What makes Atfarm biomass maps special?

The Yara N-Sensor Index is what sets Atfarm apart. It has been developed based on Yara's expertise in precision fertilisation and more than 25 years of field trials with the Yara N-Sensor. The Yara N-Sensor is a tractor-mounted remote sensing device that determines nitrogen demand by measuring the light reflectance of crops. The first Yara N-Sensor was introduced in the 1990s for use in cereals, and we've carried out more than 250 trials to refine its performance and add new programmes.


Using these crop- and region-specific calibrations of the Yara N-Sensor Index, Atfarm generates optimised biomass maps to show variability in crop development, even at advanced growth stages. This is particularly important for late nitrogen applications.




Almost all other tools on the market use the non-crop specific Normalized Difference Vegetation Index (NDVI), which is based on red and near-infrared radiation. It gives a relative value between 0 and 1, indicating only the presence or absence of green biomass. This index saturates very quickly with shoot development (canopy saturated, highest biomass) and differentiation is no longer possible. Therefore, it can only detect differences in early growth stages and should only be used for planning the first application.


So far, only the Yara N-Sensor Index can make biomass differences visible during and after shooting. The index measures not only red and near-infrared radiation, but also the spectral ranges in between. With this fine gradation and the inclusion of crop and regional data, the N-uptake can be determined even for advanced growth stages.


The Yara N-Sensor Index is insensitive to different growth stages and canopy saturation. It doesn't tend to saturate as quickly as the Normalized Difference Vegetation Index (NDVI). Depending on the crop, the index starts to saturate at around BBCH 50-60.


You can use Atfarm's optimised biomass map to plan your 2nd, 3rd and protein dressings and create Variable N-Rate Application (VRA) Maps.

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