Resource showcases weed and lime strategies
Date: 05 Apr 2017
Investigating options for herbicide resistance management and lime incorporation in Western Australia’s northern wheatbelt is an initiative of the Grains Research and Development Corporation (GRDC) Kwinana East port zone Regional Cropping Solutions Network (RCSN) group.
GRDC Western Regional Grower Services manager Roger States said the Kwinana East RCSN representatives initiated a bus tour and production of the associated publication after identifying lime and herbicides as the inputs that impacted the most on their profitability.
“Growers in the low rainfall eastern wheatbelt face highly variable seasons and manage the risk associated with this by maintaining low input farming systems,” he said.
“Major issues the Kwinana East port zone RCSN identified were management and costs associated with herbicide use and lime incorporation.”
Mr States said Geraldton port zone growers had been particularly proactive in using strategies to address herbicide resistance issues and management of soil acidity throughout the soil profile.
“With this in mind, the Kwinana East port zone RCSN prioritised a bus tour to WA’s northern cropping areas in 2016 to visit growers identified as using practices that could be applied to their own low rainfall, eastern wheatbelt environment,” he said.
“The northern growers included those trialling tactics such as mouldboard ploughing or rotary spading to incorporate lime; using high rates of lime to hasten pH change; or managing herbicide resistance by using chaff carts, windrow burning, mouldboard ploughing, chemical fallow, tactical grazing and other methods.”
He said the publication, which includes links to additional resources, outlined how soil acidity was the most severe and widespread of subsoil constraints affecting WA grain growers and represented the highest risk to production.
“Research conducted by the Department of Agriculture and Food (DAFWA) estimates soil acidity costs WA growers on average $141 per hectare per year which equates to $1.6 billion per year in lost production potential,” he said.
“Of the strategies to manage subsoil constraints, liming is estimated to have the most potential to increase profitability – by about $63/ha/yr.”
Mr States said surveys conducted by the Australian Herbicide Resistance Initiative (AHRI) in 2003 and 2010 had shown that while the incidence of herbicide resistance in annual ryegrass had remained relatively stable in the Kwinana East zone, this was not the case for wild radish.
“In 2010, 60 per cent of wild radish populations sampled were resistant to 2,4-D amine, 100 per cent were resistant to chlorsulfuron and 70 per cent were resistant to products such as Intervix® - (imazamox (33g/L) plus imazapyr (15g/L) formulation),” he said.
Roger States, GRDC
0427 565 780
Julianne Hill, GRDC RCSN initiative
0447 261 607
Natalie Lee, Cox Inall Communications
0427 189 827
GRDC Project Code GIA00005-A