World-first lucerne crop trial around Adelaide Airport brings lowers temperatures allowing easier plane takeoffs
The four-hectare trial lucerne crop at Adelaide Airport was irrigated by suburban creek stormwater stored in an aquifer.
Image courtesy The Lead, South Australia.
A business case was being finalised in 2019 for a world-first concept to grow a commercial farm crop to reduce runway air temperatures at Adelaide Airport. Trials by the airport with state-owned SA Water over three years showed the effects of lucerne can drop air temperatures by more than 3C on warm days.
In warmer thinner air, planes must travel faster down the runway, with a lighter load, to produce the lift for takeoff. Some domestic aircraft, such as the Airbus A330 and Boeing 737, can’t take off above certain temperatures. The promising findings from the Adelaide trial have attracted interstate and international interest.
The four-hectare site, 600 metres from the airport’s main runway, tried grass species tried tall fescue, couch and kikuyu grasses but lucerne, that can be cut into hay and sold as a premium stock feed, had the greatest impact on ambient temperatures. Between 12 and 15 millimetres of recycled suburban creek/aquifer stormwater was applied up to three evenings a week, monitored by more than 40 temperature and humidity sensors. A survey also found a drop in a potential hazard: the number of birds attracted to the area.
Adelaide Airport has the potential for up to 200ha of lucerne and another 50-100ha of irrigated turf around the main runway and other infrastructure. The next step would be to install a permanent centre pivot irrigation system to expand the watered area from 4ha to 7ha and allow more lucerne planting.
Economists engaged by Adelaide Airport and SA Water calculated costs and benefits of a 200ha lucerne hay harvest (producing 15-25 tonnes of hay per her hectare per year from five to seven cuts) to mean irrigation outlay could be regained in seven to 12 years. Another potential, besides fuel savings for airlines, is to gain credits by making it a carbon farming initiative.