| Researcher(s) |
Ben Fleet Gurjeet Gill |
|---|---|
| Year(s) | 2019 |
| Contributor | School of Agriculture, Food and Wine - The University of Adelaide |
| Trial location(s) |
Mallala, SA
|
This field trial was undertaken at Mallala (SA) to investigate factorial combinations of sowing time, seed rate and herbicides on the management of brome grass in wheat.
A field trial was undertaken at Mallala in 2019 to investigate combinations of wheat sowing time, seed rate and herbicide treatments to control brome grass. The average seedbank of brome grass at this site was 2877 ± 406 seeds/m2. The two week delay in sowing reduced average in-crop brome density from 567 plants/m2 to 352 plants/m2 (38%). Even though the reduction in brome density at Mallala was significant, it was a much lower reduction than that observed in the trial at Riverton (82% reduction). This difference in brome grass density with delayed sowing at these two sites highlights the large differences in seed dormancy between the populations of this weed species. Brome grass panicle density was significantly affected by wheat seed rate (P=0.039), and herbicide treatment (P<0.001) but not by the time of sowing (P=0.152). Increasing seed rate of wheat suppressed brome grass growth and reduced its panicle density. As wheat density increased from 100 seeds/m2 (low) to the highest seed rate (200 seeds/m2 – high) brome panicle density was reduced by 39%. These results support previous findings that higher crop density can be an important part of an integrated weed management program. Wheat grain yield increased consistently with the increase in seed rate or crop density. This trend correlates well with the improved suppression of brome grass panicle density observed in the trial. Not only did higher wheat density achieve superior weed suppression, it also provided a significant increase in grain yield. Herbicide treatments also had a highly significant effect on brome grass panicle density. However, there was no interaction herbicides and TOS or seed rate. This indicates that herbicides performed similarly in both times of sowing and the three seed rates. Sakura + Avadex significantly reduced panicle density as compared to Treflan + Avadex and Intercept (Clearfield technology) was used after pre-emergent Treflan + Avadex, it prevented brome plants from producing panicles (3 panicles/m2). Herbicide treatments had a large and significant effect on grain yield of wheat at Mallala (Figure 5). This is not surprising considering the high weed density present at the site and high competitive ability of brome grass. The treatment of Treflan + Avadex produced only 1.11 t/ha, which was significantly lower than the more expensive pre-emergent herbicide mixture of Sakura + Avadex (1.81 t/ha). However, when Intercept post-emergence herbicide was used, wheat yield increased further to 2.63 t/ha. In this trial, integration of Clearfield technology with pre-emergent herbicides not only prevented brome grass seed set as shown but the panicle density, it also delivered the highest grain yields.
| Lead research organisation |
The University of Adelaide |
|---|---|
| Host research organisation | N/A |
| Trial funding source | GRDC 9175134 |
| Related program | N/A |
| Acknowledgments |
We thank GRDC for funding this research project. |
| Other trial partners | Not specified |
| Crop types | Weed: Brome grass Cereal (Grain): Wheat |
|---|---|
| Treatment type(s) |
|
| Trial type | |
| Trial design |
| Sow date | Not specified |
|---|---|
| Harvest date | Not specified |
| Plot size | Not specified |
| Plot replication | Not specified |
| Other trial notes |
Please refer to the attached PDF document for detailed information on the results and discussion. |
| Sow date | 16 May and 31 May |
|---|---|
| Harvest date | Not applicable |
| Plot size | Not specified |
| Plot replication | Not specified |
| Other trial notes |
Please refer to the attached PDF document for detailed information on the results and discussion. |
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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