Canola School: Soil armour and the battle against crusting

A timely rain after seeding can erase plenty of sins, but a pounding rain can do the opposite, and lead to punishment for small canola seedlings that have to break through crusted soil.

Crusting has hampered emergence and forced some reseeding in canola fields in parts of Western Canada again this year.

Of course, there’s nothing that can be done to prevent a heavy rain right after seeding, but there are actions that can reduce the odds of crusting, explains Brunel Sabourin of Antara Agronomy in this Canola School episode.

Wet conditions in many areas last fall did not help, as farmers were forced to delay fieldwork until spring. Heavy harrows and tillage equipment were deployed this spring in the effort to manage last year’s residue and get the crop seeded.

“When we overwork a field and make it black, we don’t have that soil armour, so when the rain hits it, it tends to break up the fine clays, and create a layer that seals off and bakes in the sun, and it becomes these hard lumps of clay that canola has a terrible time trying to push through or push around,” says Sabourin.

While cereal crops can sometimes withstand equipment passing over to break up a crust, such as as light harrow, rotary hoe, coil packer, or a landroller, there’s not much that can be done to address crusting in an emerging canola field without causing serious injury.

In addition to maintaining that “soil armour” and reconsidering spring tillage, growers may want to consider higher seeding rates when seeding into uneven conditions in the future, says Sabourin.

As highlighted in this recent Canola School article on deciding whether to reseed, yield predictability and stability declines when there’s less than three to four plants per square foot.

Sabourin discusses the challenges with crusting, and strategies for maximizing emergence in this Canola School video:

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