Remote sensing picks up energy reflected from surfaces on the ground. The chemical composition of leaves, including their nitrogen and chlorophyll content, subtly changes how much energy is reflected. Hyperspectral sensors detect differences of just 3 to 5 nanometers across their entire range, a sensitivity unmatched by other remote sensing technologies.
“Other airborne remote sensing technologies pick up the visible spectrum and possibly near-infrared, just four spectral bands. That’s not even close to what we can do with this hyperspectral sensor. It’s really powerful,” Guan said.
Importantly, the research team worked out the best mathematical algorithm to detect nitrogen reflectance data from the hyperspectral sensor. They expect it will be put to use as newer technologies come on board.
“NASA is planning a new satellite hyperspectral mission, as are other commercial satellite companies. Our study can potentially provide the algorithm for those missions because we already demonstrated its accuracy in the aircraft hyperspectral data,” Wang said.
Guan says bringing this technology to satellites is the end goal, enabling a view of every field’s nitrogen status early in the growing season. The advancement will allow farmers to make more informed decisions about nitrogen side-dressing.
