Successfully controlling rushes requires a two-pronged approach that targets the invasive weed above and below ground.

Speaking at an online event, CAFRE adviser Robert Beggs highlighted the pros and cons associated with most approaches to rush control.

“Soft rush is common in NI and when it comes to control, farmers should be aware that rushes don’t always spread via seeds. They also spread via rhizomes on the roots.

“Therefore, chemical treatment on its own is just a short-term fix. It is important to address the problem below ground also,” stated Beggs.

Fixing drainage issues and improving soil fertility, combined with good grassland management, should see productive grass swards out-compete rushes.

Options

Where rushes are an issue, flailing may keep land eligible for area-based schemes, but offers ineffective control as the bank of rush seeds in the soil is not addressed.

Applying MCPA via a boom sprayer is ineffective long term. While the chemical will kill rushes shortly after application, they will regrow within the same year.

MCPA also does not kill the root structure below ground, so rushes continue to spread via rhizomes even though they are dead above ground.

The other problem with boom sprayers is that they are generally non-selective, so the chemical is applied at excessive rates and ends up in water courses, costing millions to remove to ensure water is safe for human consumption.

“One capful of MCPA can be detected in water 18 miles downstream and it takes 40 days before the chemical degrades,” said Beggs.

Weed wiping

He emphasised that weed wiping is a much more effective means of chemical control, with glyphosate (MCPA is not licensed for use in weed wipers) killing rushes above and below ground.

Weed wipers also use six times less chemical than boom sprayers, which has huge positive implications for the wider environment.

“Graze as tight to the ground as possible before using a weed wiper, and afterwards, hold off on topping when rushes start turning brown. It can take some time for the chemical to kill the root structure properly,” advised Beggs.

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