Cover crops are not controlling black-grass

If you have black-grass on your farm, ensure that you take the proper steps to control it.

A recent study by the AHDB (Agriculture and Horticulture Development Board) in the UK has shown that cover crops do not aid the control of black-grass.

The study explained that, while some of the agronomy practices used in managing cover crops can help to control it, the crop itself will not.

‘Limited’ ability to suppress weeds

The AHDB reported that cover crops had a “limited” ability to suppress weeds. The study comprised of field and pot trials. A bio-fumigant mustard and a conventional mustard were examined in the trials and were found to have no additional effect.

Paul Gosling manages weed research at AHDB. He explained the findings.

“When a cover crop is grown, many other changes to agronomy are made. This research found that it is these other changes that are far more significant for black-grass population dynamics.

The underlying switch to spring cropping is key to success.

“Get the cultivation, the use of glyphosate and the spring crop establishment right and the largest black-grass control reward will be obtained. Using a cover crop is unlikely to increase control in the following crop and could make it worse, if not managed carefully.”

Black-grass control

Black-grass control is best achieved by crop rotation. Spring cropping can reduce black-grass levels by 88% according to the AHDB.

Ploughing can reduce the weed levels by 69%, while sowing a grass ley or leaving land fallow can result in a 70-80% reduction in the grass weed.

Black-grass in Ireland

Control of this invasive weed should be a top priority for all farmers. The weed has taken hold in the UK and results in the destruction of winter wheat crops every year.

Many instances of the weed have been found in Ireland and, while some farmers are very diligent in controlling the weed, more may not know they have it.

It is important to keep an eye out for this weed (pictured above). If you do have it in your field, action needs to be taken immediately.