Complicated cropping – involving sugar beet, potatoes and other vegetables as well as winter wheat and barley – and the time and spraying commitments that go along with them make ease of management the key priority for the 90-100ha of winter OSR grown each year at Wm Kerr Farms, Easton near Woodbridge in coastal Suffolk.
“As well as having to be easy to manage as part of the demanding cropping mix we have on our mainly heavy clay loam ground, we put the premium on consistency in our rape,” stressed farm manager, Dan Kiddy who also does all the business’ agronomy.
“I’m happy to say we’ve been able to improve this substantially in recent years. Growing rape once in every 5-6 years, our five year average yields are running at 4.5t/ha. And last season our oils were a good 45% and input costs under £140/t.”
Essential to this success have been the most robust hybrid varieties established early in August in a low cost but highly effective single-pass regime, managed for the most efficient canopies with the only the most essential inputs and harvested with patience and care.
“Characteristics other than yield drive our variety choice,” Dan Kiddy pointed out. “We want crops that get out of the blocks rapidly and reliably in the autumn. They have to have high levels of phoma and light leaf spot resistance. They need to grow away early in the spring. And they must hold onto their seed until we’re ready to combine them.
“If varieties have these characteristics we know they’ll perform for us. Equally importantly, we know they’ll do so without us having to go to town on inputs or get every element of their timing spot on. With all our other crop priorities we can’t be dealing with rapes that need molly-coddling.”
For the past three seasons, Wm Kerr Farms have only been growing hybrids. Not because they are hybrids, Dan Kiddy hastens to add. But simply because the particular hybrids they are growing meet their criteria better than other varieties.
Like last year, the current crop is all DK Exalte. As well as its particular speed of autumn and spring growth and disease resistance, their preference for the variety goes back to 2016 when it remained virtually untouched by one of the worst hail storms in recent memory 10 days ahead of harvest; a storm which bleached white the entire area of another leading hybrid growing alongside it in the same field.
“The precise dividing line of damage across the field left me baffled at first,” admitted Dan. “Until I checked the drilling notes and found it exactly marked the boundary between the two varieties. This and a yield difference of almost 2t/ha convinced me that pod shatter resistance was an essential for us, not just a nice-to-have.”
As far as establishment is concerned, the Abbey Farm team has tried all sorts of regimes over the years. Seeding down the legs of a subsoiler and off the back of a Vaderstad Top Down both proved too inconsistent in the past. So until 3 seasons ago, the rape was sown with an adapted Vaderstad Rapid drill following initial Top Down tillage.
To move far less soil to retain moisture, restrict seedbed weed germination and save on labour and tractor hours at a hugely busy time, a10-year old 3m Simba Flatliner with low disturbance legs has since been fitted with a Hatzenbichler seeder unit in what Dan Kiddy regards as the best establishment system they have yet hit upon.
“The 5-leg configuration means we sow in 60 cm bands,” he explained. “This gives the
freely-branching crop the space it needs to develop a good broad canopy. Moving the minimum amount of soil at the surface ensures we’re putting the seed into moisture in a single economical pass.
“Sowing depth control isn’t as good as it might be. So we haven’t been brave enough to cut seed rates to the 25 seeds/m2 that would theoretically be about right for our band-sowing width. However, at 40-45 seeds/m2 we’re getting nice even crops that come-up rapidly to cope very well with slug and flea beetle attack.
“We’re also taking advantage of the establishment vigour we have in our chosen varieties and sowing from the second week in August to make the very most of the autumn growing window.
“Double rolling is a vital part of our recipe,” insisted Dan Kiddy. “First we roll directly along the drilling line which is at 45o to the previous tramlines, then in the direction of the old tramlines. We also have a strict 6 kph speed limit. That way we get the best possible seed-to-soil contact. At the same time, we eliminate the loose clods that shelter slugs and flea beetles.
“This regime allows our rape to grow away from both pests without too much agrochemical support. This season we needed a single main slug pelleting in most cases. And we only had to use one flea beetle spray.”
Other important elements of the establishment regime include winter barley ahead of the rape in the rotation – wherever possible – to give sufficient time for early sowing; cereal straw baled to remove slug shelter and avoid any interference with early crop growth; pre-planting glyphosate to hit early germinating barley volunteers; and 30kg/ha nitrogen spread after drilling to support early crop growth.
Pre-emergence metazachlor, quinmerac and clomazone within two days of drilling make the most of the well-consolidated seedbed conditions to deal with an inevitable combination of broadleaved weeds, including hedge mustard, cranesbill and shepherd’s purse.
An early post-em graminicide is also important to keep on top of cereal volunteers – especially where they come from preceding hybrid barley! While black-grass is by no means absent, at least one root crop in the rotation, effective glyphosate stale seedbeds ahead of all cereal plantings and early/mid-November Astrokerb in the rape continue to keep it at rogueable levels.
A single autumn fungicide, mainly targeted at early light leaf spot protection, is all that’s needed with the strong varietal phoma resistance Dan Kiddy insists upon. Although sowing a fast developing variety early means big crops at this stage, he avoids any autumn plant growth regulation.
“This season was perfect proof of why we always hold off on any growth regulation until stem extension,” he said. “The prolonged winter and intense late pigeon pressures meant the last thing our rape would have needed was an enforced pre-Christmas growth check.
“Instead, we wait for the crop to get away in the spring, then decide whether we need to apply tebuconazole before our mid stem extension/early flower Amistar/Proline spray.
“We don’t bother with a specialist PGR here either, because the combination of robust establishment in wide rows naturally gives us the standing power and lateral canopy development we need.”
Varieties that grow away rapidly in the spring, supported by half the annual 220 kg N/ha as ammonium sulphate as soon as the ground will take the spreader, give the short, intense flowering Dan Kiddy wants for the most efficient early pod-fill canopy light interception.
As well as ensuring even fertiliser spread right up to the field margins, the farm’s Kongskilde Wing Jet spreader allows the second split of nitrogen – as urea – to be accurately applied as late into flowering as possible, courtesy of its boom height adjustment.
Thick stemmed crops supported by good amounts of nitrogen for pod-fill and stay-green chemistry present an obvious challenge for harvesting. Even so, the insurance of pod shatter resistance allows the Abbey Farm team to hold-off on desiccation for as long as possible to maximise both yield and oil content while minimising red seed.
“Knowing we’ll only lose few seeds from the more mature pods even if the weather turns against us gives us the confidence not to go in with the glyphosate until the lower pods are good and ready,” pointed out Dan. “It also means we no longer bother with a pod sticker so we don’t have any of the stickiness and elevated moisture contents at combining we used to.
“Pod shatter resistance means we can afford to be equally patient with our combining too. We don’t harvest anything over 8.5%, only go in when the stems are good and dry, and combine with care to achieve the most complete thrash. We’re continually checking both in front of the combine and behind it, so we know we’re not losing much in the way of seed these days.”
While Dan Kiddy reckons they have got most things about right in their OSR management, with the combine yield meter routinely showing 8t/ha in patches he knows they have plenty of room for further improvement. However, he’s only keen to secure this if it does not involve any unnecessary equipment investment, extra inputs or loss of critical management ease and flexibility.
“OSR has to perform for us,” he concluded. “But it also has to fit in with our whole farming operation; which means not using-up precious time and sprayer capacity, in particular. Otherwise, it simply wouldn’t be worth us continuing to grow the crop.”