While the trend in recent years has been for people to talk to their plants, Canadian forest biologist Melvin Tyree has been listening. By refining sensitive electronic equipment designed for studying structural failure in metals, Tyree has managed to capture the normally inaudible high-pitched popping sounds that plants make when they are not getting enough water. Now, Tyree is adapting the equipment—tiny microphones about an inch in diameter—so farmers can know precisely how much water their crops need and when. His ambition: to save valuable water resources by revolutionizing irrigation methods. Said Tyree, a former physiologist at the University of Toronto and now a research professor at the University of Vermont: “The implications are enormous for states just east of the Rockies, where wells are drying up so quickly that within 15 years there will not be enough water.”
Tyree’s initial experiments with his invention, on hardwood and softwood trees, came to the attention of U.S.
agriculture officials in 1983. Edwin Fiscus, a scientist at the U.S. department of agriculture’s Fort Collins, Colo., crop research laboratory, read about Tyree’s work in an academic journal and invited him to Colorado to study corn. There, Tyree and Fiscus discovered that with the listening devices they could stop wasteful overwatering—especially vital in semi-arid areas where, said Tyree, corn farmers use two to three times as much water as necessary.
Water travels through plants inside slender tubes and, according to Fiscus, the columns start to crack if there is not enough moisture. Said Fiscus: “It is the minute, high-frequency noise of these fractures that the equipment detects.” Tyree’s apparatus records the sounds and then amplifies them 10,000 times.
Last month Tyree submitted a grant proposal to the U.S. department of energy for a $50,000, six-month feasibility study. If the funding is approved, Tyree plans to design a prototype for field testing under all conditions and eventually hopes to develop a tool that will ensure that farmers irrigate their crops at the best possible time. “This could save one of the nations’s valuable resources,” said Tyree. “We don’t have limitless water.”
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