Canola harvest options and decisions

It may be hard to believe but harvest for this year’s canola crop is right around the corner.  The combination of a mild winter and environmental conditions during the spring have pushed the crop several weeks ahead of average in many parts of the state.  With harvest being close for many producers throughout the state it is time to start thinking about harvest management for this year’s canola crop.  However, before determining how to manage harvest, one needs to decide harvest method that will be targeted for their crop. 

Harvest method:  Producers have two very viable options (direct harvest or swathing) for harvest of canola within the state.  A third option (pushing) does exist and may be suited for certain areas within the state but information is relatively limited so the focus of this conversation will be on swathing and direct harvesting. 

The decision to swath or direct harvest comes down to several decisions that producers have to make at a farm level as well as a field to field basis.  Overall, optimum yields are achieved in best case scenarios from direct harvesting the crop, allowing the crop to dry-down in a more traditional manner.  However, as producers know optimum conditions rarely exist.  In addition to yield, direct harvesting has the potential to produce the highest quality seed with better protein and oil content.  Furthermore, having the crop to stand in the field allows the quality to be maintained through a wide-range of environmental conditions, such as hot weather at harvesting and poor moisture conditions after swathing.  This method also has the best resilience to harvest in heavily tangled and extremely thick stands (something a lot of producers may be faced with in the coming weeks).  However, direct harvesting has the highest potential yield loss when dry-down and harvest conditions are not optimum.  This point is emphasized during severe storms.  Hail as small as pea sized can dramatically reduce crop productivity, especially late into maturity.  This would make direct harvesting more a high risk, high reward option.

While swathing does not have the overall yield potential that direct harvest does, what it does offer is flexibility to the grower.  Swathing the canola allows the grower to have a little control over when the canola matures and at what rate.  It can also offer the grower the opportunity to harvest up to 10 days prior to direct harvesting, thus allowing for more acres to be harvested in a timely fashion or allows for harvest of canola prior to moving on to wheat.  Two of the biggest advantages outside of flexibility that swathing provides is decreased shattering potential and allows for the field to even out within the windrows to allow for a more uniform crop.  There is only one major limitation to swathing and that is the potential for decreased yield and quality, which can be as high as 30% but will typically range from 0-10% yield loss.  Other issues exist for swathed canola but they can be addressed by optimizing their harvest/swathing activities. 

Managing harvest activities:

Direct harvest:  The biggest management with direct harvesting comes with when to harvest and setting up a combine.  Producers should allow for the crop to dry to 8-10% moisture before the crop is harvested.  Harvesting with more moisture and drying through forced air can be successful, however, results have been varied.  It is best to wait for the crop to dry down and use combine management to minimize shattering. 

If growers want to compare combine setup to wheat, the general rule is to slow down to about 3/4 of what is typically done for wheat harvest.  This will include ground speed, reel speed, and cylinder speed.  In addition to speed, the reel should be set high and moved back over the grain table as far as it allows.  Fan speed can be set similar to wheat, with no major advantage to slowing the fam speed.  Canola is pretty easy to thresh, so opening concave up until whole dry pods are not threshed is better than too narrow and grinding stems (which can increase overall seed moisture).  Lastly, make sure the sickle is sharp, a dull sickle can lead to increased shatter loss in front of the combine.  If the harvester believes the combine is set properly, drive a test cut and get out and look behind the combine.  The rule of thumb is that 115 seeds per square foot is equal to 1 bushel yield loss per acre.

Swathing:  One of the most important decisions, if swathing the canola is desired is when to actively swath the canola.  Maturity is determined primarily from the main stem of the canola.

Main_raceme
Figure 1. Identifying the main stem, this will be the raceme used to determine maturity

 

Percent_raceme
Figure 2. Determining color change on percentage of main stem.  Use the length of the stem to help estimate maturity.  In the picture the arrows should be at 33%, 50%, and 75%, respectively.

Once the main stem is identified; it should be broken up into sections.  When determining maturity, we look at color change.  Seed color is distinguished as changed when it possesses small patches of brown to black color (spotting).  For swathing purposes. we would like to see at least 30% seed color change (color change of a majority of the seed within the pod in at least 30% of the main stem); however, lower yield and quality loss are typically seen when the grower can delay swathing until 50-70% seed color change.  The risks associated with higher color change when swathing is both increased shatter due to swathing or rapid drying.  Once a producer has determined that the plant has sufficient color change, producers need to ensure there are no translucent or water seeds within the branching racemes.  If canola is swathed with higher amounts of these seeds, a good fraction of yield loss can be experienced especially if side branches makeup a large fraction of the overall plant.  Once it is determined that the crop can be swathed, producers need to make sure the environmental conditions over the next several days are conducive for quick but quality dry-down.  If soil moisture has been limited and hot, dry conditions are in the forecast, swathed canola can dry-down too quick and not allow for the crop to successfully “cure”.  This will result in increased seed shrinkage and potentially higher percentage of green seed. 

colorchangeprogression
Figure 3. Progression of color change for winter canola at maturity.  The top left picture shows not color change throughout the pod with some soft watery seeds. The top right picture shows spotting color change throughout the pod, with firm seeds and limited translucent seeds throughout the plant. The bottom left picture shows color change throughout the pod with some spotting still on less mature seeds. Bottom right picture shows full mature color change.  Swathing can begin when at least 30% of the pods exhibit pod color of at least the top right and bottom left.

Caution should be placed on ensuring that minimum loss occurs in the windrow or as the canola is being picked up.  Canola should be ready to harvest in 7-14 days after swathing, but if the crop contains high amounts of immature seed or seed moisture it is better to let the crop sit in the windrow longer to minimize green seeds in the load as only few of these can result in high grade loss.  Windrows are best picked up using a rubberized draper belt. These belt types have rubber or synthetic fingers and are preferred when harvesting canola as the gentle action helps reduce shattering losses. The aluminum pick-up is more suited for bunched windrows.  Crop lifter attachments that are the width of the windrow will lift it into the header in most cases. The rest of the cutter bar may be covered to prevent or reduce the amount of second-cut stubble entering the combine.

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