HOW TO USE THIS ONLINE MAGAZINE
by clicking the arrows at the side of the page.
by clicking anywhere on the page. A slider will appear, allowing you to adjust your zoom level.
and move the page around when zoomed in by dragging the page.
and return to the original size by clicking on the page again.
by entering text in the search field and click on "In This Issue" or "All Issues" to search the current issue or the archive of back issues
a PDF of this magazine.
by clicking on thumbnails to select pages, and then press the print button.
a page via email, Facebook, Twitter and more.
TO VIEW PREVIOUS EDITIONS
, click the
button at the bottom of the screen.
Beyond the Bale : Jun 07 - Jul 07
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: ú deliberation -- assessing where and how dense the weeds are (with early detection as the aim) and planning a realistic control strategy; ú diversity -- using several tools together to weaken and kill the weed and prevent it from having an adverse effect on the enterprise; and ú diligence -- persisting with a strategy to undertake correct weed-control measures, on time, every year, and paying close attention to entry sites and quarantine. 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 6WEED MANAGEMENT BEYOND THE BALE Serrated tussock strategy pays off A 20-year serrated tussock control program is one of the factors that has helped Murray and Barbara Stephenson double the carrying capacity on 'Brooklyn', at Binda, near Crookwell, NSW. When they bought the farm 25 years ago the weed was identified, but the extent of the problem was not realised until five years later, when it had spread rapidly across the 340- hectare property. It was only then that they realised it was such a prolific seeder, with new infestations rapidly occurring downwind from existing stands, or on land where soil had been disturbed. However, today the property has only isolated patches of serrated tussock, due to the Stephensons' diligence. The greatest impact of the serrated tussock infestation was on the carrying capacity of 'Brooklyn'. Where the weed was not controlled in the past, Murray estimated there was a large reduction in the stocking rate, as the weed competed with both introduced and native pastures.Today 'Brooklyn' carries 1700 Merino and first cross ewes, producing 1700 lambs a year. Little information was available about control methods 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: ú serrated tussock; ú Chilean needle grass; ú African lovegrass; ú Paterson's curse; ú silverleaf nightshade; and ú 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. ú when serrated tussock was first recognised as a problem and the Stephensons' approach was largely based on trial and error. They originally wanted to achieve maximum impact to control serrated tussock, and so their first approach was to plough out the weed from the worst-affected areas and introduce improved pastures, including clover, cocksfoot and ryegrass, in the hope that these would out-compete serrated tussock. Unfortunately, ploughing and cultivation encouraged the weed to spread further and the pasture species could not compete. Murray and Barbara soon learnt that it was necessary to treat the weeds with herbicide during the pasture- establishment phase. Serrated tussock also infests native pasture on 'Brooklyn', and in these places Murray and Barbara have relied on herbicide. The Stephensons have undertaken two key phases of the control program. For the first 15 years, they undertook an intensive spot spraying and pasture-improvement program, requiring about two weeks of full-time labour each year.This largely eradicated the larger patches of serrated tussock and reduced the number of new seedlings. Over the past five years, Murray and Barbara have been able to scale down their control program. Murray now spends only two days a year spot-spraying any new seedlings, with
Jun 07 - Jul 07 Supplement
Apr 07 - May 07