very short grazing period gives grass a long period of rest that it never had before and tame grasses have been bred to grow aggressively given the opportunity.

The rational viewpoint is that grazing can be good or bad for native grasslands, as can fire. Most of the RSAI ranchers run moderate stocking rates and may rotate pastures, but usually in a low intensity situation. In wet years, they utilize less of the production than they could get away with which likely means that some carbon is sequestered in those years. In successive dry years they may utilize more grass than what is produced, also using stockpiled grass from previous years. However, it is likely that carbon is NOT sequestered in these years and may even be released as root systems die back. There is some research supporting the variability of carbon sequestration on native grasslands and I think it is by Dr. Ed Bork from U of A. 

Historically speaking, it is obvious that grazing and carbon sequestration are not mutually exclusive or grasslands in the northern great plains would not have been able to sequester such huge carbon stores in only a few thousand years. However, the bison did not graze every acre every year. I believe every 8 to 32 years was the estimate for the northern mixed grassland. In addition, it is fallacy that the bison mob grazed. There is a Nature Conservancy (TNC) study (unpublished) that looks at explorer records and aboriginal knowledge to get a handle on this. In most cases, the bison roamed locally in small family units of 20 to 50 head. They did not migrate, but they did move in large numbers away from drought and harsh winters. And possibly away from disturbances such as lots of homesteaders. Under historic conditions, high intensity, short duration grazing rarely occurred. And under those conditions, grasslands stressed by drought or winterkill of grasses did not get grazed, thereby reducing the chances that soil-stored carbon would be released.

I am not saying there are no positive effects from grazing. There are. Grazing stimulates grasses to increase primary production in the same way that exercise builds human muscle and makes us healthier....to a point. In both cases there is a point beyond which the stress produces negative results. There are many studies that demonstrate increased production under grazing - an S curve model - and even some long term studies which demonstrate that production and therefore economics are better under moderate grazing than either heavy or light grazing / non-use. Moderate grazing stimulates the presence of forbs in a grassland when the climax condition is a few species of old growth grass. Many grassland wildlife species including insects respond positively to moderately grazed habitat.

To make sense of when grazing is good or bad, one need only go back to the range management basics: timing, intensity and duration. Timing in the northern great plains where winter dormancy is an overriding factor means 'at what point during the growing season'. The benefits of deferred grazing are well established. The rule of thumb is that for every day you defer grazing in the spring, you gain 2 - 3 days of grazing in fall or winter. Duration (the length of time) and intensity (the number of animal units per area) are interdependent. This is where Savory is right. He teaches that what is most important is the rest interval. In the northern mixed-grass, there are two relevant measurements. Jim Romo has some research that shows native grasses in SK need more than 400 days of rest to fully recover their root systems from a grazing event. SK Ag keeps referencing some research that I have been meaning to track down that says 'between 50 and 70% of leaf material must be left behind to continue plant growth on native grasslands'. 

In the end, Alan Savory may not be wrong in what he preaches, but preaching is different from practice. The problem is that it is a delicate balancing act to ensure that native rangelands have sufficient rest and recovery before another grazing event and most livestock producers do not have the flexibility or the intricate knowledge required to ensure only ever positive results."

birds like this LeConte's Sparrow need moist tall grasses and sedges. They would not be able to nest in an area levelled by "mob grazing." 

After last week's post many people contacted me with comments on Savory, grazing management and carbon sequestration. One reader recommended a web page and new book on carbon farming--which you can find right here.

Another reader used this web site on grass-fed beef to make the excellent point that if we would keep our livestock out of feedlots and on grass, the results would be better for storing carbon and protecting water.

Thanks to those who wrote in with their thoughts. This is an important discussion if we are going to find ways to make animal agriculture work in a carbon-conscious world where biodiversity and source water protection are public goods that we must all share responsibility for.