Nitrogen plant uptake is zero

[Giulia Emanuelli]

Hello everyone, I'm facing a problem with the crops of my study area. I implemented olives and applied automatic schedules for irrigation and manual operations for fertilization, then I applied automatic schedules also for the landuse "AGR". What is very strange is that,  in the final nutrient balance there is some phosphorous uptake by plants, while the amount of nitrogen uptake by plants equals zero.

I tried to increment the amount of N-fertilizers but nothing changed.

Do some of you have an explanation for this behaviour?

Thank you!