Controlling rushes this spring and summer
April 9, 2020
By Phelim Connolly, CAFRE Agri-Environment Adviser, Enniskillen, Co. Fermanagh
The presence of rushes growing in grasslands are a common sight across Northern Ireland and can be indicative of poorly draining damp acidic soils, broken down or blocked drainage systems or soil compaction from livestock and heavy machinery. Although there are as many as seven species of rush, by far the most problematic from an agricultural context is Soft Rush. Undisturbed, this plant forms large tussocks as tall as one metre and can produce 700,000 seeds in its lifetime.
Unmanaged, soft rush can significantly reduce the amount of grazing available within a field and can also reduce species diversity. Furthermore land eligibility for Basic Payment Scheme may be reduced if rushes are impenetrable and difficult to walk through.
In 2014 the CAFRE Rush Control Project was set up to evaluate and demonstrate the effectiveness of a range of different control methods best suited to Northern Ireland. Across five different sites the most effective method of control was to cut rush first and treat regrowth with a glyphosate product applied using a weed wiper. It was found that this method reduced the amount of rush by up to 68%. Spraying rushes using an MCPA herbicide product reduced rush cover by up to 55%. Cutting as low to the ground as possible without applying any chemical treatment was effective at reducing the tussock mass or vigour, however it did not reduce the overall density of rush cover.
Safe use of chemicals
Much less glyphosate chemical was required when being applied via weed wiper, and data has shown that glyphosate products applied using a weed wiper are much safer for water quality than MCPA herbicide. MCPA is known to be a very volatile product and has continually been identified by NI Water as a source of water quality problems when treatment plants are trying to bring water to drinking standard.
- Best time to control rushes is in early to mid summer when growth rates are highest.
- Younger rush is more susceptible to chemical uptake.
- Farmers should assess existing drainage systems and maintain or repair where possible
- If using an MCPA product be aware of watercourses nearby and leave a safe margin unsprayed
- A single drop of pesticide can breach drinking water limits in a small stream for 30km
- The majority of pesticide problems at water treatment plants in Northern Ireland are caused by MCPA
- Since November 2016 all sprayers are required by law to be tested and calibrated every 5 years
- All operators of spraying equipment require a certificate of competence. More info can be found HERE-Pesticide Training
- Farmers should be aware of DAERA guidance regarding Covid-19 and bringing contractors on farm to carryout work.