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Corn Research |
Weed management in corn
Dr.
Peter Sikkema, University of Guelph, Ridgetown Campus
A total of 11 field experiments were conducted
over a three year period (2006-2008) on weed management strategies in Roundup
Ready corn. Field studies were established at the Huron Research Station, the
University of Guelph, Ridgetown Campus and the Greenhouse and Processing Crops
Research Centre, Agriculture and Agri-Food Canada, Harrow, ON.
Specifically this research program concluded that:
| 1. | The optimal weed management strategy in RR corn is weed species and field specific. |
| 2. | The highest net returns to weed management strategy are field specific. Overall, there was no statistical difference between, a single application of Roundup, a sequential application of Roundup applied at early and late post-emergence, a tankmix of Roundup plus Marksman, and a sequential program of either Atrazine, Primextra or Converge applied pre-emergence followed by Roundup applied late post-emergence. |
| Weed Management Program |
Rates (per acre)
|
Corn Yield (bu/ac)
|
Harvest Moisture (%)
|
| Weedy check |
0
|
74
|
303
|
| Weed-free check |
100
|
200
|
|
| Roundup (Post 1) |
89
|
191
|
721
|
| Roundup (Post 2) |
94
|
180
|
683
|
| Roundup + Marksman (Post 1) |
95
|
194
|
709
|
| Atrazine (Pre); Roundup (Post 2) |
98
|
196
|
724
|
| Primextra (Pre); Roundup (Post 2) |
98
|
198
|
723
|
| Converge (Pre); Roundup (Post 2) |
99
|
196
|
713
|
| Roundup (Post 1); Roundup (Post 2) |
99
|
199
|
732
|
The results of the 11 field studies evaluating
various weed management studies in RR?corn are presented in the table above.
All of the above weed management strategies with the exception of the one early application of Roundup provided excellent weed control. The two sequential programs (i.e: a residual herbicide applied pre-emergence followed by Roundup applied post-emergence or the two sequential post-emergence applications of Roundup) resulted in excellent corn yields which were comparable to the weed-free check. A single late application of Roundup resulted in better weed control than a single early application of Roundup but corn yield was nine bushels per acre lower. This decrease in yield can be attributed to weed interference prior to the late application of Roundup. The tankmix of Roundup plus Marksman and the sequential programs of either atrazine, Primextra or Converge applied pre-emergence followed by a late in-crop application of Roundup resulted in similar weed control, corn yield and net returns.
This project is suppoorted through ORD.