Wet conditions followed by warm sunny days may cause soil crusting, which stops seedlings from emerging. We don’t have any research to show the best ways to break up crusting and free the crop. If a few plants have emerged, it may be best to leave them be. Two plants per square foot are better than none.
If nothing is coming through, a light harrowing might help — if the crop isn’t germinated. “But even though growers may have had success using a light harrow to break up crusting in cereals, don’t assume it will work in canola,” says CCC senior agronomy specialist Derwyn Hammond. “Harrowing too close to emergence can be really harmful to a shallow seeded crop such as canola.”
Using a roller may be worse than harrowing when soils are wet below the crust, says Murray Hartman, oilseed specialist with Alberta Agriculture. Instead of cracking up the soil surface, a roller could turn the whole topsoil zone to concrete.
Again, there is very little research on how to manage crusting. It’s trial and error. If you have techniques that have worked for you, we’d like to hear about them. Please email Canola Watch editor Jay Whetter.