If you have green seed in the canola swath, your best option may be to leave it in the field a little longer. It is still early enough in the harvest season for canola with moderate to high green seed counts in the swath to cure and potentially be taken off as No. 1.
The enzymes responsible for removing chlorophyll in canola are only active at temperatures above 5C and at seed moisture contents above 20 per cent. For this reason, canola harvested and put in the bin at the recommended moisture level of eight per cent or lower will show virtually no seed col-our change.
“Essentially, what you take off the field in terms of green seed is what you are going to deliver to the elevator or crusher,” says Matt Stanford, Canola Council agronomy specialist.
If weather has been warm and dry for several days, green seed clearing in the swath may have stopped completely. Swaths will have to get dampened by either rain or pivot irrigation, where available, to reactivate chlorophyll-clear ing enzymes in the seed. The optimal situation is to clear sufficient chlorophyll in the swath in order to get top-grade canola.
If canola receives frost while standing or within two to three days of swathing, cells can desiccate rapidly and the enzymes that clear chlorophyll can be damaged.
In this situation, green seed clearing in the swath will be slowed dramatically even if temperature and moisture requirements are met simply because the enzymes will not work properly. It is likely best to get the crop off and capture the yield that is there since the odds of a grade improvement by leaving it in the field are low. In this situation consider binning the canola separately and monitor closely for heating.
“Managing green seed levels in the swath should always be done on a field-by-field basis. Be patient, but don’t be afraid to take the crop off if frost or other risk factors are driving the decision,” says Stanford.