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The role of grazing in integrated weed management

Jack Arterburn for Progressive Cattle Published on 22 May 2020
Cow grazing

Integrated weed management is a strategy combining various preventative and control practices focused on increasing the effectiveness and reducing the cost of managing weeds.

Weeds often require multiple control methods to overcome their resilience (e.g., herbicide resistance, root sprouting), making the use of multiple control methods necessary. An integrated strategy involves implementing practices to limit the introduction and spread of weeds, providing desirable species an advantage when competing with weeds and preventing weed adaption to management by alternating and implementing a combination of weed management practices.

Loss of plant community diversity from weed invasion reduces grassland resilience to disturbances, such as drought and fire. Unfortunately, because many invasive weeds are prolific seed producers, once they are established, elimination from a pasture or range is difficult. Management should focus first on prevention, then on controlling the spread and reducing the prevalence of weeds by giving desirable species a competitive advantage and addressing underlying management problems.

Herbicides are a weed management option, although they pose many challenges. New infestations can often be controlled with herbicides, but if infestations become established, herbicide effective decreases. Herbicides can also be expensive and often become financially and logistically prohibitive if infestations establish and spread, especially in areas difficult to access. Herbicides can also negatively impact non-target vegetation, including desirable species that compete with weeds.

Grazing plan approach

Proper grazing management is a long-term strategy to minimize weed establishment by promoting the health and vigor of desirable species, which provides a competitive advantage over weeds. Appropriate stocking rates and a grazing plan that provides growing season recovery of desired plants are fundamental principles to encourage plant health and vigor. The rest period for a pasture that results in full recovery of a plant prior to being grazed again is a key to grazing management success.

Timing of grazing is an important aspect of a grazing plan. Livestock will focus first on the most desirable species, especially those actively growing and close to water. However, this is often when plants are most susceptible to overgrazing. To reduce the negative impacts of grazing, change the timing of when pastures will be grazed so that a pasture is not grazed at the same time each year during the growing season. Consider a deferred rotation grazing system that periodically allows pastures a full growing season deferment, which results in desirable species being grazed only after they have reached maturity.

Target your grazing

Targeted grazing can also be used to directly control and reduce invasive plants. Before reaching maturity, many invasive plants are palatable and highly nutritious. Targeted grazing attempts to capitalize on the different grazing preferences of cattle, sheep and goats to produce grazing income from weedy species instead of an expense.

Cattle primarily select for grasses but will also graze forbs. Conversely, sheep prefer both forbs and grasses, and goats are primarily browsers, selecting first for woody plant parts and secondarily for herbaceous plants. Taking advantage of these grazing differences can diversify an operation and utilize weedy species as a feed resource for livestock while reducing the expense of controlling weeds.

For example, short, intensive grazing periods can be used to control invasive grasses such as cheatgrass (downy brome, Bromus tectorum). Cheatgrass is highly nutritious early in its growth before quality sharply declines once seeds are produced. The goal is to set back cheatgrass and reduce seed production with heavy grazing, reducing its competitiveness and giving desirable perennial species an opportunity to compete for resources.

As soon as an area has adequate cheatgrass growth to support grazing in the fall, winter and spring, turn cattle out or fence them in an area of heavy infestation. The time frame for effective targeted grazing of cheatgrass is often short and varies each year depending on soil moisture and temperature. Cattle will frequently shift their preference from grazing cheatgrass to desirable, perennial grass species when cheatgrass matures. Once this occurs, it is crucial that cattle quickly be removed to allow desired species to have the opportunity to grow and compete with cheatgrass. Providing adequate growing season rest to encourage the vigor and health of perennial grass species will help them compete with cheatgrass.

Sheep and goats complement cattle by capturing value from broadleaf weeds. Both sheep and goats will graze herbaceous weeds, such as thistles, and goats will also select for tree and shrub leaves.

Sheep and goats can often be added to a cattle operation with little to no loss of cattle grazing because of the differences in diet preferences of the species. Consider grazing sheep and goats ahead of cattle in a pasture rotation to allow sheep and goats to target weedy species often fouled by cattle. Goats can help control the spread of woody species by selecting for saplings and have even been known to select for and eat juniper trees.

Summary

An integrated weed management plan that uses various preventative and control practices to ensure early detection of weeds and rapid response is an important part of a grazing management plan. To prevent and detect spread, manage edges of infestations first and with the greatest intensity while scouting areas with no infestation the most. Focused management that promotes desirable species, prevents weed establishment and, where possible, captures value from weedy species may provide additional options but increases grazing animal management.

Learn to identify new and existing weeds in the area and vigilantly survey pastures for weeds. Once a weed is located, execute an integrated management plan to prevent seed production and spread. Continued monitoring of treated areas, even if plants have been eradicated, is critical to ensure no new seedlings have sprouted from seeds or root systems.

Weed invasion is not a new issue and will continue to be an issue for generations. Consider the development of a long-term integrated weed management plan to encourage desirable plant species and minimize new weed establishment using proper grazing management and targeted grazing. An effective, long-term management strategy can be the difference between an annual expense and an opportunity to grow the business and pass it on to the next generation.  end mark

PHOTO: A heifer grazes cheatgrass as part of a study using GPS collars to track grazing site preference. Photo provided by Mitch Stephenson, UNL range and forage specialist.

Jack Arterburn is a Nebraska Extension Beef Systems educator for northwest Nebraska and a member of the University of Nebraska Beef Team.

Jack Arterburn
  • Jack Arterburn

  • Extension Educator – Beef Systems
  • Nebraska Extension
  • Email Jack Arterburn

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