Emerging technology detects crop nitrogen with high accuracy
Synthetic nitrogen fertilizers changed the agriculture we know during the Green Revolution, taking food and crop security to new levels. However, although nitrogen utilization efficiency has improved, concerns about inadequate performance have so far led to the overuse of fertilizers. Excess nitrogen ends up in the form of strong greenhouse gases in waterways, including groundwater and the atmosphere.It is difficult to predict the amount of nitrogen needed for a crop in any given year. The first step is to understand the nitrogen status of the crop in real-time, but manual leaf nitrogen measurement during the season is not realistic and cannot be scaled.
The first study from the University of Illinois at Urbana-Champaign installed
a hyperspectral sensor on an aircraft to quickly and accurately detect nitrogen and photosynthesis status in corn.”Nitrogen measurements in the field are time-consuming and labor-intensive, but the aircraft’s hyperspectral sensor allows us to scan the area at a rate of seconds per acre. This provides much higher spectral and spatial accuracy than similar studies. using satellite images “. said Agroecosystem Shen Wang, assistant research professor at the Center for Sustainability (ASC) and U of I. Wang’s Department of Natural Resources and Environmental Sciences (NRES). is a leading research author.”Our approach bridges the gap between field measurements and satellites and provides a low-cost, high-precision approach to managing nitrogen in cereals in sustainable agriculture,” he said.The aircraft, which has the best sensor capable of detecting wavelengths of the visible and near-infrared spectra (400-2400 nanometers), flew three times to a test site in Illinois during the growing season of the 2019. Researchers used leaf and canopy measurements of fields as factual information to compare with sensor data.The flights revealed the nitrogen properties of the leaves and canopy, and numerous parameters relating to photosynthetic capacity and grain yield were detected with an accuracy of up to 85%.
“This is close to the quality of basic truth,”
said Kayu Guan, study co-author and founding director of the ASC, associate professor at NRES. “We can rely on hyperspectral sensors in the air to gather truths on the ground without compromising even greater accuracy. At the same time, the air sensor allows us to cover a larger area at a lower cost.”
From a distance, the sensor receives energy from the ground. The chemical composition of the leaves, including nitrogen and chlorophyll, slightly changes the amount of reflected energy. The hyper-spectrum sensor detects only 3-5 nanometers differences from the full range, which is incomparable to other remote sensing technologies.caryii.online
“Other aerial sensing technologies take the visible spectrum, possibly infrared, only four spectral bands. It’s not even close to what we can do with this hyperspectral sensor. It’s really powerful,” Guan said.caryii.online
Most importantly, the research team developed the best mathematical algorithm for detecting nitrogen reflection data from hyperspectral sensors. They hope to use it when new technologies come out.caryii.online
“NASA, like other commercial satellite companies,
is planning a new hyperspectral satellite flight. Our research could provide an algorithm for these activities because we have already demonstrated its accuracy in the aircraft’s hyperspectral data,” Wang said.caryii.online
Guan said bringing the technology to the satellite is the ultimate goal that will allow us to see the nitrogen status of each area at the start of the planting season. This advance will allow farmers to make more informed decisions about nitrogen supplements.caryii.online
Ultimately, the goal is to improve the environmental sustainability of nitrogen fertilizers in agronomic systems. Guan says precision is the way to get there. caryii.online
“Basically, you can’t control what you can’t measure. So we’re putting a lot of effort into this technology,” Guan said.