Managing weeds in grazing pastures

Weed management requires planning, integrated control approaches and follow-up. For the most effective weed control you should consider weed ecology: habitat, how they spread and susceptibility to control methods.

Weed control on a whole-of-catchment scale will often achieve the best results. Local Natural Resource Management (NRM) groups can help facilitate this kind of weed management by providing information, networks, and sometimes funding.

Invasive plants in Queensland

The Biosecurity Act 2014 protects Queensland's economy, biodiversity and people's lifestyles from the threats posed by invasive plants.

Under the Act, certain species are listed as prohibited or restricted or may be declared by a local government under local laws. These species have specific requirements that anyone dealing with them must follow. This could be reporting it and not keeping, moving, giving away, selling, or releasing it into the environment without a permit.

Regardless of whether an invasive plant is on a list or not, if it poses a risk to others or the environment, by law, everyone has a general biosecurity obligation (GBO) to take all reasonable and practical steps to minimise the risks associated with invasive plants under their control.

Reducing weeds in new pastures

Weeds can be a major problem for you when establishing new pastures as they compete with sown pasture for sunlight, moisture and nutrients. Weeds are often worse in old cultivation ground.

To reduce weeds when establishing pasture:

  • spray herbicides to control grass weeds, but be careful with young legumes as most herbicides can damage them
  • plant grasses then over-sow with legumes once the grasses are established (for broadleaf weeds). Broadleaf herbicides can then be used in the establishment phase of the grass.

Reducing weeds in established pastures

Weeds are also a problem in established pasture. They can be toxic to animals, harbour feral animals, play host to insects or diseases, and affect the operation of machinery.

Physical weed control methods

Physical control measures, such as hand pulling, cutting or digging are effective with many weeds (especially woody species) however some species re-sprout if they are only cut back.

Find out more about physical weed control methods.

Using fire on weeds

Burning is useful for some species, but effectiveness varies with plant age, density of infestation and fire intensity.

Find out more about managing grazing land with fire.

Using herbicides

Herbicides may be effective, but can be expensive and time-consuming. A local spraying program is useful when treating individual plants.

Find out more about chemical weed control methods.

Developing a weed management plan

Weed management should be included in your pasture management plan. When managing weeds, it's important to:

  • be aware of existing and potential weed species on your land
  • be alert for new weeds before they become a problem and act early
  • use a variety of management methods such as burning, grazing management, herbicides and biological control
  • have a weed action strategy in place or arrange a spraying program with neighbouring property owners
  • prevent the introduction of new weeds and the spread of existing weeds by controlling the movement of stock and ensuring hay, feed, machinery and vehicles are not carrying seeds
  • monitor the success of weed control strategies for future reference.

Find out more about controlling weeds on your property.

Managing feathertop wire grass

Feathertop wire grass is a native perennial tussock grass that degrades the value of many Queensland pastures. It is recognisable by long thin leaves and a thin stem, with a distinctive tuft of wispy white hairs at the base of the leaves.

Seedlings grow quickly, producing new seed heads 6 to 8 weeks after wet conditions, especially between October and March. Greatest seed production is usually from March to April and longer if it is a wet season.

Feathertop infestation in sheep

In sheep, feathertop infestation can lead to wool discolouration and cotting (matting of wool), ill thrift and reduced wool production. Feathertop's dart-like seed is a major irritant to sheep, and shearing is the only way to relieve the pain it causes.

An avoidance strategy involves moving sheep once the seed changes from a green colour and starts to produce the seed head. However this depends on the availability of feathertop-free paddocks or agistment grazing land with sufficient pasture to feed stock for up to 8 weeks. Spell infested paddocks or stock with cattle.

Using fire on feathertop

Burning feathertop is viable if more than 25% of the pasture is feathertop, conditions are safe for burning and the pasture can be spelled for the following summer. Using a rating system for feathertop infestation will help you to decide the best management strategy to adopt.

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