One of the biggest yield robbers in canola production today is poor spray timing. I know that sounds elementary but it’s a fundamental that needs to be addressed. One yield limiting factor when dealing with poor spray timing is late weed removal.
When it comes to using Liberty herbicide, people often wait until weed pressure is heavy enough to warrant one spray application to try and nail everything at once. Unfortunately, the product isn’t as strong on large weeds so waiting is not the right strategy. More importantly, a late application allows weeds to remove precious fertility and soil moisture. So, not only do you lose yield from weed competition, you lose yield from the removal of plant available nitrogen. Here’s a little quick math to show the importance of early weed removal.
Steve’s quick math
Two-leaf wild oats, volunteer wheat or barley at 25, 50, 75 and 100 plants/ft2. Yield loss 25ft2: 3 lbs/N or 1 bu/ac = $11.00/ac Yield loss 50ft2: 6 lbs/N or 2 bu/ac = $22.00/ac Yield loss 75ft2: 9 lbs/N or 3 bu/ac = $33.00/ac
In this example, yield losses range from 1 to 3 bushels per acre or $11.00 to $33.00 per acre based on the removal of nitrogen by grassy weeds. The photo you see above is a very common occurrence on the Prairies where Liberty Link growers wait as long as possible before spraying Liberty herbicide. Bayer has reduced the price of Liberty herbicide to encourage a two-pass system much like you’d find with RoundUp Ready canola. A mind shift needs to happen to have Liberty growers spray early at the cotyledon to 1 leaf stage much like they do in RoundUp Ready canola.