Barley varieties prove their competitive edge over weeds

SOME new varieties of barley offer grain growers a non-herbicide option for grass weed control in low rainfall cropping zones due to the varieties’ weed competitive nature.

Three years of data gathered during a Grains Research and Development Corporation (GRDC) barley agronomy research investment have reinforced that certain varieties are more competitive than others in suppressing weeds.

The competitive nature of varieties has been investigated by GRDC’s Southern Barley Agronomy project investment.

Birchip Cropping Group (BCG) research officer Linda Walters says with the increasing prevalence of herbicide resistance limiting growers’ weed management options, it is important that alternative weed control methods are looked at as part of an integrated weed management approach.

“Non-herbicide methods, such as sowing competitive barley varieties, are options that growers need to be considering when planning their paddock rotations,” Ms Walters said.

Weed competition trials were established by BCG at Nhill in Victoria’s West Wimmera in 2013 and 2016, and at Curyo in the Southern Mallee in 2017.

Oats with vigorous early growth and early maturity were used to simulate brome grass weeds.

The varieties were divided into four types representing different plant architectures and growth habits that may influence competition – Hindmarsh type, Compass type, Westminster type and Urambie type.

Results from each of the three years of trials were consistent, showing that Compass type varieties that exhibit good early vigour and a prostrate canopy structure have a greater ability to compete (lowest yield loss) and reduce weed seed set.

These varieties – especially RGT Planet, Fathom and Compass – were considered to be the best options if sowing into high weed burdens.

Hindmarsh type varieties with a slow early vigour and erect growth habit had the poorest ability to reduce weed seed set.

However, La Trobe offered slightly better competition than other Hindmarsh type varieties.

Urambie type varieties were the worst competitors, with the highest yield losses over the three years of data and Westminster types were rated as poor to moderate weed competitors.

Ms Walters said selecting a barley variety was a decision that should be viewed as part of a long-term strategy, with an overarching aim to reduce seed bank levels and to maintain or improve the productivity of the paddock.

Ms Walter’s GRDC Grains Research Update paper can be viewed via grdc.com.au/resources-and-publications/grdc-update-papers.