Canola growers are leaving a lot of yield on the table. Or, more accurately, they are leaving a lot of yield “off” the table and on the ground at harvest. Estimates put losses from the harvest process alone at two to five bu./ac., on average. Early swathing adds to that total.
Growers have two key ways to recoup some of that yield. They can leave the crop standing longer, which gives side branches longer to fill, thereby increasing overall seed size and yield. And they can take steps to reduce losses while combining.
Chris Holzapfel, researcher with Indian Head Agricultural Research Foundation (IHARF) at Indian Head, Sask., led a 2013 study into straight combining canola. The study compared two swathing times and various straight cutting times. Early swathing time — at 15 to 20 per cent seed-colour change for this study — produced the lowest yields of all treatments. The other options, which were swathing at 40 to 50 per cent seed-colour change or straight combining at various dates, produced a statistical increase in canola yield over early swathing.
Based on previous research it had done showing similar results to the IHARF study, the Canola Council of Canada (CCC) recommends swathing at 60 to 70 per cent seed-colour change for yield and quality.
- From Grainews: Timing the canola harvest
“We know that not all canola can be swathed at this ideal time, given the logistics of harvest, but growers can expect an increase in yield if they can hold off swathing their first crops until at least 30 to 40 per cent seed-colour change and aim to swath the bulk of their canola at 60 to 70 per cent,” says Angela Brackenreed, CCC agronomy specialist.
Once the crop is down, the next step is to combine it efficiently — which means finding a balance between timely harvest and not going so fast that you leave a lot of bushels behind. “Harvest losses happen, and they’re probably a lot bigger than many growers want to imagine,” Brackenreed says.
Rob Gulden, professor and researcher at the University of Manitoba, led a recent canola harvest loss study, which surveyed canola fields across the Prairies from 2010 to 2012. Harvest losses ranged from 2.3 per cent to 11.2 per cent across the 310 fields. The study included a questionnaire with each grower to find management practices that correlated to those harvest losses.
A key discovery was that higher plant density reduced harvest losses. “The study showed that harvest management starts at planting, with the goal of achieving a high-density stand that will mature evenly,” Gulden says. “Getting the harvest timing right, which is a critical part of reducing losses, is linked to stand densities. Cutting seeding rates is not the best idea from a harvest management perspective.”
Higher combine ground speed was another factor that led to increased harvest losses. There is no one ideal combine speed. It varies by crop conditions and combine settings, and a grower’s tolerance for losses.
The CCC ran a series of combine clinics a few year ago featuring Les Hill, program director of agriculture and bioresources at Prairie Agriculture Machinery Institute (PAMI). Step one, Hill says, is to measure losses. This requires some work with a drop pan to see how much is thrown over the back of the combine. If losses are unacceptable, then take steps to reduce them.
Combining slower is one of these steps that can reduce losses. The loss curve tends to remain fairly flat until ground speed reaches a critical point. “When a combine hits that wall, a lot of the time it’ll start dumping grain out the back,” Hill says. It may take just a small decrease in speed — say 0.2 or 0.3 mph — to provide a significant reduction in losses, he adds.
Other adjustments such as concave spacing, fan speed and sieve settings can make a difference too. Try one variable at a time and check losses between each adjustment. Ground speed may be the last adjustment you want to make.
“In the end, the grower’s goal is to recognize where yield loss is occurring — whether that’s as a result of swathing too early or combining too fast or some other harvest factor. Windrows blowing in the wind is one of these other factors,” Brackenreed says.
“Increasing profit often comes down to a bunch of small incremental decisions that, on their own, don’t seem like a big deal,” she adds. “These can include seeding a little heavier, swathing a couple of days later and combining a fraction slower.”
How to measure seed-colour change
Seed-colour change (SCC) is considered any amount of yellow or brown on the seed.
To measure SCC, start in an area of the field that best represents the stand, stage and yield potential of the crop. Pull a plant and isolate the main raceme, which is typically the longest branch with the most pods and greatest percentage of yield. Take pods from the bottom, middle and top of the main raceme.
For 60 per cent SCC, seeds from pods at bottom third of the main raceme will be totally brown to purplish brown, seeds from the middle third will be starting to turn, and seed from the top are green but firm and will roll between your thumb and forefinger without mushing.
Check five plants in this area, then repeat in another couple of places in the field.
For a video on how to identify SCC, visit canolawatch.org.