Measuring crop fluorescence from space could improve yields

A Stanford-led study offers new ways to measure crop growth from outer space.

A Stanford University-led research team has developed an improved method of monitoring crop yields via satellite, according to their study published in Global Change Biology.

By measuring a light emitted by plants called solar-induced fluorescence, the team led by post-doctoral fellow Kaiyu Guan, said they were able to estimate a crop’s growth rate and predict its harvest yield.

Scientists have been able to collect agricultural data via satellite since the 1970s by observing colour variations visible from space. The research team was able to distinguish this fluorescent light from the spectrum of reflected sunlight that reaches satellites designed to measure gases in the atmosphere. Measuring fluorescence offers a fuller picture of crops’ health and growth-rates.

“With the fluorescence breakthrough we can start to directly measure photosynthesis instead of color,” Guan said.

A co-author of the study, David Lobell was quoted on the Stanford University website saying: “This glow that plants have seems to be very proportional to how fast they’re growing. So the more they’re growing, the more photosynthesis they’re doing, and the brighter they’re fluorescing.”

Measurements of flourescence could be compared to weather and other external factors to help scientists draw new conclusions about potential improvements to growing conditions, added Lobell. It could also be used to identify traits to breed into crops and optimise future yields.

“That helps us, for example, figure out what we need to worry about in terms of stresses that crops are responding to,” Lobell said. “What should we really be focusing on in terms of the next generation of cropping systems? What should they be able to withstand that the current crops can’t withstand?”