Using clubroot resistant genetics and lengthening rotations are highly recommended practices for managing clubroot on the Prairies. But is there more farmers could do?
“Ninety per cent of those clubroot spores can die with a two-year break, so one in three rotation, that’s really critical, if you have a shorter rotation than that, and you’re looking at improving your ability to manage clubroot,” says Keith Gabert, agronomist with the Canola Council of Canada.
The challenge though, is that the remaining 10 per cent of spores even after lengthening rotation is still way too many spores — billions of spores per gram of soil, to millions of spores per gram of soil, is still a significant infestation that puts a lot of pressure on clubroot genetics, says Gabert in this Canola School episode.
“One of the additional tools that we’d like growers to consider, is some patch management,” says Gabert, which can be as simple as leaving the area undisturbed, seeding the area to grass, or by adding lime to the soil and incorporating it well.
Canola Council research suggests that if through liming soil pH can be brought up to about 7.2, the calcium present and the pH adjustment make it and inhospitable environment for clubroot galls.
Gabert’s biggest tip is to start small — transportation and logistics of ag lime for large areas means sharpening your pencil and figuring out where it’s best and most appropriately placed.
Adjusting soil pH is a logarithmic scale and proportionally more and more product is needed to push that soil pH up to 7.2, Gabert explains.