How it operates

N Sensor determines a crop's Nitrogen demand by measuring the crop's light reflectance.

Sensing technology applied to agriculture is based on the typical light reflectance curve for vegetation. Using this information N Sensor can measure the crop, translate the data into an application rate and send a signal to the spreader or sprayer rate controller, which will adjust the levels of application.

The average application rate is always determined by the operator before spreading begins.

The N Sensor measures light reflectance from the crop from four different angles, covering a total area of approximately 50m². Measurements are taken every second with the system designed to operate at normal working speeds and all bout widths. A fifth sensor positioned skywards measures the intensity of light allowing the sensor system to compensate for different light conditions while operating.

The whole process of determining the crop's Nitrogen requirement and application of the correct fertilizer rate happens instantaneously, with no time delay. This enables 'real time agronomy' to be possible.

Does N Sensor need DGPS?

The Yara N Sensor system operates as a stand-alone system - without the input of a GPS signal. However, it can easily be connected to a Differential GPS (DGPS) signal to allow Location, sensor and application information to be plotted enabling the production of 'biomass' and Nitrogen application maps for the field.

What is the Operator Input?

The time an operator needs to devote to N Sensor has been kept to a minimum. Before N Sensor is used a simple calibration procedure is required for each field. This process involves scanning a small area of crop to measure the average sensor reading. An optimum Nitrogen rate is then calculated, for that area, using either farm practice, N Tester or N Plan. This optimum Nitrogen rate is then keyed into the computer in the tractor cab and assigned to the average sensor reading.

As the tractor passes over the field, the Yara N Sensor will vary the rate around this average optimum, according to the crop's requirements. If required, the user can restrict the range of application rates by setting maximum and minimum levels.

What crops and when?

N Sensor can measure the light reflectance of any crop but the system requires software to translate that reflectance information into an application rate.

Currently, software has been developed for Winter Wheat, Winter Barley, Spring Wheat and Spring Barley, Winter Oilseed Rape and Potatoes. Ongoing research by Yara is focusing on use in terms of timings and other agronomic practises.

Software has also been developed for the protein application in cereals.