The researchers hope their tractor-mountable N-Checker (for "nitrogen-checker") apparatus will help farmers determine in real time how much fertilizer to apply. By preventing waste, the system could decrease the cost of crop production and dramatically cut the nitrogen-laden runoff responsible for algal blooms and other damage to wetlands and waterways.
Steve Finkelman, Paul Nordine and their colleagues at Containerless Research, Inc. of Evanston, Ill., Louise Egerton-Warburton and partners at the Chicago Botanic Garden, and graduate student Tim Smith of the University of Illinois, Urbana-Champaign, will present their new technology July 19 at the InfoAg 2005 Conference in Springfield, Ill.
"With our technology, we are able to easily see what is hidden from conventional instruments," says Finkelman. "The system eliminates interference from light reflected at a leaf's surface and allows us to see light re-emitting from within."
Depending on the plant, leaves reflect, transmit and absorb varying amounts of light. Polarized light that enters a leaf's interior can lose its polarity and be re-emitted as "depolarized" light. The depolarized light reveals nitrogen content and other properties the proprietary sensors in the N-Checker can detect.
Changes in nitrogen levels change the way light interacts with the molecules in the leaf, characteristically affecting the spectrum of light that re-emits from the plant. Chlorophyll molecules, in particular, contain nitrogen atoms that play a critical role in photosynthesis.
The researchers have experimented wi
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25-Jul-2005