Although canola’s calcium requirements are relatively high (about double the level of sulphur and phosphorous, according to the Canola Council of Canada), deficiencies are rarely seen in western Canada.
When deficiencies do occur, it is often as a result of highly saturated soils, which do not allow the plant to take up adequate nutrients.
That was the case in the spring of 2011, says the Canola Council of Canada’s Gregory Sekulic, when agronomists in western Canada were noticing purple, crisp leaves, interveinal chlorosis and “ribbon stems.”
Although soil samples can provide information on calcium levels, the ideal range for canola has yet to be identified. As for tissue samples, they may provide an indicator of deficiency (and a confirmation of your diagnosis), but will do little to address the cause (i.e. perhaps there are adequate levels in the soil, but they are not available to the plant, as in the case of waterlogged lands).
For the majority of soils in western Canada, calcium levels are sufficient and the odds of seeing a response to calcium applications are low.
For more information, check out the Canola Council of Canada’s Canola Encyclopedia: Managing Other Nutrients. Of course, you can also have a look at some of the key symptom of calcium deficiency in the above video with Sekulic, filmed at this year’s CanoLAB in Saskatoon.