IN an attempt to control rushes, equine farmers should be aware one drop of MCPA herbicide can pollute our loughs and rivers for up to 30km – but there are plenty of alternatives to choose from.

Irish Water and NI Water have reported frequently detecting high levels of selective herbicide MCPA in rivers, lakes and abstraction points in many drinking water sources in Ireland. Although MCPA is removed in the water treatment process and drinking water is of a high quality standard, MCPA does not bind to soil particles, so it is prone to leaching, directly into watercourses or via land drains. Once in the water it can take 3-4 weeks to break down without treatment.

MCPA is widely used for controlling the growth of weeds like the Common Soft Rush, which has flourished in grassland following wet weather periods in recent years. Weed-wipers can manage rushes more efficiently than conventional boom sprayers using less chemical with a dramatic reduction in spray drift by ‘wiping’ the top of the weed. Weed-wipers are only licensed for use with glyphosate, a chemical that has potentially less impact on water quality as it can break down in the water environment much more quickly than MCPA.

There are plenty of alternatives to MCPA for the control of rushes, including Gallup or Roundup (both glyphosate-based herbicides) which uses less chemical than conventional sprayers and breaks down a lot quicker. At a recent event in Castlederg, farmers were informed by Terence Henry from the College of Agriculture, Farming and Rural Enterprise (CAFRE) about the environmental plus for use of glysophate-based herbicides.He also warned that it is not a one off solution.

“A very dense infestation of rush is not good for biodiversity. If rushes are dense, you don’t get other plants in the base of the sward and birds like breeding waders do not like heavy covers of rush. You might have to come back again the following year and you need to have a range of other management strategies right to properly control or eradicate rushes. If you use a mulcher instead of a topper, you give grass a better chance of competing with rushes. Every time you cut a rush, you weaken its root system. The plant that grows back will be very green and is more likely to take up the chemical.”

CAFRE carried out weed-control trials as part of their Rush Control Technology Project, NI Water have worked in conjunction with CAFRE in The Water Catchment Partnership since 2013 and endorse their advice on weed-wipers and best pesticide practices.

Irish Water, working in partnership with a range of organisations involved in the National Pesticides and Drinking Water Action Group (NPDWAG), is also embracing a non-use of pesticides where possible. They are asking the farming community to consider in each case whether they need to use pesticides at all. Minimising pesticide use not only helps to protect water quality but also has wider environmental benefits.

For example, leaving areas unsprayed can help native flowering plant species to grow and support a range of insects including bees and other vital pollinators. One third of Ireland’s bee species are threatened with extinction and by helping the bee population survive and thrive, we are also helping to protect our precious water sources.