Monsanto Canada Inc.

Monsanto Canada Inc.

September 05, 2007 11:30 ET

New Study Shows Continuous use of Roundup Ready® Soybean and Roundup Ready® Corn is a Viable and Effective Production System for Eastern Canadian Growers

GUELPH, ONTARIO--(Marketwire - Sept. 5, 2007) - A new six-year cropping study completed by the University of Guelph and Agriculture and Agri-Food Canada (AAFC) on the agronomic fit of Roundup Ready® corn and Roundup Ready® soybeans in Eastern Canadian cropping systems has confirmed that incorporating the Roundup Ready system into cropping rotations is a viable and effective production system for Eastern Canadian growers.

The study - titled, "Long-term effects of Roundup Ready Compared to Conventional Herbicide Systems in Ontario" - also found that the use of Roundup Ready crops over the six-year period was sustainable in both conventional and no tillage production systems. When winter wheat was added to a Roundup Ready soybean/corn rotation, growers also tended to get yield benefits in corn and soybean production in subsequent years.

The study also confirmed what many growers already know about the Roundup Ready system - the use of glyphosate consistently provided better mid-season weed control in corn and soybean when compared to conventional herbicides.

There are also many more findings that should benefit Eastern Canadian growers and help them plan their crop rotations for maximum weed control and improved yields.

"Growers may be interested in the study's finding that shows the inclusion of winter wheat in the rotation resulted in a different weed community than in corn and soybeans," said Dr. Clarence Swanton of the University of Guelph's Department of Plant Agriculture and one of several authors of the study. "As well, over the six years of this experiment at the locations tested, we found little evidence for an increase in weeds that have a natural tolerance to glyphosate in the Roundup Ready system nor did volunteer crops of Roundup Ready soybean or corn create a problem for us."

The objective of the study - which was funded by Monsanto Canada - was to compare the effects of continuous use of glyphosate or conventional herbicides on weed control, weed biodiversity, crop yield and yield stability of glyphosate-resistant corn and soybean grown in rotation with, or without, winter wheat.

Some growers in Ontario have been cautious about growing more than one Roundup Ready crop, thinking it isn't viable or that it might not be a good agronomic choice. Now with some thorough, multi-year research on the long-term effect of Roundup Ready systems compared to conventional herbicide systems, they have the data they need to make an informed choice.

"This new study provides valuable, science-based research that gives growers the confidence to grow both Roundup Ready soybeans and Roundup Ready corn if that is the best option for their farm," said Dr. Mark Lawton, Monsanto's technology manager, Eastern Canada. "It's a sound agronomic decision, as well as the best economic one in terms of weed control and yield."

Lawton added that Monsanto gets a lot of questions from customers in Eastern Canada about proper agronomic management of Roundup Ready crops, particularly about what impact growing multiple Roundup Ready crops might have on managing glyphosate resistance on their farm.

"Good stewardship practices such as field scouting, starting with clean fields and adding other herbicides and cultural practices will help growers manage the likelihood of developing glyphosate resistance when they choose to grow both Roundup Ready soybeans and Roundup Ready corn on their farm," said Lawton. "We're very pleased to fund this sort of valuable research for the benefit of growers and appreciative of the opportunity to collaborate with both government and university researchers on this study."

About the Study

- Conducted by researchers at the University of Guelph and Agriculture and Agri-Food Canada - Dr. C. J. Swanton, University of Guelph; Dr. P. H. Sikkema, University of Guelph; Dr. A. S. Hamill, AAFC; Dr. F. J. Tardif, University of Guelph; Dr. R. H. Gulden, University of Guelph.

- Six years of field trial work took place at five locations in Ontario (two no-tillage and three conventional tillage) between 2000 and 2005.

- Treatments included a two crop rotation system: Roundup Ready corn/Roundup Ready soybeans compared to conventional corn/conventional soybeans; and a three crop rotation system: Roundup Ready corn/Roundup Ready soybeans/winter wheat compared to conventional corn/conventional soybean/winter wheat. All rotations were grown at all locations each year.

Summary of key findings

- Over the six years of the study, the continuous use of Roundup Ready crops was a viable production system for conventional and no-till cropping systems.

- The use of Roundup agricultural herbicide provided better mid-season weed control in both Roundup Ready corn and soybeans compared to conventional herbicide weed control programs.

- Volunteer Roundup Ready soybeans or corn were not a weed management issue.

- Yields of Roundup Ready crops were equal to or better than conventional crops.

- The inclusion of winter wheat in the rotation had a tendency to improve corn and soybean yields.

- Over the six years of the study, there was little evidence for the selection of weeds that were naturally tolerant to glyphosate in the Roundup Ready system.

- In no-tillage corn and soybeans, more weed species were observed in the conventional herbicide system than with the Roundup Ready system by mid-season.

- In conventional tillage soybeans, the number of weed species observed was the same in both herbicide systems. In conventional tillage corn, the number of weed species observed was greater in the Roundup Ready system.

- The inclusion of winter wheat resulted in a different weed community than in corn or soybeans.

A complete copy of "Long-term effects of Roundup Ready Compared to Conventional Herbicide Systems in Ontario," is available from the University of Guelph, Department of Plant Agriculture or Monsanto Canada's Eastern Business office in Guelph, Ontario.

Contact Information

  • University of Guelph
    Dr. Clarence Swanton, Professor
    Dept. of Plant Agriculture
    (519) 824-4120, ext. 53392
    or
    Monsanto Canada
    Dr. Mark Lawton
    Technology Manager, Eastern Canada
    Eastern Business Office, Guelph
    (519) 821-0790