As British grown oilseed rape starts to signal towards a slight recovery, how can growers get the best from the crop? CPM finds out more…

Flexibility within a variety is key.

By Charlotte Cunningham  

Looking cautiously around the countryside, oilseed rape crops are largely looking well, with carpets of evenly established yellow flowers a sight for sore eyes after a challenging few years.

Though the mighty mouth of the cabbage stem flea beetle proved an opponent too great for many growers, with more knowledge about how to grow OSR to avoid the worst of beetle pressures, and high crop values going forward, it could be enough to attract growers once again reckons Duncan Durno, arable technical manager at Openfield.

“Despite the challenges, OSR is still an incredibly important break crop,” he says. “There’s a lot of crops looking very good and I think growers are starting to get more confident with getting OSR up and away to mitigate the risk of flea beetle damage. This is also supported by some very strong prices at the moment – adding to the attraction.”

A successful crop starts long before a drill is pulled out of the shed, and comes largely down to choosing the right variety, believes Duncan. “In light of what we’ve seen and learnt about the habits of the CSFB, flexible drilling windows seem to be one of the best tactics for avoiding the worst of it.

“Flexibility within a variety is key because the ‘ideal’ window will vary from farm to farm. For example, in the South there seems to be a trend towards drilling later, whereas those in the North tend to benefit more from earlier drilling. The conditions have to be the driver for sowing a crop – not the variety.”

But flexibility and the ability to get up and away also has to translate into good yields, adds Duncan, and so it’s important to select varieties which are stacked with good agronomics too. “This is an opportunity to think about what kind of drilling window you tend to sway towards and what other qualities you might need to support that. For example, good stem strength and TuYV resistance might be a must-have for early drilling. Traits pod shatter resistance also help to add reliability and inherent strength to a variety.”

Duncan says there are four key varieties in the Openfield portfolio which offer both flexibility and a strong performance: Ambassador, DSV Duplo, DK Excited and Tennyson.

A hybrid from the Limagrain stable, Ambassador is one of the highest yielding and most consistent OSR varieties on the 2022/23 AHDB Recommended List with a gross output of 106%. Proven on farm over the past three seasons, Ambassador is now the most widely grown variety across Europe, note Duncan. “Flexibility in drilling date is provided, with the variety being well suited to both the early and late window, with notable autumn and spring vigour.”

Agronomically, it’s a good choice too as Ambassador is fully loaded with traits, including TuYV and phoma resistance, as well as Limagrain’s N-Flex trait, explains Liam Wilkinson, arable crops development officer at Limagrain. “Ambassador was the first commercially available variety to contain the trait. The development of N-Flex has focused on how OSR moves plant protein and transforms nitrogen into yield.

Our research has proven that hybrids containing the trait use each unit of available N more efficiently than those which don’t have it. In the field, this translates into varieties with the N-Flex trait producing more stable yields year to year, with less in field yield variability.”

Also boasting good autumn vigour is DSV Duplo. “With many people drilling later to hopefully miss the worst of CSFB pressures, Duplo is an ideal choice,” explains Duncan. “In fact, with earlier flower development, it’s probably not one you’d want to put in the earlier slot.”

Duplo is also one of DSV’s ‘triple-layer’ varieties, explains the firm’s Sarah Hawthorne. “DSV Duplo was initially fast-tracked into the UK market because of its exceptionally strong establishment but it’s proven to be a strong and resilient variety throughout the growing season.

“As well as TuYV and pod shatter resistance, the variety also has Rlm7 plus multigene resistance to phoma stem canker and the DSV N-efficiency trait allied to a deep rooting system to help ensure robust growth in virtually all conditions – including droughts.”

Though it doesn’t form part of the RL, Dekalb’s DK Excited is a strong option worth considering, points out Duncan. “In Bayer’s own trials, it’s come out on top for yield, and also boasts a whole host of other important traits like rapid establishment, early growth habit and vigour – as well as TuYV resistance.”

Breeder, Matthew Clarke, says that DK Excited is the “next step up” in Dekalb’s OSR breeding programme. “Looking at both our breeding trials and commercial data, DK Excited has been proven to give consistently high performance across a wide range of European environments in addition to those in the UK. This level of yield consistency, added to the Dekalb yield protecting traits of pod shatter and disease resistance, translates into a very robust hybrid for all UK growers.”

And finally, Openfield are championing Tennyson, a newly recommended variety from Elsoms. “With a wide drilling window, Tennyson is a great choice for growers looking to build flexibility into their drilling programme,” says Duncan.

Recommended for growers in the East and West regions, Tennyson also boasts a top agronomic merit score on the AHDB variety selector tool, adds Jack Holgate, crop manager at Elsoms.

During the 2022/23 launch, the RL team noted Tennyson as a variety with a high gross output (104%), high resistance to lodging and very high resistance to stem canker (9) – pointing out that this resistance is based on different genetics to most varieties on the RL. It also boasts a score of 7 for light leaf spot and benefits from TuYV resistance too.

From this year, the variety will be sold as primed seed, and Jack adds that this is beneficial for establishing a uniform crop of OSR. This is something Openfield is particularly interested in, and the firm has been carrying out its own trials to look at the benefit of priming technology (see box ‘Primed for success’).

Once established, managing the crop with the correct nutrition is also vital for getting the best from OSR, notes Duncan. “One of the most important considerations for rape is sulphur – it’s a very sulphur-hungry crop and nitrogen use efficiency is largely governed by sulphur ratios.”

But with input availability across the board thrown into jeopardy of late, the outlook for sulphur supplies is equally precarious, explains Openfield’s Lucy Hassall. “There’s definitely been a lot of concern leading up to the new season reset with regards to availability. Ultimately, CF Fertiliser not running the factory at Ince is a big issue. A lot of UK farm supplies have traditionally come from this plant, namely DoubleTop, SingleTop and Sulphur Gold.”

In a situation where supply is limited, the best course of action would be to consider switching to a Yara 26/35 grade, which still has high levels of sulphur, explains Lucy. However, this too is in short supply. “Each supplier has only been allocated a small amount, and ultimately, as soon as it’s come in, it’s gone back out again. Origin is another potential source, but again it’s the same story and we just can’t get hold of any.”

With high sulphur products in short supply, but high demand, Lucy says there’s been a shift towards growers looking for lower grades (27/12) with a mind to go with a little and often approach to application. “But even these sources have come back with low offers. It’s a real concern.”

The only readily available option at present is urea sulphur, she explains. “In particular, we’ve turned our attention to polysulphate sources.”

Polysulphate is made up of sulphur, potassium, magnesium and calcium, and the world’s only polyhalite mine is operated by ICL in North Yorkshire. The firm’s Scott Garnett explains why polysulphate could be an important part of crop nutrition plans going forward – and in particular, this season. “It’s a natural mineral that we mine here at Boulby, North Yorkshire. Because it’s a rock, there’s no manufacturing involved – we simply mine it underground and cut it to size. It’s also got the lowest carbon footprint of any other mineral fertiliser out there.”

Compared with traditional sulphur sources – which are known for leaching – polysulphate also offers a more sustained supply of sulphur to crops, he adds. “The nutrients held within the rock crystals are released over a prolonged period. This can be up to 50-60 days, compared with just a few weeks from other sources. This means that the sulphur is readily available to the plant for longer, which when growing a tricky crop like OSR is highly beneficial.”

Polysulphate doesn’t, however, contain nitrogen, so Lucy advises going with a nitram/polysulphate programme.

Though interest has been growing year-on-year, Scott says the current challenges have actually shone a light on how beneficial other resources, like polysulphate, can be. “What’s more, it’s a very sustainable resource, which is particularly important at a time where growers are struggling to reserve the supplies they require.”

Primed for success

Priming seed to encourage germination is common practice in high value crops, and in a bid to incorporate the same strategy for success into OSR, Openfield has been carrying out trials on primed OSR seed for the past two seasons. “The technology is proven in many high value crops where crop uniformity is critical, and we wanted to see if this evenness of germination and establishment could be used to our advantage in the fight against CSFB,” explains Duncan.

This season, Openfield is running primed and non-primed seed comparisons in farm scale strip trials using Elgar seed, from Elsoms.

So how have they fared so far. “Large scale plots were drilled side-by-side using primed and non-primed seed from the same seed lot to allow accurate comparisons and assessments to be made,” he explains. “Plant counts at 17 days post drilling showed 78% establishment in the primed plot and only 28% in the non-primed – an impressive start,” notes Duncan.

Pre-winter growth area index (GAI) assessments were done on 20 November, before any winter defoliation had taken place. Results were again very positive, with the non-primed plot showing a GAI of 2.4 and the primed plot showing a GAI of 2.99, explains Duncan.

“Even more impressive is the evenness of crop canopy across the whole of the primed plot with all plants of an equal size and at the same growth stage.”

Crops were assessed for spring regrowth and early flowering with both these timings showing a more even crop development in the primed plot he concludes. “With this level of crop uniformity, it will help growers to optimise input efficiency with improved timing of nutrient and crop protection applications.”

Better buying, better selling

To remain at the forefront of arable farming and to maximise the value from every hectare of crop grown requires a keen understanding of the grain market, the seed to supply it, and the fertiliser to feed the crop.

Through this series of articles, CPM is working with Openfield to provide a market insight and help farmers to focus on these major business decisions to ensure better buying of inputs, and better selling of the produce.

Openfield is Britain’s only national farming grain-marketing and arable inputs co-operative, and is owned by over 4000 arable farmers. Openfield’s team works with a total of 6000 farmers to supply some of the biggest and best-known names in the British food and drink manufacturing industry.

But there’s more than just grain to Openfield, supplying seed and fertiliser, providing grain storage and offering expert advice on grain marketing and risk management. This delivers innovative supply chain solutions to its farmer members and consumer customers.