Researchers have uncovered a picture of plant health that is invisible to the naked eye by using rapid pulses of polarized light. The portable light source and detector can reveal over- or under-fertilization, crop-nutrient levels, and perhaps even disease. The tractor-mountable system works on corn, spinach and other crops by picking out minute differences in leaf color.
The N-Checker (nitrogen-checker), as it has been dubbed, could help farmers determine in real time how much fertilizer to apply. This would decrease the cost of crop production, cut wastage and dramatically reduce the run-off responsible for algal blooms.
Researcher Steve Finkelman said the technology revealed previously hidden attributes. “With our technology, we are able to easily see what is hidden from conventional instruments.
“Other devices use both red and infrared wavelengths,” said Finkelman. “Those devices tend to be imprecise because they measure bulk chlorophyll content, which can result from a number of factors.” He added that 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 uses two red-light sources that cut down on sensor and polarizer costs and increase the system speed. The N-Checker can take 1000 measurements per second while moving at roughly 5 miles an hour.