Although it’s been proven that high pH soil will not stop the spread of clubroot disease, liming has been used as a tool to curb the disease in other parts of the world. Early results from a research project underway in Alberta show raising the pH of acidic fields with lime could potentially aid in suppressing the pathogen.
“Our goal is to provide farmers with a different tool to control the disease, so what we’ve been doing is using different formulas of lime at different rates,” explains Sheau-Fang Hwang, plant pathologist with Alberta Agriculture and Forestry, in this Canola School video.
Hwang is involved in a research project that started last year, studying the effects of liming and whether it could help slow the breakdown of genetic resistance to clubroot. Year one included trials on two clubroot-infected fields with low pH of 5.7 and 6.3. (Hwang notes scientific literature indicates a pH of 7.4 or higher is less conducive for clubroot spore development.)
Presenting the preliminary findings at Canola Week in Saskatoon this winter, Hwang said they saw increased above-ground biomass, decreased disease severity and incidence, and no phytotoxic effects from applying lime in year one.
“It’s just the beginning, and it gets people excited, but we really have to do some more due diligence to make a conclusion,” she says. “Overall, if you increase the pH to a neutral level, it will not encourage the spores to germinate.”
Hwang notes further research is also needed to determine how results differ depending on initial pH, initial nutrient levels (ie. calcium) and initial spore concentrations. The type of lime can also be a factor, as some products break down much quicker than others.
Further greenhouse and field research is planned for 2018.
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