Combining no tillage farming and integrated weed management (IWM) strategies can reduce graingrower reliance on herbicides and help create long term sustainable and profitable cropping practices.
The University of Western Australia (UWA) Institute of Agriculture graduate, Frank D’Emden, won the 2006 Australian Agriculture and Resource Economics Society (AARES) masters thesis prize for a study on southern Australian grain growers’ adoption of conservation tillage.
His Co-operative Research Centre for Australian Weed Management (Weeds CRC) funded research highlighted the importance growers place on weed management issues in no till systems.
“Rapid no till adoption alone can lead to greater herbicide reliance and subsequent higher herbicide resistance risk, unless integrated weed management strategies are simultaneously implemented,” Mr D’Emden said.
No till farming, which is based on the absence of tillage, more diverse rotations and retaining stubble cover, is practised on more than 95 million hectares globally.
Adoption of no till in WA grain growing regions has increased significantly in the past 15 years and more than 80 per cent of WA broadacre farmers now practice one or more aspects of the system.
“While growers are aware of the soil conservation and seeding timeliness benefits of no till, they are equally concerned about the long term sustainability of weed management options in the system,” Mr D’Emden said.
“Growers face a trade-off between conserving soil and potentially developing increased reliance on herbicides.
“The universally popular knockdown herbicide glyphosate can remain a cost effective tool if growers apply it as part of an integrated management plan,” he said.
Glyphosate effectively substitutes for tillage and is recognised as one of the most valuable herbicides in modern farming systems, due to its cost effectiveness, broad weed control spectrum and safety.
“Although there are currently low levels of glyphosate resistance, WA growers need to be aware that this can change dramatically, so they should adopt IMW strategies now, including diverse crop rotations,” Mr D’Emden said.
He used a duration analysis approach to analyse the influence of lower glyphosate prices on the probability and timing of no till adoption.
“The significance of the glyphosate price reducing, relative to diesel, influences no till adoption, along with the perception that long term no till enables crop establishment with less opening season rainfall,” he said.
As Esperance Natural Resource Management (NRM) Development Officer, Mr D’Emden aims to show growers how to integrate environmentally and economically sustainable NRM investment into their business plans and provide information about how such investment can ultimately pay for itself.
“If no till is to be sustained in the southern wheatbelt, developing IWM practices compatible with no till systems is very important.”
Dr Rick Llewellyn, Mr D’Emden’s main supervisor at UWA, agreed the research was strategically important for the future of cropping systems in Australia’s southern wheatbelt.
“Frank’s research helps growers understand the key drivers of implementing profitable soil conservation practices and shows what might be needed for high adoption levels and, most importantly, sustained adoption in other regions,” Dr Llewellyn said.
“Growers place considerable value on locally generated information, especially local extension events and consulting services, which have been major drivers of no till and IWM adoptions.
“GRDC, CSIRO Sustainable Ecosystems, SANTFA and WANTFA are supporting further research based on Mr D’Emden’s thesis with a follow-up national study that involves revisiting growers and assessing current adoption practices to find the key to more rapid adoption in new regions.
“Further research will determine if on-farm improvements result from exposure to local no till adoption, including grower’s proximity to innovators and opportunities to observe the benefits of no till,” Dr Llewellyn said.
Frank D’Emden, Telephone (+61 8) 9083 1111
Dr Rick Llewellyn, Telephone (+61 8) 8303 8502
Professor Kadambot Siddique, Telephone (+61 8) 6488 7012, Mobile 0411 155 396