BLACKGRASS SEED dormancy is high this autumn following cool, wet conditions throughout seed maturation, according to latest research findings.

Effective autumn herbicide programmes with a strong residual element will be important where blackgrass is a problem, growers are advised.

The Sustainable Arable LINK project, funded by DEFRA, HGCA, Simba, Syngenta and Monsanto, found the average blackgrass seed germination across the country was 28% (see table).

The results signify a more protracted germination period for blackgrass this year, similar to that of 2002, said study coordinators.

There is quite a bit of blackgrass germination in fields now, but not as much as last year, said Sarah Cook from ADAS Boxworth.

“Conditions were cool and damp when seeds were maturing – this has led to increased dormancy.”

Correct autumn cultivation choice, as well as herbicide programme, will be extra important this year, she noted.

“The crucial thing with ploughing is that it must be done properly and all the seeds covered and buried to a depth they cannot emerge from.”

“Cultivating to a depth of 15-20cm should be adequate.”

Minimum tillage does not fully cover seeds, so under shallow cultivation significant levels of blackgrass may germinate after drilling, she added.

Year

Mean % blackgrass
seed germinating

Conditions during
blackgrass seed maturation

2001

 62

Hot and dry 

2002

 22

Cold and damp

2003

 57

Hot and dry 

2004

 28

cool and damp