One of the many big problems facing modern agriculture is the excessive use of fertilizers. Crops, especially corn and wheat monocultures, need a lot of fertilizer, but it is very difficult to fertilize precisely the right amount. This leads to widespread overuse of fertilizers, which then run off into waterways, contributing to the release of large amounts of greenhouse gases.
Scientists and researchers have been working on all sorts of ways to minimize fertilizer use to just what is needed, and one of the main parts of these attempts is to more accurately measure fertilizer levels in fields. Once we know exactly how much is present, it’s easier not to overdo it. A promising step forward just announced by researchers at the University of Illinois at Urbana-Champaign, and it relies on sensors attached to aircraft.
The new system uses hyperspectral imaging spectroscopy sensors in the form of the ASD FieldSpec 4, a palm-sized device that can collect image data on an incredibly precise granular basis. These devices capture much more detailed imaging data than the human eye can see. This apparently includes nitrogen levels in plant leaves.
The researchers used the hyperspectral sensors to measure plant leaves at different levels of photosynthesis, which correlates with the quality of plant fertilization. They then created an algorithm that can take this hyperspectral data and produce results on nitrogen levels.
This system is sensitive enough that the researchers actually attached the sensors to planes flying 500 meters above cornfields in Illinois, and by flying back and forth just three times, they found that they could capture an amazing amount of data. The researchers went into the field to do ground nitrogen tests to compare and found that the aircraft system provided about 85% accuracy, which is close enough to the field tests that the researchers say airplanes could replace it. . And, of course, flying an airplane over a field is much more efficient than going out and collecting hundreds of soil samples for nitrogen analysis.
The next step for the researchers is to try to use their algorithm with satellites equipped with hyperspectral sensors; the United States and India work on that kind of stuff.