The effect of combinations of crop row spacing, seedbed utilisation and pre-emergence herbicides on ryegrass management in barley


Research organisatons
Funding source

Trial details

Researcher(s) Gurjeet Gill and Ben Fleet
Contact email
Contact phone 08 83137744
Year(s) 2019
Contributor School of Agriculture, Food and Wine - The University of Adelaide
Trial location(s) Site 3, Minnipa, SA
The effect of combinations of crop row spacing, seedbed utilisation and pre-emergence herbicides on ryegrass management in barley locations

Investigate the influence of barley row spacing, seedbed utilisation and herbicides on ryegrass management.

Key messages

The herbicide treatment had a significant effect on annual ryegrass (ARG) plant density (P<0.001) in this field trial at Minnipa. Favourable rain events in May were highly suitable for the activity of both pre-emergent herbicides investigated in this trial. Averaged across the row spacing and seed boot treatments, Trifluralin and Boxer Gold reduced ARG plant density by 20% and 90%, respectively. The density of ARG spikes was significantly influenced by the row spacing (P<0.001), seed boot treatment (P=0.027), and the herbicide treatment (P<0.001). The 25cm row spacing had 20% lower ARG spike density than the 37.5cm row spacing treatment. The splitter seed boot treatment had 12% lower ARG spike density than the narrow seed boot treatment. Trifluralin only reduced ARG spike density by 20% compared to the untreated control, whereas Boxer Gold caused a 73% reduction in ARG spike density. ARG seed production was also significantly affected by the row spacing (P=0.003), seed boot (P=0.01), and the herbicide treatment (P<0.001). The normal (25 cm) row spacing set 38% less seed than the wide row spacing. The splitter seed boot treatment also had 32% lower ARG seed set compared to the narrow seed boot. ARG produced 4792 seeds/m2 in the untreated control, which was reduced by 11% by Trifluralin and 69% by Boxer Gold. Presence of ARG at 262 plants/m2 in the untreated control, reduced barley grain yield by 8% compared to Trifluralin or 16% compared to Boxer Gold. However, it was still profitable to control ARG with effective herbicide treatments. Based on cash grain price of Feed Barley of $250/t in 2019, Trifluralin would be expected to increase the gross margin by $32/ha as compared $71/ha increase for Boxer Gold.

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 N/A

We thank GRDC for providing funding for this research project and Bruce Heddle for hosting this trial.

Other trial partners Not specified


Crop type Barley
Treatment type(s)
  • Herbicide: Type
  • Sowing: Method
  • Sowing: Row spacing
Trial type Experimental
Trial design Randomised,Replicated,Blocked

Minnipa 2019

Sow date Not specified
Harvest date Not specified
Plot size Not specified
Plot replication Not specified
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
Site 3, Minnipa, SA Not specified
Derived trial site soil information
Australian Soil Classification Source
Trial site Soil order
Site 3, Minnipa, SA Anthroposol
National soil grid Source
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.

Site 3, 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
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.

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Trial last modified: 19-05-2020 11:03am AEST