Limagrain: Survey shows importance of drilling conditions for OSR success

LG Seeds' William Charlton
LG Seeds’ Will Charlton.

Strong prices and good autumn establishment has renewed confidence in oilseed rape as many growers consider a return to the crop in 2022, according to Limagrain UK’s arable marketing manager, Will Charlton.

“Growers have struggled to find an alternative non-cereal break crop to fill the gap in the rotation and which also offers such strong gross margins,” he said. “Good conditions last August and prices well in excess of £400/t at planting has seen the oilseed rape area rebound, with the planted area for harvest 2022 up about 361,000ha.

“We believe that the market has the potential to grow even further as growers implement a wider range of strategies to cope with cabbage stem flea beetle (CSFB) and newer varieties bring improved yields, vigour and agronomic characteristics to the rotation.”

To support growers and help to mitigate the financial impact of a crop failing to establish, in 2021, Limagrain worked closely with partners in the seed trade to set up an Establishment Scheme.

“The scheme accounted for 19,000ha of OSR planted in 2021, representing 8.3 per cent of the total hybrid area and 6.2 per cent of the total certified area so a significant area of the rape in the ground.”

“This has provided us with an extremely useful insight into when crops are drilled which we have been able to track against weather at the time,” Mr Charlton said. “Most of the OSR in 2021 was drilled in the first two weeks of August – much earlier than it had been pre the neonicotinoid ban when the typical drilling date was the third week of August.”

He points out that when plotted against the weather, the data showed that where drilling was carried out in dry conditions, subsequent crop loss was closely correlated.

“However where there was rainfall in or about the two weeks from drilling, plant survival was much more likely,” he added. “This data reinforces the need for moisture when drilling oilseed rape for successful establishment as this allows the crop to germinate and grow up and away from CSFB as quickly as possible.”

Mr Charlton’s advice is to drill for conditions, not calendar date, and choose a variety with adaptability that can cope with this. For example, a very vigorous hybrid such as LG Aviron, LG Antigua, Ambassador or Aurelia gives growers the flexibility to wait for the right conditions.

There are several agronomic practices that can help mitigate CSFB damage

“These are all based on increasing branching to minimise larval damage,” Mr Charlton said. “Seed rate is key – if the crop is too thick it reduces the plant’s ability to branch out and the beetles head for the main stem, where emerging larvae cause the most damage. However, in a well branched out plant, the larvae spread out to the side branches and the plant can cope much better.

“An effective autumn and spring PGR programme will also help to manipulate branching, and minimise damage from CSFB larvae.”