Remote Sensing

Variable Rate Nitrogen on OSR and Cereals

The Technology

Remote sensing technology enables precision fertiliser applications reflecting the N-status of crops within a field. Using GPS, it guides the applicator to deliver the right type and optimum rate of fertiliser in real time as it moves over the field.

How it works

Sensors on the fertiliser applicator measure the crop’s light reflectance at specific wavelengths relevant to crop chlorophyll content and biomass. These sensors have their own light source and operate independently of ambient light conditions. Computer algorithms derived from field trial data determine N-demand each second, and send information to the variable rate spreader or sprayer which adjusts fertiliser rates across the field in real time.

Hummingbird have an OSR and Wheat VRN system based on GAI. The OSR VRN product is based on prior GAI readings taken remotely from Satellite, and the wheat system is based on biomass and rate of growth measurements. The user has the flexibility to apply either more N on less growing parts of the field, or more N on areas where biomass production is higher.


Figure 1 (below): First time through the crop, the lower biomass areas are going to receive more N. This may be reversed next time if the crop is not responding.

Farmer / Agronomist Benefits

Variable fertiliser application has been shown to increase cereal yields by 3.5% and oilseed rape yields by 3.9%, with N-savings of up to 14%, and a carbon footprint reduction of up to 30%. Reduced lodging and faster intake speeds from optimally fertilised crops can increase combine performance by up to 20%.

Key Researchers and Stakeholders




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