Mob grazing is attracting a lot of attention lately, especially among people who are fans of other intensive rotational grazing systems. Usually, mob grazing is an extreme form of rotational grazing, in which high numbers of cattle are grazed in very small areas – for very short periods of time. Often, cattle are given a new area to graze daily (or more frequently) and formerly grazed areas are allowed to rest for several months or more before being grazed again. The intensity of grazing in individual paddocks varies by the rancher or grazier running the system. In some cases, that intensity can be very high. Proponents list off multiple benefits to the land from mob grazing, including increased soil organic matter, weed control, and “grass health”.
My purpose for this post is not to make any kind of final judgement on mob grazing, but to point out a few things that concern me from a prairie conservation perspective – and perhaps slow down the mob grazing bandwagon just a bit. Those of you who have followed my blog for any length of time are aware that I’m generally a fan of using grazing as a tool for prairie management. There is abundant data showing benefits of grazing to wildlife habitat and plant species diversity, both on my own sites and others. I don’t advocate grazing for all prairies, but I do think prairie managers should look at grazing with an open mind, and consider how it might help them achieve specific objectives.
In the case of mob grazing, however, I’m very concerned about what I’ve seen in my (limited) personal experience, and even more concerned that I’ve been unable to find ANY published research on the topic. I think there are good reasons to cautious before buying into anything supported only by testimonials, so I’m nervous about how strongly mob grazing is being promoted. To be clear, I’m approaching this from a prairie conservation perspective, not a graziers perspective, so my thoughts should be taken in that context.
Impacts on Soil Organic Matter
Returning to the purported benefits of mob grazing, let’s look at soil organic matter first. While there are various explanations of how mob grazing affects organic matter in the soil, the general idea seems to be that mob grazing cattle eat about 60 percent of the standing vegetation and stomp the remaining 40 percent into the soil. Thus, soil organic matter increases and becomes more productive. This has never jived with my understanding of soil organic matter (soil carbon) production, so I checked with four prominent scientists around the country who study soil nutrient cycling, including soil carbon. When I asked them if the claims from mob grazing advocates made sense, their response was unanimous and strikingly blunt. To quote one of them, “That’s totally bogus”.
In reality, soil organic matter is formed mainly by belowground processes, including root decomposition, root exudates, and mycorrhizal carbon inputs. In prairies, a substantial percentage of plant roots are abandoned to decompose each year and replaced with new roots. Those old roots provide organic matter in abundance, and more importantly, that organic matter becomes a stable part of the soil profile – and is added to and enhanced by the other two processes listed above. My panel of experts said that stomping vegetation into the soil might provide a slight and temporary increase in organic matter near the soil surface, but that it would be unstable and wouldn’t last long. It’s the stable supply of organic matter deeper in the soil profile that actually drives plant productivity, and that supply comes from plant roots themselves. In fact, the experts suggested that the kind of vegetation stomping I asked them about was likely to have fairly negative consequences. They thought that soil compaction and disruption of soil structure as a result from heavy trampling would probably decrease -not increase – plant productivity. None of this means soil organic matter can’t increase under mob grazing, but any increase would be due to the same belowground processes listed above.
As an aside, I’ve heard some rotational grazing proponents talk about why fire is a bad thing in grasslands because it burns up vegetation that would otherwise be incorporated into the soil – thus, fire decreases organic matter in soil. This is clearly not the case, and has been thoroughly dismissed by multiple researchers who have shown stable or increasing levels of soil carbon under frequent fire.
Impacts on Weeds
A second purported benefit of mob grazing is weed control. First, of course, we need to define what a “weed” is. As has been discussed in this blog before, it’s a very subjective term. Generally, there are two categories of plants that people consider to be weeds; opportunistic plants that take advantage of weakened dominant plants (e.g. ragweeds, annual grasses, and other short-lived rapidly-reproducing plants), and truly invasive species that are non-native to a particular ecosystem and become dominant to the expense of other species. Let’s look at each of those two in the context of mob grazing.
If opportunistic plants are the weeds of concern, it seems unlikely that mob grazing would help suppress them. Mob grazing proponents say that the high grazing intensity makes cattle eat – or stomp – all plants in the paddock, thus removing the weeds that cattle wouldn’t normally eat. Unfortunately, while that might be true in the short-term, it’s the recovery from that grazing that’s more important. Opportunistic plants are successful because they can recover from intense disturbances faster than others. Big strong grasses are the biggest competitors to those “weeds”, and those grasses are greatly weakened by severe defoliation. Until those grasses and other major perennials recover their dominance of the plant community again, opportunistic plants run rampant. If the time until the next grazing bout allows those grasses to fully recover their vigor, those opportunistic plants will eventually fade – but only until the next grazing bout. In other words pulses of intensive grazing will result in flushes in opportunistic plant abundance as well. I would argue that most opportunistic plant species are non-threatening in any regard, but if suppressing them is an objective, the smart strategy is to strengthen the surrounding plant community.
It is possible to reduce the abundance of opportunistic plants in pasture through periodic moderate grazing. Mob grazing that moves animals through paddocks quickly enough that the lower leaves of grasses are left ungrazed, could actually stimulate the matrix of grass to thicken, due to increased growth of rhizomes and tillers (stems). Higher density of grass that chokes out other plants might be seen as beneficial from a grazing standpoint if grass is the only thing the grazier wants – especially in tame grass pastures. However, from a plant diversity and wildlife habitat standpoint in native praireis (the perspective I’m coming from) it’s certainly not a good thing.
In the case of truly invasive plant species, the story is a little more complicated because every invasive species has its own unique strategy for becoming dominant. In most cases, the invasive plant has been released from pests and pathogens that suppressed it in its native habitat, and the plant species in the community being invaded have not had time to develop strategies to combat it. In some cases, concentrating cattle grazing into a relatively small area can lead to the defoliation of an invasive species that would otherwise avoid being grazed. If that ability to remain ungrazed while surrounding plants are weakened by grazing is the primary way that invasive plant gains dominance, that defoliation could reduce its spread. However, in most cases, the story is much more complicated, and invasive plants use a more diverse mixture of advantages and strategies to force their way into plant communities. Weakening the surrounding plant community through something like mob grazing is likely to increase the spread of invasive plants rather than decrease it. I would use extreme caution when testing mob grazing as a tool for controlling invasive plants.
Impacts on “Grass Health”
When I first heard the claim that mob grazing increases grass health, my initial response was, “I didn’t know the grass was sick!” It’s hard to glean from the various claims what the specific benefits to grass health are, or how that health is defined. I also have a hard time understanding why mob grazing would provide any benefits to grass plants that other kinds of grazing systems don’t – as long as those other grazing systems include a mixture of grazing and rest periods. As with all other plants, I think its important that grasses are allowed to flower and produce seed periodically, and mob grazing may do that (depending upon the length of the recovery period) – but many other grazing systems do the same, without some of the potential risks I see from mob grazing. In some cases, I think grass health refers mostly to soil organic matter, which I addressed earlier. Until I hear more specifics about how mob grazing affects grass health, I can’t really respond more.
Other Benefits – Livestock and Wildlife
I’m not sure how this system can be good for livestock performance – especially when paddocks are grazed very intensively. Forcing a cow to eat plants it wouldn’t normally eat seems to override the cow’s effective inherent ability to optimize its own diet. Why would it benefit a cow to eat plants – or plant parts – that are not the best available choices within a larger pasture? I have the same concern with some other rotational systems, but this takes it to an extreme. In order to gain weight, cattle test and refine their forage intake on a daily basis, constantly adjusting what they eat based on the phenology of the plants. Under extreme mob grazing, cattle have to eat the least palatable plant species and plant parts along with the good stuff. I don’t understand the logic of that strategy, and, in fact, even some proponents of mob grazing admit some “inconsistency” in livestock weight gains. The only research project I know of that has started looking at weight gains and other aspects of mob grazing has found very poor livestock performance during its first season (2011). Again, I’m not saying that cattle can’t gain weight in mob grazing systems, only that I think people should be cautious about accepting that claim.
An additional benefit promoted by mob grazing advocates is that the system increases the carrying capacity of pastures. This is a tricky claim to evaluate, because it depends upon your definition of carrying capacity. On the one hand, it’s surely possible to increase the number of cattle in a pasture, and claim that the carrying capacity of the pasture is now higher – though you can do the same with any grazing system. On the other hand, a more formal range science definition of carrying capacity is “the maximum animal numbers which can graze each year on a given area of grassland for a specific number of days without inducing a downward trend in forage production, forage quality, or soil.” In other words, carrying capacity isn’t just the number of cows you can put in a pasture, it’s the number of cows that doesn’t degrade that pasture over time. This latter definition can only be evaluated by long-term data, which doesn’t currently exist for mob grazing systems.
From a wildlife perspective, it’s hard to say what the impacts of mob grazing would be. Much depends upon the size of the grazing area, the intensity of grazing, and the length of recovery time. Clearly, very intense grazing that stomps vegetation into the soil will have extremely negative impacts on any nesting birds or invertebrates in that immediate area. On the other hand, the majority of the site is always in a recovery phase with no active grazing, so there should be a nice diverse mixture of habitat conditions available. My guess is that mob grazing could be beneficial for many wildlife species – in terms of habitat structure – depending upon how it’s set up.
A bigger issue is that of plant diversity and overall ecological resilience. While I think that many people overstate the potential negative impact of cattle grazing on “sensitive” prairie plants, including some rare wildflowers, the impacts from mob grazing on those plants could be a legitimate concern. I think all prairie plants can put up with some degree of defoliation, even when it’s repeated multiple times over a season or two, but I think we would need some careful study of how intensive mob grazing impacts could affect prairie communities before introducing it as a potential management tool. The potential soil impacts of more extreme versions of mob grazing are particularly concerning. I’m sure historic prairies were exposed to high concentrations of bison grazing, but I have a very hard time believing that bison stuck around one place and grazed so intensively that they forced themselves to eat substandard forage. Until I see some well-supported research on the recovery of plant communities, I’m not comfortable exposing native prairies to that kind of severe disturbance.
I’m not against grazing in prairies, and I’m not even against mob grazing per se. There may be circumstances under which mob grazing, or some variation of it, could be used to achieve certain objectives. In tame grass pastures, for example, where tilled land has been converted into forage grasses and the sole purpose of the site is to feed cattle, mob grazing might be worth a try. In those kinds of pastures, the native plant and soil communies have already been severely altered, so out-of-the-box experiments have a relatively low risk of making things worse. I still don’t buy most of the claims about the purported benefits to livestock, grasses, or soils, but as long as cattle producers test the system with eyes wide open, who am I to say they shouldn’t?
However, in native prairies and rangeland, I think the potential risks of the more extreme versions of mob grazing far outweigh any purported benefits, at least until there is some actual research that says otherwise. We have abundant evidence that many aspects of native prairie plant and soil communities do not recover well from tillage, and mob grazing impacts can come uncomfortably close to those of tillage, in my opinion. There are countless other options for using grazing – even intensive grazing – to suppress dominant grasses, control invasive species, create wildlife habitat structure, and achieve other objectives. I strongly support active experimentation with grazing techniques that could help us with our numerous prairie conservation challenges, but with grazing, as with anything else, it IS possible to have too much of a good thing.
For those interested, here are two links to relevant research papers on soil carbon (organic matter) and fire/grazing, followed by three non-scientific reports on mob grazing.
Kitchen et al, 2009. (Effects of fire on mowing on soil carbon and other factors.)
Johnson and Matchett, 2001. (Effects of fire and grazing on belowground processes)
An even more glowing review of mob grazing
Great thoughts Chris! I’m wondering if ‘mob-grazing’ events have similarities to fires and therefore can provide alternatives in areas where burning is not possible. It seems to me that non-selective grazing can help keep the ‘candy’ and high palability plants in the grassland since they are subject to the same above ground dieback as the lesser palatable plants.
Hey Nelson, thanks. I think grazing can do some of the same things as fire, though extreme mob grazing would also have soil impacts that fire wouldn’t have. Still, using intensive (but not THAT intensive) grazing can certainly remove vegetation much like fire. There are some obvious differences, but depending upon the objectives you might be able to achieve similar things with both. In terms of the candy, or very palatable plants, short-term intensive grazing might have some advantages over continuous season-long grazing, but I don’t think mob grazing would have any advantage over any other system that defoliates those plants and then allows them to recover again. Other rotational systems, patch-burn grazing, and lots of other variants of grazing/rest systems can maintain high palatability plants just fine.
In a certain way, it seems logical that by defoliating all the plants at the same time (including less palatable ones that typically go ungrazed) you might tip the balance toward those palatable plants a little more than grazing systems in which only the more palatable plants are grazed. That’s not been my experience, however. It’s not so much the grazing, but the recovery that matters most. Most of the palatable plants people are most concerned with are long-living slow-moving plants that can dominate nearby plants – or at least hold their own – just by moving steadily and incrementally outward. Leaving those palatable plants ungrazed (or haying after they’re done blooming) is often the best way to encourage their continued presence and even increased abundance. Defoliating them makes them shrink back, and even if the rest of the community is also defoliated, the palatable plants are usually not the ones that recover first, so they don’t gain an advantage from that (unless everything else is defoliated EXCEPT them, which of course doesn’t happen). It’s also important to know that those palatable plants can take an awful lot of grazing, and still persist, or even thrive, as long as they get a rest period now and then. Stories abound of eastern gamagrass plants that pop up after decades of no one seeing them in heavily grazed pastures… Many (most?) conservative forb species do very well under periodic intensive grazing, with rest periods in-between.
Anyway, the idea of “leveling the playing field” to favor plants that often get grazed first usually doesn’t pan out well – but it’s gotten a lot of people to jump on the mob grazing bandwagon anyway.
I appreciate your skepticism. I think that Mob Grazing seems like a bizarre concept as well. I think that it is premised on the idea of buffalo herds moving though an area and absolutely hammering it, then moving on. It seems super labor intensive and doesn’t permit animals to get much exercise. Some people love it and swear by it on irrigated pasture. But, I honestly cannot see it working on short grass prairie. The idea, as far as I understand is to graze in late phase two, and three, and never knock the grass or plant back to phase 1 or early phase 2. And as a result, the root system is supposed to respond. Also, the theory is more like take 50%, leave 50% (not 60/40). It is an interesting idea, but, I am glad that you think that it sounds a little weird. I went to a Jim Gerrish grazing seminar at the Quivira Coalition annual meeting. He had some interesting points. Check his stuff out if you want.
Thanks Reba – great to hear from you!
I always appreciate your balanced thinking, Chris. Thanks for pulling this all together and laying it out.
Hi there, Marva! Thanks – good to hear from you.
I cannot comment on the effects of mob grazing on grasslands but I can say repeated mowing favors cool season grasses in the northern prairies. Mowing and mob grazing do have similarities in that all growing vegetation is removed and in the process removes the shading needed for weed control. Only burning every third year is a great tool in controlling Canada thistle, it does poorly in a highly shaded environment, Perennial sowthistle is the same.
Sticky, compacted, high Magnesium soils favor thistle, overgrazed dairy pastures in MN have only a robust crop of Canada thistle to show in the summer. Pastures actually become nutrient deficient over time and do take some inputs to keep them healthy. Cattle don’t break out of fences because of stubborness, they want to get to the other side for more nutritious grazing as shown by Dr. William Albrecht.
My first thought was, “Mob grazing would be about as damaging as turning your pasture into an ATV recreation area.”
I do think grazers help add diversity. To me the benefit is mainly a structural one for wildlife and the addition of a new trophic levels to the ecosystem. The manure may not directly help increase soil carbon, but there is a whole compliment of organisms that benefit from it. The fact that cattle can utilize cellulose and return a portion of this energy into the food chain can increase the amount energy that is available to the entire system. The larger the available resource, the more species the ecosystem can support.
In addition to manure, the protein source grazers create is utilized by a whole host of species. I am one of them. I enjoy a good steak myself.
However, if grazing occurs to the point that plants’ ability to harness energy is reduced more than the energy that grazers are able to capture from cellulose … then the resources available to cattle, and the entire system, has been reduced. Consequently, one would expect diversity to suffer. I expect this management regime will show a reduction in species diversity over time. This reduction in diversity will result in less energy being recycled within the system. The long term result will most likely be a lower productivity for the pasture.
It will be interesting to see the results of objective measurement for this management regime. The suggestion that they are using these stocking densities in Africa is really not a supportive argument to me.
Thank you for pointing out that definitive data do not exist to support “mob grazing” and that cautious steps are necessary when implementing such a practice. Because, some grassland types (shortgrass as one example) indicate negative effects with such a treatment, it then stands to reason that a mid- or tallgrass region during a period of excessive dryness and/or heat might also experience a similar negative effect. Unfortunately, on a daily basis, careful attention to what is happening-on-the-ground is not always possible. Given the vagaries of busy people and their lives it would be very easy for one to cause unintentional harm within a very short period of time.
Unfortunately, it is difficult (or impossible in some instances) to reconstruct and make anew something that has been lost.
I’m interested in your thoughts about mob grazing as I’ve been working on my own little project to see how I might use something kind of like this to rehab a 500 acre pasture with some severe weed problems.
One of the differences in what I’m doing is that I’m working with cattle that I trained to eat weeds. In 2004, I developed a way to teach cows to eat weeds in 10 hours over 7 days. It works because, as it turns out, weeds are just as palatable as grass, and often even more so. That’s kind of surprising to a lot of people, but I have a slightly different understanding of palatability based on decades of research done by Fred Provenza and his colleagues at Utah State University. What they discovered is that palatability is a function of the nutrients and toxins in a plant in combination with the animal’s individual needs. Animals choose what to eat based on subconscious, internal feedback, increasing intake of foods high in nutrients, decreasing when they experience toxins in the plants, and then adjusting to get the right amount of protein and carbs.
Over the past 8 grazing seasons I’ve trained groups of cattle to eat Canada, musk, Italian, bull, distaff, sow and milk thistle, spotted, diffuse and Russian knapweed, whitetop/hoary cress, leafy spurge, and more. I have multiple reasons for wanting cows to do this. First, I figured, like you, that one of the reasons weeds were increasing while our “preferred species” were decreasing was pressure on the preferred. In my experience now, cows grazing weeds spreads the pressure to the weeds, and reduces pressure on grasses. Second, herbicides are expensive and don’t really seem to be working, and they can cause harm to some of the species we’d like to protect, further reducing competition. Third, lots of ranchers just aren’t interested in big fencing projects, and in the arid west, the kind of fencing required to do a mob grazing project is really significant.
I have first hand knowledge about this fencing problem from my 3-year, WSARE funded project in Boulder County, Colorado. The herd I’m working with has animals I trained to eat late-season diffuse knapweed and dalmatian toadflax back in 2007, a couple generations of off-spring, and some animals that learned from the original trainees. The purpose of the project is to manage grazing to see if we can use the weed-eating cows to reduce weed populations and increase “preferred species.” I’ve been interested in the buzz on mob-grazing, not knowing if it works or not, so I’ve done some experimental pastures, though I’ve never grazed to the degree shown in some of your pictures here. Actually it’s been more of an effort to “focus” the animals.
Every year I build about 3 miles of fence, and what I’ve learned is that fencing is time-consuming and very difficult in this area. My cooperating ranchers just think I’m crazy, and I agree with them now. I’ve also found that my trained animals actually do a great job of focusing themselves. They really seem to prefer the weedy areas, particularly what was once a 200 acre prairie dog town that emptied when they all died of the plague in 2009. In fact, in 2009, they ate very little grass and really focused on weeds. That trend changes a little each year, depending on what’s available in the pasture. But it makes sense to me knowing that they are picking the high protein plants to increase weight gain. They have also decided to try all kinds of plants that I never taught them to eat. You can see more about what I’m learning at my web site at and .
I have one more year in my grazing project and I have to say that I’m not sure I’ll come up with anything conclusive about the natural forces at work. We do have less knapweed and more grass, but three years just isn’t much time in the grand scheme. I’ve already concluded that while the cattle can be used to modify the vegetation, and are particularly good when they’ve had a little education. The problems I encounter aren’t cow-related, but human related and those have kept me from really accomplishing what I had hoped to.
I’ve taken up enough of your time, but I just wanted to make contact, because I thought we had some thoughts in common and that you might be a resource that I could share information with to maybe make sense and paint a better picture of what’s going on.
Keep up the thoughtful writing!
Kathy – thanks for the reply. I’m glad to hear you’re experimenting. I know others that have had good luck training cattle to focus on particular weed species (and some that have failed after many attempts to get them to focus on other species, especially sericea lespedeza). I think that kind of training can be a good tool. However, I also think it can be a little deceiving when cattle or other livestock are eating the tops of perennial weeds, because some people assume that the weeds have been controlled. There are some very good examples where years of this kind of focused grazing has made a pasture look really good, and then the grazing was changed up and the weeds reappeared at the same density they’d been at originally (e.g, http://er.uwpress.org/content/24/3/145.abstract). Doesn’t mean it’s not a good idea, it’s just important to have realistic expectations. At least some invasive plants – like many native plants – can withstand some serious levels of repetitive grazing just fine, biding their time until they get a shot at freedom again. Grazing them and preventing them from making seed can be a great way to keep them from getting worse while applying other treatments, but it may or may not achieve long-term control on its own. I would guess that in the case of invasive plants that are short-lived and/or rely heavily on seeds for their spread, repetitive grazing would be a great option. For others that are long-lived and/or rhizomatous, it may be less effective. And the story is surely more complicated than that…
Regardless, it sounds like you’re doing some good innovative thinking – keep up the good work! And thanks again for the thoughtful response.
This is a case of not understanding all you know about mob grazing. No good manager limits his stock’s groceries or hurts his resource. It seems we all have the same misconception when first learning about mob grazing. We assume its all about the smashing down of vegetation, which it is not. It is simply exposing as many plants as possible to grazing for the shortest possible time. Animal performance is the captain of this ship, so you would rarely see the kind of trampling pictured here. In fact many times it will be the opposite with much standing, but clipped grass left behind. This grass recovers quickly and maintains its vigor. It is simply a way to more effeciently utilize the resource. It does require more of the stockman and may not always be feasible.
John, I appreciate the comment. I’m sure there is a wide range of applications of mob grazing, as with other grazing systems. What I can tell you is that the example in my photos is from one of the leading advocates of mob grazing in the central U.S. Regardless, as I said in the post, I’m all for grazing and innovation, and if people find a way to make something like mob grazing work for them – excellent. In addition, my main emphasis is on potential impacts on native prairies, not on tame grass pastures, which is where, I think, most mob grazing is taking place.
A friend sent me your blog, and I felt I should respond to some of your thoughts.
Regarding fire, there are humid climates and species of grass and trees where fire plays a beneficial role when used carefully. Prairie ecosystems can receive some small benefit from fire every 50 years or so, but frequent fire is extremely damaging to native prairies, such as been and is practiced in the flint hills of kansas and the osage area of Oklahoma, where the ecosystem is on the verge of collapse. Fire is destroying the soil there as well as the wildlife. Research I have read shows a slight 45 day increase in growth from making the nutrients tied up in plant materials available by burning, followed by a huge decrease in productivity after that is gone.
Regarding mob grazing, I don’t know where your pictures come from, but they are pictures of severe over grazing, which is not the same thing as mob grazing. Those who are serious practitioners of mob grazing are not baring the ground like that, they are leaving plenty of litter on the ground, moving frequently enough to get good animal performance, and both plants and animals are doing well.
It is not the trampling of plants into the soil that increases organic matter and builds soil. It is the litter on the soil that keeps the soil moist, maintains a good soil temperature, creates good germination sites for more grass seedlings, and eventually decays into good soil as more litter is added over time just like mulching a garden. The concentration of dung and urine, feeding the soil microbes, and speeding the process of decay, so soil can be be improved much faster than at low stocking rates. It is also the pulsing of plant roots which die and regrow as the plant regrows that improves organic matter.
You are correct that mob grazing will not eliminate unwanted plants. But most people who have been managing grazing and has any training at all knows that we manage for what we do want, not for what we don’t want.
In a prairie ecosystem grazing is the best tool to use to make improvements, but it must be managed correctly. Mob grazing is just managing time and space as is any other form of grazing, the skill of the grazier determines success or failure, not the terminology.
Kim, Thank you for your thoughtful reply. A few responses.
Fire: I’d be interested to see the research you mention about fire “destroying” soil. I included a couple of papers at the end of my post on the topic (from the Flint Hills), and I would not interpret the results of those and other research projects I’m aware of as having long-term negative impacts on fire. I do agree that the kind of frequent large-scale application of fire that happens in some parts of the Flint Hills can negatively affect some species – prairie chickens, for sure, and some herps and invertebrates. Too much of a good thing again. Fire every 50 years in most prairie ecosystems would create a high probability of invasion by trees and other problematic species. Doesn’t mean you could mitigate some of those issues in other ways, but I think there’s strong evidence for the importance of fire (and fire/grazing combinations) for maintaining ecological processes.
Mob Grazing Photos: I agree with your interpretation of the photos as overgrazing. However, they’re taken at a pasture managed by one of the leading proponents of mob grazing in Nebraska, someone who has been very influential in others starting to try mob grazing. I hope you’re right, and this is not typical of mob grazing elsewhere, but it’s one of the primary models around here, and matches what I have seen promoted in magazine articles. As I’ve said in other responses here – and in the original post – I’m not trying to say all mob grazing is bad. I think the more extreme version has negative impacts on native prairie sod. If it works for you, great.
Soil organic matter: I don’t know that I would give the soil litter as much credit as you do for building germination sites, but it certainly helps keep soil moist and regulates temperature. I get excellent germination of grass and forb seedlings on bare ground when we restore cropfield to prairie, so germination can happen successfully without that litter, but that doesn’t mean it’s not important. The research is clear that the plant roots (as you mention) are the primary creator of soil carbon.
You’re absolutely right about the importance of the skill of the grazier. The system is less important than having a manager who evaluates and adapts management to meet objectives and match conditions. Sounds like you’ve found a method that works for you – and I congratulate you.
Thanks again for the reply.
I just wanted to support your comment about not giving litter that much credit for helping seeds germinate. The ability of litter to prevent seedling establishment is one of the primary reasons people mulch gardens. A layer of organic material keeps the weed seeds from establishing.
As Kim mentioned, the litter does insulate the soil. However, it does it at the wrong time. It keeps the soil cool longer in Spring slowing plant growth. During the warmer months the vegetation has already developed. This vegetation shades the soil helping to keep it cool. I am sure leaf evaporation also plays a large role.
I have read research that gives credit to the rapid growth following fire to a release of nutrients. I have also read other research that shows this small recycling of nutrients is not a significant factor. I am sure there are impacts on vegetation. However, I think other aspects like water availability, light, and increases in soil temperature are more important. The main reason growth rate is quickly reduced after the first flush following fire is competition for light.
One misconception I see from a lot of people discussing mob grazing (or any type of land management) is the idea that a formula is all we need for success. Eat 60% Trample 40% and everything will work out fine… This is one of those formulas. Grazing livestock with widely different preferences and needs in widely different ecosystems with such a formula is a set-up for disaster. Many graziers know this, and many more should. If someone ever gives you a grazing formula for success, in the back of your head remember, thats their formula for their specific pasture this season.
Grazing livestock is more of an art than a science and we must realize that the cutting edge of grazing innovation is never highly research because of the need to continue to adjust variables based on the awareness of the changing variables around us. For instance: Grazing cattle from the South to the North (via paddock rotation) during a cold rain from the North is not the same as grazing cattle from the North to the South during a warm rain from the South. These variables may not change much overall, but they express my thought. The amount of important changing variables is limitless. Everyday is different for everyone. My neighbor shouldn’t graze exactly the way I do, there is that much difference across fences.
That being said, it is very important that we all continue to do our own research on our own pasture. Not knowing what happened last year will hinder your ability to do better this year. We should also learn what others around us and far off are doing. This allows us to keep our imagination fresh and bounce ideas.
Concerning bison: I remember hearing/reading about horsemen riding across the prairie and having to cross an area where a huge herd of bison had traveled. If I remember right they were lucky to have brought grain for their horses because there wasn’t any forage to graze their horses. Once you think about a herd of a Million Bison, its not far fetched to think that they didn’t leave behind much.
Concerning research: Be careful what you wish for. I know guys that have read research showing that continuous grazing has no differing affect on pasture than rotational grazing. That maybe how best to read that particular data, but I still don’t buy it. Ask any grazier that uses some type of time controlled management with rest periods and all will tell you that it is worth it. I studied Zoology in college and have come to the conclusion that you can always find what you want to find. Even truly objective science can leave out very important variables.
And remember, when you are on the cutting edge, you might bleed a little.
Thanks for the post.
Grady – Lots of good points. Bottom line: if what you’re doing works for you and your land, and you’re being honest in your evaluation – keep doing it. And Amen to your point about no formulas for success. I agree completely.
Bison – no doubt there were huge swaths of land grazed very short by bison in some years. In fact, much of the patch-burn grazing I’m experimenting with has similar appearance. I’m not at all against that kind of periodic intensive grazing. I don’t like the kind of overgrazing shown in my photos.
Research – the Briske et al. paper you mention did a good job, I think, of looking across the board at whether there are broad differences between continuous and rotational grazing (though they used an unfortunate snarky tone at times). It was good science. It doesn’t mean that rotational grazing can’t provide excellent results, and one of the authors of that paper that I know is careful to point that out when talking about the paper. My take away from that research is that there are lots of good ways to grazed livestock that can lead to success – for the rancher and the land. No one system is automatically better than another. You make the same point, I think.
Thanks for the reply!
I think people who graze this heavily give cattle a bad reputation. It is crazy to graze beyond the intercalary meristems. You are preventing the leaf from recovering and forcing the plant to resprout from tillers. I would not even do this to a blue grass pasture. If you take all the leaf material the plant possesses, then you are severly increasing the time needed for recovery.
The only instance where mob grazing seems useful is when the objective is to destroy the vegetation. They do something similar to control the invasion of wood species in utility corridors in the Northeast.
Great article. Thanks!
Hi Chris. Managed grazing is having cattle at a given location for a given reason for a given point of time. High stock density grazing can be an effective tool in a graziers tool-box. Calling ‘mob-grazing’ an extreme form of rotational grazing is certainly a misnomer or is just silly vernacular. High stock density grazing can be a very practical use in the landscape. HSD grazing is predicated on rest and residuals, both of which are high (not what is in your pictures). Many have mentioned the positives of this above (Kim Barker). One positive I see is adding a great deal of manure and urine uniformly into a paddock. Which brings me to question your pictures. You said on Kim’s response this was a ‘mob-grazing’ proponent’s farm. Perhaps so, but even running 50K (not hsd grazing) manure deposition every few square meters is normal. Running 200K will perhaps have a manure deposition every square 1.5 meters (estimates). Your photos show very little manure deposition and of course no residual. It looks like a poorly managed over-grazed paddock, it is not managed grazing. If i saw what you did, I would question the practicality as well. Thanks.
Thank you Jason. I’m glad to be hearing from people who are pushing back against the kind of “mob grazing” in my photos and calling it poor range management. In terms of the vernacular, I described mob grazing as an extreme version of rotational grazing because it increases the stock density and decreases the residence time of the herd in each “paddock” as compared to other versions of cell grazing, rotational grazing, or whatever we’re calling it. The use of extreme was not meant to have a negative connotation, but to show that it is near one end of a spectrum.
I’d be interested to hear more about the potential positive and negative impacts of uniform application of manure and urine, and how those impacts might differ between a tame grass pasture and a native prairie. I would think there would be some fairly strong impacts to native plant and soil communities (remembering that my blog and this post focuses on native prairie ecology and conservation). I think one of the more important aspects of successful prairie management is actually creating heterogeneity, rather than homogeneity of growing conditions for plants and animals. I’m not sure homogenizing and concentrating nutrient inputs would fit that very well, but I’m open to the idea.
You’ve really truck a cord here, Chris. Lots of great feedback!
For some of us non-professionals, cattle grazing will always be viewed as the chief problem with prairies in the West, ex. Donahue’s “Westerrn Range Revisited”. For us, it remains a tough sell to be convivnced that prairies need cattle grazing in any form.
Ted, this is why I find writing this blog so fulfilling. The readership of any particular post spans a very wide spectrum of ideas, opinions, geography, and backgrounds. I learn something from every post – some from the research I do as I write, but often much more from the people who respond with their own perspectives. What a great gig!!
Chris, I’m sorry about the spelling errors above (at least three). I was hurrying. I think part of my problem with cattle grazing is that it often seems to be either a) an attempt to pander to local livestock interests or b) an attempt to turn restorations into money-making centers. Do cattle really make prairie lands more diverse and stable? I have doubts.
Ted, You’re certainly welcome to your doubts! : )
Here’s the thing. I don’t think grazing is necessary on all prairies. On the other hand, I think grazing can be a useful tool for meeting specific conservation objectives on some prairies. From a plant community perspective, for example, it can help suppress dominant grasses and release short-lived plant species – without long-term damage to long-lived perennial plants. I have sites where my large grazing exclosures (burned, but not grazed) have much lower floristic quality than burned/grazed portions of the same prairie. Does that mean everyone should graze their prairies? Of course not, but it sure seems to indicate some potential benefits on my own prairies.
If you broaden objectives beyond plants, I think the habitat manipulation value of grazing can be very helpful when trying to create patchy heterogeneous vegetation structure for a wide variety insect and animal species. In some cases it’s difficult to get some of those habitat conditions (e.g., short-cropped grasses with abundant tall forbs) without grazing. Again, it’s not for everyone or every prairie, but in some places, and for some objectives, I think it’s worth a look.
In terms of pandering to livestock interests, I don’t know that I’d use that word. My own prairies are being grazed because my data and observations are both showing better results in burned/grazed than burned/ungrazed sites (for my objectives, which include plant diversity, floristic quality, and heterogeneous habitat structure). On the other hand, the vast vast majority of native prairie land that remains in North America is privately owned by farmers and ranchers. I’d sure rather see it grazed than plowed, wouldn’t you? Given that, it seems reasonable for us to find ways to graze those prairies economically so they can continue to pay their own way. If they don’t, the landowner will either lose the land or he (or the next landowner) will farm it so they can pay the taxes and support their operation. Most ranchers I know are trying their best to balance natural resource needs with conservation needs. It’s not easy, and none of us have all the answers, but I sure think it’s worth working on.
Anyway, if you’re really interested, you can read lots more of my thoughts on prairie grazing by doing a search from the search window on the blog’s home page for “grazing”. You’ll find all kinds of things, including guesses, observations, and hard data that show why I think the way I do. Then you can decide for yourself. Or you can continue to think it’s a bunch of hooey, and I’m fine with that too! There’s more than one way to skin a cat! I certainly don’t have all the answers. Again, that’s why I enjoy writing this blog – it helps me keep learning.
The only thing I’d ask is that you don’t dismiss it too easily, without looking past the “eastern bias” that exists. It’s easy to look around the midwest and see only the prairies that have been destroyed by chronic overgrazing and years of broadcast herbicide use and conclude that grazing is evil. It’s really not that simplistic.
Either way, I hope you continue to join in the discussion! (and the blog’s about much more than just grazing, obviously, so we can disagree on that and still find plenty of common ground!!)
Just an additional thought from me on this discussion in general… Responding to comments on this (and some other posts) is much like walking a tight rope through a mine field!! In a good way, of course!
Grazing is good. Grazing is bad. Too much grazing is bad. Can’t have enough grazing.
Fun, isn’t it??
“In God we trust. Everyone else must bring data.” W. Edwards Deming
Chris, That’s what I love about your blog. You actually take measurements and present them. I expect some plant species may actually benefit from this type of grazing regime. I just do not think these are desirable species from the view point of ranchers or conservationists. I think this grazing regime would set back efforts that have taken considerable time and sweat to achieve. The well tended prairie pasture is a rare jewel in our landscape that is driven by the ever changing target of maximum production.
We own a hillside that was a former pasture. At that time, the pasture vegetation was exotic cool-season grasses, sweet clover, and a lot of woody vegetation (mostly non-native). We knew that it was once native prairie but only found a couple of native plants initially.
With chainsaw, herbicide and fire, the former pasture is now resembling (although very degraded) the native prairie it once was.
So how did the native prairie transform into a pasture with only non-native grasses present? Repeating what the experts tell us. Take a native prairie (eastern), introduce cows and Eurasian grasses, nitrogen load the soils with manure and urine, and over time the nitrogen rich system tips the balance from deep-rooted native plants to short-rooted Eurasian grasses. Conversely, we reversed this trend by bringing fire into the mix to reduce the nitrogen and hence tip the balance back to the native plants.
Interesting read this post! Seems to me that there may be a wide difference as to how all of us define a “prairie”??
David, your example is a great one for discussion. I’ll likely have an entire post on this subject later, but here’s a short version. I agree that invasive grass introduction (purposefully and accidentally) is a major factor in the degradation of those sites. More importantly, I think were chronic overgrazing and broadcast herbicide application that paved the way for the invasion and converted the plant community from a diverse native mixture to the more simplified community that exists now. Where I differ from some in my interpretation is that I don’t think it was grazing, per se, that caused the problem, but chronic and repetitive OVERgrazing. I am absolutely convinced that periodic grazing is, at worst, neutral to tallgrass prairie plant communities. I can see no reason why even the most sensitive plants wouldn’t be able to survive through years of (even intensive) grazing as long as they were given rest periods. It’s the lack of rest periods that is the killer over time. AND – probably more importantly, at least in the landscapes around here, is the history of herbicide application. As you know, it only takes one episode of 2,4-D to change a plant community for ever. How many grazed landscapes have escaped that fate over the many decades since that herbicide became available? Not many. Prairies can recover fairly well from grazing, many plants can even recover – eventually – from chronic overgrazing. Many fewer can recover from 2,4-D. When I was in Missouri this year, I was visiting some of their “nicest” prairies. Most had livestock ponds on them. I don’t think previous owners likely dug those ponds for fishing, so I – and the locals – are assuming they had a history of grazing. Yet they’re beautiful prairies that are now the subject of heated discussion about whether or not any cattle should ever be allowed into them. An interesting discussion to watch.
Anyway, my only point here is that while it’s certainly possible to destroy or degrade a prairie with grazing, it’s also possible to maintain a high quality prairie community with certain types of grazing (in many instances). Some people default to the simpler position that any grazing is bad for prairies. I simply disagree.
My next post will be grazing free, I think, so I can do something next week besides respond to comments!
– I’m kidding, of course, this is fun!
And a quick addendum to my last comment and then I’ll shut up. When I say I’m absolutely convinced that periodic grazing is neutral or better for tallgrass prairie communities, that assumes that steps have been taken to mitigate some of the potential negative impacts from cows standing around in water, trampling the same mineral/stock tank areas each year, etc. Small prairies don’t work well for grazing because there isn’t the space to shift some of those impacts around, and impact areas are an unreasonably high percentage of the total area that remains. As I’m always careful to say (except in my last comment) – not every prairie can or should be grazed. In many cases (probably most cases in states like Illinois) it’s not an appropriate or feasible strategy.
Good comments. And yes, most any pastureland/rangeland course (at universities for example) has included the management practice of broadleaf herbicide control at some point in its history.
Most prairie experts for our area (Wisconsin) do not believe that large herbivores play a significant role on our prairies. However, this is not the same as saying they do not believe that grazing played a significant role. The little guys, rodents and insects for example, likely played a significant grazing role.
With the exception of some of our sensitive goat prairies and sandstone outcrops areas, which still show visible scars of overgrazing, I have often wished we had a few cows (better yet bison) to provide more vegetation structure variation, especially in the planted prairies.
Thanks for keeping this blog interesting!
Hi David –
Holstein heifers grazed in planted prairies at the Arlington Ag Research Station north of Madison (the former York/Empire Prairie) and we saw just what you described — more variation in the vertical structure of the vegetation. After two years, there was a slight increase in the absolute cover of Kentucky bluegrass & smooth brome, but not at the expense of C4 grasses or native forbs. We were implementing summer-only rotational grazing to look at the quality and yield of C4 grasses as a forage source for farmers, but the results suggest that we need a third grazing period earlier in the spring to target the cool season grasses.
It looks to me like there could be a role for prescribed grazing in managing some planted prairies that are dominated by grasses. In the managed grazing systems that farmers are using in southern Wisconsin, cows become acclimated to a diet of highly palatable, high quality grasses and legumes– and that’s what they go for when you put them in a prairie. A dainty Holstein doesn’t want to eat a tough, fibrous rattlesnake master leaf or a smelly, stiff-stemmed sunflower, aster or goldenrod when there are leafy big bluestem, smooth brome and red clover plants nearby. The nitrogen in their manure and urine is also more labile than the nitrogen in the soil, and this could benefit native forbs which are not as nitrogen efficient as the C4 grasses, but I don’t know that there’s any peer-reviewed research on that part of the nitrogen cycle and plant-soil-herbivore interactions (but Chris might know of some?).
David, Grazing reduces nitrogen in the system as long as the cattle are not being supplementally fed.
True, nitrogen is removed, but is the quantiiy significant?
Suppose a really high stocking rate of one cow per acre for a season long enough to add 450 pounts of calf.
The 450 pounds would be 400 pounds of water and 50 pounds of muscle,etc containing protien, a part of which is nitrogen, so much less than 50 pounds of nitrogen is removed.
I think the true amount of nitrogen removed is much less than the amount most folks add to their front yard.
Now consider that there are lots of sources for nitrogen including thunderstorm precipitation and the most imortant being nitrogen fixing plants. A lazy legume can produce 40 pounds of nitrogen per acre and sweet clover has been measured at over 200 pounds of nitrogen per acre added to the system.
I live in the Nebraska Panhandle, and the stocking rate here is closer to one pair per ten acres for the summer. We have had dramatic improvements in the prairie range with management and no addition of nitrogen or nitrogen fixing plants.
Chris, do you have some better numbers?
You guys are way above my head with the nitrogen talk. I know what I learn from others. Keep talking – maybe I’ll learn something.
I have always read that algae are the biggest input of nitrogen into the prairie ecosystem. The other things you mentioned are significant, but not the biggest contributor. This may be the reason you have been able to improve your prairie range without the addition of nitrogen fixing plants. However, I still think native legumes are very important.
I think what is most important for healthy prairie is to remove non-native species, including non-native legumes, rather than focus on the amount of soil nitrogen. Many plants can grow over a surprisingly large range of soil nitrogen levels. However, the ecology of a prairie can be absolutely destroyed by the addition of a non-native legume. A good example is crown vetch. The damage to the ecosystem occurs even though the non-native legumes are increasing the total soil nitrogen.
James (and Rex),
Thanks for the interesting feedback. I am not a soils guy, but I can add a little more info on the site we own. We have one area where it looks to me that they piled hay to feed the cows as the site is now heavy with organic soils (elevated about 6 inches over the mineral soil) and only wants to grow stinging nettle now (better than what was orignally there). Sweet clover has been a major, major problem and we have worked hard to remove all plants. Native legumes are increasing but the most conservative ones are still present in isolated small pockets. The exotic cool-season grasses which use to be very dense are being replaced by native grasses (mostly the small panicums) and sedges (many varieties). In the last few years, warm-season grasses have been on the rise. Management consist of removing the sweet clover, burning, and non-native woody removal. We have done nothing to control the exotic cool-season grass. After our initial work many years ago, the exotic cool-season grasses really took off and covered everything. It was a beautiful very green pasture! Gradually, with the only management practice of fire and sweet clover removal, the site has largely transformed to a degraded native prairie. We find a few new conservative plant species each year. The cool-season exotic grasses are still present, but are a minor component now in a lot of the areas. It has been a fascinating process to watch.
Jerry Volesky has a several year study underway at the UNL Barta Brothers Ranch near Bassett, NE concering mob grazing. I attended the field day last summer. The study is in the second year.
Last years strip looks much like the rest of the prairie, a really close look would be required to see any shift.
The study is a one time per grazing season intensive grazing of a strip. Everyday the cattle are moved onto a new strip sized to be fully grazed or trampled in a day.
There should be results published every year on the progress. It is my understanding that they are measuring soil organic matter, forage production, gain and species composition.
Jerry’s office is at the UNL Extension campus in North Platte.
Can someone please explain to me where a natural prairie has ever existed without herbivores?
I don’t understand the notion that a prairie can exist for long without the grazing animals that are a natural part of that ecosystem. I suppose it can be maintained for a short time with fire to remove the previous year’s growth until the negative baggage from repeated fire catches up and the downward spiral accelerates, but the downward spiral is inevitable.
Some of the comments here seem to indicate that a prairie is like a garden, and can be tended and cared for to be whatever kind of garden a person wants. It is not, It is an ecosystem that can collapse, weakening the survivability of the planet. The idea of a prairie as a garden might work on a garden sized plot, but would be disastrous when thinking in terms of thousands or millions of acres.
The big trick in all of this is defining what a prairie is to various people. The great thing about this blog is that it’s read (and responded to) by a wide variety of people, who have a wide variety of opinions on the subject.
Many eastern tallgrass prairie enthusiasts are working with prairies that are so small that grazing is not logistically feasible, and they have some very productive and diverse plant communities that have resulted from years of fire and/or haying management. The only grazing those easterners have seen is the kind that keeps a pasture below a few inches in height year round. You can understand why they would be skeptical of grazing in prairies. One of my hopes with this blog is to highlight ways in which grazing can be non-threatening, and even useful in maintaining the kinds of values they see in tallgrass prairies (which tend to be heavily weighted toward plants and a few rare insects – I’m way overgeneralizing here).
Contrast that perception and experience with many people in the western tallgrass and mixed grass ecoregions (and elsewhere) where prairies are larger and almost all are either hayed or grazed. The use of fire is spotty (but growing) in these western areas – as compared to very prevalent in the eastern tallgrass, and grazing is seen as a given. Process is much more important than species composition in terms of what a prairie is “supposed” to be.
You might be interested in this post on the subject. https://prairieecologist.com/2010/11/09/measuring-success-in-prairie-conservation-–-species-composition-vs-structure-and-process/
And this one: https://prairieecologist.com/2010/12/29/the-problem-with-calendar-prairies/
I’m stuck in the middle, as a person who thinks the easterners need to pay more attention to process and critters other than plants and butterflies, see prairies as more dynamic, rather than as a plant community that should look the same every year. At the same time, I think westerners need to focus much more on the species that are either very rare or missing altogether from large swaths of prairies that are managed for process, without remembering species composition. Also, there are quite a few misperceptions about fire that mirror the eastern misperceptions about grazing.
It’s all very interesting, actually. I find that I learn a tremendous amount from people that are both east and west of me. I hope they’re learning as well. None of us understands it all.
“Can someone please explain to me where a natural prairie has ever existed without herbivores?”
No prairie exists without herbivores. However, there are many prairies that have a high diversity level which have not received grazing by cattle or bison in many decades. The herbivores in these prairies are mainly invertebrate.
“I don’t understand the notion that a prairie can exist for long without the grazing animals that are a natural part of that ecosystem.”
The reason prairies can exist without cattle or bison is because these animals are not so important to the ecosystem that their absence would cause it to completely collapse. These animals result in important changes in vegetation and wildlife usage. However, a quality prairie can be maintained without grazing because micro-organisms are the most important drivers of diversity.
“I suppose it can be maintained for a short time with fire to remove the previous year’s growth until the negative baggage from repeated fire catches up and the downward spiral accelerates, but the downward spiral is inevitable.”
Fire keeps woody species from invading prairie. Without regular fire prairies turn into woodlands. I have seen prairies of the highest quality maintain their diversity even under an annual fire regime. Please look at some of the other posts on Chris’ blog to learn about the importance of regular fire to prairies.
“Some of the comments here seem to indicate that a prairie is like a garden, and can be tended and cared for to be whatever kind of garden a person wants. It is not, It is an ecosystem that can collapse, weakening the survivability of the planet. The idea of a prairie as a garden might work on a garden sized plot, but would be disastrous when thinking in terms of thousands or millions of acres.”
Different management options result in different outcomes. Increasing fire frequency results in an increase in warm season grasses. Appropriate grazing decreases grasses helping restore diversity. Lack of fire causes an invasion by woody species. These facts have been repeatedly proven true by those managing or conducting research on prairies.
The objective of management is not to create a garden. The objective of management is to continue the conditions under which the ecosystem developed that are necessary for its continued existence. Size is an important factor in preserving the prairie ecosystem. If the largest components like Bison and Prairie Chickens are to be maintained then thousands, if not millions, of acres are exactly what needs to be present.
You are correct that prairie is an ecosystem that can collapse. Plowing, herbicide, extreme drought (like occurred in the dust bowl), and chronic over grazing all has contributed to the decline of the prairie biome.
A great summary on the prairie! Thank you.
I have a hard time believing the great bison herd grazing the American grasslands approached anything like mob-grazing. It is my understanding the bison like to keep moving while grazing, thus the need for very large land tracts to maintain a healthy bison herd.
Chris, thanks for creating an excellent discussion of the topic of “mob grazing”. Over the past 40+ years I have had the opportunity to work with many ranchers and landowners and helped design all kinds of grazing systems. When the new buzz word of “mob grazing” became popular, I tried to find a definition from every person who talked about it. The conclusion is – there is no definition. Each person has a different idea of what mob grazing is, what it will do, and how to apply the concept. What is prairie; what is overgrazing; what is utilization; and finally what is litter? During the 2010 grazing season I had a paddock stocked with 13,000 lbs of cows/acre grazing on a 6 acre paddock for 2 days in early July. The major portion of the paddock was an overflow site with 5 – 6000 lbs of forage growing. t
The herd flattened all vegetation they did not graze. My thought was this was an example of “mob grazing”. After talking to several people who were experts in mob grazing, I was told that all the litter would become organic matter and the paddock would respond with more productive and diverse vegetation if given sufficient rest. I did not graze the paddock until July 29, 2011. The major warm season plant, big bluestem, still did not show the vigor and production that was observed in the adjoining paddock. My observation was the plants had not fully recovered from the loss of production from the trampling during the previous July grazing. The conclusion that I came up with was that the trampled plants did not carry on photosynthesis for the remainder of the 2010 growing season, while the adjoining paddocks did. More lbs of beef were harvested from the adjoining paddocks while the mob grazed paddock was recovering back to the level of the other paddock. It has been mentioned that conditions are different on every ranch, and every pasture. This is so true and no grazing system will work the same on two different operations. At this point my conclusion is – whatever “mob grazing” is, it may work some place but it probably is not something that is sustainable on diverse rangeland plant communities. Thanks again Chris for the excellent discussion topic.
A great summary of the issue and a nice specific example – thank you. I think you’re absolutely right about the lack of definition about what mob grazing is, and it shouldn’t be a surprise, given the fact that it’s relatively new and is being done be a very diverse group of people spread across wide geography. Hard to encapsulate it. Just like – as you said – many other things (prairie, litter, overgrazing, etc.)
The most important thing here is probably that everyone needs to be thoughtful and careful to measure impacts and success of whatever strategy they’re using (grazing, fire, haying, etc.) and not to do something just because someone else says it’s good, without measuring the way it works on your own land.
Chris and commenters I want to commend all on the thoughtful discussion.
You can skip the narrative and dive into the points below:
I have 30 years of experience as an NRCS range specialist and grazing specialist. I was raised on a small place near Abilene Texas so I’ve been around grazing pretty much all my life. I became aware of Short Duration Grazing advocated by Allen Savory in the early 1980s and worked with some of those systems in rangelands throughout Texas. They are complicated, sensitive and required consistent and continuous high levels of management. Some worked and some did not. I also saw high intensity-low frequency, and many other grazing systems at work along with fire and the other tools of range management.
I became aware of Greg Judy’s efforts with MOB grazing after being transferred to Iowa and now work with almost 10 of these systems from dairy to cow/calf. The difference between rangeland/prairies and pastures is day to night and I would not approach range management like pasture management. In pastures we can start over – in our rangelands on my home ranch we can never start over.
Point #1 Impacts on Soil Organic Matter –
cattle recycle about 85% of what they eat and deposit bacteria filled organic matter on the soil surface for worms and beetles to bury. I am also convinced, no data, that the pulses of root die back and regrowth from mob grazing events can beat preservation prairies in carbon storage where that cycle occurs about once per year instead of two to four times. That is why i believe soil O.M. impact is fast.
Point #2 Impact on weeds:
Like Kathy I’ve helped ranchers teach cattle to eat canada, musk and other thistles etc. I agree that the perennials may survive long term but their impact is lessened immediately. In the mob systems I work with two awesome things are occurring. Musk thistle which is a biennial decreased more than 80% by the second year. In oak savannahs we are seeing up to 1000 oak, walnut, and hickory seedlings per acre after mob grazing with plenty surviving into year 2 and 3. My observation is that the forage that grows after a grazing event with 90+ days rest can outcompete most annual weeds. The tree seedlings are savannah species that are used to waiting out herbaceous vegetation, fire and even some grazing then bolting past the forage to dominate their space. I work with pasture so it’s more of a turf versus bunch scenario, weed seeds have a hard time finding bare ground. Acorns from our 150 year old oaks can be pushed into the soft soil by hooves and some grow!
Point #3 What is MOB Grazing
In the Midwest for pasture – 250,000 pounds of liveweight per acre or more, grazing for a day or less, with not less than 45 days rest up to 120 days rest. This will be different for range and for drier and for changes in weather and on and on. The art is in high stock density, long rest and being careful to not abuse livestock in the last trimester or early lactation.
Point #4 When does it work?
Mob grazing is a tool and nothing more as a grazing management system. It works when the landowner is putting in the effort and has the intelligence to make it work. I’m working with the TNC now to use MOB grazing on reed canary grass dominated floodplain that should be sedge meadow. Other methods can work but are erased by each flood event. We are trying grazing, 2011 is first year, to check impact in a 99% dominated reed canary area where there is no hope otherwise to get some sedges back into the mix.
Point #5 Forage Health
As Rick Warren might say “it’s not about the grass” We are seeing natives, legumes, and many desirable species show up after the first grazing event. Even though there is little research the proof is still in the pudding. The oldest MOB system that i work with has doubled cow/calf numbers in 3 years with no seed, no fertilizer, no forage degraded, fewer weeds, and they sell grass-finished beef at 6 chain groceries competing with grain fed.
You are close enough for show and tell next growing season. Let’s continue to chat.
Reply to David above concerning the species shift over time.
I expect that prairies tend towards diversity over time regardless of management. Gabe Brown tells of inventoring the plants on a a cool season mostly exotic grass pasture near Bismark, ND and finding 61 different plant species. The pasture was being rest rotation grazed. You observe similar results with fire or spot spraying of an occassionally agressive legume.
What a great post and discussion you have generated. We manage land that was once prairie and I am always eager to learn from the experiences of others. The issue of soil carbon and fire has long been of interest. I read the study that you posted from Kitchen et al, 2009. I want to clarify that the study points out that plots which were burned showed a decrease in soil carbon over time, not an increase.
Also, one school of thought which often advocates for higher stock density is holistic management. Holistic grazing planning uses cattle as a tool to achieve management goals. As a managers, we have to know what we want to see on the ground, understand the effects– positive and negative– that the tool of grazing can have, plan, monitor, and realize that if our plan isn’t moving us where we want to go, it’s time change the plan. I think Allan Savory’s (and others) work in this area is fascinating, and might offer guidance to those who have had negative experiences with high stock density.
Thank you again for prompting such a great discussion.
Thanks for the response. The Kitchen paper is accurate, but a little misleading if you’re looking for TOTAL soil carbon. The test they use for measuring carbon in the soil involves sieving out almost all of the roots before the measurement takes place. It’s a good way to standardize that particular measurement (SOM), but it makes it sound like total soil carbon is lower. You have to factor in the increase in plant roots in the soil and remember that soil carbon is in a continuum from live roots to dead roots to root fragments to mineralized material that’s actually available to plants. I should have clarified that in the post – sorry. The paper does make it sound like there is a slight decrease in soil carbon because they measured a standardized factor (SOM) when there is actually an increase because of the higher root mass post burning.
It’s an awfully complicated thing, and I don’t pretend to understand it all. I checked with one of my soil expert friends before responding to this just to make double sure I wasn’t being confusing again!
Re: response to Rex,
I do think you are right. There are many management practices that will help an ecosystem recover; to launch the trajectory towards sustainable native diversity. Some may work faster than others, each may highlight its own unique features, but they all get the ball rolling. We spend a lot of time debating the merits of individual management techniques, sometimes with the fever of a political rally, and I wonder if it distracts us from the larger picture, which, in my mind, is getting restoration occurring on a much larger landscape scale?
I have been fortunate to work with many landowners. Each has their own ideals and values, financial resources, background in ecology, and ecological “potential” in the land they own. And each will define their own unique journey in building a deeper relationship with their land. What is most rewarding, and in my opinion the best measurement of success, is to witness their land ethic grow stronger. We cannot bring every piece of land back to an “award winning” prairie, but we can help each landowner develop a healthy and sustainable land ethic.
Chris, I think one further point should be made. The carbon in dead prairie foliage does not decompose nearly as rapidly as that found in forests. I can pile deciduous tree leaves a couple feet tall and by the next Fall it is completely decomposed. In contrast, when I tried to compost dried prairie vegetation it did not decompose even after a couple years. It would not decompose even when high nitrogen green lawn clippings were added. After a few season I gave up trying to compost my dead prairie vegetation. I finally decided the only way to dispose of it was burning. I added it one pitch fork full at a time to an outdoor fireplace. My neighbors would have surely called the fire department if I ignited it all at once.
The point is … dried prairie vegetation does not decompose and get incorporated back into the soil. The only way to cycle the nutrients is to burn it. Also, I think fire is the primary method nutrients in manure gets recycled back into the system. We do not have cattle in our prairies. However, after a fire all that remains of the deer droppings are little ash pellets.
Your point about prairie foliage not decomposing is the reason why cellulosic fuels are having a hard time finding traction (and investors). The lignin resists breakdown much as the modern corn varieties do not break down in the soil.
In isolation the prairie foliage may be slow to break down but it does go somewhere on the prairie, it is not all duff buildup. Different soils and the life in that soil will have an impact on how much duff buildup there is. In my restored acres I have 12 different soil types, all in the same 1/4 section. One area in particular of a few acres is soil type 1874 (Lohnes sandy loam). This area produces a beautiful sward of grass every year, burn or no burn. In fact I avoided burning this area early on because there was very little duff buildup. I would say by July of a non-burn year you will find very little trace of the previous year’s vegetation. This area lies on a lttle crest, is well drained and seems to a lot going on beneath the surface.
Doug, I’ve never marked stems from previous years to see how long they persist. I’ve only piled them and saw they did not decompose. I expect the reason you are not seeing duff on your prairie is because productivity is so much lower in dry sites. Dead stems and leaves build up much more quickly in very productive mesic prairies. This makes the duff more visible. New growth really covers up the dead leaves and stems. This might be why you are not noticing it anymore after July. I think it is still present. A prairie that has not been burned in a long time will have a larger spacing between the grass clumps. Once the buildup of dead stuff is removed the grasses will fill into these newly opened up areas.
I tried looking for a duff decomposition study in prairies. It is alluding me.
Here is a litter mass decomposition study for prairie in Texas.
After 48 weeks about half the litter of the fastest decomposting species (Helianthus maximilianii) remained and about 2/3 of the litter of the slowest decomposing species (Schizachyrium scoparium) remained. You can also see how the decomposition rate flattens out over time. After the easy to decompose stuff is gone the remain stuff decomposes really slowly.
Another cool thing about this study is you can add the word gilgais to your vocabulary.
One of the functions of cattle and other large herbivores to the prairie ecosystem is to speed the process of decay, or nutrient cycling. Without this nutrient cycling, health and productivity declines. Many of the microbes in the rumen of herbivores are the same as soil microbes, so this is a win-win. Fire is an extremely poor substitute for the grazing of the herbivore and the subsequent microbial decay process that begins in the rumen.
A pile of ash simply cannot do what millions and millions of microbes can do when it comes to building soil.
My observation is that cow patties break down very slowly and consume space just like duff. Burning the pasture will get rid of the cow patties which results in an increased area for the grasses. As Chris previously stated, soil building is much more about what is going on under the soil than above it.
The nutrient value in the grass and its ability to support bacteria in a rumen are a huge factor in longevity of cow pies. A herbivore grazing lush green grass produces almost runny cow pies that may be gone in a week. The same animal grazing a high lignen, low protien grass after killing frost will produce a cow pie that on dry sites may last until a hail storm physically tears it apart the next year.
Thanks for the additional information.
The site I describe, soil type 1874 is very productive and does not show the duff buildup as does other areas in the same restoration. I think this particular area is more conducive to very active soil microrganisms, ants, earthworms and the like. These unpaid workers are clearing the litter from the previous year faster in this area than in others. To those looking to learn more about life in the soil I suggest the book Eco-Farm available at http://www.acresusa.com. The discovery of this book in the early 1990’s really opened my eyes to the value of a complementary soil management system.
The 1/4 section I restored in 1993 was farmed conventionally with chemicals for a period of about 25 years, prior to this it was prairie. I have followed an organic protocol since the restoration and the health and production of the prairie really has to be seen to be appreciated. I spent a weekend last summer taking photos of the Monarch Butterflies on the Meadow blazing stars, Monarchs that had spent their entire life right on our prairie. There is something very powerful about creating or recreating a habitat that allows this to happen.
Great work on your prairie. Earthworm are getting a lot of attention in our area (Wisconsin). It turns out that nearly all of them are non-native. Apparently, with the exception of the Driftless region, there were no earthworms in the state due to the last glacial period. They are a concern in the northwoods as they quickly consume forest duff changing the plant and animal communities on the forest surface.
I used to hunt deer at Pressy Wildlife Management Area south of Broken Bow. There was, at that time, a farm right across the road from one of the parking area that hada large number of goats grazing. when I got the chance to ask one of the local folks about them I was told it was to reduce the amount of musk thistle. Any truth to that.
I’ve heard of and seen examples of goats used to control musk thistles a few times. You can make them eat the thistles, but unless you keep hitting the same plants over and over, the thistles regrow as soon as the grazing stops. Since musk thistles only bolt and bloom one season, I suppose if you could keep them cropped down all season long you’d eliminate those particular plants, but to get that level of grazing, I think you might also be opening up the plant community, which would favor next year’s musk thistles. I don’t think it’d be my preferred choice for control methods. Musk thistle is essentially a big dandelion. It likes situations where the grass is weak. Weakening the grass is the last thing you want to do. For long-term control you want to strengthen the grass stand (and other native plants) – the thistles will diminish proportional to that grass stand strength.
Pingback: The year my blog broke | Ian Lunt's Ecological Research Site
Yea, that home schoolin will never work, those kids will never make it.
I am a mob grazer and have a few comments:
1. In the world of microbe building, soil coverage is key. Bare ground loses nutrients.
2. Anyone who has gardened understands the moisture-retention benefits of mulching or getting organic matter on the ground. It positively impacts microbial life below the surface.
3. Having visited mob grazed ranches from northern Missouri to South Texas, I’ve seen firsthand the benefits of mob grazing. I’ve talked with ranchers who’ve been mob grazing for years and listened to them tell how their native grasses returned, cacti were choked out, etc. I’ve stood on the fence lines and compared the neighbor’s pastures to theirs.
4. I’m not sure why no scientific studies have been done but I guarantee you it would put a huge dent in the input market if ranchers figured out the benefits of high intensity grazing.
5. Brix readings from ranches transitioned to mob grazing are readily available, meticulously tracked, and show great improvement in sugar content of forage.
The saddest thing about being an unconventional rancher is the contempt (and even scorn) you’re met with from the traditional world. I work diligently to help these worlds meet and interact civilly. After all, we all want the same things: better animal performance, higher carbon content in soils, increased microbial life, and all the benefits thereof. And mob grazing delivers in a big way.
Never mind. I have an answer about scientific research. Who pays for that? Which big ag input company is going to finance a study showing their product is unnecessary? Remember the dung beetle research at A&M in the 80s? Funding yanked. Why? Lobbyists for worming companies didn’t like people saying, “You don’t need this stuff!”
This post by Chriz Helzer is terrible science in my opinion. Not one mention of any of the leaders in mob grazing – Allan Savory, Ian Mitchell-Innes, Greg Judy, Joel Salatin, Abe Collins, Chad Peterson, for example, and I suspect that none of these pictures are from their ranches. Am I right, Chris? If I am correct about these pictures, then a much more honest title for this blog post would have been “A Photo Tour of the Worst Examples of Mob Grazing I Could Possibly Find Anywhere.” If you are going to criticize the METHOD, you need to analyze the method as practiced by those using the method correctly. Otherwise all you are doing is criticizing the practitioner. And worse, you are polluting the internet with bad science (or bad journalism or both) and you are going to mislead people in an area which just so happens to be critical to the very survival of life itself on the planet (see below). What if I wrote an article that was titled “A Skeptical Look at Fire” and posted a bunch of pictures of houses on fire and forest fires and burning cars and such. I’d rightly get laughed off the internet. The bad thing about fire is improper use of fire, not fire itself. If Chris is unconvinced that mob grazing is a good thing, then he should visit the ranches of the leaders listed above and write a report on them. My understanding is that Greg Judy was bankrupt and now owns 3 farms and leases 7 others as a result of tightly managed grazing (I think he switched to mob grazing in 2007). Landowners WANT Greg to do his thing on their land because of the vast improvement they see. That seems like success to me. Regarding organic matter input to the soil, it appears that Chris has not read Joel Salatin’s article on Mob Stocking found here http://www.acresusa.com/toolbox/reprints/May08_Salatin.pdf because Joel says “Perhaps the most beneficial result of this ultra-high stock density is the organic matter added to the soil via fully developed root mass that naturally occurs when a plant reaches phenotypical maturity. Adolescent plants do not form the pounds and miles of plant material below the soil that mature ones do. The mob shocks the plant into shedding much of that mass to concentrate (self- prune) the energy reserves into sending forth new shoots. The resultant flush of organic matter dwarfs even the above- ground manure and urine load. This pasture pulsing, very much like a heart beat, is like CPR for the soil and its myriad inhabitants. Plants self-direct their bilateral symmetry above and be- low the soil horizon. When I see that sea of waving tall forage, in my mind’s eye I see an equal sea of root hairs loosening and feeding the soil food web. It’s a wonderful picture.” Irresponsible science and journalism like this, in my opinion, is a very real threat to the very survival of all life on planet earth. Conventional agriculture and wrong headed thinking about conservation is KILLING our ability to feed ourselves. This article warns that the UK has perhaps 60 years before their farmland is totally depleted … http://www.telegraph.co.uk/earth/agriculture/farming/6828878/Britain-facing-food-crisis-as-worlds-soil-vanishes-in-60-years.html … thankfully, there is a solution and it is Holistic Management of Herbivores such as that practiced by the leaders of the mob grazing movement. Please see Allan Savory’s 20 page report relating global climate change to holistic management involving herbivore herds … http://www.achmonline.org/Resource/A%20Global%20Strategy%20for%20Addressing%20Global%20Climate%20Change.pdf Savory reports that there are now 12 million hectares under holistic management worldwide … there’s a long way to go (he estimates about 4.9 billion hectares of rangeland worldwide) but it’s a start … Savory’s movement has a name, by the way. It’s called the Brown Revolution and here is an article about some guys helping with it … http://www.theatlantic.com/national/archive/2011/09/the-brown-revolution-increasing-agricultural-productivity-naturally/245748/1/ … great article. And thank God the Brown Revolution is finally starting to get the attention of Wall Street. John Fullerton of the Capital Institute is involved in the Howell project. So Chris, I’m working hard to ensure that your great grandchildren (and mine) have a future and I am convinced that Allan Savory’s plan is the only plan that can save us (excluding direct intervention by God). I would urge you to have a second look at mob grazing by visiting the leaders’ ranches and by reading a little more thoroughly before you make negative blog posts. Thanks!
Thanks for the response. A few comments. First, you’ll notice that I was clear in my article that I was approaching this topic from a prairie diversity perspective, and that I didn’t say that mob grazing was bad, or that no one should do it. I did express some concerns based on much of what I read from testimonials made by people who were promoting it. Second, I’ve approved every single response to this post, including yours, to allow for a full range of opinions on the topic to be included for anyone who stumbles upon this when searching for information on mob grazing. I do think the absence of peer-reviewed research on this topic is a big concern. There are boatloads of research papers on the impact of fire on grasslands, and much research on grazing – just not on mob grazing, per se. I think that research would help find ways to maximize the benefits and minimize any negative impacts of what is a very flexible management system.
I’ve said plenty in my other responses to comments here, but I’ll add one more thing. I’ve appreciated the responses from those who use and/or support mob grazing. I have learned a lot from reading those and the supporting information provided. Mob grazing is a much broader topic than I was initially aware, and I’m glad to hear that. Yes, I’m aware of the names you mentioned, and I think their work is worth looking at. However, I will also tell you that the photos in the blog post were taken from a site being managed by a grazier who is seen a prominent leader in mob grazing. After hearing from many other mob grazers, I’m glad to hear that they are as disturbed by the photos as I was.
I’m not a fan of Allan Savory’s methods. Others are welcome to their own opinion. There will be plenty to discuss and experiment as we move forward together. I think a particular grazing system is much less important than the thoughtfulness of the grazing manager. Hearing from people who are clearly thoughtful managers of grazing gives me hope that we’ll continue to learn and manage our resources well.
Dave and Chris – Keep it going! I’ve had discussions with the extension folks and researchers who want peer reviewed – same issue is that USDA ARS is beginning that research but no one seems to want to fund the research by Iowa State, Missouri etc. I’ve seen with my own eyes the benefits of ultra high density (UHD) grazing. For prairies – Rangelands I was taught to call this high frequency low intensity grazing. Hard on animals and great for rangelands. Short duration grazing on range and UHD or mob grazing on pasture is the top end for management. Not everyone is capable of doing it. I’m working with the TNC here in Iowa to mob graze a frequently flooded area to reduce reed canary grass and try to promote the native sedges, prairie cordgrass and other species that should be there. Fire+grazing is the natural way to manage and both when used appropriately work. I love mob grazing but honestly it’s like trying to teach organic chemistry to a first grader for many of the livestock producers I come in contact with. So is prescribed burning. We have more in common than we have differences and the difference between pasture and rangelands is ginormous in terms of ecological diversity, fragility, etc etc. Thanks again for the posts. As iron sharpens iron – this debate will help us sharpen our awareness.
Alright Jess … I’ll keep it going because I believe this topic is so vital …
First, Chris, prairie diversity perspective? That’s your priority? Do you mean the more diversity of species you see the better? If that is what you mean, then I would challenge you to visit one of the leading mob grazers’ ranch in your area – for example, the one where you took those pictures — and count species. Grass/legume species, bird species, insect species, worms, spiders, centipedes … hey, get out your microscope while you’re counting and check microbe diversity. Have you ever done this? I think this would be a fun project. I would guess that the mob grazier species count would be much higher. Secondly, perhaps you have approved every post prior to mine, but you told me you deleted one of my posts because I guessed whose ranch it was where you took those pictures and you did not want to name him. Personally, I think it is important for people to know as much as they can about those pictures you took – where they were taken, what were the circumstances, etc. Also, did you get permission from that ranch owner to take those pics? And to post them online? Did you ask him to respond to this negative article?
Thirdly, you are concerned about absence of peer-reviewed research. Well, as radical as this may sound, I have come to believe that “peer reviewed research” in the life sciences is all too often a detriment instead of a benefit to humanity. My definition of good science is science that benefits humanity over the long haul and there are two major fields in our world today where “peer reviewed science” is actually a detriment to humanity: agriculture and medicine. And the two are related. Tillage and faulty grazing management (and Allan Savory says range burning) has been causing desertification for thousands of years. Joel Salatin reports (Salad Bar Beef p. 50) that Homer (the Iliad and Odyssey guy) wrote that he walked across the whole of N. Africa where the Sahara desert is now and never left the shade of a tree. Google the terms “Sahara granary Rome Carthage” for more info on this. Joel also relates a story about one of his intern’s great grandmother who traveled from Mexico to British Columbia through what is now desert in the western USA and she told of lush prairie existing there at that time. Most “peer reviewed science” today in agriculture centers around tillage, genetic modification and petroleum based fertilizer. Take a flight of fancy for a minute and imagine if Stalin, Mao, Pol Pot and Hitler had a conference on how to do mass murder and they commissioned a bunch of scientists to write “peer reviewed papers” on the topic. Would “peer reviewed research” be a good thing in this case? No. Peer review would not be helpful at all. Not bad or good actually. Just irrelevant. An extreme, fanciful example to be sure. But it illustrates my point, which is … if the “peers” are all reviewing and approving papers which are harming the soil which in turn harms our ability to feed ourselves over the long term (ergo harms humanity) — and they are with tillage and bad animal management — then “peer reviewed research” is of no benefit. So my observation has been that by and large, mainstream agricultural science with it’s peer reviewed research is harmful to humanity, not helpful. That’s not to say that peer review as a concept is a bad thing. I’m just saying that peer reviewed research in the field of agricultural science has not helped mankind so far.
How about medicine? Heroic medicine is great. I’m thrilled that I can go to the emergency room and get a broken bone set and get a deep cut stitched up and have surgery for this or that and not feel a thing while they are doing it. That’s wonderful. But the whole idea bequeathed to us by Pasteur and his disciples that “germs are bad” and we need to “nuke em with antibiotics” is a losing approach as we are now beginning to see with antibiotic resistant bacteria. I won’t go into detail here, but as it turns out, viruses and bacteria are only pathogenic if the “terrain” (environment) in the organism is wrong (unnatural) because of unnatural foods being eaten (primarily), stress, lack of proper exercise, etc. If we (or animals) are in harmony with nature, primarily by eating natural, unprocessed foods, then these microbes are not pathogenic. This theory was known in Pasteur’s day, discovered by a French scientist named Antoine Bechamp, but was brushed aside for reasons we can only speculate about. My theory is that drug companies wanted to sell drugs. And had we listened to Bechamp, we would hardly ever be sick and hardly ever need drugs. Bad for sales. Instead we listened to Pasteur and so everyone gets sick and needs lots of drugs. Which means lots of sales. Anyway, I heard about Bechamp from … guess who? Joel Salatin. And Joel uses Bechamp’s theory on his animals (and presumably on himself also). He reports that he does not medicate any of his animals at all. He simply gives them the proper nutrition and thus they stay healthy. Interestingly, Weston Price in his monumental study in the 30’s – see “Nutrition and Physical Degeneration” – confirmed this theory in humans as well. See my blog article on this topic here … http://truthmatters.info/weston-price-natural-food-health/
So my opinion is that you have a much loftier view of “peer reviewed research” than you should have. I think you should pay far more attention to guys like Joel Salatin who – rather than trying to please some peers in academia and be politically correct – are instead pleasing the peers who really matter – their customers, their families, their communities. And people like Joel are not just talking and writing – they’re DOING IT. “IT” being feeding large numbers of people in a very healthy way from incredibly small areas of land AND healing the land while they are at it … AND teaching others to do the same.
I can agree with your desire to have a “hands down” look at the biodiversity comparing different grazing management systems. It would be nice to see what species benefited from the different grazing methods. Perhaps it would be nice to have a side-by-side trial to see what the impacts were.
How, if at all, is the way wild bison herds of North America grazed (prior to settlers arrival) similar to mob grazing?
Jonathan – it’s a very good question. The first part of the answer is that most of what we know about historical bison grazing is based on conjecture and from watching today’s bison herds interact with prairies and fire. Today’s herds are different in many ways from those historical herds, starting with the fact that they’re usually confined to pastures of 10,000-25,000 acres or less. Nothing like the wide open prairies of yore.
That said, the consensus among ecologists who study both contemporary and historical bison grazing is that there was a very strong interaction between fire and grazing. Fires led to intensive grazing in recently burned areas – especially during the spring and early summer. Those bison likely grazed those burned areas pretty hard and consistently during that period, and then broke up into smaller groups and roamed more widely in mid-to-late summer and into the fall/winter.
I think one big difference between managed grazing and mob grazing (and their ilk) and historic bison grazing was that the bison grazing would have maintained intensive grazing for weeks or more at a time, rather than for very short periods, and the grass would have been much shorter when they moved on than is common in many rotational grazed pastures. This isn’t good or bad, just the way we think things worked. In addition, because bison had free choice of what to eat on a large scale, they likely were more selective (eating mostly grass) than cattle are in many cell grazing pastures where they are confined to a small area and have to eat what’s available. This isn’t to say cattle aren’t selective in cells – they are – but their selection is more limited than it would have been historically in wide open country. Managed grazing tends to put a priority on maintaining consistent vigor of grasses, so cattle are pulled out before grasses are over stressed and then brought back again when they’ve recovered. Some mob grazing systems hit the grass harder than that, depending upon objectives. Historic bison would have probably hit the grass hard and long enough that it would have taken a year or two (or more) for those grasses to recover their vigor. This would have created some different habitat structure and provided lots of spaces for opportunistic plants to fill in some of the gaps between those otherwise dominant grasses. Mob grazing has the potential to create some of that open space as well, but there’s also a difference between the effects of a one-time defoliation and repeated defoliation over weeks or more. Again, not necessarily good or bad – just different.
I don’t spend too much time worrying about historical grazing patterns, though they’re interesting as context under which plant/grazing interactions developed. I think what’s most important now is to figure out how to use fire, grazing, and other tools to address the objectives we have for a particular site.
Thanks for the question.
Good try but I read a book that was written based on an interview with one of the gentlemen who actually did the bison hunting and participated in their near destruction first hand. I’ve got it loaned out and can’t remember the title but purchased it from Amazon. Dr. Fred Provenza from Utah State extension.usu.edu/behave/.com and Ed Jackson who spent a career at yellowstone also confirmed the observations from the book. Fred knows more about animal psychology than anyone I’ve ever met and is worth a long plane flight or drive to meet. Ed is a grouchy old retired fed running a bison herd on 2000 acres in south central Iowa who practices what we preach – not a relative of mine by the way.
Grazing historically worldwide is a predator driven system more than any other factor. In Africa elephants are first into ungrazed areas because nothing eats them. Then zebras, then wildebeast etc. down to the litttle bitty dik-dik that everything eats. Bison and elk based on the above routinely roamed in family groups of 20-40 and only did the massive stampedes like on movies when there was a significant threat. Then they re-sorted and life continued. These groups becasuse of proximately and never knowing when they had to run for their lives ate primarily grass but also ate enough forbs and some shrubs that it mattered. Predation occurred either with native americans, wolves, bears, mountain lions etc almost every day or every other day. Staying in one place for long invited disaster. The observation is that these family groups grazed an area were attacked and moved enough to leave the range of the predators or at least far enough to be left alone.
Mob grazing mimics the heavy use and long rest that the folks above believed happened. That coupled with fire whenever the natives could get the prairie to burn and natural fires shaped both the vegetation, the human cultures and the animal populations. That is why we’ve all been amazed by what a well timed and conducted prescribed fire can do – and even a wildfire on occassion. That is also why I see native prairie plants, oak and hickory regeneration in historic savannah areas and incredible changes in biomass produced both above and below ground with short graze high stock density long rest management on PASTURES. By the way lewis and clark probably didn’t get a good picture of what things were like normally. Disease preceded them and entire native tribes were gone as their guides showed them along — so there was a boom in animal numbers as the top level predator had been removed – 2-5 years or so.
I believe mob grazing is a potential tool on rangelands but is much harder to practice. In Utah and other western states those ranchers are basically herding on daily basis to get cattle out of riparian areas and into uplands. I visited with one of Ted Turners ranch managers to get their take and several others. There is plenty of research on animals patterning to a specific geography. Ask provenze (BEHAVE.com)
Like most agriculture, I am convinced that high management = high profits and good conservation. High management doesn’t mean plowing, planting, spraying, chopping or any of that – it is about intelligently using natural tools like grazing and fire with judicious sprinklings of the other stuff to achieve the ecosystem we want. Sort of working with nature instead of fighting against creation.
Jess, I’m not sure herd size or make up is necessarily the key point. Whether bison were in large groups or small groups doesn’t necessarily mean grass in any particular place was grazed once a summer or repeatedly. High quality forage attracts animal grazing. The grass could have been grazed by the same herd for weeks on end or – more likely – by different groups of bison moving through at different times. Either way, I think it’s likely that the grass was grazed multiple times during the same year (and probably not at regular 35 day intervals). Since we can’t study the old days, we have to go off of the few accounts we have (which were necessarily observational and largely in the absence of widespread fire) and our ability to extrapolate from what we see today. I’ll still default to my statement about history being important in terms of understanding the context of how plant and prairie communities evolved, but that the main need for today is to design management treatments that address threats and move us toward objectives we have today. We don’t have consensus (clearly) among ranchers, farmers, ecologists, or others about what threats or objectives are most important today. Thus, we come up with different strategies aimed at different objectives. That’s great. I expressed some concerns about the mob grazing I’ve seen in terms of the threats and objectives I see as important. Others expressed their opinions from their own perspectives. It’s a nice dialogue. And as you say, pastures and rangeland are very different and should be approached very differently.
Regardless, I have to admit that I’m quickly tiring of this topic. The original post was not meant to denigrate those who have made mob grazing work for themselves. It was meant to express some concerns about the lack of research on the topic and some potential concerns I saw in the way it might be applied to native prairies (rangelands). I made it clear what my objectives and opinions were and included some links at the end to articles that were positive about mob grazing so people wouldn’t take my individual opinions in isolation. I’ve pretty much said what I have to say, and unless people bring up new ideas in future comments I’m probably done responding. There are plenty of other forums for discussing the value of various pasture systems.
Isn’t it also probable that the “native” prairie vegetation co-evolved with a lot of grazers other than bison and elk? I visited the Nebraska museum of natural history in Lincoln (on the University’s campus) and was floored by the shear number of forage dependent species that called North America home until very recently. I mean elephants, camels, bison, hog like things that were the size of cows, antelopes, and then there were other predators than wolves too – cheetahs and lions. Every wonder why pronghorn are SO stinking fast…?
It seems to me that we lost a great deal of faunal diversity at teh start of the holocene. What did the great grasslands look like even just a few thousand years ago?
Edmund, you’re certainly right that we’ve had a diversity of large grazers in the fairly recent (geologically speaking) history of the prairies. How much of a legacy from them can still be seen in today’s plant communities is hard for me to say. I am very careful about looking backward to guide today’s management. Of course, we need to understand the history of how grasslands developed, and the forces that guided the evolution of species and their interactions. But since the world is very different today (fragmentation, climate change, invasive species, loss of major predators, etc. etc.) we need to be designing our management to fit today’s world – and more importantly, today’s objectives. So, you’re right that bison and elk were not the sole influences on the development of the plant community. On the other hand, the major tool available to us today is cattle (and some other livestock), so we need to figure out what we want out of our plant communities and then how to achieve that using the tools avialable to us – livestock, fire, mowing, herbicides, etc.
Good questions – thanks!
I’ll keep this simple – Manage within a resource’s capability to respond.
Also, I’ve never seen a good example of mob/mig/hi, etc.. in arid (short grass) conditions. Its not safe to try, they are too fragile and respond way to slow to management decisions.
I greatly appreciate your posts, however using pictures from research to bias your point is a little on the low side. Jerry does good work and his research is good, but its just that- research; its what we learn from it that is important.
Additionally there is one thing that has not been discussed enough here and that is the rest associated with a grazing event. In the central region of the US, it is generally beneficial to defer grazing at least one year if not at least two years in a system of mob grazing.
Lastly, you should never see a lot of bare ground as a result of garzing unless, (ecologically speaking) it should be there. Thanks for your time and keep up the fight.
Pingback: Cattle Farming: “Flash Mob” Grazing | The Ultimate Organic Fertilizer
Pingback: everything you know about livestock and climate change is backwards (maybe) | The Handsome Camel
This has recently been published about Mob grazing. A study being done by the Arizona State University on just this subject and it is ongoing. Just thought you’d appreciate this here. Anyway below is the link and a vital paragraph at the beginning.
“The Arizona State University-SoilCarbon Nation team is examining the adaptive multi-paddock (AMP) grazing management technique that involves using small-sized fields to provide short periods of grazing for livestock and long recovery periods for fields. The method mimics the migrations of wild herd animals, such as elk, bison and deer. The science team proposes a whole system science measurement approach in comparing AMP grazing with conventional, continuous grazing methods.”
Sorry, I had the incorrect link:
It reads to me like they’ve already decided what they’re going to find and are promoting the results before the project starts. An unfortunate method of science communication.
For me while I find it interesting, I don’t feel the same blanket techniques work everywhere. For example the popular Alan Savory and his solutions. Every situation is different and unique and there are different vaiables. For example I think Joel Salatin’s method works fantastic for him in that area’s ecosystem and the fact that his farm was once barren dirt and rock, but I don’t think it would be a good fit in many parts of the west. Interestingly Joel Salatin acknowledges this. There is a video of where he goes to a California Ranch and walks the property and admits he doesn’t know the climate and even vegetation type, but to allow the steep slopes to heal with whatever native vegetation will come back. His rule is if you cannot drive a tractor on it, don’t graze it. This seems to me to be different than Alan Savory who have the short sighted philosophy of one size fits all and that is not true. He speaks of greening up deserts through grazing, but many deserts don’t support the heavy grasslands on historical floodplains they one did. Here is the video below, it was interesting to me because I know that the grassland grazing practices in much of California have been ruined by mismanagement.
Joel as always makes good comments as do you. What I would ask you to consider is that the principles of ecology work everywhere but adaptations for climate, grazing animal used, and the management ability of the rancher/farmer have to be factored in. The young woman is obviously intelligent and interested. Joel talks about laying out the paddocks pretty much as I would. The key point where he appears to hesitate is paddock size for her herd because California has a mediterranean climate with green winters and dry brown summers. CA also has primarily annual grasses on rangeland compared to perennials for the rest of the U.S. Makes it a bigger challenge to manage well. If the first settlers wrote of grass that was bridle high then if we rebuild soils, and move toward the native vegetation it seems like we might be able to get that back – mob grazing is trying to mimic to the best of our ability the grazing pattern, density, rest cycle etc. that was observed when the first settlers arrived. We won’t get it perfect but I see a bigger danger in people plowing up those lands to crop them because livestock don’t make enough profit in a poorly managed slow rotation system. Really Joel is right, Savory is right, You are right and I am right – not 100% and people have to ignore the exaggerations and pick out the principles at work in the successes.
Jess Jackson: “What I would ask you to consider is that the principles of ecology work everywhere but adaptations for climate, grazing animal used, and the management ability of the rancher/farmer have to be factored in.”
Actually Jess I did make another quick comment after that one, but the system would not record it. Maybe time needs to elapse before writing another one. I was acknowledging the importance of not attaching importance of certain techniques to work in every area. While there are basic fundamentals, they do have to be tailored to specific regions as even Joel acknowledged in that video where he was recommending leaving the hills to go wild with native cover. Interestingly in those hills and other California hills which are labeled as Oak-grassland Savanna, they originally were not grasslands, but rather chaparral covered. I believe the Central Valley was definitely more of a prairie-wetlands mix. At one time it was said that over 500,000 Tule Elk were in that valley, now there is a mere token remnant in a tiny little reserve off Interstate 5. But who knows the impact of not only Elk but other mega-fauna which roamed the area at one time. In any event, my background is mostly with Chaparral country and obviously things work far different in the cold wet Boreal forest where I presently reside in Sweden. So yes I am aware of major differences
I totally enjoyed the information, my husband and I are on different sides of the fence on this issue.