Detecting Plant’s Health Through Light
a plant’s health is usually judged based on the leaf’s appearance. what if you can do more than just telling if the plant is disease free?
researchers from Illinois in the United States developed a field-based optical sensing system that depicts plant health using rapid pulses of polarized light. the researchers dubbed their invention, the N-checker could help farmers determine how much fertilizer to apply in real time. this could decrease crop production costs and dramatically reduce algal blooms. the tractor-mountable system works on corn, spinach, and other crops by picking out minute differences in leaf color. researcher Stee Finkelman of the containerless research said that with the technology, "we are able to easily see what is hidden from conventional instruments. the system eliminates interference from light reflected at a leaf’s surface and allows us to see light reemitting from within." depending on the plant, the leaves reflect, transmit, and absorb varying amounts of light, explains Finkelman. the depolarized light reveals nitrogen content and other properties that the sensors in the n-checker can detect. changes in nitrogen levels alter the way light interacts with the molecules in the leaf, affecting the spectrum of light that reemits from the plant. unlike other devices, the n-checker uses two red-light sources that can differentiate between the several types of chlorophyll molecules and thus reveal nitrogen-dependent plant health information. Finkelman said that devices that use both red and infrared wavelengths”tend to be imprecise, because they measure bulk chlorophyll content, which can result from a number of factors." the researchers also see opportunities for this technology in the detection of potassium, phosphorous, and other nutrients. (www.scienceagogo.com)