It only makes sense to apply fertilizer where it’s needed, and only where it’s needed. For a long time, agricultural machinery and technology companies have focused on achieving this goal, including German company Fritzmeier Umwelttechnik.
The company’s technology, called the ISARIA Crop Sensor, uses four different wavelengths delivered with LEDs and up to 2000 measurement values per second to index vegetation. Mounted on the front of a sprayer or a tractor pulling fertilizer application equipment, this optical sensor information is used to assess nitrogen uptake of the crop while driving through the field.
As Fritzmeier Umwelttechnik’s Bernhard Limbrunner explains in the video below, the vegetation index values are plugged into an algorithm with yield potential maps and historical data to adjust nitrogen application rates in real-time.
When asked how it’s different from other optical sensors used to assess nitrogen requirements, Limbrunner says most systems use two wavelengths to assess vegetation, instead of ISARIA’s four wavelengths.
“One advantage of this is that you have no saturation. Saturation happens when you have high nitrogen uptake, like we have in European conditions, then these other vegetation indexes are not able to differentiate the crop,” he explains, noting it can measure up to 250kg N/ha.
It’s also not affected by time of day or sunlight.
After years of testing, Limbrunner says absolute calibrations have been developed for winter wheat, winter barley and oilseed rape production in Europe. Producers in Europe are also using it for potatoes, onions, tulips and other salad crops, he says.
In addition to nitrogen application, the company notes the system can be used for crop monitoring and other needs-based field treatments, including application of growth regulators and biomass dependent application of desiccants.
It was developed over 20 years of research at the Chair of Agronomy and Organic Agriculture at the Center of Life and Food Sciences Weihenstephan of the Technische Universität München (TUM).
With a universal frame the fits on any tractor, the ISARIA communicates with the variable rate controller via a Windows-based tablet or through an ISOBUS terminal.
Limbrunner says they plan to bring the sensor technology to North America, but he doesn’t say when, as they’re still focused on developing their distribution network in Europe.