United Kingdom
September 16, 2024
Over the past few years, there has been a lot of discussion around the optimum sowing window for OSR. Growers have long speculated on the perfect conditions for successful establishment. As breeders, we would always emphasise a key point when considering your drilling window is planting to the conditions rather than a specific calendar date. We are starting to hear success stories at harvest from farmers who observed environmental conditions, and when required, moved away from the traditional late July-August sowing window when they did not suit.
The traditional sowing window always made sense for the open pollinating ‘conventional’ varieties of OSR, which generally have slower autumn vigour than their hybrid counterparts. Hybrid varieties from the Limagrain portfolio such as Aviron, LG Avenger and the clubroot tolerant variety LG Scorpion, are fast establishing and particularly vigorous varieties, making them extremely well suited for later drilling.
The increased autumn vigour offered by hybrids means that later sowing is not only a viable option, but a strategic choice, as these hybrids establish quickly and reach optimum winter biomass faster than traditional conventional varieties.
With the rain received over the first couple of weeks of this September, the conditions are suitable or even optimal, with ample soil moisture present for the crop to get away. Though I would caveat this with a reminder that it is still crucial to get the 30kg N/ha of autumn fertiliser applied to the crop to make it a success.
When drilling later, there is always the worry of potential damage from adult flea beetle, due to there being less biomass present than in an early sown crop. Later sown crops however should emerge after the majority of adult CSFB have migrated. Research from ADAS in 2020/21 points out that crops sown on the 15th of September showed minimal damage on the plants from adult CSFB, at just 3%. On top of this, plants sown on the 15th of September also demonstrated a marked reduction in the number of larvae found in plants, meaning a reduced risk from larvae damage. *
Other benefits of later sowing include the reduced risk from a range of common diseases, as well as increased opportunity for weed control. A lot of the weeds and volunteers from the previous crop will have already emerged and a stale seedbed can be achieved before drilling.
* https://www.unitedoilseeds.co.uk/images/uploads/documents/Sacha_White_-_Reducing_the_Impact_of_CSFB.pdf
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