Effect of Paraquat and Glyphosate Applied Preharvest on Canola Yield and Seed Quality
Brian Jenks, North Dakota State University - $20,700

In Europe, canola is straight combined. A unique combine header manufactured in Europe has been developed to straight combine canola. In 2004, a replicated large-scale trial was conducted in Rugby, ND to compare straight combining canola with this header versus the traditional method of Swathing. Straight combining had 235 pounds per acre higher yield than swathing with similar seed and oil quality. This trial indicates that straight combining canola can be done successfully. However, the seed moisture and dockage was considerably higher with straight combining due to the fact that the stems were still green. The use of a desiccant prior to straight combining would have resulted in a drier crop at harvest.

Paraquat (Gramoxone Max) is a desiccant that is labeled for preharvest use in many crops including soybean, dry bean, field pea, chickpea, lentil and sunflower. Paraquat applied preharvest in canola could facilitate direct combining by drying down slow maturing areas of the field and allow growers to combine canola fields earlier.

Paraquat is not labeled yet in canola: however, USDA-IR-4 will be conducting residue trials in 2005 to establish a tolerance. Paraquat would likely receive full registration as early as 2008.

This study will be conducted to help determine the proper application window and harvest timing for paraquat. In addition, we believe there will be interest in glyphosate applied preharvest in the future. The interest in glyphosate would be more for weed control since the majority of acres in North Dakota are glyphosate-resistant. Paraquat will usually be the desiccant of choice since glyphosate activity is much slower.

Objectives:
1. Determine the effect of paraquat applied preharvest at three timings on canola yield, seed moisture and seed quality.
2. Determine the effect of glyphosate applied preharvest at three timings on canola yield, seed moisture and seed quality.
3. Compare yield, seed moisture, and seed quality of swathed canola to paraquat and glyphosate-treated canola.
4. Determine the effect of harvest timing following a paraquat or glyphosate application on canola yield, seed moisture and seed quality.