Oilseed rape (OSR) crops across the country are showing a stark contrast this autumn. Recent rainfall has brought much-needed relief in many areas, but establishment remains highly variable between fields, underlining just how influential drilling date, seedbed conditions and early management decisions continue to be.
Crops sown during the last week of July and early August have generally enjoyed favourable conditions. “These early plantings benefitted from residual moisture in the soil, which supported even germination and vigorous early growth,” says Sarah Hawthorne, sales & marketing manager at DSV. “Many of these crops are already at the four true leaf stage or more, putting them in a stronger position to cope with pest pressure and the increasing risk of weather extremes as autumn progress.
In contrast, OSR drilled from mid-August onwards has faced a tougher start. Dry conditions delayed germination in many fields, and although rainfall has now triggered emergence, these crops are noticeably smaller and more vulnerable.
“Later-drilled crops are struggling to get going and remain at risk for longer,” Sarah continues. “In some fields, plants are only just at cotyledon stage while others are further ahead, so there’s a real mix even within the same field. That variability leaves them more exposed to slug damage, weeds and pigeon grazing.”
Despite these challenges, she stressed that the door for drilling hasn’t fully closed. “With soil moisture now improving and temperatures still favourable, crops drilled through late September can still establish well. Success depends on good seed-to-soil contact and using vigorous varieties like Duplo and Cognac that can get away quickly in tougher conditions.”
In some fields, plants are only just at cotyledon stage while others are further ahead, so there’s a real mix even within the same field. That variability leaves them more exposed to slug damage, weeds and pigeon grazing.
– Sarah Hawthorne, sales & marketing manager at DSV
“Phosphate is critical for rooting and early growth, but a significant proportion of what’s applied can become unavailable in the soil,” explains Rhodri Morris, commercial director at De Sangosse.
“In some soils, more than 80% of applied phosphate can quickly become locked up, particularly in acidic and alkaline conditions, and this can be worsened by dry autumns that limit natural nutrient release. Placing phosphate with the seed gives young plants immediate access, and where early signs of deficiency appear, soil nutrient activators can help unlock bound phosphate and make the most of what’s already there.”
“Phosphate deficiency typically shows as stunted plants, dull green or purpling leaves and poor root development. Risk is higher in high pH or acidic soils, or in compacted areas. Soil analysis may indicate adequate phosphate levels, and plants may even appear healthy above ground, but tissue tests can reveal deficiencies that limit growth. Digging up plants to check roots, supported by both soil and tissue analysis, is the best way to confirm whether additional support is needed.”
“Using placement fertiliser that has phosphate protection technology offers crops the best chance of building strong roots and maintaining growth, even in later-drilled fields,” Rhodri adds.
You can learn more about this in our Phosphate Efficiency Pays Hub
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Slug grazing remains one of the biggest threats, particularly in uneven crops.
“OSR plants are vulnerable to slug damage until they reach four true leaves,” warns Rhodri. “This year we’ve got fields where some plants are safely at that stage, while others in the same field are still at cotyledon – and that makes the whole crop vulnerable.”
The treatment threshold for oilseed rape is just one slug per trap, assessed using bait such as chicken layers’ mash beneath tiles or pots. Where this level is reached, Rhodri stressed the importance of acting quickly with a well-formulated ferric phosphate pellet. Reliable control depends on both accurate application and the high palatability, rapid efficacy and durability of pellets, ensuring consistent protection.”
Find out more about effective slug control in our Ferric Focus Hub
Visit The HubOSR plants are vulnerable to slug damage until they reach four true leaves. This year we’ve got fields where some plants are safely at that stage, while others in the same field are still at cotyledon – and that makes the whole crop vulnerable.
- Rhodri Morris, commercial director at De Sangosse.
Encouragingly, flea beetle numbers appear to be lower than expected so far this season. Nonetheless, regular monitoring remains crucial, particularly through the use of water traps, to catch any localised flare-ups and act swiftly if thresholds are breached.
“This autumn has created a real split between crops.” Sarah concludes. “Some are racing ahead, others have been struggling to get going. But conditions remain favourable for drilling, and there is still time for crops established in late September to perform well.
With careful management now – right nutrition, slug control and pest vigilance – growers can still bring later-drilled crops through to a strong position for spring.
In the De Sangosse Phosphate Efficiency Hub we talk about how to unlock bound phosphate and key micronutrients to boost nutrient efficiency and early crop performance.