Thousands of grain producers will be put under unnecessary pressure to rethink sustainable farming practices that benefit the environment if proposed changes to the use of two key herbicides are approved.
This is according to Grain Producers Australia Southern Region Director Mark Schilling, who is just one of thousands of grain producers who rely on timed applications of paraquat and diquat in their programs to ensure a strong harvest result.
The practice of desiccation as a use pattern is set to be banned under changes proposed by the Australian chemical regulator that are currently out for public consultation open until the end of October.
“We’re faced with the issue of whether making sustainable choices for our farming systems by growing pulses is even possible," he said.
"Pulses offer soil nutrition benefits and allow us to control weeds that can host pests and diseases in a way not possible while growing cereal crops."
The Australian Pesticides and Veterinary Medicines Authority (APVMA) flagged a number of potential rate of use or practice changes for the two chemicals in late July.
Having the ability to use paraquat and diquat in this way allows growers to grow pulse crops that naturally benefit soil nutrition through nitrogen fixation, control weeds such as ryegrass that are perpetually at risk of developing resistance to other herbicides and successfully harvest profitable pulse crops.
Mr Schilling, who is a grain grower on the Yorke Peninsula in South Australia, said the fragile nature of ripening seed pods and tendency for pulse crops to ripen unevenly makes desiccation an important practice to ensure seed quality and yield can be maximised.
In October and November, when pulses are typically harvested, weather stresses from heat or wind are a risk that can be reduced with timely desiccation and harvest.
Mr Schilling said strong winds were a particular concern in this period of crop development and if growers couldn't desiccate pulse crops to manage harvest timing, they faced up to 30-40 percent in yield losses from just one wind event.
“Pulse crops have so many benefits in cropping rotations, particularly as they fix nitrogen to the soil, which reduces reliance on artificial inputs," he said.
“The real issue we face is that without being able to desiccate our pulses, we can’t capture our crops in that key window to evenly ripen for best yield outcomes and kill off ryegrass that is about to seed.
“Growing pulses that can’t be desiccated may end up being an economical and risk-based decision that growers may choose to opt out.”
Mr Schilling said more research was needed to develop suitable chemicals for weed control and pulse varieties and practices that are not reliant on desiccation for harvest.
The APVMA makes decisions for approved uses of chemical products based on human, animal or environmental safety risk factors by consulting scientific information and estimating potential risk.
A number of other common uses of paraquat and diquat are set to be banned or altered as a part of the APVMA review that will affect not only the grains industry, but other commodities such as bananas, orchards and vineyards, potatoes and rice.
Among the reasons the uses of paraquat and diquat have been assessed as a risk relates to environmental and animal exposure concerns.
GPA Interim Chief Executive Pete Arkle said it is important for industry and growers to inform the APVMA consultation process with relevant Australian examples of how the chemicals are used in practice and other relevant environmental and animal data.
“GPA has concerns the science being relied on in the APVMA review are not real-world examples that represent how these chemicals fit within Australian context,” he said.
“GPA is preparing a submission to the APVMA process and is calling for spray data from growers to help inform our work.
“Whether this is from automated systems, or your on-farm rates, dates and crop type, this is all useful information.”
ENDS
Further information:
GPA Southern Region Director Mark Schilling - 0408 859 308
GPA Interim Chief Executive Pete Arkle - 0488 772 656
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