Hybrid grass 'could reduce flooding impact'

By Mark Kinver
Environment reporter, BBC News

Image caption,
The plots of the hybrid grass were planted on clay-rich soil, which is prone to run-off

A hybrid farmland grass, developed by a team of UK researchers, could help reduce flooding, a study has shown.

A team of plant and soil scientists said tests showed the new cultivar reduced run-off by 51%, compared with a variety widely used to feed livestock.

They added that rapid growth and well developed root systems meant that more moisture was retained within the soil rather than running into river systems.

The novel grass is a hybrid of perennial ryegrass (Lollium perenne) - which is widely planted by farmers for grazing livestock - and meadow fescue (Festuca pratensis), which has environmental stress-resistant characteristics.

Greener grass

Co-author Kit Macleod, senior research scientist at the James Hutton Institute based in Aberdeen, said a long-term project had been developing novel forage grasses but their environmental benefits had not really been tested.

"So I had the idea to... set up an experiment to look at how these novel grasses could be good for not only production from a farmer's perspective but also reducing run-off," he told BBC News.

"There is a lot of interest in how we manage agricultural landscapes to produce multiple benefits - particularly in relation to environmental stresses, such as changing precipitation and temperature patterns."

Over a two-year period at the Rothamsted Research site in North Devon, the team found that the hybrid grass reduced run-off by up to 51% compared with perennial ryegrass and by 43% compared with meadow fescue.

"We think that how [the runoff was reduced] was to do with changes in the soil structure, and how this grass changed that," Dr Macleod explained.

"It creates more storage capacity for water. Over a two-year experiment, we saw that there was a change in the soil structure as a result of a wetting and drying of the soil in clay-rich soils, and that can increase the amount of structure and hence storage of water.

"But also the rapid growth of the roots, which these Festuca are well known for, suggested that it had created extra structure to increase the storage capacity."

However, he was keen to stress that the grass was not a "magic bullet" that could prevent flooding; it would only help reduce the volume of run-off from grazing meadows into flood-prone areas of river systems.

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