Starting clean with a pre-seed burnoff application helps reduce early-season weed pressure, which helps your crop get off to a good start. Remove weeds early, before they rob moisture and nutrients from the crop and that clean start is critical in producing in-the-bin yield.
It’s easier to control weeds at smaller stages. Winter annual weeds such as flixweed, shepherd’s purse, narrow-leaved hawk’s-beard and stinkweed are particularly bad. They remove a significant amount of soil moisture in the spring as they are very inefficient water users.
Plants can detect crowding
Some plants can detect when another plant is crowding it. They can sense the difference in the wavelength of light reflected off bare soil and other plants. If the crop “feels” competition, it might put more energy into growing taller instead of producing seed.
These physiological changes can happen early in the season. Numerous studies have been conducted across a number of different crops showing that a pre-seed herbicide is crucial to securing yield.
Research shows early weed control is critical
Research from the University of Saskatchewan shows that early weed control is actually more important than early seeding in producing yield. The study was conducted in wheat but researchers say the results hold true for canola.
In a 2008 study by Neil Harker of AAFC (Weed Technology 22-747-749), waiting to control weeds at the 6- to 7-leaf stage could cost seven bushels per acre in yield loss.
A pre-seed burnoff also reduces risk if weather causes a delay in post-emergence application. According to the Canola Council of Canada, “Weeds present when the crop emerges will have a substantially greater negative impact on the yield of the crop if the pre-emergent application is missed altogether."
As important as it is to “start clean”, it’s also critical that the crop emerges into a clean field so that it can avoid early season competition.
Add a tank-mix partner that offers extended control to your glyphosate when you spray pre-seed. Since glyphosate only controls emerged weeds, the product with extended control gives your crop longer protection during that critical weed-free period.