Control of barley grass in a pasture-wheat-barley rotation

2019 - 2021

Research organisatons
Funding sources

Trial details

Researcher(s) Catherine Borger (DPIRD)
Madi George
Brad Joyce (ConsultAg)
Tiarna Kanny
Contact email catherine.borger@dpird.wa.gov.au
Contact phone 0467816082
Year(s) 2019 - 2021
Contributor Department of Primary Industries and Regional Development WA
Trial location(s) Yandanooka, WA
Related trials
Control of barley grass in a pasture-wheat-barley rotation locations
Aims

Barley grass is becoming an increasingly problematic weed in Western Australia. A GRDC funded project sought to increase adoption of integrated weed management tactics for barley grass, by working with grower groups to develop regionally appropriate rotations for optimal control.

A survey indicated that in growers in the northern wheatbelt felt that barley grass was most likely to be a major problem in pasture, and a common response is use of Group A herbicide to remove grass in pasture. However, given how easy it is to develop Group A resistance, the group wanted to investigate other chemical and non-chemical options in pasture, as well as the impact of late seeding and pre-emergent herbicide for barley grass control in crop.

This three year trial aimed to investigate slashing and spray topping in pasture in 2019, and then time of sowing and pre-emergent herbicides in wheat in 2020 and canola in 2021.

Key messages

Three years of control reduced barley grass density from over 1000 plants/m2 to 2-14 plants/m2 across the whole site.

The diverse rotation, including pasture and canola break crops, allowed a range of herbicides from different mode of actions and control of late emerging barley grass cohorts.

Two years of seed set prevention was not sufficient to remove the barley grass. Barley grass has a seedbank that lasts at least 3-4 years.

Yandanooka WA 2019 Mixed species

The barley grass density at the start of the season was over 1000 plants/m2 and the site was very uniform.

Spray topping or slashing resulted in 100% control of barley grass. The dry conditions prevented regrowth.

Yandanooka WA 2020 Wheat

The higher seeding rate increased initial crop density. By August there was no difference in wheat tillers, due to a dry start to the season.

Barley grass density was initially low, with best control by TriflurX® and Sakura®. However, none of the pre-emergent herbicides offered full control, probably due to the low rainfall at the start of the season. New cohorts of barley grass emerged and weed density was high, given that there was no seed set in 2019.

Due to poor crop growth, the trial was updated to include a brown manuring treatment, and Spray.Seed® was applied to the whole trial area to avoid excessive barley grass seed production.

Yandanooka WA 2021 Canola

Barley grass density was lowest in the treatments with either TriflurX® or QPE with Roundup Plantshield®, compared to Roundup alone. Barley grass panicle number was too low to show a significant difference between treatments, but barley grass seed production was reduced in the treatments with TriflurX® or QPE® compared to Roundup alone.

The crop was healthy and highly competitive in 2021 due to high rainfall. The weed density was too low in all treatments to impact crop establishment or yield.

Lead research organisation Mingenew-Irwin Group
Host research organisation Department of Agriculture and Food WA
Trial funding source GRDC UOA1903-004SAX
Trial funding source DPIRD WA
Related program Demonstrating and validating the implementation of integrated weed management strategies to control barley grass in the low rainfall zone farming system
Acknowledgments

We would like to thank the Soullier family for providing the site, and Madi George and Kathryn Fleay at MIG for their assistance with the trial management and measurements.


Other trial partners University of Adelaide
Download the trial report to view additional trial information

Method

Crop types Mixed species
Wheat
Canola
Treatment type(s)
  • Herbicide: Timing
Trial type Demonstration
Trial design Randomised,Replicated,Blocked

Yandanooka 2019 Mixed species

Sow rate or Target density Not specified
Sowing machinery

Note that the trial was volunteer pasture. The sowing date indicates when the pasture emerged and the harvest date indicates when the pasture reached maturity. However, the pasture was not sown or harvested.

Sow date 14 May 2019
Harvest date 18 November 2019
Plot size 2.5m x 30m
Plot replication 4
Plot blocking Yes
Plot randomisation Randomised block design.
Fertiliser Not specified
Herbicide

Treatments

  1. Spray top, early
  2. Slash to prevent seed set
  3. Spray top, early and late
  4. Spray top, late

26 August 2019. Early spray top. Ester at 500 mL/ha, glyphosate at 2 L/ha, plus 0.2% wetter and 1% Amsul

17 September 2019. Late spray top. Ester at 500 mL/ha, glyphosate at 2 L/ha, plus 0.2% wetter and 1% Amsul

17 September 2019. Slashing

Yandanooka 2020 Wheat

Sow rate or Target density 40 or 120 kg/ha
Sowing machinery

Wheat cv. Chief

DBS bar (15m, 30cm spacing), John Deere box 

22 cm row spacing

Sow date 30 April 2020
Harvest date 18 November 2020
Plot size 2.5m x 30m
Plot replication 4
Plot blocking Yes
Plot randomisation Randomised block design.
Fertiliser

30 April 2020. MAPSZC 50 kg/ha, Urea 30kg/ha

Herbicide

Treatments:

  1. Wheat 40kg/ha, TriflurX® 1.5L/ha
  2. Wheat 40kg/ha, Luximax® 500mL/ha
  3. Wheat 120kg/ha, Luximax® 500mL/ha + Monza® 25g/ha
  4. Wheat 40kg/ha, TriflurX® 1.5L/ha + Monza® 25g/ha
  5. Wheat 120kg/ha, TriflurX® 1.5L/ha + Sakura® 118g/ha

25 August 2020. Spray.Seed 1.5L/ha over trial area. Due to dry start and high weed density, crop was brown manured

17 March 2020. Glyphosate 2L/ha and 2,4-D ester

30 April 2020. Pre-emergent herbicides applied according to treatments

Yandanooka 2021 Canola

Sow rate or Target density 2 kg/ha
Sowing machinery

Canola cv. InVigor®

DBS bar (15m, 30cm spacing), John Deere box 

22 cm row spacing

Sow date 16 April 2021
Harvest date 19 October 2021
Plot size 2.5m x 30m
Plot replication 4
Plot blocking Yes
Plot randomisation Randomised block design
Fertiliser Not specified
Herbicide

Treatments

  1. Two x Roundup Plantshield® 0.9kh/ha
  2. TriflurX® 1.5L/ha, two x Roundup Plantshield® 0.9kh/ha
  3. Two x Roundup Plantshield® 0.9kh/ha, QPE 250mL/ha 3-5 leaf
  4. TriflurX® 1.5L/ha, two x Roundup Plantshield® 0.9kh/ha, QPE 250mL/ha 3-5 leaf

15 Apr 2021. TriflurX® 1.5L/ha.

14 May 2021 and 8 Jun 2021. Roundup Plantshield® 0.9kh/ha.

14 Jun 2021. QPE® 250mL/ha.

Download the trial report to view additional method/treatment information

Download results

Trial results Table 1. Wheat and barley grass density and barley grass panicle number for each treatment. Note that barley grass density data is back-transformed from a log transformation.

# Treatment 1
Treatment 2
Wheat (plants/m2) Barley grass density (plants/m2) Barley grass panicles (heads/m2)
1 Wheat 40kg/ha TriflurX® 1.5L/ha 63 9.6 26
2 Wheat 40kg/ha Luximax® 500mL/ha 49 11.5 24
3 Wheat 120kg/ha Luximax® 500mL/ha + Monza® 25g/ha 83 11.7 25
4 Wheat 40kg/ha TriflurX® 1.5L/ha + Monza® 25g/ha 62 9.3 17
5 Wheat 120kg/ha TriflurX® 1.5L/ha + Sakura® 118g/ha 100 2.3 45

Barley grass density plants/m2


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Barley grass panicles heads/m2


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Wheat plants/m2


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Trial results Table 2. Canola and barley grass density, barley grass panicle number, barley grass seed number and canola yield for each treatment. P and LSD values are included for separation of means. Note that barley grass panicle data is back-transformed from a squa

# Treatment 1
Barley grass density (plants/m2) Barley grass panicles (heads/m2) Grain yield (t/ha) Crop Establishment (plants/m2) Barley grass seeds (seeds/m2)
1 2 x Roundup 14.2 6.1 2 26 281
2 TriflurX®, 2 x Roundup 6.9 1.3 2 24 49
3 2 x Roundup, QPE 4.2 0.5 1.9 27 12
4 TriflurX®, 2 x Roundup, QPE 1.7 0 1.9 26 0

Grain yield t/ha


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Barley grass density plants/m2


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Barley grass panicles heads/m2


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Barley grass seeds seeds/m2


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Crop Establishment plants/m2


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Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Yandanooka, WA Not specified
Derived trial site soil information
Australian Soil Classification Source: ASRIS
Trial site Soil order
Yandanooka, WA Chromosol
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

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Climate

Yandanooka WA 2019


Observed climate information

Rainfall trial total (mm) 237mm
Rainfall trial gsr (mm) 233mm

Derived climate information

Yandanooka WA

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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

2019 trial report



Trial last modified: 10-02-2022 13:26pm AEST