Gulden: Evaluation of Harvest Losses and Their Causes in Canola Across Western Canada
Date: April 2013
Term: 3 years
Status: Completed
Researcher(s): Rob Gulden, University of Manitoba, N. Harker, AAFC Lacombe AB, L. Hall and C. Willenborg University of Alberta and S. Shirtliffe University of Saskatchewan
SaskCanola Investment: n/a
Total Project Cost: n/a
Funding Partners: n/a
Project Summary
In a three-year project, researchers conducted surveys for harvest losses of canola on farms across western Canada. Researchers concluded that total on-farm harvest losses in canola are a complex phenomenon with many interacting variables that are difficult to separate. However, management factors that contribute to higher canola yield and harvest management variables such as combine speed and combine separator type contributed significantly to harvest losses, clearly indicating that producers have some level of control over the amount of canola seed that is left behind in the field after harvest.
Canola is a crop with a high potential for seed shatter and previous research has shown seed losses can be substantial. In a three-year project led by researchers from the University of Manitoba surveys for harvest losses of canola on farms were conducted across western Canada in four regions, Winnipeg MB, Saskatoon SK, Edmonton and Lacombe AB from 2010 to 2013. The objectives of the on-farm surveys were to find out if harvest losses were similar across production areas of western Canada, what factors strongly contributed to harvest losses, and if harvest losses in canola have changed over the past decade.
A total of 310 fields were surveyed across the three Prairie provinces from 2010 to 2012. Shortly after harvest, canola yields and harvest losses were determined using a vacuum cleaner method. As well, for each field, producers were asked to respond to a questionnaire that addressed general agronomic information and specific harvest related facts about how the field was harvested. Environmental variables for wind incurred at harvest were also determined from the nearest publicly available weather station.
The results from the study showed that canola yields and harvest losses were different among regions and were strongly affected by year. Overall, the canola harvest losses were about 5.9%, which were similar to results from a small, regional study conducted ten years before. However due to higher canola yields of modern cultivars, absolute harvest losses have increased substantially in the past decade, as well as an increased number of seeds added to the volunteer canola seedbank.
Researchers concluded that total on-farm harvest losses in canola are a complex phenomenon with many interacting variables that are difficult to separate. The results clearly indicated that management of harvest losses begins at the time of planting canola. Management factors such as adequate canola densities that contribute to high canola yield and earlier swathing dates resulted in proportionally lower harvest losses.
Harvest management was also an important contributor to harvest losses in canola. Some producers consistently achieved very low harvest losses indicating that there is considerable room for improvement and reductions in the total proportional canola harvest losses on some farms across western Canada. At harvest, combine speed and combine separator type contributed significantly to harvest losses, although combine manufacturer and combine type (rotary or conventional) did not influence the total proportion of canola harvest losses.
In a smaller regional trial in Saskatchewan in 2010 and 2011, no differences were identified in total harvest losses between side-by-side direct-harvested and swath-harvested canola. There was however, a difference in thousand-kernel weight (TKW) between the two harvest methods. Lost seeds of the direct-harvested canola were about 7% larger in size than the seeds recovered from the windrowed canola. Researchers would like to see a more intensive on-farm examination of direct-harvested in comparison to swath-harvesting canola.
Throughout this study, about 42% of the fields were treated with a fungicide at flowering to prevent sclerotinia. The study showed that the application of a fungicide at the time of flowering resulted in an overall reduction in the proportional total harvest losses in canola of about 1.4%. This reduction alone was not sufficient to pay for the use and application of that fungicide, however it does not include any potential yield benefits attributable to the fungicide application.
Researchers also looked at other factors such as variety choice. Although it may play a role, the results from this survey suggest that other factors may be equally, or more important in contributing to total harvest losses in canola. Neither time of day of swathing nor time of day of combining alone proved to be a significant factor contributing to total harvest losses. Environmental factors (the significance of year) did play an important role in harvest losses in canola, but the results showed these were not exclusively related to wind speeds and more research is needed.
Overall, management factors that contribute to higher canola yield and harvest management variables were among the leading factors that contributed to the consistent differences in total harvest. Producers do exert a significant amount of control over the losses incurred during canola harvest and that some reduction in proportional total harvest losses in canola is possible through improved management.
Full Report PDF: n/a