The area of winter oilseed rape is expected to increase this autumn, primarily due to the substantial increase in the price of oilseeds.
Other attractions to winter oilseed rape for tillage farmers are the potential nitrogen savings when good growth and development is achieved in the autumn/winter period, along with alternative weed control options, according to Shay Phelan, Tillage Specialist with Teagasc.
“Winter oilseed rape can be profitable in its own right, but profitability should be viewed across the entire rotation,” he said.
“Yield increases in winter wheat up to 19pc after breaks for disease have been recorded in Teagasc experiments when compared to continuous wheat. The area of winter oilseed rape increased significantly by 44pc in 2022.”
Many growers, he said, are now seeing the benefits of including it in the farm crop rotation as it is an ideal break from cereal rotations and a good entry for first wheats.
“Other benefits include spreading the workload, soil structure improvement, and it can be used to control difficult grass weeds. Again in 2022, many growers were able to reduce the amount of nitrogen (N) required to grow the crop.
“This was a significant saving this year given the cost of fertilisers. Early drilling is essential for growing oilseed rape. August-drilled crops generally perform better than September-drilled ones and it may be easier to prevent pigeon grazing of large canopies, which in turn will reduce the amount of N needed.”
When growing oilseed rape crops, a mid-August to early September sowing date (ideally before September 10) is recommended, however seedbed quality, i.e. fine and firm, is as important as the sowing date.
In terms of varieties, the Department of Agriculture’s Recommended Winter Oilseed Rape (WOSR) list is the best source of information.
Conventional varieties or hybrids can be sown in August, but in September, you should only use hybrids, according to Mr Phelan.
“Look for varieties with good traits such as light leaf-spot resistance and pod-shatter resistance,” he said. “Seeding rate: sow 60-80 seeds/m2 to establish 30-50 plants/m2 in the spring. Varietal differences in vigour and thousand seed weight, along with seedbed condition and sowing date must be accounted for.
“Poor seedbed and late sowing will need higher [10pc] seeding rates.”