Yara Digital Products

Maximise your return
on nitrogen applications
How much nitrogen should you apply to your cereals? Find out with the free N-Tester BT.

Why use the N-Tester BT?


Easy and affordable

Maximise return on N applied and improve yield quality with field specific N-rate recommendations based on the real N-uptake of your cereals.

Agronomically robust

The N-Tester BT has been field tested across hundreds of trials and developed by Yara Research & Development for over 25 years.

How does the N-Tester BT work?


The N-Tester BT

The device uses an LED and light sensor to instantly measure the chlorophyll content of a crop when you clamp it onto the newest fully developed leaf of a crop. This green level shows the N content of the plant.

These N-Tester values are automatically sent to your mobile device via Bluetooth™ connection. No internet or cellular signal is needed to record or take measurements.


The Atfarm App

Atfarm uses an algorithm powered by Yara agronomists to calculate the current N balance of your field based on the N-uptake measurements from the N-Tester BT. Decades of field trials by Yara ensure these calculations are accurate.

All you have to do is enter information about your field: crop type, variety, growth stage, target yield estimate, soil N supply, N already applied. After measuring your crops, you get an N recommendation that shows you the exact N needs of your crops.


Your N-rate recommendation

Open the Atfarm app and easily find the N-rate recommendation for your crops (shown in kilos of nitrogen per hectare).

The N-rate recommendations from the N-Tester BT are designed to help fine-tune N-applications during the growing season and help you maximise the yield return for every kilo of N you apply.

When to use the N-Tester BT?


Optimise nitrogen use on your fields in 8 steps

  • AtFarm

    Turn your N-Tester BT on by holding the On/Off button until the LED on top turns blue.

  • AtFarm

    Open the Atfarm app and select your farm and field.

  • AtFarm

    Scroll down to the N-Tester section and tap Start measurement.

  • AtFarm

    Add your crop and growth stage information.

  • AtFarm

    Tap Start measuring. The app will now check the connection between your smartphone and N-Tester BT. This may take a few seconds.

  • AtFarm

    Calibrate your N-Tester by holding down the head of the device and taking an empty reading.

  • AtFarm

    Measure the youngest leaves on at least 30 plants across your field.

  • AtFarm

    Tap Get the N-Tester value. Take measurements while walking across your field in a zig-zag pattern. This helps you get readings from crops growing in all the different soil qualities in your field.