September sowing central to successful Hampshire OSR recipe

Early September is David Northway’s sweet spot for drilling OSR at Breamore Estate on the eastern edge of Cranbourne Chase near Fordingbridge in Hampshire. But because he insists on the most vigorous, fast-developing hybrids, he is content to sow his annual 80-100ha crop right through to the end of the month.

Since the late-1990’s when cabbage stem flea beetle compounded the cropping challenge he has long had from gamebirds, pigeons and slugs, Mr Northway has developed an OSR growing recipe that allows the crop to remain an important and eminently profitable part of his 550ha rotation.

As well as September sowing, this includes direct drilling the particular hybrids he finds best suited to the estate’s generally thin and hungry ground into long cereal stubbles with a companion crop following seedbed fertilisation.

Together with ensuring the crop has all the inputs it needs to achieve the reliable 4t/ha average he targets at oil levels of 46% or more, this recipe ensures the crop continues to remain a key element in the estate’s rotation alongside first wheat and both winter and spring barley.

“We have stretched our rotation to only grow winter OSR once every five or six years these days, adding peas or poppies (initially for pharmaceutical use but now for seeds in baking) as an additional break,” points out Mr Northway.

“Drilling before mid-August isn’t really an option for us with our very tight staffing and busy cereals harvest, even when we grow the earliest maturing wheats. At the same time, we’ve learnt that drilling in September gives us the best results – even if conditions mean we have to extend it beyond the middle of the month.

“Later sowing means we’re more likely to have decent seedbed moisture. What’s more, our OSR then emerges after the flea beetle peak. Close to the south coast too, September drilling means we don’t run the risk of the crop going into the winter too proud and thick. With the very much warmer and growthier starts to the season we seem to be getting, this is becoming especially important.

“It’s essential we grow the right varieties for this slot, of course. We’ve found picking the best, fast-developing as well as vigorous hybrids is key.

“Dekalb breeding remains our first choice for its all-round strength. We’ve had particular success with DK Extrovert, DK Expansion and DK Exsteel in the past, and our current favourite is DK Excited.

“It continues to be one of the most vigorous and fastest developing hybrids in the field-scale trials we run each year to give us the best variety feedback. Rapid spring as well as autumn growth development means it recovers really well from any setback. Half our current crop is DK Excited, which we always prioritise it for the most challenging fields and headlands.

“Three years ago when we first had it in our trials, DK Excited stood out for its recovery from serious pheasant grazing when it drew the short straw and was the closest strip to one of our many woods. We thought we had lost it completely, but as soon as the shooting season started it came back through and did us well. On our ground it isn’t too tall, either, making it much easier to manage and combine than many.”

Mr Northway also appreciates the variety’s combination of good light leaf spot, stem canker, TuYV and verticillium as well as pod shatter resistance, together with a sclerotinia behaviour better than the first variety on the RL claiming tolerance, and a nitrogen use efficiency better than the original variety claiming the character.

This latter attribute and a switch to coated urea for its slower release characteristics has given him the courage to cut his spring nitrogen application from 190kg/ha to 160kg/ha this season in an attempt to further improve his OSR-growing efficiency.

“Like most, we have always tended to err on the generous side with nitrogen,” he says. “But as we are looking for a consistent 4t/ha these days rather than trying to push to 4.5t and beyond, we really shouldn’t need the extra fertiliser; especially if we grow varieties like DK Excited proven to lose less yield than others when N supply is limited.

“In addition to two spring applications, we also put on 30kg/ha of N in the specialist AgriiStart OSR fertiliser we spread on our cereal stubbles immediately ahead of drilling. So, our total N use is under 200kg/ha this season compared to well over it previously. It will be interesting to see how our own crop and the 10 specific varieties we have in our trials respond to this.”

The starter fertiliser is applied ahead of drilling at Breamore simply because the dual hoppers of the estate’s Amazone Cirrus drill are both in use – sowing 10kg/ha of buckwheat alongside 50seeds/m2 of OSR.

Replacing the estate’s tine-based Amazone Cayena with the disc-based Cirrus two years ago has been part of David Northway’s desire to move progressively less soil – to improve its structure and health as well as minimising the moisture loss than easily can be the difference between crop success and failure on the drought-prone land.

Cereal stubbles of about a foot also help to protect the soil surface from moisture loss after combining, while confusing flea beetles and providing the best micro-climate for OSR establishment.

The buckwheat companion that has been standard practice for several years has also really helped the OSR with its phosphate mining ability and in nursing the crop and sheltering it from flea beetle; especially with a dual hopper on the new drill allowing it to be given a much better and more even start than when it previously had to be broadcasting-on with the fertiliser.

“We still see some beetle damage each season,” Mr Northway notes. “But we haven’t lost any crop recently; and, in contrast to some of the conventional crops we were still growing back in 2019, our preferred hybrids have been able to shrug off any larval damage remarkably well.”

Encouraged by the £55/ha SFI payment for companion cropping, he is adding fenugreek to the companion mix this autumn for the off-putting smell it has shown to both beetles and pheasants. He is also including berseem clover for its root penetration and nitrogen fixing, hoping these additions will give a valuable extra establishment edge in coping with any tricky conditions.

Even though he hasn’t sprayed for flea beetle in the past two years, he isn’t going for the no-insecticide SFI option, though; mainly because he needs to keep the flexibility to deal with cabbage stem weevils which reached threshold levels both last season and this.

“Since we lost neonics we have been putting a lot more effort into learning how best to grow oilseed rape,” concludes Mr Northway. “This work has definitely paid off in a recipe focussed far more on consistency rather yield-chasing that suits our ground, system and needs well.

“There’s always room for improvement. As well as tweaking our companion cropping, we are looking at different ways of boosting plant health and micro-nutrition, in particular, to improve our OSR growing efficiency still further.

“Having said that, with the oil and other bonuses we achieve, the margins we are making from OSR are not far short of milling wheat even at crop values of barely £400/t. “And without the clean break it gives our rotation we really wouldn’t be able to grow the decent milling wheats that are the backbone of our business.”