Effect of combinations of seed rate and herbicides on ryegrass management in wheat

CC BY 4.0

Research organisatons
Funding source

Trial details

Researcher(s) Ben Fleet
Gurjeet Gill
Contact email gurjeet.gill@adelaide.edu.au
Contact phone +61428592825
Year(s) 2020
Contributor School of Agriculture, Food and Wine - The University of Adelaide
Trial location(s) Minnipa, SA
Effect of combinations of  seed rate and herbicides on ryegrass management in wheat locations

This field trial at Minnipa was undertaken to investigate factorial combinations of seed rate and herbicides on the management of annual ryegrass in wheat.

Key messages

A field trial was undertaken at Minnipa in 2020 to investigate combinations of wheat seed rate and herbicide treatments to control annual ryegrass. The average seedbank of annual ryegrass (ARG) at the site was 2012 ± 461 seeds/m2. ARG plant density was significantly influenced by herbicide treatment (P=0.008). Boxer Gold and Sakura + Avadex controlled ARG plant density by 63% and 70% respectively. Consistent with the trends observed for ARG spike density, ARG seed production was also significantly influenced by herbicide treatments (P<0.001) and while not significant there was a trend towards suppression of ARG seed production when wheat seed rate was increased (P=0.096). When averaged across all the seed rate treatments, the untreated control produced 13,155 ARG seeds/m2. The Boxer Gold treatment reduced ARG seed set by 69% to 4,018 ARG seeds/m2, while the Sakura + Avadex treatment reduced it by 70% to 3,849 ARG seeds/m2. Such high ARG seed set even when using pre-emergent herbicides highlights the importance of an integrated weed management strategy that incorporates diverse crop options such as hay and includes other cultural methods such as harvest weed seed collection and improved crop competitiveness. Consistent with the level of ARG control, herbicide treatments had a significant effect on wheat grain yield with Boxer Gold (1.869 t/ha) and Sakura + Avadex (1.871 t/ha) both increasing grain yield by 35% compared to the control (1.384 t/ha).

Lead research organisation School of Agriculture, Food and Wine - The University of Adelaide
Host research organisation SARDI Minnipa Agricultural Centre
Trial funding source GRDC 9175134
Related program GRDC - Weeds

GRDC for funding this research project and the local farmer for providing land for the trial.

Other trial partners Not specified
Download the trial report to view additional trial information


Crop types Weed: Ryegrass Cereal (Grain): Wheat
Treatment type(s)
  • Herbicide: Type
  • Sowing: Rate
Trial type
Trial design

Minnipa 2020 Ryegrass

Sow date Not specified
Harvest date Not specified
Plot size Not specified
Plot replication Not specified

Minnipa 2020 Wheat

Sow date 6 May 2020
Harvest date Not applicable
Plot size Not specified
Plot replication Not specified
Download the trial report to view additional method/treatment information
Trial source data and summary not available
Check the trial report PDF for trial results.
Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Minnipa, SA Not specified
Derived trial site soil information
Australian Soil Classification Source: ASRIS
Trial site Soil order
Minnipa, SA Calcarosol
National soil grid Source: CSIRO/TERN
NOTE: National Soil Grid data is aggregated information for background information on the wider area
Actual soil values can vary significantly in a small area and the trial soil tests are the most relevant data where available

Soil properties



Derived climate information

No observed climate data available for this trial.
Derived climate data is determined from trial site location and national weather sources.

Minnipa SA

NOTE: Exact trial site locality unknown - Climate data may not be accurate

Some data on this site is sourced from the Bureau of Meteorology

SILO weather estimates sourced from https://www.longpaddock.qld.gov.au/silo/
Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data , Environmental Modelling and Software, Vol 16/4, pp 309-330. DOI: 10.1016/S1364-8152(01)00008-1.

Trial report and links

2020 trial report

Trial last modified: 20-03-2023 16:20pm AEST