You might think you know your land inside and out, but getting back to basics can improve pasture productivity.
“It’s important to look at this basic stuff because it helps tune the eye,” said Ross Adams, range management specialist with Alberta Environment and Parks.
“It’s easier to integrate livestock into the system if you understand the behaviour of the rangeland system and the grazing animals.
“Your management will be better if the underlying behaviour of the system is better understood.”
Effective range management focuses on the land, animals, and grazing system, said Adams in a July 16 Cows and Fish webinar.
“No two ranches — and no two pastures — are the same,” said Adams. “There’s no one-size-fits-all approach. It requires monitoring and the application of a set of fairly simple principles that allow beneficial grazing systems to be developed to address the unique challenges in an operation.”
While the tactics may vary from ranch to ranch, the underlying principles are the same across the province: Balancing forage supply and demand; avoiding grazing during vulnerable periods; distributing livestock impacts across the landscape; and allowing for effective rest.
“It’s about managing grazing activities on rangeland in a way that recognizes the natural constraints of ecosystems and applies the principles of range management,” he said.
Balancing forage supply with demand is the first — and most important — step.
“If too much is being consumed, there’s really no way to manage around that,” said Adams.
‘Decreasers’ versus ‘invaders’
Forage supply will depend on things such as moisture, soil health, topography, plant communities in the pasture, litter, the level of disturbance — basically anything that impacts plant health and growth.
“All of those will come together to determine the composition of the community and influence how productive those plant communities are.”
Some plants — called ‘decreasers’ — are relatively intolerant of grazing disturbances.
“They’re called decreasers because, as grazing or other disturbance intensity increases, they tend to decrease in dominance,” he said.
“They are replaced in the stand by increasers or invaders, which are more tolerant of disturbance. They’re usually more grazing tolerant, but are also usually shorter in stature, less productive, and in many cases less palatable.”
As the level of grazing increases, the plant community starts to shift from highly productive decreaser species to one that is less productive and less attractive to livestock.
“Comparing very heavy grazing to light or moderate grazing, you’re going to have a much more productive plant community at those light to moderate levels of disturbance than at heavy or very heavy.”
But productivity isn’t the only consideration, he added.
“Plants need to maintain enough leaf tissue that they’re able to meet their growth needs, maintain their root systems, and set seed for the next growing season,” he said. “If too much of that leaf material is removed by grazing animals, the plant will begin to lose vigour and productivity, and at high levels of disturbance, the plant may die.
“It’s important to recognize that some fraction of productivity must be left to maintain the plants to keep them on the land.”
Avoiding grazing during vulnerable periods — the next tenet of effective range management — is also key.
“For range plants in Alberta, they’re most vulnerable when they’re coming out of dormancy and initiating new growth in the early spring,” he said.
That’s when plants draw on stored carbohydrate reserves from the previous year to initiate growth. By the early part of summer, plants have enough leaf material “to meet their fuel demands,” and can tolerate grazing better.
“If grazing is done in this early period when they’re relying entirely on stored sugars, this can really weaken plants and limit growth and productivity later in the growing season,” he said. “It requires the plants to dig deeper into limited carbohydrate reserves to replace those leaves that are lost to grazing.
“But if grazing is deferred later into the season once they have more leaf tissue above ground, the impacts of grazing are much less severe.”
Distributing livestock evenly reduces the impacts of grazing.
“Livestock are attracted to certain features on the landscape, and if left to their own devices, they will avoid other areas,” said Adams. “Over time, we need to overgraze the preferred areas and leave forage resources unused in areas they’re less likely to visit.”
Active management of livestock distribution means understanding what makes your animals tick. Cattle tend to prefer spending their time close to water sources, on open grasslands, and on level terrain. So you may need to develop water sources in under-utilized areas or herd the animals to other parts of the pasture in areas of rough terrain, he said.
More predictable forages
The final consideration is providing enough rest after grazing — “and this means growing season rest.”
“Plants need time to replace lost leaf material, build up stores of carbohydrates before the next growing season, and to set seed and complete their lifecycles. This can only be done during the growing season,” he said.
“Plants that have been heavily grazed will require more time and more rest to recover than lightly grazed plants.”
Plant type will also play a role in that, he added.
“Grasses have their growing points at or near the soil surface, so unless vegetation is being very closely cropped, there will be some growing points after grazing to initiate new growth,” he said.
“But on trees and shrubs, the growing points are up in the air, and if they’re grazed off, that effectively turns off that part of the plant. So it takes trees and shrubs a much longer time to recover.”
These foundational range management practices already exist on ranches across Alberta, said Adams, but by seeing your pasture with fresh eyes and a beginner’s mind, you can manage the land more effectively — and make the most out of your productivity.
“The benefits of a stewardship approach to rangeland management is that it provides a more stable and predictable forage base from year to year,” he said.
“If you know how the system works and how you would expect it to behave, you can anticipate how systems might respond to different disturbances and how to address an issue when it does come up.
“It allows you to be proactive rather than reactive.”