Care needed with post-OSR cultivation

Ongoing lack of rain will make growers’ choice of post-OSR cultivation techniques more important than ever, if long-term volunteer problems are to be avoided.

Burying OSR seed too early can fail to break its dormancy, leaving growers to cope with sporadic volunteers for over five years, a leading independent agronomist warns.

"Research has shown that OSR seed on the surface needs at least 5mm of rain to germinate," explains Richard Overthrow, agronomist at NIAB TAG. "Large parts of the country haven’t had this amount of rainfall, especially in the South."

Despite TAG trials conducted over a decade ago which supported findings from Rothamsted Research, growers are often tempted to cultivate following consistent dry weather. "But if the seed is buried without at least starting the germination process, it can lay dormant for five years or more," points out Mr Overthrow.

"Short rotations are those most likely to suffer from problems arising from OSR volunteers," he explains. "Growers are best off delaying cultivations until sufficient rain has fallen; a simple yet effective management technique. It is easy to spot when the time is right as seeds will be germinating on the soil surface."

Mr Overthrow says getting rid of volunteers is not just a matter of pride for the grower. "OSR volunteers can carry diseases through to following crops, such as damping off diseases and alternaria, as well as becoming readily infected with other diseases due to having no seed treatment.