Ploughing is seeing a resurgence this year for those keen to tackle black-grass, but its importance is also being emphasised as a route to avoiding the risk of follow-crop effects where sulfonylureas have been applied during the last cropping year.


Stick to the label and plough before drilling vulnerable crops such as oilseed rape, says Bayer CropScience, because the winter-like conditions that extended into spring delayed applications of sulfonylureas. Consequently, active substances applied in late April or May may not have had sufficient time to degrade in soils - putting subsequent crops, especially those sown in early autumn, at a higher risk of crop effects.


"Lower than average temperatures and lack of rainfall can reduce the speed at which sulfonylureas break down," says Phillippa Overson, combineable crops campaign manager at Bayer CropScience.


"Early-sown crops established with minimum tillage techniques may be particularly at risk but the potential for crop effects can be reduced by fully inverting or mixing soils.

"We would generally recommend ploughing before drilling rape in any season but this year - with the late spring, prevailing weather and pressure to drill - it’s even more important."


Where Atlantis WG (mesosulfuron + iodosulfuron) has been used in a previous crop, follow-crop options are limited to winter wheat, winter barley, winter oilseed rape, spring wheat, spring barley, spring oilseed rape and sugar beet.


As each field situation is different, Ms Overson says growers need to follow the label carefully.