News & Media

Agribusiness Crop Updates 2013: Compete with weeds using paired row sowing

Released on

Released on:
Monday, 18. February 2013 - 13:15

Results of a project comparing crop sowing techniques to better manage weeds will be delivered at the 2013 Agribusiness Crop Updates.

Herbicide-resistant weeds are common throughout the Wheatbelt and with the problem expected to increase over time, the development of effective non-herbicide strategies is vital.

Research by the Department of Agriculture and Food, funded by the Grains Research and Development Corporation, which demonstrates the benefits of improved crop competition on weed growth and crop yield will be discussed at the Agribusiness Crop Updates on 25 and 26 February.

Led by research officer Peter Newman, the project evaluated the interaction between paired and single row sowing, wheat seeding rates and herbicides to assess the various benefits of increased crop competition.

“Crop competition is one of very few effective non-herbicide weed control tools available to Western Australian grain growers,” Mr Newman said.

“Weeds compete with crops for resources, the crops need to fight back or the weeds will win.

“Our research confirmed the outcome of previous crop competition trials – that as crop density increases, crop biomass increases and weed growth and seed set decreases,” he said.

The two department trials were sown with Mace wheat on sites with high weed densities; one in Mingenew with ryegrass and the other at Binnu with wild radish.

Paired row sowing of the wheat was achieved by mounting a Stiletto seeding boot onto a single tyne and spacing paired rows 75mm apart.

“The paired rows effectively doubled the length of crop row in a paddock compared to a single crop row at the same row spacing, reducing in-row competition between crop plants and resulting in a higher number of crop seeds germinating,” Mr Newman said.

“Grain samples processed for screenings, hectolitre weight and protein from both trials demonstrated no negative effect on grain quality from the increased seeding rate.

“The Mingenew site clearly verified the benefits of increased crop density, with a 65 per cent reduction in ryegrass seed set when comparing low and high seeding rates in an area that received no ryegrass herbicide.

“The area treated with pre-emergent herbicide also benefited from high crop density via paired row sowing, increasing the effectiveness of Sakura® herbicide from 95 per cent to 99 per cent reduction in ryegrass seed set.”

The Binnu trial confirmed that increased crop competition also has an effect on wild radish, with increased wheat density resulting in a significant reduction in wild radish biomass.

Mr Newman said the research clearly demonstrated the benefits of crop competition as a non-herbicide control method for both ryegrass and wild radish. The challenge will be to work out a cost-effective way to increase crop competition with weeds.

To learn more about the crop competition for weed control, register for the 2013 Agribusiness Crop Updates by visiting

Media contacts: Jodie Thomson, media liaison                         +61 8 9368 3937