Apply nitrogen more efficiently in 5 steps

Get nitrogen rate recommendations based on the real nitrogen uptake of your crops with the free N-Tester BT.
How much nitrogen should you apply to your crops?      
Find out with the free N-Tester BT.


Why use the N-Tester BT?

Optimise your nitrogen investment with the N-Tester BT from Atfarm. Find out how much nitrogen (N) to apply to your crops this season.


“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

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.

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.

Download the app

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

Winter barley

Spring barley

Winter rye

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

Step 1: Activate your free 1 year N-Tester BT subscription

The N-Tester BT device ships to you for free and will arrive within 14 days.

Step 2: Connect your N-Tester BT to Atfarm on you smartphone

Download the Atfarm app onto your mobile device. Then follow the on-screen instructions to wirelessly connect your new N-Tester BT.

Step 3: Calibrate your N-Tester BT

Calibration before use makes sure every reading is accurate. The Atfarm app will guide you through the 2 step process.

Step 4: Measure crops across 1 field

Take 30 measurements across your field. Your smartphone will vibrate, chime or both when a measurement is recorded.

Step 5: Get your N-rate recommendations from the Atfarm app

Instantly see your recommendations along with other on-field information about your crops.