Weed management - Weeds need strategic attack
Careful planning and timely use of several weed and pasture management tactics are the keys to cost-effective weed management, according to a new set of weed-control guides and case studies from AWI
With more than $40 million spent each year on weed control in the sheep industry alone, and a further $1.8 billion lost through diminished production and pasture quality, weeds are a massive financial burden on Australia’s livestock industries.
Elisa Heylin, AWI’s project officer for sustainable production systems, says drought conditions and patchy summer rainfall mean woolgrowers have to be particularly vigilant about weeds this year. She points out that pastures degraded by drought are vulnerable to weed invasion, and early action to stop weed entry and seed setting is clearly the best strategy to reduce the impact of weeds. “As most weeds thrive on bare ground and respond quickly to rain, they often establish readily after drought, and can be difficult to remove if not treated early.”
Dr Heylin says the longer-term recovery of healthy pastures can depend on effective and early weed management. Particular attention should be paid to areas where stock has been fed and where new weeds could have come in with purchased feed.
AWI, together with Meat and Livestock Australia (MLA), has released a series of new weed-management guides and case studies. These outline three key steps to managing weeds in a grazing system:
- deliberation – assessing where and how dense the weeds are (with early detection as the aim) and planning a realistic control strategy;
- diversity – using several tools together to weaken and kill the weed and prevent it from having an adverse effect on the enterprise; and
- diligence – persisting with a strategy to undertake correct weed-control measures, on time, every year, and paying close attention to entry sites and quarantine.
These ‘3Ds’ of weed management in grazing systems can help reduce the costs of weeds. They focus on implementing a program of weed management rather than simply spraying weeds as they emerge. In fact, a pasture that is competitive at the right time can stop many weeds from establishing in the first place. Careful planning and timely use of several weed and pasture management tactics are the keys to cost-effective weed management.
AWI and MLA determined through a workshop and surveys the six weeds to be the highest priority for the southern grazing region, and the weed-management guides provide detailed information for these:
- serrated tussock;
- Chilean needle grass;
- African lovegrass;
- Paterson’s curse;
- silverleaf nightshade; and
- Onopordum thistles (Scotch thistle and Illyrian thistle).
The publications, include a best-management-practice guide for each of the six weeds and four case studies for each weed of how graziers in NSW and Victoria are managing them. The case studies include the weed-management program used on each farm, how it has worked and the economic benefit or cost of the strategies.
The case studies illustrate the range of strategies used to best suit each situation. “The key message from all of the farms is that if you can find one of these weeds early enough, do all that you can to remove it, as once weeds are established it becomes much harder, or even impossible, to eradicate them,” Dr Heylin says.
See also: Serrated tussock strategy pays off
Return to Beyond the Bale Issue 28 index page.