YARA Passive N-Sensor - the original | Precision Decisions

YARA Passive N-Sensor

Passive N-Sensor

N-Sensor Passive and N-Sensor ALS – two systems, one philosophy

In 2006, Yara launched the new N-Sensor ALS (Active Light Source), which works in a similar way to the classic N-Sensor to determine a crop’s Nitrogen demand by measuring the crop’s light reflectance. Both systems make use of the same field trial based agronomic algorithms for optimum site-specific fertilization and both are connected to a vehicle terminal where crop and GPS data is stored for processing.

The major difference between the two N-Sensors is that the ALS Sensor has its own built in light source. Instead of using daylight for the measurement the N-Sensor ALS is constantly beaming its own source of light at the crop, using Xenon flash lamps, and recording the reflectance. This enables N-Sensor ALS operation independent from ambient light conditions, even at night.


  • The N Sensor ALS was awarded the RASE Gold Medal in 2008
  • Cereal yields increased by 3.5% where the same intensity of fertilizer was used
  • Oilseed yields increased by 3.9% through the Absolute-N calibration
  • Nitrogen savings of up to 14% have been recorded where N Sensor was used
  • Increases in nitrogen use efficiency have reduced the carbon footprint by 10-30%
  • Combine performance was increased by 12-20% due to reduced lodging, lower losses, and faster intake speeds
  • Protein levels in cereal crops showed greater consistency averaging 0.2-0.5% above target
  • An 80% reduction in lodging rates (compared with crops where nitrogen was applied under conventional practices)


  • Bring the optimal fertilizer rate in every part of the field
  • Enhance the crop potential all over the field
  • Increase fertilizer efficiency
  • Decrease nitrogen residues in soils post harvest
  • Increase yield
  • Quality is more homogeneous
  • Reduce harvesting time and cost
  • Reduce risk of N losses to the environment