Arable crops

How Much Nitrogen is in your Crop?

Atfarm uses satellite imagery to create various maps which have different functionalities. There are the standard NDVI maps that show the variation in biomass in the field, however the range of NDVI alone is limited so there is a lower range of variation (0-9 scale). I’d recommend using the ‘optimised map’, which uses NDVI and teams it with the algorithm from the N-Sensor, to give a range of more than 25 colours - meaning a higher level of variation shown and therefore more accuracy. Another map option is the nitrogen uptake map, which gives you an approximation of the nitrogen uptake by your crop, based on the biomass and colour variation.

If you want to create a variable nitrogen rate application (VRA) map from these it is simple to do so in Atfarm. The system uses the optimised map to create the variability map and assigns different nitrogen rates to the different levels of variation. As the user, you will input your chosen fertiliser product and target rate as well as a minimum and maximum, so the system is very flexible.

Another aspect of Atfarm that will be particularly useful for taking the guesswork out of what rates of nitrogen to use on cereals is the Yara N-Tester BT. The N-Tester BT is a non-destructive handheld device that enables you to analyse how much nitrogen is in your cereal crop and then get a variety-specific recommendation. You can also link the N-Tester BT reading when choosing your target rate for the VRA map for the same field.

So overall, Atfarm enables you to put on what the crop requires and where, rather than blan-ket applications of nitrogen across whole fields. This gives a much better level of nitrogen use efficiency and in turn, better return on your investment.