Researchers have been cultivating hybrid grasses for years, primarily to increase growth and tolerance to extreme weather. But only recently have they considered developing a grass that specifically aims to reduce water run-off – the rapid movement of rainfall from grasslands to rivers that can cause flooding.
A large team of UK soil and plant scientists sought to combine a hybrid species of grass called perennial ryegrass, commonly used for grazing in the UK, with meadow fescue, a hardy strain that can thrive in a cool climate. They hoped to amalgamate the rapid growth rate of the ryegrass with the expansive root systems of the meadow fescue, believing this would increase the ability of the plant to hold water, thereby delaying water run-off.
It worked: the team discovered that the new hybrid grass, festulolium, reduced run-off by up to 43% compared with meadow fescue and by 51% compared with the more common perennial ryegrass.
An additional advantage of the new grass is its durability in the face of a changing climate, making it doubly useful for farmers. “It provides resilient pasture for food production”, says Kit Macleod, Catchment Scientist at the James Hutton Institute, one of the research organisations responsible for the breakthrough. Mary Dhonau, Chair of the Flood Protection Association, which advises the public on flood risk mitigation, argues that “adaptation is the only way forward”, when it comes to dealing with the UK’s wet weather. “I wouldn’t hesitate to recommend the use of festulolium as part of a toolkit to reduce flood risk”, she adds.
Siraj Tahir, Flood Specialist and Research Engineer at Arup, also believes the innovation has the potential to reduce both the intensity and severity of floods. But he warns that reducing the volume of water in rivers could worsen the impacts of drought and have knock-on effects on the ecosystem. He cautions that use of the grass will require careful management, stating that, “the benefits of flood reductions will need to be balanced against the impacts that may be caused by low flows”. – Fionán O’Muircheartaigh
Photo credit: Kit Macleod/James Hutton Institute