Late-drilling still an option for oilseed rape

Growers unable to drill oilseed rape until last month due to the wet summer can rest assured that sowing the crop in September is not necessarily a bad thing.

Later drilled oilseed rape can still produce a profitable crop – if it is a phoma-resistant hybrid variety variety with vigorous development, says Chris Guest, managing director of LS Plant Breeders.

Weather data shows that September-drilled rape is still an option, says Mr Guest, who has analysed daily temperatures or the last two autumns at LSPB headquarters in Impington, near Cambridge.

Analysis shows that temperatures totalled 1,131°C between the start of September and end of November in 2021 and 1,163°C for the same period in 2022. This is more than ample for successful rapeseed development, says Mr Guest.

“If we want to reach the 8-leaf stage with a robust plant based on 8mm root neck diameter and a tap root of more than 8 cm before winter, we have to accumulate 150°C for germination and around 120-150°C per leaf pair.

“Calculating both figures together, we need minimum 750°C for a sufficient development before winter, and based on the temperature data from Impington, we can still reach that stage, even with ultra-late sowing dates going right up to the end of September.

Caution needed

“There are a number of provisos. Most important is to say that late sowing is advisable only for hybrid varieties with their vigorous development, Also that late sown oilseed rape crops are more at risk to phoma, so a good phoma rating is advised.”

LSPB hybrid Murray, with its vigorous growth habit and exceptional RlmS phoma resistance, is a good example of a variety suited to late drilling – depending on farm location and adjustments like modifying your sowing rate.

“In a challenging season like this, it is worthwhile considering late sowing if your temperature data is comparable with ours from Impington,” says Mr Guest, who points out that many growers now have their own weather station.