Fertiliser applications and canopy manipulation treatments have been keeping our High 5 oilseed rape growers busy this month, as Louise Impey finds out

Tim Goodman, North Hill Farms, Salisbury

This year started with a field-specific tidy up of weeds for Tim Goodman, farm manager at Wilton Estates in Wiltshire.

Depending on the weed burden, he made good use of Fox (bifenox) for broad-leaved weeds including hedge mustard, shepherd’s purse and charlock, while Panarex (quizalofop) was employed on grassweeds and Crawler (carbetamide) aimed at blackgrass.

“We only missed one field due to the end of February cut-off date with Crawler,” he recalls.

Otherwise, phoma and light leaf spot were eventually dealt with by a single application of Kestrel (tebuconazole + prothioconazole), with the tebuconazole rate increased a bit on the varieties where some growth regulation was required.

At the beginning of March, he applied 300kg/ha of Double Top (27N, 30SO3) to his entire oilseed rape acreage, ensuring that the crop had adequate nitrogen and sulphur. “We thought about splitting this application, but the crop started to move as the weather improved, so it was best to get it all on.”

See also: An apt way to boost oilseed rape yields

His next two applications of liquid nitrogen fertiliser will be based on the SOYLsense variable rate application system, according to canopy development and crop requirement.

“The first of these will be all about manipulating the canopy size, while the second targets yield production,” he explains. “In total, we’re looking at applying 220-250kg of N, in three fairly equal splits.”

By the end of the month, Mr Goodman hopes to have made a green bud application of metconazole, to promote branching and increase the number of flower sites. At the same time, he will assess whether pollen beetle numbers have reached thresholds, and include an insecticide where appropriate.

“Pyrethroids are still effective on this farm,” points out Mr Goodman. “So that will be our first choice for their control.”

Flowering sprays are a way off and won’t be considered yet, he adds.

He is pleased with the crop’s progress to date. “Plant populations aren’t too high and crops are really beginning to move. The hybrids are probably slightly ahead of the conventionals at the moment.”

For more on this: See all of the articles on High 5 OSR yields

Andrew Gloag, Busby House, North Yorkshire

The beginning of March saw Andrew Gloag’s oilseed rape crops looking very good in North Yorkshire, despite 11.5in of rain since mid-December.

No further weed control has been required since the autumn and a single fungicide application of half rate Prosaro (prothioconazole + tebuconazole), which went on in November with propyzamide and boron, was very effective.

But he has just applied a second half-rate of Prosaro, together with some boron, to maintain crop cleanliness and keep them on track.

“At the moment, we’re keeping a careful eye out for pollen beetle,” he says. “There haven’t been any yet, but if thresholds are reached before the crop is flowering, a pyrethroid will be applied.”

Otherwise, his plan is to apply a total of 250kg/ha of nitrogen, together with the required 80kg/ha of sulphur.

“We started applying our liquid fertiliser on 8 March,” he reports. “We rely on the N Sensor for application rates, and to date we have applied between 30-110kg/ha. Left to my own devices, I would have applied 80kg/ha across the board.”

The second application will be made according to the N Sensor in the last week of March, after which he will review how much has been applied. “Because we’re on liquids, going through the canopy isn’t an issue.”

At this stage, all of the crop will get 50kg/ha of Nufol on the pod, he adds.

Sclerotinia will be tackled with a two-spray approach – the first application will be based on 1 litre/ha of Amistar (azoxystrobin) or an SDHI mix, which will then be followed up three weeks later with an application of full rate Filan (boscalid). “We’ll reduce that to half rate if it’s very dry.”

There have been no spring weed issues except for a small area of companion planting, which had to be sprayed with 0.35 litres/ha of Galera (clopyralid + picloram), as winter frosts hadn’t done the job.

Mr Gloag’s only other observation is that the main raceme on all his hybrid varieties has just started to look stunted. “Whether it’s due to some recent frosts or waterlogging, it’s hard to say. But the crop will compensate for it by branching.”

The High 5 Challenge

In this year’s High 5 OSR Challenge in association with Dekalb, Farmers Weekly will be following two 5t/ha growers, who will be sharing their experiences through the coming season. Our growers: Andrew Gloag farms about 1,450ha in North Yorkshire growing winter wheat, OSR and barley plus beans. Tim Goodman manages the Wilton Estate’s 1,400ha of arable cropping, with OSR following barley. Keep up to date with the High 5 OSR Challenge at online www.fwi.co.uk/high5. Driving OSR Value As the UK’s leading oilseed rape breeder, Dekalb is helping growers secure the greatest value from their OSR whatever the conditions with its unique combination of yield-protecting traits in plant types suited to every system. Through www.osrgrowersclub.dekalb.co.uk it is sharing the latest technical guidance, growers’ experience and best practice to help maximise the performance of their OSR crops.