IVMP Seed-head Suppression Trial
Bahia grass (Paspalum notatum) poses a significant challenge for vegetation managers in South East Queensland due to prolific seed-head dispersion. In order to explore the best way to suppress seed-head production, the Integrated Vegetation Management Project (IVMP) is currently conducting a 12 week experiment.
In this experiment, a single application of various herbicides and plant growth regulators were applied to replicated trial plots. Untreated plots (control plots) and monthly mown treatment plots were also established for comparison. The experiment is intended to run for 12 weeks, with the interim results presented here showing what has occurred over the first 6 weeks.
Overall, most of the treatments are still performing very well 6 weeks after application. In fact, all 12 of the chemical treatments equalled or outperformed the mown treatment in reducing the number and height of seed-heads produced. This is surprising considering the chemical treatment plots had not been mown since the start of the experiment (approximately 6 weeks prior), while the mown treatment plots had been mown less than two weeks prior!
No seed-heads have yet been produced in the plots for the best performing treatments, i.e 100% seed-head reduction at this stage. In fact, most treatments trialled have provided ≥ 90% reduction in seed-heads after 6 weeks.
The effects of the treatments on seed-head height are very similar, as one might expect. Average seed-head height in the control plots was 43cm and was already up to 37cm in the recently mown plots. In comparison, the worst-performing experimental treatments had an average seed-head height of 29.5cm, while the few seed-heads produced in the most promising treatments had an average height of only 7cm.
Promising results are evident on trial plots
The effect of the treatments on sward height was also relatively similar. Average sward height in the control plots was approximately 11cm, while it was 8.5cm in the recently mown plots. The best performing treatments had sward heights of 6-7cm, with most other treatments having sward heights of 7-8cm.
These results are suggesting that if you want to keep the Bahia grass green and suppress its seed-head production, a number of treatments being assessed are proving effective. It is also clear that a number of the treatments will be effective should your aim be to transition out the Bahia grass in an area under management.
In this experiment, a single application of various herbicides and plant growth regulators were applied to replicated trial plots. Untreated plots (control plots) and monthly mown treatment plots were also established for comparison. The experiment is intended to run for 12 weeks, with the interim results presented here showing what has occurred over the first 6 weeks.
Overall, most of the treatments are still performing very well 6 weeks after application. In fact, all 12 of the chemical treatments equalled or outperformed the mown treatment in reducing the number and height of seed-heads produced. This is surprising considering the chemical treatment plots had not been mown since the start of the experiment (approximately 6 weeks prior), while the mown treatment plots had been mown less than two weeks prior!
No seed-heads have yet been produced in the plots for the best performing treatments, i.e 100% seed-head reduction at this stage. In fact, most treatments trialled have provided ≥ 90% reduction in seed-heads after 6 weeks.
The effects of the treatments on seed-head height are very similar, as one might expect. Average seed-head height in the control plots was 43cm and was already up to 37cm in the recently mown plots. In comparison, the worst-performing experimental treatments had an average seed-head height of 29.5cm, while the few seed-heads produced in the most promising treatments had an average height of only 7cm.
Promising results are evident on trial plots
The effect of the treatments on sward height was also relatively similar. Average sward height in the control plots was approximately 11cm, while it was 8.5cm in the recently mown plots. The best performing treatments had sward heights of 6-7cm, with most other treatments having sward heights of 7-8cm.
These results are suggesting that if you want to keep the Bahia grass green and suppress its seed-head production, a number of treatments being assessed are proving effective. It is also clear that a number of the treatments will be effective should your aim be to transition out the Bahia grass in an area under management.
posted by Steve Hampton at
5:34 AM
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