The reliance on chemicals has been deemed “too good to last” by WeedSmart, which is encouraging croppers to extend their weed knowledge and adopt a multi-pronged approach.
The industry-led group aims to promote the long-term sustainability of herbicide use on Australian broadacre farms.
WeedSmart’s way of achieving this is a method helpfully called the ‘Big 6'.
The ‘Big 6’ includes practices such as rotating crops and pastures, mixing and rotating herbicides, and double knocking (following a round of herbicide use with a different chemical or non-herbicide tool).
Double knocking is especially important when using glyphosate, which is the world’s most important herbicide.
Any possible resistance to this chemical needs to be stamped out immediately, according to WeedSmart.
WeedSmart’s Cindy Benjamin said no one tool would do the job anymore.
“Just as herbicides alone have failed, so too will harvest weed seed control or crop competition if they are not part of a planned and multi-pronged assault on the weed seedbank,” Ms Benjamin said.
“This is the underlying principal of integrated weed management.”
Economic models done in 2006 showed integrated weed management (IWM) had strong potential to out-perform herbicide-only systems, regardless of the weed in questions.
“Herbicides provide high level control and are considered an essential component of broadacre cropping systems, however, other tactics that specifically target weeds that have escaped herbicide control are what makes IWM systems more profitable in the long-run,” Ms Benjamin said.
“It will always be a numbers game and IWM consistently wins, usually by a considerable margin, primarily due to lower weed seedbank numbers and conservation of the highly effective herbicide resources for tactical use over time.”
When developing an integrated weed management plan it is useful to collate historical information about past weed control activities, test weeds for herbicide resistance and create a plan with your agronomist.
It is ideal to include three of more of the ‘Big 6’ tactics in each crop, fallow or pasture phase.
“Diversity is key,” Ms Benjamin said.
“Some people prefer to have a set cropping sequence while others choose the crops in response to seasonal or market conditions, but either way it is important to look for ways to add as much diversity to your farming system as possible and to keep downward pressure on weed numbers at every opportunity.”
For more information about managing herbicide resistance, visit: www.weedsmart.org.au
19°C