Thursday, February 20, 2025

Proposed desiccation ban jeopardises pulse crop viability: GPA

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Grain Producers Australia (GPA), Media Release, 8 October 2024

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.”

For more information visit www.grainproducers.com.au.

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