Stale seedbeds are recipe for black-grass success

High levels of seed dormancy are expected to give rise to unpredictable and protracted levels of black-grass germination this season growers are being warned. However, with plenty of moisture in the ground, the advice is to take every opportunity to use stale seedbeds, in addition to the use of pre-emergence herbicides to maximise black-grass control this autumn.

Results from HGCA-funded research have shown that dormancy in black-grass seed samples this year is very high, with only 17 per cent of seed germinating. This is the highest level of dormancy since testing began in 2001, states the research, and high dormancy is likely to mean a more protracted germination period for black-grass.

"Growers have got to use every available opportunity to hit black-grass when they can this season," says Chris Bean, technical manager at UAP. "Black-grass is already emerging in fields that have been combined but different conditions across the country are giving rise to different germination patterns."

Mr Bean says that it is possible that the situation could be compounded by dormant black-grass seed germinating from last year's crop that should have emerged last autumn or spring, in addition to seed in this year's crop. "If you experienced high levels of seed dormancy last year then it's especially important not to miss out on the opportunity and benefits of stale seedbed techniques," he comments.

He advises growers to get cultivations done as soon as possible after harvesting and then roll to conserve moisture, before leaving as long as possible before drilling. "Allow 2-3 weeks if you can and then burn off with glyphosate," says Mr Bean.

"Previous years have shown up to 90 per cent control of total black-grass populations from successful stale seedbeds.

"In some years people have managed to leave drilling longer and complete two sprays but its likely there'll only be the opportunity to go once this year, so it's key to get it right," he stresses.

"Turnaround times will naturally be tight this season but there is moisture in the ground and some black-grass should germinate. Where people can create a stale seedbed - then they should do it, but it will be essential to follow up with a full pre-em herbicide programme," he concludes.