Sixty-eight random canola fields in Western Canada provided interesting insight into the best management practices for establishing a high yielding canola crop.
The canola producers who are achieving the greatest canola yields are seeding shallow and directly into chemfallow (or crops with inherently short stubble). They are seeding at earlier dates and with narrower row spacing. They also avoid seeding canola into canola stubble.
Yantai Gan with Agriculture and Agri-Food Canada (AAFC) led a study to investigate the best management practices that more advanced and experienced canola producers from across the major canola production zones of Western Canada are using. A total of 68 canola farm fields were randomly selected and sampled across Alberta, Saskatchewan and Manitoba. The survey started in spring 2011 and collation of all needed data finished by October 2012. An AAFC research team made multiple trips to those individual farm fields to count seedling emergence, measure seeding depth and row spacing, sample relevant soil properties and collect various yield-related variables.
The study found a very large variation in terms of farming practices and approaches used in canola production across individual farm fields. Some of the cropping practices were adopted by the majority of the canola producers, whereas other practices were used only by a few individual farmers. This presented challenges for statistical analysis, and highlighted the need for more research into many of these areas.
Stubble type or preceding crop had a significant effect on canola yields for the 68 fields. Canola yields were highest on chemfallow. Cereal stubble was next, with barley, oats and wheat stubble producing similar canola yields. Legumes and corn followed. The three fields surveyed where canola was seeded into canola stubble produced the lowest yields among all fields surveyed, yielding only 54 percent of the average yield in fields where canola was seeded into cereal stubble.
No-till increased yield relative to fields where pre-seeding tillage was used, although the increase was marginal.
The survey showed no yield difference for canola that received pre-seed glyphosate versus canola that received no pre-seed herbicide treatment. About 40 percent of the producers grew their canola on cereal stubble, 17 percent on chemfallow, and the rest on other crop stubbles. Of the canola fields surveyed in the project, 30 percent of the fields used potassium (K) fertilizers in the canola production, and received an average of 25 percent seed yield increase compared with those canola fields without using potassium fertilizer.
Six of the 68 producers harvested their canola crops by straight combining. Their seed yield was significantly higher compared to canola harvested using the conventional swath-combine method (24 percent higher).
In his observations, Gan suggests that judging canola productivity based on seeding rates is not scientifically sound. Instead, the actual plant density — the number of plants that emerge — should be used in predicting canola crop yields. Producers should take note of typical survival in their regions, and adjust their seeding rate accordingly to achieve the target plant stand.
Results from the 68 fields also indicate that deeper seeding, wider row spacing, increased stubble height of previous crops, and delayed seeding after April 25 can all reduce canola seed yield.