For ranchers counting on boosting plant diversity through intensive rotational grazing, a recent study may yield disappointing results.

Jessica Grenke, a PhD student at the University of Alberta’s department of biological sciences, found through an observational study that highly intensive rotational grazing does not benefit plant diversity more than less-intensive rotational grazing.

“This is not an experiment, per se, this is an observational study. We’re able to speak directly to what is actually happening across Canada, across the northern Great Plains. There’s really very little theoretical about this research,” Grenke says. “It’s quite firmly applied.”

In her study, Grenke and her colleagues, Edward Bork, Cameron Carlyle and Mark Boyce, along with her supervisor, James Cahill, looked at adaptive multi-paddock grazing, or AMP grazing, where one paddock is grazed with dense herds of livestock for a short period, then left to recover.

According to Grenke, AMP grazing was created to mimic historical grazing patterns. Producers who use the AMP method are often drawn to the idea of grazing in a way that is natural between the grasslands and grazers and can therefore maximize production.

However, the reality of modern life likely constrains how closely today’s ranches can imitate the grazing patterns of the original bison herds.

“We live in a very different world, obviously. Our knowledge of what grazing looked like back then is also, of course, limited. But even if our knowledge was perfect, we live in very, very small, contained ranches, relative to those historical migratory grazing systems.”

 To conduct their study, Grenke and the other researchers found pairs of producers across the Great Plains — one who didn’t use the AMP grazing method, and one who did. They surveyed 18 ranch pairs and examined vegetation in the pastures.

In the end, what they found was that AMP grazing does not increase plant diversity. Grenke speculated on why this could be.

“I think the simpler answer is that perhaps AMP grazing acts as an ecological filter — it is a more extreme grazing disturbance by definition. And under that definition, you would expect there to be fewer numbers of species able to withstand that kind of disturbance in the long term.”

Grenke says this research, funding by Agriculture Canada, is important to maintain the grasslands and the sustainability of ranchers.

“There’s so much value to knowing what’s actually happening on the landscape,” she says. 

“We can speak directly to policymakers about what this kind of grazing management is doing in this ecosystem. So that kind of ability to more directly answer a question is pretty rare in science… (adaptive and intensive rotational grazing) is very globally widespread, and it’s increasing in popularity. And there is a lot of harm that can occur when this kind of practice is being sold with a limited understanding of what it’s doing to the landscape. I think this can make or break people’s ranch sustainability in the long term.”

U of A researchers have found other benefits to AMP grazing over less-intensive rotational grazing, including improved water infiltration and carbon sequestration.

This article is part of a series. For more see:

• Grazing can AMP up carbon sequestration, U of A researcher says
• Longer rest period drives water infiltration in grazed pastures, researcher says

The post AMP grazing no better for plant diversity than less intensive methods, U of A study finds appeared first on Canadian Cattlemen.

With persistent drought a reality of life in Western Canada and beyond, ranchers across the country are looking for solutions to keep their pastures flourishing even when moisture is lacking.

Through a study done with the University of Alberta on rotational grazing, Dr. Timm Döbert may have helped find a solution.

A post-doctoral fellow at the U of A and part of the research team, Döbert published a paper in 2021 looking at how adaptive multi-paddock (AMP) grazing increased water infiltration.

“The major finding was definitely that AMP-grazed ranches had around 30 per cent more water infiltration,” he says. “If we look at the actual practices, we found that the rest period is driving those benefits. So it’s not the herding effects, it’s not how many animals are on the ground. But it’s the rest periods out of those two factors.”

AMP is an intensive rotational grazing practice that focuses on having long rest periods between grazes. The thought behind this is to manage the land in a way that is reminiscent of how the buffalo would have grazed the grasslands before settlers started farming the land. According to Döbert, 80 per cent of cattle producers practice rotational grazing, but only five to 10 per cent practice AMP management.

The project Döbert was involved with was completed in March of 2021, where a group of U of A researchers looked at 70 different ranches from across the Prairies, comparing those using AMP grazing with those that didn’t. Spearheaded by Dr. Mark Boyce, the study took five years and looked at not only water infiltration, but also carbon sequestration, nitrogen concentrations, microbial communities and more.

Specifically, for the work Döbert did, they examined the difference between water infiltration when it came to AMP grazing or not. 

“Infiltration is not necessarily 100 per cent correlated to availability,” Döbert says. “But obviously, if more water is infiltrating into the soil, there’s a much greater chance that more water is also going to be available over time. So again, it’s not 100 per cent correlation. But the chance that more water is available, because significantly more water infiltrates is greater.”

Other things that impact water infiltration according to the study is the litter in the soil, and the bulk density — or the compaction — of the soil.

“We found that bulk density, so when there’s more compaction, basically, the water infiltration goes down, which is pretty much intuitive, but we still had to test for this,” Döbert says. “And then litter on the contrary, if you have more litter, like dead plant material right on the ground, this is benefiting water infiltration.”

Going forward, Döbert says he hopes ranchers consider using AMP management to create more water infiltration.

“Looking at the water infiltration, it shows very clearly a rest period is very important. So how this then translates to a rancher being willing to implement certain changes, I think that really comes down to the rancher being open to changes and being willing to talk to people already doing something in the space.”

Döbert also emphasized the importance of protecting natural grasslands, saying native grasslands are needed to sequester more carbon from the atmosphere and create biodiversity.

“Protecting grasslands is really at the heart of all the work we’re doing,” he says. “There’s a lot of benefit by really using them sustainably and more regeneratively.” 

This article is part of a series. For more see:

• Grazing can AMP up carbon sequestration, U of A researcher says
• AMP grazing no better for plant diversity than less intensive methods, U of A study finds

The post AUDIO: Longer rest period drives water infiltration in grazed pastures, researcher says appeared first on Canadian Cattlemen.

In Dr. Mark Boyce’s many years in carbon research, five of them have been spent at the University of Alberta, looking at carbon sequestration in grasslands that have been grazed using adaptive multi-paddock (AMP) management.

Boyce is the chair of the Alberta Conservation Association in Fisheries and Wildlife. His lab, Boyce Lab, at the University of Alberta, conducted a five-year research study known as the Agricultural Greenhouse Gases Program. In this study, they evaluated the carbon sequestration of AMP grasslands, as well as their storage potential, when compared to other grazing systems. This study includes the research and findings of Dr. Timm Döbert regarding water infiltration.

“Initially, I was skeptical of… this AMP thing, because it had gotten so much hype and there was not good science to go on with the evaluation of it,” Boyce says.

However, after five years of research, Boyce says there’s a reason AMP has the hype behind it.

“I would say this is a highly successful project for the standpoint of evaluating this AMP grazing,” he says.

“These guys who have been doing the AMP grazing are really believers in it and if they’ve been doing it, and they’re making money at it, and they really support it, there’s something going on. And now we’ve got the data to basically go with those questions that people have with scientific sample and design.”

Boyce says that grasslands sequester more carbon than any other ecosystem in the world.

“Grasslands have most of the biomass below ground, so you have the leaves that come out on the surface, they do all this carbon capture, and then they safely sink all that carbon in into the roots and rhizomes, as opposed to trees that have all their biomass above ground,” he explains.

Many forests are fire-maintained ecosystems, meaning they rely on periodic fires to clear out dead organic material and create ecological balance. However, fires release the carbon trees have stored over time.

“Every 130 years or so it all goes up in smoke,” Boyce says “Carbon in the soil is going to stay there for thousands of years.

“Grasslands, if they burn, typically what will happen is you’ll get a spring burn, like April May, when everything’s dry before the green up happens. And you’re just burning off the residual stems, there’s not much carbon there. Most of the carbon is safely in the soil.”

Retaining carbon, creates rich, black soil that is good for plants.

When it comes to AMP grazing, the practice of grazing a high density of cattle for a short time and then allowing the land to rest for a long time is what helps the soil sequester carbon.

“Rest is really effective at ensuring that plants are really able to sequester carbon,” Boyce says. “Now, some grazing is good… some level of grazing actually stimulates productivity, stimulates primary production, stimulates carbon sequestration and storage.”

Going forward, though, Boyce says more work needs to be done to maintain native grasslands, which are better at sequestering carbon because they have deeper taproots. When grasslands are tilled and seeded, the roots often don’t go deep enough to sequester carbon deep into the soil.

He also says that Canada needs a carbon registry.

“There are many reasons why it would make so much sense that we had a team of ecologists and atmospheric scientists putting together criteria for how one would deal with land use change, and reward landowners for doing it right, for managing their land appropriately.”

He says this would be beneficial for Canadian ranchers, as well, because currently, Canadian cattle producers can’t apply for carbon credits.

This article is part of a series. For more see:

• Longer rest period drives water infiltration in grazed pastures, researcher says
• AMP grazing no better for plant diversity than less intensive methods, U of A study finds

The post AUDIO: Grazing can AMP up carbon sequestration, U of A researcher says appeared first on Canadian Cattlemen.