Scientists develop 'interactive' crop system that signals water, fertilizer needs of individual plants

An invention designed to monitor crops grown during long space missions now allows thirsty terrestrial crops to signal their need for water and fertilizers to farmers. The system was developed by researchers from the University of Colorado-Boulder and consists of high-tech leaf sensors measuring leaf thickness and water deficiency, which communicate wirelessly with computers and crop tenders. The system could revolutionise agriculture in water-stressed regions around the world.

Along with continuous breakthroughs in biotechnology and nanotechnology, it is this type of inventions with major implications for global agriculture that may make the most optimistic long-term biofuel scenarios more realistic.

Interactive agriculture
According to research associate Hans-Dieter Seelig from CU-Boulder's BioServe Space Technology Center, which develops products based on space life science research, the interactive technology includes a tiny sensor that can be clipped to plant leaves charting their thickness, a key measure of water deficiency and accompanying stress, Data from the leaves could be sent wirelessly over the Internet to computers linked to irrigation equipment, ensuring timely watering, cutting down on excessive water and energy use and potentially saving farmers millions of dollars per year.

Based in large part on Seelig's 2005 CU-Boulder doctoral thesis in aerospace engineering sciences, the technology was further developed at BioServe, a NASA Research Partnership Center for the commercialization of space. It was originally designed for use in conserving water for plant growth during long-term space flight. The new system was optioned to AgriHouse Inc., a high tech company from Colorado, in March by the University of Colorado Technology Transfer Office, giving AgriHouse the exclusive right to negotiate a license with CU within 12 months. "We think this is an exciting technology, and the implications for the agriculture industry are enormous," said Seelig.

Existing technology like soil moisture sensors used to assess a crop's water needs do not always provide an accurate picture of existing plant and field conditions.

"What we are developing is a non-intrusive device that gently rests on the plants and lets them interface with the digital world. Basically, this is a device that will allow plants to talk to humans and communicate their needs, like when to water and apply fertilizer." - Richard Stoner, AgriHouse founder and president.

Less than one-tenth the size of a postage stamp, the sensor consists of an integrated-circuit chip that clips to individual plant leaves and collects and stores information, said Seelig. When the leaves lose enough water to contract to a critical width, the sensor can wirelessly signal computers:
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The computers, for example, could instruct individual pivot irrigation systems used widely on Colorado's eastern plains to dispense set amounts of water to particular crops, automatically turning the motors that drive them on-and-off and conserving water and energy in the process, he said.

"Farmers today rely on standard practices that include a good eye and a green thumb," said Stoner. "But this new system can tell a farmer precisely when a plant's water uptake potential is at its peak, which could conceivably decrease the number of watering days for certain crops by up to a day or two each week."

Economists estimate that agricultural activity accounts for about 40 percent of the total freshwater use in the United States. About 60 percent of all crops in the United States are irrigated using water from lakes, reservoirs, wells and rivers.

Stoner likened the plant communication aspect of the invention to a scene in the 1986 comedy musical film, "Little Shop of Horrors," when a giant carnivorous plant tells humans to "feed me." "This technology allows plants to say, 'water me,' " he said.

High eastern plains water-use has led to lawsuits against Colorado for violations of interstate water compacts, including a recent $30 million payment to Kansas for overuse of the Arkansas River, said Seelig. A recent U.S. Supreme Court lawsuit against Colorado and Nebraska for overuse of Republican River water threatened to shut down all Colorado wells impacting the river if solutions for reducing irrigation water are not found. Farmers irrigate nearly one-half million acres on the eastern plains from the Ogallala Aquifer that directly impacts the Republican River, he said.

The researchers have been experimenting with cowpea, a legume, but believe the new leaf-sensor technology would be transferable to a variety of crops, including corn, wheat, potatoes, sugar beets and pinto beans. In the future, it might also be applicable to monitoring large swaths of urban grass like city parks, Stoner said.

"This device is very precise, and will allow a plant to receive just the right amount of water," said Seelig. "If a plant can tell a water valve when to open and when to close, farmers are going to save a lot of money."

Background
In 1997, Stoner and AgriHouse teamed up with BioServe and NASA on plant-growth experiments and hardware shipped to Russia's Mir Station, experiments which led to the development by AgriHouse of a commercial, all natural crop-boosting product known as "Beyond." AgriHouse has received two NASA Small Business Innovation Research contracts in recent years to develop and manufacture high performance food production systems for Earth and space, said Stoner.

Stoner is the principal investigator on a US$150,000 Small Business Technology Transfer research grant awarded in May by the National Science Foundation to AgriHouse to develop the new technology. Seelig is an institutional investigator on the effort. In 2006, Seelig was awarded a US$10,000 proof-of-concept grant for his research from CU's Technology Transfer Office.

Image: The new technology invented at the University of Colorado at Boulder involves tiny sensors clipped to plant leaves to wirelessly monitor the water needs of crops. It has been optioned to AgriHouse Inc. of Berthoud, Colo. Courtesy: AgriHouse Inc.

More information:
University of Colorado: CU-Boulder Invention May Allow Thirsty Crops To Signal Farmers - June 14, 2007

Seelig, Hans-Dieter, "The assessment of water deficit stress in plants using optical measurement methods", University of Colorado, Phd. Thesis, 2005.

Hans-Dieter Seelig, et. al, "Non-Contact Measurement Methods of Detecting Plant Water Deficit Stress for Space Flight Growth Chamber Application"[*abstract], SAE Technical Papers, Document Number: 2004-01-2455, January 2004.