Maximise your returnon nitrogen applications

How much nitrogen should you apply to your cereals? Find out with the free 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 and Atfarm app work together to identify your N-requirements.
N-Tester light 1

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 precision 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.

Calibrated for most cereals

N-Tester BT is currently individually calibrated for most cereals: 

Winter Wheat 4

Winter wheat

Winter barley 

Spring barley 

Winter rye 

Winter triticale

Winter triticale 

When to use the N-Tester BT?

Get N-Rate recommendations based on the N-uptake of your cereals for the 2nd, 3rd and protein dressings. 

1st application 

Stem elongation
2nd application 

Flag leaf development
3rd application 

Spike development
Protein dressing 


Optimise N use on your fields in 5 steps

Order your free N-Tester BT in Atfarm –
Upgrade section

Connect your N-Tester BT to your mobile device using Atfarm app

Calibrate your N-Tester BT 

Measure 30 crops across 1 field

See your N-rate recommenda-tions in the Atfarm app

“Monitoring the crops through the season, with the N-Tester, will give accurate recommendations based on what the nitrogen levels are in the crop.

With more accurate rates for each field, the use efficiency will increase, meaning you’re getting the most out of the nitrogen that you are applying.”

Natalie Wood 
Agronomy Operations Manager,
Specialist in Crop Nutrition and Digital Tools.