| Researcher(s) |
Catherine Borger (DPIRD) Ben Whisson (ConsultAg) |
|---|---|
| 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) |
Tarin Rock, WA
|
| Related trials |
|
Barley grass is becoming an increasingly problematic weed in Western Australia. A GRDC funded project sought to increase the 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 growers in the southern lakes region of Western Australia often had pasture as the main rotation choice after cereal. In contrast to other areas of the wheat belt, some growers in this region considered barley grass a valuable (early) feed in pasture as well as a weed in crops. However, growers found that barley grass could have a large impact on crop yield. Growers were interested in either controlling barley grass or suppressing barley grass in crops while allowing it to survive in pasture.
Most group members felt their barley grass was resistant to herbicides (especially low-level resistance to Group A, Targa®). However, growers were unwilling to stop using Targa®, even if efficiency was reduced against barley grass, as it effectively controlled other grass weeds. Growers wanted to pair Targa® with other products in the pasture to kill barley grass, and then control surviving barley grass in crop with best practice pre-seeding herbicides.
The trial aimed to investigate pasture barley grass control in 2019, pre-emergent herbicides in barley in 2020 and oats in 2021.
Early application of selective herbicide (Group 1, A) gave excellent control of barley grass. While fewer barley grass plants meant less pasture biomass, it’s important to remember that the seeds on the mature barley grass would injure livestock. Further, these barley grass plants could host cereal crop disease.
Spray topping prevented viable seed set of barley grass while leaving the greatest pasture biomass.
Good barley grass control in the 2019 pasture was still evident in the 2020 and 2021 crops.
Late sowing of barley in 2020 (delayed 4 weeks) was relatively ineffective in controlling barley grass and crop yield was slightly reduced.
Late sowing of oats in 2021 (delayed 7 weeks) gave excellent weed control, but the crop yield was severely reduced.
Early application of selective herbicide (Group 1, A) gave excellent control of barley grass. Late application of selective herbicide had higher pasture biomass as there were more barley grass plants growing in the pasture. However, it’s important to remember that the seeds on the mature barley grass would injure livestock. Further, these barley grass plants could host cereal crop disease.
Late sowing of barley in 2020 (delayed 4 weeks) was relatively ineffective in controlling barley grass and yield was slightly reduced.
Late sowing of oats in 2021 (delayed 7 weeks) gave excellent weed control, but the yield was severely reduced.
| Lead research organisation |
Lakes Information and Farming Technology |
|---|---|
| Host research organisation |
Department of Agriculture and Food WA |
| Trial funding source | GRDC UOA1903-004SAX |
| Trial funding source | DPIRD WA UOA1903-004SAX |
| 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 Ashton Gray for providing the site, Justine Tyson at ConsultAg for her assistance with the trial management, Nerys Wilkins and Pete Gray (DPIRD) for assistance with trial measurements. |
| Other trial partners | University of Adelaide, ConsultAg |
| Crop types | Pasture: Mixed species Cereal (Grain): Barley Forage: Oats |
|---|---|
| Treatment type(s) |
|
| Trial type | Demonstration |
| Trial design | Randomised,Replicated,Blocked |
| Sow rate or Target density | Volunteer pasture (oats, subterranean clover, vetch) |
|---|---|
| Sowing machinery |
12m controlled traffic farming system, equaliser, liquid system. Row spacing: 27.7cm. The pasture was sown on 6 June 2019. The harvest date indicates when the pasture reached maturity. However, the pasture was not harvested. |
| Sow date | 6 June 2019 |
| Harvest date | 18 November 2019 |
| Plot size | 2.5m x 40m |
| Plot replication | 4 |
| Plot blocking | Yes |
| Plot randomisation | Randomised block design. |
| Herbicide |
23 July 2019. Targa® at 300mL/ha sprayed on appropriate treatments 5 September 2019. Glyphosate® at 400mL/ha sprayed on appropriate treatments 17 September 2019. Paraquat® at 500 mL/ha on appropriate treatments |
| Sow rate or Target density | 50 kg/ha |
|---|---|
| Sowing machinery |
12m controlled traffic farming system, equaliser, liquid system. Row spacing: 27.7 cm.
|
| Sow date | 28 April 2020 |
| Harvest date | 19 November 2020 |
| Plot size | 2.5m x 20m |
| Plot replication | 4 |
| Plot blocking | Yes |
| Plot randomisation | Randomised block design. |
| Herbicide |
|
| Sow rate or Target density | 45 kg/ha |
|---|---|
| Sowing machinery |
12m controlled traffic farming system, equaliser, liquid system. Row spacing: 27.2 cm. Oats cv. Wandering.
|
| Sow date | 29 April 2021 29-04-2021 and 17-06-2021 |
| Harvest date | 15 December 2021 |
| Plot size | 2.5m x 20m |
| Plot replication | 4 |
| Plot blocking | Yes |
| Plot randomisation | Randomised block design |
| Herbicide |
|
| # |
Treatment 1
|
Barley grass density (plants/m2) | Pasture biomass (g/m2) | Barley grass panicles (heads/m2) | Barley grass seeds (seeds/m2) |
|---|---|---|---|---|---|
| 1 | █ Untreated | 1920 | 559 | 1178 | 17043 |
| 2 | █ Targa® | 2063 | 352 | 2 | 13 |
| 3 | █ Spray top glyphosate | 2068 | 514 | 1133 | 10781 |
| 4 | █ Targa® + spray top glyphosate | 1858 | 293 | 2 | 7 |
| 5 | █ Targa® + spray top paraquat | 1924 | 243 | 2 | 0 |
| # |
Treatment 1
|
Treatment 2
|
Screenings (%) | Barley grass panicles (heads/m2) | In-crop barley grass (plants/m2) | Grain yield (t/ha) | Pre-seeding barley grass (plants/m2) |
|---|---|---|---|---|---|---|---|
| 1 | █ Untreated | █ Early sowing in April | 0.15 | 962 | 587.5 | 1.09 | 59.3 |
| 2 | █ Targa® | █ Early sowing in April | 0.16 | 48 | 28.1 | 2.04 | 2.3 |
| 3 | █ Spray top glyphosate | █ Early sowing in April | 0.15 | 97 | 63 | 1.99 | 1.9 |
| 4 | █ Targa® + spray top glyphosate | █ Early sowing in April | 0.17 | 54 | 12.6 | 2.07 | 8.1 |
| 5 | █ Targa® + spray top paraquat | █ Early sowing in April | 0.16 | 61 | 10.5 | 1.87 | 2.3 |
| 6 | █ Untreated | █ Late sowing in May | 0.3 | 676 | 399.9 | 0.77 | 58.7 |
| 7 | █ Targa® | █ Late sowing in May | 0.32 | 106 | 40.6 | 1.37 | 1.6 |
| 8 | █ Spray top glyphosate | █ Late sowing in May | 0.23 | 72 | 33.8 | 1.58 | 1.7 |
| 9 | █ Targa® + spray top glyphosate | █ Late sowing in May | 0.31 | 48 | 28.1 | 1.57 | 3.9 |
| 10 | █ Targa® + spray top paraquat | █ Late sowing in May | 0.32 | 51 | 51.8 | 1.44 | 1.6 |
| # |
Treatment 1
|
Treatment 2
|
Screenings (%) | Barley grass density (plants/m2) | Barley grass panicles (heads/m2) | Grain yield (t/ha) | Crop Establishment (plants/m2) | Barley grass seeds (seeds/m2) |
|---|---|---|---|---|---|---|---|---|
| 1 | █ Untreated | █ Early sowing | 1 | 598 | 291 | 2.7 | 114 | 6514 |
| 2 | █ Targa® | █ Early sowing | 1.6 | 88 | 106 | 3.6 | 105 | 1256 |
| 3 | █ Spray top glyphosate | █ Early sowing | 1.2 | 138 | 137 | 3.3 | 125 | 2628 |
| 4 | █ Targa® + spray top glyphosate | █ Early sowing | 1.1 | 116 | 85 | 3.5 | 118 | 1016 |
| 5 | █ Targa® + spray top paraquat | █ Early sowing | 1.5 | 136 | 99 | 3.6 | 114 | 1109 |
| 6 | █ Untreated | █ Late sowing | 8.6 | 1 | 0 | 1.6 | 48 | 0 |
| 7 | █ Targa® | █ Late sowing | 7.4 | 0 | 0 | 1.9 | 51 | 0 |
| 8 | █ Spray top glyphosate | █ Late sowing | 8 | 0 | 0 | 1.8 | 54 | 0 |
| 9 | █ Targa® + spray top glyphosate | █ Late sowing | 8.3 | 0 | 0 | 1.9 | 48 | 0 |
| 10 | █ Targa® + spray top paraquat | █ Late sowing | 7.7 | 0 | 0 | 1.8 | 51 | 0 |
| Rainfall trial total (mm) | 176mm |
|---|---|
| Rainfall trial gsr (mm) | 171mm |
| Rainfall trial total (mm) | 206mm |
|---|---|
| Rainfall trial gsr (mm) | 127mm |
| Rainfall trial total (mm) | 426mm |
|---|---|
| Rainfall trial gsr (mm) | 356mm |
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.
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Note that PBR cover is administered through the Plant Breeders’ Right Act 1994 (