Weeds under control: Professor Leslie Weston holds some panic grass. Photo: supplied

Tackle summer weeds to reduce seed bank

Recent rain means summer weeds are flourishing and researchers from the Graham Centre for Agricultural Innovation say careful management and correct identification are crucial to tackling the problem in fallow paddocks.

Recent rain means summer weeds are flourishing and researchers from the Graham Centre for Agricultural Innovation say careful management and correct identification are crucial to tackling the problem in fallow paddocks.

Charles Sturt University (CSU) Professor Leslie Weston and Dr William Brown’s research through the Graham Centre focuses on weed and crop management.

“Fleabane, panic grasses including hairy panic and witchgrass, windmill grass, wild melons and feathertop Rhodes grass are important summer fallow weeds encountered across southern Australia.

“They cost producers considerable amounts of money in control, reduce soil moisture and impact on livestock health,” Professor Weston said.

Dr Brown said summer rainfall allows for the germination and spread of warm season weedy species.

“The shift to no-tillage cropping systems and stubble retention in fallow can result in greater soil moisture throughout warm summer months, facilitating weed growth,” Dr Brown said.

“The reduction in use of grazing livestock in crop paddocks to remove summer fallow weeds has also increased need for use of herbicides for summer weed management.

“Some summer weeds are either tolerant or even resistant to the use of systemic herbicides such as glyphosate and contact herbicides such as diquat or paraquat so careful management coupled with correct identification is important to limiting the spread of these summer weeds.”

The researchers said reducing the seed bank now will have an impact on the weed burden in coming years.

“A combination of integrated weed management (IWM) practices and timely chemical control strategies will result in reductions of summer fallow weeds and also reduce inputs into the weed seed bank over time,” Professor Weston said.

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