Following an early start to harvest, and in some cases, the land cleared and ready to go, Agrii seed technical specialist, David Leaper says growers need to focus on three areas to set next year’s crop up for the best start.
Agrii expects an upturn in the overall national crop area following a 40-year low. By the end of July, the company had seen a 50% uplift in OSR seed sales compared with the same period last year.
AHDB data has shown that yields so far are 21% above the five-year average. Add to that a price above £400/t and it is easy to see why farmers may see it as worth sowing this season, notes David.
His three focus areas are:
Consider sowing a companion crop now and the OSR later
Companion crops help hide small OSR plants from adult CSFB, both visually and by masking the volatile compounds emitted by oilseed rape, which attracts CSFB. They also improve soil structure and increase nutrient availability for the crop. Although popular, most companion crops are sown at the same time as the OSR because of time pressures, but an early season allows the sowing to be split, explains David.
“The advantage of splitting the drilling is that in a month’s time, there will be a good green cover to sow the OSR into, protecting the OSR and negating any of the difficulties that come with an early sowing.
Adjust seed rates
“Historically, we have always advocated sowing hybrid varieties at 50 seeds/m2, but with CSFB, this has crept up to around 60 seeds/m2.
“Sowing early allows the opportunity to go back down to 50, you could even go lower to 40 seeds/m2, but as you still need to account for potential losses, I’d recommend no lower than 40,” says David.
Reducing the sowing density will account for an extra month’s growth, and it has benefits further on in the year by providing more room for additional branching in the spring, he explains. This can help mitigate the effects of CSFB larvae by keeping them out of the main stem and in the lower side branches, where their yield impact is minimal.
Select the right variety
With early drilling, farmers are tackling one issue – the adult CSFB – while opening the door to another – the CSFB larvae. However, David says that the right variety can help alleviate some of the additional pressures an early drilled crop is subjected to.
“You need a variety with good light leaf spot and Verticillium resistance, as well as an adaptable growth habit which can compensate for any damage once it gets going again in the spring.
“Agrii trials over several years show a strong relationship between larval damage and early spring biomass, which then corresponds to yield. One variety that has stood out with its early spring biomass is RGT Kanzzas. It also has the best light leaf spot score of any variety we have ever tested and its growth habit suits a later planting if there’s a change of plan,” he concludes.
