Determined focus on crop architecture delivers Hampshire OSR consistency boost

A determined focus on achieving the most productive winter OSR architecture from establishment onwards is paying dividends in improving the consistency of the crop at Leckford Estate in the Test Valley near Stockbridge in Hampshire; a consistency that is particularly vital for the Estate’s substantial cold-pressed rapeseed oil business.

“Most of our 480ha of mainly silt clay loams over chalk – including a good part of what used to be RAF Chilbolton – certainly aren’t ideal for oilseed rape,” explains arable and livestock manager, Tom Adami. “The ground isn’t strong enough. And it doesn’t take much of a dry summer for the old airfield taxiways to be brutally apparent.

“The cold-pressed business which uses only our own produce and sells Leckford-branded oil across the country is demanding as a customer, requiring regular deliveries of the right quality of cleaned rapeseed throughout the year. But it’s right on the doorstep; provides us with rapeseed cake for our 250 cow beef suckler herd and 400-strong finishing enterprise; and means we can earn margins not far short of first wheat if we get things right. It also gives us a reliably good entry for the breadwheat that is our Number One earner.”

Cabbage stem flea beetle hitting the average yield to 2.5 t/ha and wiping out a good 20% of plantings in 2019 was the trigger for Tom Adami and his Agrii agronomist, Iain Richards to ‘change-up’ their OSR recipe. Previously averaging 3.0-3.3 t/ha, the implemented changes have resulted in consistent yields of over 3.5 t/ha since 2020 with few, if any, areas of crop failure.

Averaging 3.8 t/ha, last season’s 68ha of DK Exsteel was their best ever, with the heavier land doing almost 5.5 t/ha. And they will be really disappointed if the even more promising crop they have this season doesn’t comfortably exceed 4.0 t/ha across the business.

Well-rooted enough to withstand all but the worst of summer droughts, wall-to-wall evenness, thick stem collars and strong branching right from the base are all testaments to the success of the team’s approach.

“The first essential for this architecture is a robust hybrid that takes-off rapidly from the word go,” Mr Adami stresses. “The cold-pressed business needs the right tasting oil as well as plenty of it. So, we tend to try a small area of a new variety each year alongside our favourite as a look-see in oil quality as much as performance terms. And once we’ve found a variety that does us well, we’re reluctant to change until we find something substantially better.”

“DK Exsteel remains our first choice for the third year in a row for its combination of autumn and spring vigour, disease resistance and standing power,” says Mr Richards. “It may not have TuYV resistance, but it continues to do us well as a real all-rounder.

“What’s more, it is the single most consistent variety we have ever had in national Agrii trials, and one of only three to merit inclusion for more than five years. With a gross output of 5.3 t/ha (107 % of controls) it was the second-highest performing variety in last season’s trials – within a whisker of the top slot and ahead of all three top varieties on the 2023/24 RL.

“The primed seed of the new hybrid we’re trying alongside it definitely gave an initial boost, but by flowering, the DK Exsteel was miles ahead of it in biomass and branching. And this despite not growing away too early in the spring, which we appreciate on the relatively cold ground here. It will be very interesting to see how their performances compares at harvest. Especially so, as the newcomer doesn’t have the pod shatter resistance, we’ve found a real aid to combining flexibility with OSR direct combined without desiccation for cold-pressing.”

As well as a variety that will push on to develop the thick collared, well-branched crops they are looking for on their ground from a sowing rate of 50 seeds/m2, Tom Adami and Iain Richards consider direct drilling, seedbed fertiliser and double rolling the keys to their establishment success.

Drilling into relatively long cereal stubbles, and companion cropping are also giving them a useful edge in combatting CSFB, as is regular farmyard manuring and close attention to early winter agronomy, in particular.

“We only grow OSR twice in our 12-year wheat-based rotation, which typically includes a quick crop of pea and barley arable silage for the beef herd ahead of a three and a half year herbal ley, an alternative spring-sown break (oats or peas) and spring barley,” points out Mr Adami. “We’ve found growing it once every six years about right here. And, while we maintain our rotation in rough blocks for convenience, we generally keep fields with the same crop separate from each other to create a patchwork across the arable area. This biodiversity really helps agronomically as well as environmentally.

“Back in 2020 we replaced Simba SL cultivation followed by Vaderstad Rapid drilling with a single pass Claydon hybrid drill to preserve moisture, reduce costs and improve timeliness. We apply AgriiStart OSR (providing 30 kg/ha of N with protected phosphate and a balance of key micro-nutrients) through the main hopper so it goes into the ground mixed with the seed from a separate small seeder at no more than 1” deep.

“Accompanied by steady and immediate double rolling for the best slot closure and seed-to-soil contact and separate ferric phosphate pelleting, the rapid, even emergence that this gives us has been fundamental to the improvement we’ve seen,” he insists.

“With 60% establishment our norm here, we aim to bring 20-30 plants/m2 through to the spring – and the right ones at that. By which we mean well-rooted, robust, thick-stemmed plants with the space as well as the capacity for the best branching – the sort of stands that can cope well with moderate CSFB larval burdens.”

Having suffered horrific CSFB larval levels from early drilling in the past, the Leckford team never now aim to drill before mid-August. As time is so critical with the OSR following either winter wheat or spring barley (all of which is baled), this is also because they find getting the crop in well always much more important than getting it in early.

With so little time to spare, any particular concerns over soil structure are addressed with the subsoiler ahead of the previous cereal. FYM from the beef cattle applied to improve soil health and condition goes on either ahead of winter wheat or one of the spring cereals in the rotation too; neatly also avoiding any extra soil trafficking risk before OSR drilling.

“Leaving a good 6” of cereal stubble – primarily to avoid combine damage from the flints – seems to have helped confuse the flea beetle and definitely helps protect the OSR seedlings from drying winds,” Mr Richards adds.

“Following a trial in two fields last season, we put all last year’s crop in with a buckwheat companion – sown immediately ahead of the rape on the lightest of discs (for the best trash spreading) because there’s no extra capacity on the drill. As this has been valuable, we’re planning to include fenugreek and a legume (probably berseem clover) as a companion mix from the coming autumn. As well as being better for soil health and biodiversity, the new SFI payment makes such a mix even more attractive.

“Being far from purist direct drillers, we are also now very lightly discing our OSR stubbles after harvesting to break open the thick collars our regime is producing and help reduce slug pressures in the following wheat. It’s encouraging to find recent NIAB CSFBSmart experience suggesting this may disrupt adult CSFB emergence. Anything we can do to reduce pressure on the following season’s crops nearby has to be good.”

Flea beetle management aside, Tom Adami and Iain Richards’ early OSR agronomy is all geared to giving the crop the best possible opportunity to achieve their target architecture. They know that anything that sets the crop back can really make it struggle, so they work hard to ensure nothing gets in the way.

Keeping a close eye on their crops every two or three days going into the winter – walking them at different times of the day and night – they are happy to apply two graminicides wherever cereal volunteers become problematic.

They also routinely employ the growth regular and fungicide Architect (mepiquat-chloride + prohexadione-calcium + pyraclostrobin) in the late autumn to improve structure as much as control disease. And they generally include an insecticide with it to target CSFB larvae at their most vulnerable stage as they move from the soil into the plants.

Finding targeted nutrition as valuable as traditional pest control in many cases these days, they routinely employ foliar molybdenum and boron from early post-drilling – with magnesium if necessary – alongside the phosphite-based biostimulant, Nutri-Phite PGA to promote rooting.

They always put on a good 60 kg/ha of N (as protected urea) together with polysulphate as early as possible in the spring to ensure their crops never lack the nutrition they need to grow away from the winter strongly. Up to 130 kg/ha of N is then applied in two further splits to Green Area Index (GAI), soil mineral nitrogen level and field history.

As branching is far more important to them than shortening crops that are as thick-stemmed and well-rooted as theirs, the stem extension spray goes on relatively late – almost at yellow bud. This also gives them the flexibility to hold-off on their sclerotinia spraying, so a single application invariably suffices – with an insecticide wherever seed weevil numbers reach their threshold.

“Alongside milling wheat, OSR is very much the bread and butter of our arable rotation,” concludes Mr Adami. “While we certainly don’t throw the kitchen sink at it, we have learnt we have to give it everything it needs if it is to deliver the performance we want. With the Estate’s cold pressed business to supply, we need consistent performance above all else, and can’t afford more than minimal crop failures.

“Learning more about how to achieve and maintain the most productive crop architecture every year, we now see a consistent 4 t/ha as a realistic target even on our mediocre oilseed ground. We are really pleased with how far we’ve come in a short time and are always looking to do as many things as we can just that little bit better.”

Expertise & Establishment support 

Bayer CTMs are on-hand to work with growers and agronomists to support variety selection, working together to best achieve your goals. In additional support, the DEKALB OSR establishment scheme is here to provide extra reassurance to growers in challenging times. All Dekalb varieties have strong development characteristics, helping them grow away from establishment challenges, however, should your crop fail due to flea beetle or other pressures, you’ll be credited by your seed supplier with £100/bag.

 Find out more