Although the N-Tester 2011 and N-Tester 1995 can't connect to the Atfarm mobile app via Bluetooth® wireless technology like the N-Tester BT, you can use them in combination with the Atfarm mobile app without any restrictions.

Once you've installed the Atfarm mobile app on your mobile device and added your farms and fields to your Atfarm account, you can start analysing your crops with the N-Tester.

Please note before you start:

• Read here what's required to use the N-Tester.
• These crops and varieties are supported for the N-Tester Recommendations in United Kingdom.
• Fertilise your field no more than one week after the N-Tester reading.
• We don't currently take fertiliser restrictions into account for the N-Tester Recommendations. When fertilising your crops, please remember to take into account the maximum nitrogen requirement according to government fertiliser restrictions.
• The N-Tester can't indicate future soil nitrogen supplies, such as from applied nitrogen that plants haven't yet absorbed due to drought. Please use your experience to evaluate the nitrogen recommendation.

Follow these steps to connect and measure with the N-Tester:

1) Install the app

If you haven't already done so, download the free Atfarm mobile app for iOS and Android smartphones and tablets from the common app stores. Simply scan the QR code below with your smartphone or tablet camera and follow the link to download and install the Atfarm mobile app. Alternatively, search for 'Atfarm' in the app store.

2) Prepare the analysis in the app

Begin the analysis in the Atfarm mobile app as follows:

1. Log in to the Atfarm mobile app on your mobile device.
2. Add or select your farm.
3. Add or select your field.
4. Scroll down to the N-Tester section on the field page.
5. Click Start N-Tester reading.
6. Appears only the first time: Select your N-Tester from the list of N-Tester models.
   • You can manage your N-Tester models in the settings.
7. Select the variety from the first dropdown.
   • Differences between varieties are considered in the calculation using correction factors.
8. Select the growth stage of your crop.
9. Enter the grain yield expectation for this year in t/ha in the first input field.
10. Select the Soil Nitrogen Supply (SNS) from the next dropdown.
11. Enter nitrogen already applied since planting/seeding in kg N/ha in the next input field.
12. Select if this is the last dressing.
13. Click Start measuring.
14. Activate location tracking on your mobile device. As N-Tester Recommendations are not only crop specific, but also country and region specific, we need to know where your fields are located.

3) Measure your crops

Once you've successfully prepared the measurement in the Atfarm mobile app, you're ready to measure your plants.

Before you begin, please note the following for accurate results:

• Measure in mostly dry weather. A little drizzle or fog is fine, but avoid measuring in a downpour, both for your own good and for accuracy. Large water droplets can alter the measurements and give inaccurate readings. If there is a little dew on the leaves of your plants, you can brush off the drops before measuring and still get accurate results.
• Make sure that your mobile device and the N-Tester have enough battery power so that the device doesn't switch off during the measurements. If this happens, you'll have to restart the whole measurement process.
• To obtain a representative average reading, measurements must be taken randomly across the field on at least 30 representative plants.
• For best results, move through the field in a W pattern. The blue dot on the map shows your current position. Each N-Tester reading is geolocated on the map with a pin icon for easier sampling.

• Make sure the field has enough sulfur. A sulfur deficiency, like a nitrogen deficiency, will make the leaves lighter and the nitrogen recommendation may not be correct. Other nutrients have no significant effect.
• Avoid atypical field areas, such as areas with distinctly different soil properties, such as sand banks or similar.
• Select a plant at the correct growth stage (BBCH 30-51) and measure at the centre of the blade of the youngest fully developed leaf. Measurements on less developed leaves may lead to higher recommendations.
• Avoid grained or thick leaf tips, leaves with visible drought stress, or rolled leaves. You want to base your final nitrogen rate recommendation on the healthiest plants in each area of your field.

You're now ready to measure your plants:

1. Switch on your N-Tester and set it up for measurement.
   • Use the N-Tester 2011 user manual/N-Tester 1995 user manual to learn how to set up your device and take measurements.
   • N-Tester 2011: As you select the crop and variety directly in the Atfarm mobile app, crop and variety data is no longer required and maintained on the N-Tester 2011. For crop type and variety, simply enter any crop type and variety or select Other.
2. Take a reading of your plant.
   • Place the leaf inside the measuring head using the center line as a reference. The lens must be completely covered.
3. Go to the next plant and take another reading.
   • Measure at least 30 plants in total.
4. Switch off the N-Tester when you've finished taking readings.

4) Get the recommendation

Once you've completed the readings, proceed as follows to get the recommendation:

1. Enter the three digit value shown on the N-Tester screen after the measurements in the input field in the Atfarm mobile app.
2. Click Get recommendation.
3. The nitrogen recommendation in kg N/ha for your crop is displayed on your screen.
   • The recommendation is saved under N-Tester Recommendations on the field page.
   • Click Show more insights to see the average N-Tester value and the inputs you entered for the measurement.
   • Click Show N-Tester values to see the N-Tester value. The N-Tester value is an intermediate result obtained by the N-Tester.
   • Click Repeat measurement to repeat the readings.
   • Click the three dots in the top right corner and select Delete measurement to delete the measurement.

Tip:

Use the N-Tester Recommendation to create Variable N-Rate Application maps in Atfarm. To do this, enter the recommendation in kg/ha as your target N-rate.

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