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Weed Management

Bayer Crop Science

Roundup Use In Grassland

Selective Weed Control

Roundup can be used to control difficult weeds in existing grass leys where reseeding is impractical due to soil type or being located in environmentally sensitive areas. It is also ideal where restricted pasture or high stocking levels do not allow for the stock exclusion period required by selective broad-leaved herbicides. Applications are made using the weed wiping technique. Under Cross Compliance rules, (GAEC 11), there is also an obligation to prevent the spread of certain noxious and non-native invasive weeds. Spot treatment is allowed even within buffer zones where spraying would not normally be allowed, such as field boundaries under GAEC 14. More detailed notes on spot treatment in paddocks and field borders are available.

Provided seeds have not matured, treated seeds will be killed ensuring minimum seed return.

Target weeds include:

  • Broad-leaved Dock

  • Curled Dock

  • Creeping Thistle

  • Spear Thistle

  • Bracken

  • Common Nettle

  • Ragwort

Stock Exclusion: Because of the high safety and environmental profile of Roundup, grassland with no poisonous weeds can be wiped and grazing animals returned as soon as the leaves are dry. This allows maximum utilisation of pasture and ease of pasture management.

In grassland with poisonous weeds, safe and effective control can be achieved by allowing 5 days undisturbed after wiping to allow herbicide to be translocated to the roots before cutting and removal of poisonous weeds. This way grazing can be resumed and weeds will not re-grow.

Caution: Treated poisonous weeds (including Ragwort, Hemlock, Water Dropwort and Bracken) must be removed or allowed to completely degenerate before re-grazing or conserving.

Grassland Renewal

As swards age the original grass mixture is out-competed and weeds begin to dominate. When re-seeding Roundup is widely used to ensure effective destruction of worn-out grass leys and pastures, as it will completely kill deep-rooted grasses and perennial weeds. The clean start provided enables successful grass establishment and maximised grass production.

A newly sown sward gives much more flexibility in grassland management. New swards have a much longer growing season than old permanent grass, this is especially true for those based on current varieties of Italian Rye-grass or late growing Perennial Rye-grass varieties.

Caution: Direct drilling should not be carried out into treated long-term leys in the same autumn where there is any mat. Direct drilling can be carried out after 5 days on 1-2 year leys without mat. Where cultivations of any sort have taken place there are no restrictions on drilling.


  • Weed Management

    Roundup Best Practice: Seed Germination

    All agrochemicals need to target weeds in a receptive condition to achieve the best results. Factors affecting the performance of Roundup are detailed in this section to help achieve the very best results every time it is used.

  • Weed Management

    Roundup Best Practice: Growth Stage

    All agrochemicals need to target weeds in a receptive condition to achieve the best results. Factors affecting the performance of Roundup are detailed in this section to help achieve the very best results every time it is used.

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