Bird strikes during take-off and landing are well known for the safety risk they pose and the resulting costs incurred. According to the U.S. Federal Aviation Administration statistics, more than 262 people have been killed and 250 aircraft destroyed worldwide as a result of wildlife strikes since 1988.
An average of 14,300 gallons of jet fuel was released in each of these dumps. Waterfowl, gulls, raptors, and pigeons/doves represented 80 per cent of the reported bird strikes causing damage to U.S. civil aircraft from 1990-2015.
The reason birds are attracted to runways is, of course, because of the grass that grows around them, which attracts insects the birds use as a food source. Some birds also nest in grass and feed on the grass itself.
As a result, airport managers are looking for means to reduce the risk of bird-strikes by planting grass that attracts fewer insects and fewer birds. Airports in Great Britain, the Netherlands, Denmark and other countries are testing special airport grass solutions on their airfields with the purpose of making take-offs and landings safer, notes Frank Hansen, product specialist for DLF in Europe.
“DLF companies have been selling mixtures for airfields for a very long time, so it was a natural step to begin selecting for this purpose — we benefit from experience in both forage and turf species which has allowed us to make quick progress,” he says.
DLF’s new ClearSky pilot project involves using specially-crafted tall fescue grass seed combined with a maintenance program ensuring optimal growth and creating an erect, spiky-by-nature habitat that’s too dense for small birds to tackle and too spiky for larger birds to find navigable.
New Zealand’s Wanaka Airport is currently taking part in a ClearSky trial. Operations Manager Ralph Fegan met with DLF turf manager Peter Griffiths earlier this year to check on the progress of the three-year trial.
“Wanaka has a unique microclimate and there’s no one-size-fits-all solution, so the Wanaka trial is one of our preferred world test sites due to the cold temperature. It’s holding up really well to the frosts and is looking good,” Griffiths says.
The tall fescue contains special endophytes — naturally occurring fungi that live inside plants — that decrease the attractiveness of the grasses for feeding insects, and hence also for insect-eating birds and animals.
“This isn’t turf or lawn grass — the breeder’s eyes shouldn’t focus on visual merit, and there is no goal of increasing yield or quality as in forage breeding,” Hansen says.
Maintenance and appearance is also far from what is common in the realm of forage or turf, meaning ClearSky project participants have also had to change their attitudes when it comes to the grass. For periods of the year the visual aspect is “less than beautiful”, as Hansen calls it, with discoloration and uneven appearance.
“We focused a lot on the morphology of the turf types and selected plants with stiffer leaves and shoots, and with a high number of persistent stems. Tall fescue is also not the fastest-growing grass. To ensure fast cover we have tested a number of ‘nurse species’ options. These species will decline with time while the tall fescue takes over.”
Perennial ryegrass turf types are excellent nurse plants, and annual ryegrass varieties can, in some situations, replace the perennial ryegrasses. For both of these nurse species, DLF has taken some unique approaches, employing tetraploid perennial ryegrass turf-type varieties from within its 4turf product range, producing strong plants that compete less with the tall fescue. It has also used diploid turf types of annual ryegrass.
For extreme conditions DLF has a unique alternative with the denser tall fescue type of Festulolium: the variety Fojtan. Fojtan produces less dry matter than a normal forage tall fescue and is very dense and highly persistent.
—with files from wanakaairport.nz
