10-07-2012 17:54 PM | News

The severe impact of lodging in oilseed rape



ADAS are estimating that 50% of winter oilseed rape crops have lodged this year and oilseed rape company Grainseed is pointing out the vital role that lower biomass varieties with strong stem stiffness and high resistance to lodging will play this year and in the future.

Neil Groom, Technical Director of Grainseed, reports that there is a high degree of lodging around the country. “Unsurprisingly with high rainfall and high winds that have been an unwanted characteristic of this year’s spring and summer weather, we are seeing much more lodging this year than we have seen for many years. And there are very obvious varietal distinctions. It has been the low biomass varieties with high ratings for stem stiffness and lodging risk, such as Es Astrid, Es Alienor, Es Cubic and Es Agatha, that have literally stood the test of time.”

Some industry pundits have been quoted as saying that oilseed rape lodging has been a locality or soil issue, rather than a varietal issue. When you see rape varieties side by side on the same site and some are badly lodged and others are upright, it must be the intrinsic stem strength, resistance to lodging plus crop height of the individual variety that keeps it standing, he points out.

Neil advises that lodging can cause significant and costly problems in terms of crop management. “Lodging doesn’t just cause problems with harvesting; there’s the issue of canopy health, speed of grain dry down and ease of desiccation management.”

“Lodged crops take a lot more time and effort and cost a lot more to combine and to dry down. Crops that have lodged create high humidity within the canopy and this encourages disease such as Alternaria and Botrytis. Sclerotinia will also keep spreading in lodged crops by plant to plant contact. I have seen some crops here in the ‘dry’ Eastern Counties, generally taller hybrids, that lodged at early flowering and where the pods in these crops are rotting in the field.”

With lodging potentially costing a significant amount in terms of yield loss and increased management costs, choosing a variety that is resistant to lodging will become higher up the list of priorities now and will increase interest in the low biomass varieties once again.

Neil Groom explains that the HGCA list ratings for resistance to lodging refer to the plants ability to resist going over at flowering, whereas the stem stiffness rating refers to the plants ability to resistance lodging between flowering and harvest. “You need high ratings for both these plus a shorter or low biomass variety to resist lodging effectively. The popular low biomass conventional Astrid has 8 ratings for both resistance to stem lodging and stem stiffness and a height of 142 cms and it is standing really well in the field this year. Alienor, which has become more popular because of its very early maturity and vigour, also has 8 ratings for resistance to stem lodging and stem stiffness and a height of 147 cms. Cubic is the same as Astrid but with a height of 144 cms,” he points out.

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