Featured Research

from universities, journals, and other organizations

Field Of Beams: Novel System Uses Polarized Light Pulses To Reveal Crop Health

Date:
July 29, 2005
Source:
National Science Foundation
Summary:
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.

Bearing the NSF logo, the original depolarized light-sensor apparatus assesses stressed plant leaves in this controlled greenhouse at the Chicago Botanic Garden under the direction of Louise Egerton Warburton. The researchers have also field tested both systems from cart and body based platforms.
Credit: Steven Finkelman, CRI

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.

Related Articles


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.

###

This research was supported by NSF Grant #DMI-0319826
SBIR Phase I: Polarization Sensing of Stress Levels in Vegetation
http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=0319826



Story Source:

The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.


Cite This Page:

National Science Foundation. "Field Of Beams: Novel System Uses Polarized Light Pulses To Reveal Crop Health." ScienceDaily. ScienceDaily, 29 July 2005. <www.sciencedaily.com/releases/2005/07/050727060608.htm>.
National Science Foundation. (2005, July 29). Field Of Beams: Novel System Uses Polarized Light Pulses To Reveal Crop Health. ScienceDaily. Retrieved November 28, 2014 from www.sciencedaily.com/releases/2005/07/050727060608.htm
National Science Foundation. "Field Of Beams: Novel System Uses Polarized Light Pulses To Reveal Crop Health." ScienceDaily. www.sciencedaily.com/releases/2005/07/050727060608.htm (accessed November 28, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Friday, November 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA's First 3-D Printer In Space Creates Its First Object

NASA's First 3-D Printer In Space Creates Its First Object

Newsy (Nov. 26, 2014) The International Space Station is now using a proof-of-concept 3D printer to test additive printing in a weightless, isolated environment. Video provided by Newsy
Powered by NewsLook.com
Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Reuters - Innovations Video Online (Nov. 26, 2014) Innovative recycling project in La Paz separates city waste and converts plastic garbage into school furniture made from 'plastiwood'. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Blu-Ray Discs Getting Second Run As Solar Panels

Blu-Ray Discs Getting Second Run As Solar Panels

Newsy (Nov. 26, 2014) Researchers at Northwestern University are repurposing Blu-ray movies for better solar panel technology thanks to the discs' internal structures. Video provided by Newsy
Powered by NewsLook.com
Today's Prostheses Are More Capable Than Ever

Today's Prostheses Are More Capable Than Ever

Newsy (Nov. 26, 2014) Advances in prosthetics are making replacement body parts stronger and more lifelike than they’ve ever been. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins