Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Field of beams

26.07.2005


Novel system uses polarized light pulses to reveal crop health

By firing rapid pulses of polarized light at corn, spinach and other crops, researchers have uncovered a picture of plant health that is invisible to the naked eye. Using a portable light source and detector technology, the researchers can differentiate minute differences in leaf colors - indicators of over- or under-fertilization, crop-nutrient levels and perhaps even disease.

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 with two versions of their apparatus. The original version channels broad-spectrum light from a xenon flashlamp through a series of calcite crystals to illuminate each corn, sugar beet, cotton or other broad-leaf crop with a tiny, transient spot of polarized light. Moving from leaf to leaf, that system can measure nitrogen levels in 60 plants per minute.

Instead of a broad-spectrum lamp as its source, the N-Checker uses two red-light sources that cut down on sensor and polarizer costs and increase the system speed. The red region of the electromagnetic spectrum is important because it reveals not just total chlorophyll content, but also relative amounts of the various types of chlorophyll molecules.

"Other devices use both red and infrared wavelengths," says Finkelman. "Those devices tend to be imprecise because they measure bulk chlorophyll content, which can result from a number of factors." By using two specific, visible, red wavelengths, the N-Checker can differentiate among the several types of chlorophyll molecules and therefore reveal nitrogen-dependent plant health information.

The N-Checker can take 1000 measurements per second--at least every 10th of an inch--while moving at roughly 5 miles an hour. At that speed, a farmer could survey and fertilize tens of acres in a day, or hundreds of acres per day with a multi-sensor system.

Joshua Chamot | EurekAlert!
Further information:
http://www.nsf.gov

More articles from Agricultural and Forestry Science:

nachricht New gene for atrazine resistance identified in waterhemp
24.02.2017 | University of Illinois College of Agricultural, Consumer and Environmental Sciences

nachricht Researchers discover a new link to fight billion-dollar threat to soybean production
14.02.2017 | University of Missouri-Columbia

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>