OSR crops look ‘backward’ but ‘promising’, according to a Scottish grower who is putting several hybrid varieties to the test. Abby Kellett reports.
Despite particularly wet weather, oilseed rape crops have come through winter ‘exceptionally well’, according to Neil MacLeod, farm manager at Southesk Farms, Montrose, something which he believes is due to the establishment achieved from the highly vigorous hybrid varieties grown on the estate.
SY Harness and Incentive make up the most of the 170 hectares (420 acres) of OSR grown on the estate, but to assess whether his current variety choice could be bettered, he is also taking part in a large scale grower plot trial alongside Bayer.
Varieties within the trial include:
The treatment of the plots has been identical to the farm standard, comprising 30kg/hectare of nitrogen at drilling, half rate Frelizon (penthiopyrad+ picoxystrobin) in the autumn to protect against light leaf spot (LLS) and variable rate potash in February.
In terms of development, crops are about three weeks behind where they would be in a normal season, according to Mr MacLeod, but good establishment has meant they have come through winter well, despite the harsh weather conditions.
He says: “We had quite a good November weather-wise, but since then we have had a lot of rainfall and more recently it has been extremely cold. However, crops are looking better than they have in the past few years, despite being considerably backward.”
Bayer’s commercial technical manager for northern Scotland, Grant Reid, says crops were helped by developing a good root network early in the season.
“It stems back to getting a good root with a 1cm wide root collar, meaning crops were well equipped to handle the tough winter.
“As soon as soils warm up, I would expect crops to grow away quite rapidly. However, my concern is if the weather turns too quickly and crops grow too fast, there is a risk stems will crack and crops could be at risk of lodging later on in the season.”
Similarly, Mr MacLeod fears crops may be vulnerable to bolting and so plans to apply ammonium sulphate in foliar form in order to get nutrients into the plant quickly and will apply the subsequent 180kg/ha of nitrogen in two splits rather than three.
This season, Mr MacLeod has discovered that a helpful by-product of growing 100ha (250 acres) of oil radish as a cover crop is that it provides an alternative feed source for pigeons, preventing damage to OSR plants which has helped maximise crop biomass.
Of the varieties within the trial, InVigor 1035 looks to be one of the better performing varieties, while InVigor 1030 appears more backward. However, with an oil content of about 47.1 per cent, InVigor 1030 could prove the more profitable once oil bonuses are accounted for, according to Mr MacLeod.
Despite the autumn fungicide application, when LLS levels were measured in February, some plots had quite high levels of latent disease.
Mr Reid said: “We tested DK Exalte and InVigor 1035 for LLS in autumn as part of the OSR SpotCheck Project and there was no sign of the disease. However, more recent tests have shown DK Exalte had 73 per cent infection and InVigor 1035 had 57 per cent infection, despite both having resistance ratings of 7. This highlights the extent of LLS pressure this season.”
Where LLS pressure is high, Mr MacLeod plans to apply a prothioconazole-based fungicide at mid-flowering and again at late-flowering.
“I am very pleased with the performance of the varieties I am currently growing, but there is good competition within the trials and I am excited about the prospects of them all as they all look promising. I think we will start to see bigger differences in the coming weeks when spring really kicks in,” says Mr MacLeod.