Oilseed rape growers looking to make the most out of early August drilling can now pick up a free 20-page guide, co-produced by Opico and Bayer, which brings together the latest guidance from across the industry.
Featuring experts from ADAS, NIAB and Wright Solutions, the new publication features a wealth of advice for early drillers alongside the establishment essentials.
Sowing in the first two weeks of August has been invaluable in allowing crops to get away and survive cabbage stem flea beetle grazing in recent years, so the guide says, but moving forward from the traditional mid-to-late August window brings with it a number of challenges that should be addressed.
Chief amongst these is the danger of increased cabbage stem flea beetle larval burdens in the spring. While the phoma pressure is reduced, earlier drilling can also add to the risk of light leaf spot, clubroot and, possibly, also verticillium and turnip yellows virus.
There can also be increased agronomic pressure due to overly-large canopies which are susceptible to pre-mature stem extension in mild winters and serious damage from frost and snow during cold conditions.
Higher lodging risk is also highlighted, especially where there is a combination of higher seed rates and better establishment results in dense stands of thinner-stemmed plants.
A more obvious issue is the reduced time between harvesting the previous crop and establishing oilseed rape. This has obvious implications for the previous cropping, straw management, grass weed control and correcting any soil structural problems, as well as machinery and workload issues at the peak of cereal harvesting.
The Guide to Early OSR Drilling brings together these potential issues, while identifying a series of rotational, varietal, machinery and management priorities to help avoid these pitfalls in a series of easy-to-read sections.
Rotational priorities
- OSR should not be sown if there is insufficient moisture in the seedbed or compromised soil structure.
- Structural issues need to be corrected ahead of the crop in the rotation where possible, and ground with a history of clubroot problems should be avoided.
- Winter barley is said to offer the best entry, with winter oats, winter wheat and spring barley also considered suitable, providing that their maturity is not delayed by genetics or management.
- Leaving long cereal stubbles will ensure the most rapid combining and effective straw chopping and spreading while providing the OSR with a good micro-climate for establishment.
- Companion crops can improve establishment, while cover crops with brassica sown later in nearby fields may be useful in ‘trapping’ migrating cabbage stem flea beetle.
Variety priorities
- As well as establishing vigorously, varieties should be rapid in their development to get crops away but not so fast that they produce excessively-forward, pre-winter canopies.
- Varieties that are earlier or faster in their spring regrowth can provide extra tolerance to high levels of cabbage stem flea beetle larvae.
- Standing power with the best combination of stem stiffness and lodging resistance is more essential than ever.
- Strong light leaf spot resistance is also crucial, combined with good resistance to verticillium where possible.
- Turnip yellows virus resistance can be a useful safeguard, although only in addition to more important priorities.
Machinery priorities
- Single pass establishment is essential, with speed balanced by sufficient care and precision in seed placement in particular.
- Where soil conditions allow, no-till drilling is preferred. Alternatively, low disturbance remedial work should be tackled as part of a tailored seeding regime.
- Seed should be sown into soil that has been re-consolidated after any disturbance to ensure good depth control and seed to soil contact.
- Machines should be able to cope with long stubbles and trash; fertiliser should applied with the seed; and, ideally, a companion crop and slug pellets should be applied at the same time.
Management priorities
- Seed rates leading to a higher than ideal plant population should be avoided to ensure the most productive canopies and stems, with reduced susceptibility to cabbage stem flea beetle.
- The reduced threat from phoma should give more flexibility to delay autumn fungicide treatment, therefore targeting against the higher light leaf spot risk.
- An early autumn application of metconazole may be needed to regulate growth when the crop is particularly forward – especially if it is also very thick.
- Large canopies coming out of winter put the onus on careful spring N management for Green Area Index and effective plant growth regulation.
- Levels of cabbage stem flea beetle larvae can be reduced by sheep grazing or mechanical defoliation but this must neither be too intense nor too close to steam extension to avoid compromising yields.
“Making the new Guide available as widely as possible to growers and their advisers across the country this summer will, we very much hope, help them to take full advantage of the particularly good prospects for OSR in the coming season with the least risk,” commented Bayer OSR campaign manager, Lizzie Carr-Archer.
Copies of the guide will be available free of charge from Bayer and Opico, and will available from the Opico/Sky/HE-VA stands at Groundswell and Cereals. Alternatively, it can be downloaded from www.opico.co.uk