“Sometimes we can do well with half-fertilizer and half-herbicide rates, but we generally get our highest economic returns when we use the full inputs in canola.”
Canola can provide high returns, but not without a healthy dose of care and expensive crop inputs. At a recent field day, Agriculture Canada weed scientist Neil Harker described a five-year study to determine whether it’s possible to cut fertilizer and herbicide rates and still come out ahead.
“The idea of this study was to determine the inputs that were most important in canola and barley,” said Harker.
“Sometimes we can do well with half-fertilizer and half-herbicide rates, but we generally get our highest economic returns when we use the full inputs in canola,” said Harker.
However research on barley found that the crop can still do well with less herbicide and less fertilizer.
The study looked at a simple canola/barley rotation for the past four years. By using 50 per cent nitrogen rates, researchers were able to get a little more yield than expected.
“So we’re thinking about doing some N mineralization studies as we think perhaps that we’re getting more N mineralization than normal,” said Harker.
The study, which was initially to be four years, was continued for a fifth year after the researchers spoke to growers on the research committee who wanted to know how long it took to get poor, low-input plots back to high production.
The researchers have taken best management practices and applied them to all the plots, which are located in five sites across Western Canada.
“In canola, we’ve used an RR hybrid and we’ve put glyphosate on twice, and we’ve also pre-seeded with Roundup so we gave it a good chance to recover from weedy issues. We’ve also put on the full fertility and the high seeding rate of a good variety,” said Harker.
Harker said, “In barley we’ve gone to all AC Metcalfe, we’ve put on Axial as a herbicide for wild oats and we’re seeing how long it takes to recover.”
Researchers found that if they put on fertilizers without herbicides, they ended up feeding the weeds and created more weeds than if they’d simply gone without inputs, said Harker.