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 the Birchip Cropping Group (BCG) as part of the GRDC’s Southern Barley Agronomy project investment, which is a collaboration between the South Australian Research and Development Institute (a division of Primary Industries and Regions SA), the New South Wales Department of Primary Industries and BCG.
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.
The Hindmarsh type group comprised Hindmarsh , Spartacus CL and La Trobe ; the Compass type group comprised Fathom , Scope CL , Compass , RGT Planet and Commander ; the Westminster type group comprised Westminster , Oxford and Grange R ; and the Urambie type group comprised Urambie .
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 high weed seed set).
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.
“Choosing a competitive variety and managing it to be competitive will help to reduce weed burdens and potentially reduce the amount of yield loss, when used as part of an integrated approach to weed control.”
She said determining the competitive ability of varieties would help in the development of management packages around new varieties to aid growers’ variety selection.
The overall aim of the Southern Barley Agronomy project is to improve grower productivity and industry sustainability through the successful adoption of improved barley cultivars.
Research is investigating agronomic practices to improve barley production in crop environments typical of Victoria, SA and southern and central NSW. Improved agronomy practices and packages for new varietal releases will be developed to align production with market and industry requirements.
Featured Image: BCG’s Linda Walters says non-herbicide weed control methods, such as sowing competitive barley varieties, are options that growers need to be considering when planning their paddock rotations. Photo: BCG