Button grass toxic to livestock

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Image of button grass infestation
Severe button grass infestation in Queensland reduced mungbean yield by 69 per cent. PHOTO: Dr Bhagirath Chauhan, University of Queensland

Button grass (Dactyloctenium radulans) is a summer weed species that may provide valuable forage in Western Australia’s summer/autumn feed gap, but it should be grazed with caution as over-grazing can result in nitrate-nitrite toxicity for sheep and cattle.

In Queensland, button grass is a problem weed as densities of 10, 26 and 43 plants per square metre reduced mungbean yield by 36, 53 and 69 per cent respectively.

GRDC research by the Western Australia Department of Primary Industries and Regional Development (DPIRD) and the University of Queensland is studying button grass ecology to identify management opportunities.

Button grass can seed prolifically (up to 15,000 seeds per plant) and generally emerges in summer following rainfall, surviving as long as moisture is available. Where no follow up moisture is available, it is short-lived, setting seed in just six weeks. This means seed produced in early summer can germinate in late summer or autumn, if there is further rainfall.

Initial button grass seed germination ranges from less than five per cent in WA to 30 to 61 per cent in Queensland. Seeds lose their dormancy over a few months as the seed coat degrades. On the soil surface seeds generally germinate or degrade quickly with five to eight per cent of seed remaining viable after 12 months. However, seed buried at two centimetres or more will not easily germinate or degrade, with up to 50 per cent remaining viable after 12 months. Therefore, it is more effective to manage button grass in a zero-tillage system where more seeds are left on the soil surface.

More information

Dr Catherine Borger, WA DPIRD
0467 816 082
catherine.borger@dpird.wa.gov.au

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