High Rainfall Zone Ryegrass
Ryegrass management in Southern Australian high rainfall zones.
Project: Demonstrating local strategies to enable integrated and profitable management of annual ryegrass seed banks in high rainfall zone (HRZ) farming systems of Australia.
The Weed Science Research Group led this project, collaborating with Southern Farming Systems and Mackillop Farm Management Group, funded by the Grains Research and Development Council (GRDC).
Demonstration sites
Each site contained four annual ryegrass management strategies of increasing intensity, which were developed with local agronomists. The aim was to demonstrate which strategies provide effective and profitable ryegrass management in the Australian HRZ. Locations, plot layouts, management strategies and data collected for each demonstration site are shared within the tabs below.
- Five sites were established in 2018 and sown to break crops, and then cereals in 2019.
- Three sites were continued for 2020: Frances (Faba Beans), Berrybank (Wheat) and Hamilton (Spring-sown Chickpea).
Project catalyst
Widespread resistance to post-emergent herbicides used in cereals means there is strong reliance on pre-emergent herbicides for annual ryegrass control. Annual ryegrass seed banks in the HRZ tend to be high and there is late emergence of weeds due to the long and cool growing season. These late emerging plants contribute to high seed set that maintains populations. As a result, annual ryegrass populations quickly rebound when management pressure is reduced.
Late maturity of cereals means that 50% or more of the ryegrass seed can be shed prior to harvest, reducing the efficacy of harvest weed seed controls. On the positive side, moderate populations of annual ryegrass (<100 plants per m2) have less impact on yield than they do in other regions.